AGGREGATE PROPERTIES OF SOME HONG KONG ROCKS

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3 AGGREGATE PROPERTIES OF SOME HONG KONG ROCKS GEO REPORT No. 7 T.Y. Irfan, A. Cipullo, A.D. Burnett & J.M. Nash Chapter ORDINANCE

4 - 2 - Hong Kong Government First published, January 1992 First Reprint, April 1995 Prepared by: Geotechnical Engineering Office, Civil Engineering Department, A OR Civil Engineering Building, X 3 l 101 Princess Margaret Road, " j \ \ Homantin, Kowloon,,_.~,_^^ Hong Kong. 1.. ^ This publication is available from: Government Publications Centre, Ground Floor, Low Block, Queensway Government Offices, 66 Queensway, Hong Kong. Overseas orders should be placed with: Publications (Sales) Office, Information Services Department, 28th Floor, Siu On Centre, 188 Lockhart Road, Wan Chai, Hong Kong. Price in Hong Kong: HK$ 120 Price overseas: US$19.5 (including surface postage) An additional bank charge of HK$50 or US$6.50 is required per cheque made in currencies other than Hong Kong dollars. Cheques, bank drafts or money orders must be made payable to HONG KONG GOVERNMENT

5 - 3 - PREFACE In keeping with our policy of releasing information of general technical interest, we make ayailable some of our internal reports in a series of publications termed the GEO Report series. The reports in this series, of which this is one, are selected from a wide range of reports produced by the staff of the Office and our consultants. Copies of GEO Reports have previously been made available free of charge in limited numbers. The demand for the reports in this series has increased greatly, necessitating new arrangements for supply. In future a charge will be made to cover the cost of printing. The Geotechnical Engineering Office also publishes guidance documents and presents the results of research work of general interest in GEO Publications. These publications and the GEO Reports are disseminated through the Government's Information Services Department. Information on how to purchase them is given on the last page of this report. A. W. Malone Principal Government Geotechnical Engineer April 1995

6 EXPLANATORY NOTE This GEO Report consists of eight Technical Notes on selected aggregate properties of various granitic and volcanic rocks in Hong Kong. These Technical Notes were prepared by the Planning Division of the former Geotechnical Control Office as part of the Fresh Rock Testing Programme which was initiated in The Technical Notes are presented in separate sections in this Report. Their titles are as follows : Section Title Page No. 1 Aggregate Properties of Medium-Grained 5 Granite from Turret Hill Quarry. T.Y. Irfan & J.M. Nash (1987) 2 Aggregate Properties of Monzonite from 25 Turret Hill Quarry. T.Y. Irfan (1987) 3 Aggregate Properties of Coarse-Grained 47 Granite from Lai King. T.Y. Irfan (1987) 4 Aggregate Properties of Fine-to Medium- 69 Grained Granite from Ma Yau Tong. T.Y. Irfan (1987) 5 Aggregate Properties of Fine- and Fine- 91 to Medium-Grained Granites from Anderson Road. T.Y. Irfan & A. Cipullo (1987) 6 Aggregate Properties of Medium-Grained 123 Granite from Diamond Hill. A. Cipullo & T.Y. Irfan (1988) Aggregate Properties of Fine-, Medium-, and 147 Megacrystic Granites from Lamma Island. T.Y. Irfan (1989) 8 Aggregate Properties of Volcanic Rock Types 179 from 'Spun 1 Sites at Mount Davis and Chai Wan. A.D.. Burnett (1989)

7 - 5 - SECTION 1 : AGGREGATE PROPERTIES OF MEDIUM-GRAINED GRANITE FROM TURRET HILL QUARRY T.Y. Man & J.M. Nash This report was originally produced as GCO Technical Note No. TN 2/87

8 - 6 - FOREWORD In order to help provide the Materials Division and the Hong Kong Geological Survey with much needed data on the characterization and possible usage of each of the Territory's major rock types the Office initiated the Fresh Rock Testing Programme in This report forms part of the Fresh Rock Testing Programme and is one of a series of reports which presents the results of selected aggregate and index laboratory testing carried out on fresh block samples of discrete rock types. The rock type described in this report is a mediumgrained, inequigranular, megacrystic, GRANITE from the Turret Hill Quarry, Shatin. The authors wish to acknowledge the role played in the field sampling and sample preparation by TO's W.C. Lee and M«K. Chan and in the laboratory testing by K,H. Lee and other laboratory staff. The cooperation and assistance of the Quarry Management and the Materials Division is also acknowledged. (A.D. Burnett) Chief Geotechnical Engineer/Planning

9 - 7 - CONTENTS Title Page 5 FOREWORD 6 CONTENTS 7 1. INTRODUCTION 8 2. SITE DESCRIPTION AND SAMPLING 8 3. GEOLOGY Site Geology 8 3.2" Description of Test Sample 8 4. AGGREGATE TESTING AND CHARACTERIZATION Sample Preparation and Testing Methods Classification and Characterization of Aggregate Test Results 9 5. DISCUSSION ON TEST RESULTS Suitability of Rock as an Aggregate CONCLUSIONS REFERENCES 11 LIST OF TABLES 13 LIST OF FIGURES 20 LIST OF PLATES 22 Page No.

10 INTRODUCTION One of the objectives of the Fresh Rock Testing Programme outlined in the Technical Note "Laboratory Characterization Testing of Fresh Rock (Irfan & Purser, 1985) is to determine the aggregate properties of rocks commonly used in Hong Kong for concrete and roadstone aggregate and to recommend alternative rock types based on the results of testing. Major rock types recently mapped during the course of the new Geological Survey of Hong Kong are sampled and subjected to limited selected physical index and aggregate tests. It was decided to publish the results of the agregate testing at each sampling locality in the form of technical reports at the request of CGE/M and on recommendation of the Aggregate Working Group. This Technical Note on the aggregate properties of medium-grained granite from Turret Hill Quarry forms the first report in the series. This report gives the results of selected aggregate and rock index tests carried out on fresh granite samples from a particular locality in the quarry and discusses the results and suitability of the rock as aggregate in comparison with the typical aggregate acceptance values. Only the selected rock material properties are considered when assessing the suitability of the rock. Other rock factors as well as environmental, operational and haulage factors will be the dominant factors in determining the suitability for development of a particular source of suitable material. 2. SITE DESCRIPTION AND SAMPLING The sampling site is the disused Turret Hill Quarry located on the southwestern flank of Turret Hill (Nui Po Shan), east of Shatin (Figure 1). The site was originally used as a borrow area in the mid-1960's and 70 f s which was then turned into an aggregate quarry in the late-1970 f s. Rock extraction ceased at the quarry at the end of 1984 when the contractor had completed the formation of rock slopes (Plate 1) in accordance with the Contract. This sampling site was chosen for Fresh Rock Testing Programme bacause of its ease of access and nature of fresh rocks present. The sampling locality is situated at the estern end of the quarry on third bench from the toe (Plate 2). Block samples of easily manageable size were collected from the face in granite for testing. 3. GEOLOGY 3.1 Site Geology The quarry is shown to be located in medium-grained granite, (gm), on the new 1: geological map (Figure 1). Addison (1986) reported that this granite is intruded by thin sheets and dykes of fine-grained granite in the quarry area. A monzonite intrusion is present at the eastern end of the quarry. A northwest-southeast trending fault traverses granite near the northern side of the quarry. At the sampling locality, the medium-granite is fresh and moderately to widely jointed. Some major joints are reddish brown stained. Occasional vugs of quartz and mica occur in the rock. 3.2 Description of Test Sample Engineering geological description (c. BS 5930 ; 1981)* The rock is very

11 - 9 - strong, light pinkish grey, crystalline, fresh, medium-grained GRANITE with an average grain size of 3 to 5 mm and inequigranular texture. Detailed description. The rock consists of subhedral grains of quartz, alkali feldspar, plagioclase feldspar and biotite. Quartz forms about 35$ of the rock and biotite less than 5%. Alkali feldspars are generally light pink in colour. No modal analysis was carried out. Detailed description of the medium-grained granite is given in 1 Addison (1986). The minimum and maximum sizes of grains are 1 mm and 7 mm respectively (average size of 3 to 5 mm). 4. AGGREGATE TESTING AND CHARACTERIZATION 4.1 Sample Preparation and Testing Methods The block samples collected from the site were broken by using a sledge hammer and rock breaker into smaller size specimens. These were then fed into a laboratory jaw crusher (Plate 3) to prepare mm and nominal 20 mm size aggregates (Plate 4). Selected physical rock index tests were performed on the irregular lumps of rock using the methods recommended by ISRM (1978). These included the determination of bulk density (dry and saturated), mineral grain specific gravity, porosity (total and effective) and water absorption. Point load index testing (ISRM, 1985) was carried out on irregular lumps to determine the strength of the rock. The aggregate testing included aggregate crushing value, ACV, aggregate impact value, AIV, water absorption, flakiness index, Ip, and elongation index Ig, on standard size (10-14 mm) aggregates according to the methods recommended in BS 812 (BSI, 1975) and Los Angeles abrasion value, LAAV, on 20 mm nominal size aggregates according to ASTM C-131 (ASTM, 1981). 4.2 Classification and Characterization of Aggregate Numerous classification and descriptive schemes exist to characterize aggregates. A number of commonly used schemes were critically reviewed and found unsatisfactory from many points of view by the Geological Society Working Party on Aggregates (Collis & Fox, 1985). This Working Party recommended a new classification system called CADAM (Classification and Description of Aggregate Materials) to be used for both commercial and contractual purposes. This CADAM scheme is adopted here to describe and classify the Hong Kong aggregates. Table 1 shows the classification of aggregate in this study by the proposed CADAM scheme. A more detailed petrographic evaulation of the aggregate is given in Table Test Results The results of standard tests carried out on irregular specimens are given in Table 3, The results of tests carried out on laboratory crushed aggregates are shown in Table 4. Limited test results are available on 10 mm and 20 mm nominal size aggregates from the quarry carried out in 1979 and These are given in Table 5.

12 DISCUSSION ON TEST RESULTS The rock index tests given in Table 3 show that the fresh, medium-grained granite from the Turret Hill Quarry site is a very strong rock with a point load strength value of over 10 MPa (or uniaxial compressive strength of over 250 MPa using a conversion factor of 25; ISRM 1985) and has very low water absorption and porosity properties. The test results given in Tables 3 and 4 are those of the tests carried out on a few block samples chosen from one locality in the quarry. The test results may therefore not be representative of the whole rock type occurring in the quarry or the Territory, With this in mind, a comparison of the aggregate test results carried out on laboratory crushed specimens (Table 4) is made with the limited test results available on the quarry run material (Table 5). The results are similar in terms of aggregate impact value, water absorption, elongation index and relative density except in the flakiness index where a lower value was obtained on laboratory crushed specimens. 5.1 Suitability of Rock as an Aggregate The test methods adopted and their limiting values for determining the suitability of rock for various aggregate uses, both vary considerably from specification to specification in response to application, climate, availability of materials, etc. In Hong Kong, both the test methods and acceptance values for aggregates to be used in concrete and as roadstone are generally those recommended in the British Standards (Government of Hong Kong, 1977), namely BS 882, BS 1621, BS 812. In general, fresh granitic rocks have been traditionally used for both concrete and as roadstone in Hong Kong although volcanic rocks have occasionally been used for some special aggregate purposes (e.g. as friction course for Kai Tak Airport runway extension). A comparison of the test results in Tables 4 and 5 with typical UK aggregate acceptance values (Table 6) indicates that the aggregates produced from the medium-grained granite in the quarry are within the acceptable limits for use in concrete and as roadstone. However, in terms of both aggregate impact value (or aggregate crushing value) and Los Angeles abrasion value, they have rather high values making the aggregate from the medium-grained granite less desirable, compared to the fine-grained granites or basaltic rocks, for wearing courses and some special purposes such as heavy duty concrete floor. No soundness tests to determine the durability of the aggregate have been carried out for the reasons that the rock tested was fresh and the aggregates from fresh granites are known to-be durable. However, it is recommended that the soundness tests should be carried out if the proportion of discoloured (weathered) rock is significant. No tests have been carried out to determine potential alkali-silica reactivity since this is not expected to be a problem in the case of aggregate from coarsely crystalline granitic rocks. 6. CONCLUSIONS The laboratory test results carried out on aggregate produced from fresh, medium-grained granite samples collected from the Turret Hill Quarry are

13 within the commonly accepted limiting values for general use in concrete and as roadstone. The aggregate impact value (or crushing value) and the Los Angeles abrasion value test results are rather high and near to the specified limiting values thus making the aggregate from this rock type less desirable for special uses such as wearing courses and heavy duty concrete floors compared to aggregates from the fine-grained granites or basaltic rocks. In this investigation, the tests were all carried out on fresh rock samples. Aggregates produced from slightly weathered granite grade are, however, also generally suitable for various uses (see Choy'& Irfan, 1986 and Collis & Fox, 1985), but they may have lower strength and abrasion characteristics. Their suitability, particularly in-service performance, should also be assessed for particular aggregate use by durability and soundness tests and petrographic examination. The test results for the current laboratory crushed sarnies are comparable to the documented test data for quarry run aggregates available from the quarry when it was operational. However, for the latter case the state of weathering of the samples tested and their exact geological characteristics are not known. 7. REFERENCES Addison, R. (1986). Geology of Sha Tin, 1: Sheet 7, Geotechnical Control Office, Hong Kong, 85 p. (Hong Kong Geological Survey Memoir No. 1). American Society for Testing Materials (1981). Specification for Concrete Aggregates (ASTM C33-81). American society for Testing Materials. American Society for Testing Materials (1976). Test for soundness of aggregates by use of sedium sulphate or magnesium sulphate. Test Designation C American Society for Testing Materials» American Society for Testing Materials (1981). Test for resistance to abrasion of small size coarse aggregate by use of the Los Angeles machine. Test Designation C American Society for Testing Materials. British Standards Institution (1983). British Standard Specification for Aggregates from Natural Sources for Concrete (BS 882 : 1983)* British Standards Institution, London, 7 p. British Standard Institution (1975). Methods for Sampling and Testing of Mineral Aggregates, Sands and Fillers (BS 812 : Parts 1 to 3). British Standards Institution. British Standard Institution (1976). Code of Practice for the Structural Use of Concrete for Retaining Aqueous Liquids (BS 5337 : 1976). British Standard Institution. British Standard Institution (1981). Code of Practice for Site Investigations (BS 5930 : 1981). British Standards Institution, London, 147 p.

14 British Standard Institution (1960. Slag Aggregate (BS 1621 : 1961)* Bitumen Macadam with Crushed Rock or British Standards Institution. Choy, H.H. & Irfan, T.Y. (1986). Engineering Geology Studies for the Extension of the Anderson Road Quarries. GCO Report No. ADR 12/86, 71 p. Collis, L, & Fox, R.A. (1985). Aggregate : Sand, Gravel and Crushed Rock Aggregates for- Construction Purposes. Geological Society Engineering Geology Special Publication No. 1, Geological Society, London, 220 p. Department of Transport (1976). Edition. H.M.S.O., London. Specification for Road and Bridgeworks, 5th Government of Hong Kong (1977). General Specification for Civil Engineering Works, Public Works Department. Hong Kong Government Printer. Higginbottom, I.E. (1976). Section General requirements for rocks and aggregates. In Applied Geology fpr Engineers, H.M.S.O., 378 p. Hosking, J.R. & Tubey, L.W. (1969). Research on Low Grade and Unsound Aggregates. Road Research Laboratory Report L.R* 293* Road Research Laboratory, Crowthorne, 30 p. Irfan, T.Y. & Purser, P.J. (1985). Laboratory Characterization Testing of Fresh Rock. Unpublished Technical Note in folio (7) in Planning Division File GCP 1/10/145. ISRM (1978). Rock Characterization Testing and Monitoring. ISRM Suggested Methods (ed. E.T. Brown). Commission on Testing Methods, International Society for Rock Mechanics, Pergamon Press, 211 p. ISRM (1985). Suggested method for determining point load strength. International Society for Rock Mechanics Commission on Testing Methods. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, vol. 22, No. 2, pp ~~~ Shergold, F.A. (1948). A review of available information on the significance of road-stone tests. Road Research Technical Paper 10, DSIR, H.M.S.O., London. Standards Association of Australia (1985). Aggregates and Rock for Engineering Purposes. Part 1 -Concrete Aggregates (Australian Standard" )* Standards Association of Australia, 16 p.

15 LIST OF TABLES Table No. Page No. 1 Description and Classification of Aggregate 14 by the CADAM System 2 Petrographic Evaluation of Aggregate 15 3 Rock Index Properties of Medium-Grained Granite 16 from Turret Hill 4 Test Results on Laboratory Crushed Aggregates 17 from Turret Hill 5 Aggregate Test Results from Turret Hill Quarry, British Standard and Other Acceptance Values for 19 Test Results on Roadstone and Concrete Aggregates

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17 Table 2 - Petrographie Evaluation of Aggregate SAMPLE REF LOCATION/GRID REF SAMPLING DATE PETROGRAPHIC EVALUATION OF AGGREGATES HK 3663 EG 003 Turret Hill Quarry, Shatin 84020E 82760N SAMPLE SIZE/WEIGHT Bulk sample 50 kg Sub-sample 1 kg flo - 14 mm) AGGREGATE PROPERTIES Particle Shape (BS 812:1975) Surface Texture (BS 812:1975) Coating Cleanliness (Dust etc) GEOLOGICAL PROPERTIES Rock Type (GSS Classification) Mineralogy Major Constituents Minor Constituents Cementing Materials Expansive Minerals Weathering of Particles Organic Material Content GENERAL COMMENTS ADDITIONAL INFORMATION Mainly irregular, some angular shaped, small percentage of elongated particles Crystalline None Some dust resulting from aggregate crushing Medium-grained GRANITE (gm) Quartz, Alkali Feldspar, Plagioclase Feldspar, some Biotite (5%) Chlorite, muscovite Crystalline, no cementing minerals Chlorite (?), small amount Fresh, no staining None Granite is inequigranular and megacrystic Compiled by JMN/TYI Date

18 Table 3 - Bock Index Properties of Medium-Grained Granite from Turret Hill Rock Index Property Average Value Range Mineral Grain Specific Gravity, (g/cm3) Bulk Density Dry (g/cm3) Saturated (g/cm3) Water Absorption (%) (Saturation Moisture Content) Porosity Total (%) Effective (%) Point Load Strength (MPa) Legend : + Limited test results on 4 irregular lumps

19 Table 4 - Test Results on Laboratory Crushed Aggregates (10-14 mm) from Turret Hill Aggregate Property Test Value Aggregate Crushing Value, ACV (%) 23 Aggregate Impact Value, AIV {%) 24 Los Angeles Abrasion Value, LAAV {%) 29 Water Absorption <» 0.5 Flakiness Index, 7 (20)* Elongation Index, i E <j) (30)* Legend : * mm aggregate

20 Table 5 - Aggregate Test Results* from Turret Hill Quarry, (20 mm aggregate) Aggregate Property 1979 Test Value JC Fines Value (kn) Aggregate impact Value, AIV (?) n.d. 27 Aggregate Abrasion Value, AAV (?) 5 n.d. Water Absorption (?) n.d. 0.5 Flakiness Index, IF (?) Elongation Index, IE (?) Relative Density Cg/cm3) Legend : + Test results from Materials Division ] File Q 3/2/8 n.d. Not determined

21 Table 6 - British Standard and Other Acceptance Values for Test Results on Roadstone and Concrete Aggregates Test Test Value Use Authority Aggregate Crushing Value, ACV (%) Maximum 30 C.R. Higginbottom (1976) Aggregate Impact Value, AIV (%) Maximum 45 + Maximum 30* C.R. BS 882: $ Fines Value (kn) Minimum 50* More than 100* More than 150* R.C. R. C. Hosking & Tubey (1969) BS 882:1983 BS 882:1983 Aggregate Abrasion Value, AAV (%) Maximum 10 (diff. cond Maximum 12 (av. cond.) R. DoT (1976) Los Angeles Abrasion Value, (ASTM C-131) LAAV Maximum 30 (diff. cond Maximum 40 (av. cond.) Maximum 35* C. C. R. Australian Standard (1985) Shergold (1948) Water Absorption (Porosity) Less than 3 + C.R. Higginbottom (1976) BS 5337:1976 Bulk Density (g/cm3) More than 2.60 C.R. Higginbottom (1976) Flakiness Index, IF Less than 35*** C.R. BS 882:1983 Magnesium Sulphate Soundness (%) Maximum 18 (5 cycles) C.R. ASTM C33-81 Sodium Sulphate Soundness Maximum 12 (5 cycles) Maximum 12 (5 cycles) C.R, C. ASTM C33-81 Australian Standard (1985) Legend : R - Road aggretates, C - Concrete aggregates, ** For heavy duty concrete floor, *** For C20 and * For wearing surfaces, over concrete grade, + General use

22 LIST OF FIGURES Figure No. Page No. 1 Location Map Showing Geology of the Site 21 and the Adjacent Areas

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24 LIST OF PLATES Plate No. Page No. 1 General View of Turret Hill Quarry 23 2 Sampling Site 23 3 Laboratory Jaw Crusher 24 4 Crushed Rock Aggregate from Medium-Grained 24 Granite

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27 SECTION 2 : AGGREGATE PROPERTIES OF MONZONITE FROM TURRET HILL QUARRY T.Y. Man This report was originally produced as GCO Technical Note No. TN 3/87

28 FOREWORD In order to help provide the Materials Division and the Hong Kong Geological Survey with much needed data on the characterisation and possible usage of each of the Territory 1 s major rock types the Office initiated the Fresh Rock Testing Programme in This report forms part of the Fresh Rock Testing Programme and is one of a series of reports which presents the results of selected aggregate and index laboratory testing carried out on fresh block samples of discrete rock types. The rock type described in this report is a quartzmonzonite from the Turret Hill Quarry, Shatin. The author wishes to acknowledge the role played in the field sampling and sample preparation by GE J.M. Nash and TO f s W.C. Lee and M.K. Chan and in the laboratory testing by GE K.H. Lee and other laboratory staff. The cooperation and assistance of the Quarry Management and the Materials Division is also acknowledged. (K.A. Styles) Atg. Chief Geotechnical Engineer/Planning

29 CONTENTS Title Page 25 FOREWORD 26 CONTENTS INTRODUCTION SITE DESCRIPTION AND SAMPLING GEOLOGY Site Geology Description of Test Sample AGGREGATE TESTING AND CHARACTERIZATION Sample Preparation and Testing Methods Classification and Characterization of Aggregate Test Results DISCUSSION ON TEST RESULTS Rock Index and Aggregate Properties Suitability of Rock as an Aggregate CONCLUSIONS REFERENCES 31 LIST OF TABLES 34 Page No. LIST OF FIGURES. LIST OF PLATES ^2 ^

30 INTRODUCTION This Technical Note on the aggregate properties of fresh monzonite forms the second report in the series of aggregate properties of selected Hong Kong rocks and is part of the Fresh Rock Testing Programme, the aims of which are explained in the unpublished Technical Note by Irfan & Purser (1985). The monzonite samples under discussion were collected from the Turret Hill Quarry and were subjected to selected laboratory physical index and aggregate testing. This report presents the results of these index and aggregate tests and discusses the results and suitability of monzonite from this locality as aggregate in comparison with the typical aggregate acceptance values. In assessing the suitability of the rock as aggregate, only the selected rock material properties are considered. Other rock properties such as jointing, weathering and overburden, as well as environmental, operational and haulage factors should also be considered in determining the overall suitability for development of a particular source of material. 2. SITE DESCRIPTION AND SAMPLING The sampling site is the disused Turret Hill Quarry (Plate 1) located on the southwestern flank of Turret Hill (Nui Po Shan), east of Shatin (Figure 1). The site was originally used as a borrow area in the mid-1960 f s and 70 T s which was then turned into a granite aggregate quarry in the late-1970's. Rock extraction ceased at the quarry at the end of The sampling location is situated near the western end of the quarry on the fourth face from the base of the quarry (Plate 2). Block samples of easily manageable size and weight were collected from the fresh monzonite sill occurring on the face for testing. While this sill material is thus clearly not of sufficient size to form an economic source of monzonite it does provide a typical representative of this rock type for testing and assessment. 3. GEOLOGY 3.1 Site Geology The main rock type in the quarry is medium-grained granite (gm) intruded by thin sheets and dykes of fine-grained granite (Addison, 1986). Monzonite occurs as a relatively thin sheet (sill) of 0.8 to 1.2 a width, near the western end of the quarry dipping at about 35 towards southeast (Plate 2). The extent of the sill is not known and on the 1: geological map it is shown as a discontinuous outcrop. The sill is irregular in shape and the contact with granite is fused. No obvious alignment of feldspar megacrysts is present. The joints are generally medium-to widely-spaced and tight. 3.2 Description of Test Sample Engineering geological description (c.bs 5930:1981). The rock is extremely strong, medium grey coloured, crystalline, fresh, medium- to coarsegrained, quartz-monzonite with an inequigranular and porphyritic texture. Detailed description. The rock consists of phenocrysts of both alkali and plagioclase feldspars (up to 45?O in a medium-grained matrix of feldspars,

31 biotite and quartz. Quartz forms about 13% of the roek and biotite and hornblende about 4.3?, the rest being feldspars. Modal analysis was carried out on one thin section only. The results are given in Table 1. Phenocrysts of feldspars are up to 20 mm but generally 5 to 10 mm in size. Some of the plagioclase feldspars show slight alteration to sericite in thin section (Plate 3)» Detailed description of quartz-monzonite occurring in the Shatin area is given in Addison (1986). 4. AGGREGATE TESTING AND CHARACTERIZATION 4.1 Sample Preparation and Testing Methods Standard (10-14 mm) and nominal 20 mm size aggregates (Plate 4) were prepared using a laboratory jaw crusher. Selected physical rock index tests were also performed on the larger irregular lumps of rock using ISRM recommended methods. Aggregate testing was carried out according to the methods recommended in BS 812 (BSI, 1975). The rock index tests included the determination of bulk density, mineral grain specific gravity, porosity and water absorption (ISRM, 1978) and point load testing (ISRM, 1985). The aggregate tests included aggregate crushing value, aggregate impact value, water absorption, flakiness and elongation indices (BSI, 1975) and Los Angeles abrasion value (ASTM, 1981). 4.2 Classification and Characterization of Aggregate The CADAM scheme recommended by the Geological Society Working Party on Aggregates (Collis & Fox, 1985) is used to describe and classify the aggregate (Table 2). A more detailed petrographic evaluation of the aggregate is given in Table Test Results The results of rock index tests are given in Table 4. The test results on laboratory crushed monzonite aggregate are tabulated in Table 5. Limited aggregate test results from the material quarried between 1979 and 1980 are available 0 but these results are highly likely to be for granite rather than monzonite as the latter has very limited outcrop in the quarry. 5. DISCUSSION ON TEST RESULTS 5.1 Rock Index and aggregate Properties The rock index tests given in Table 4 show that the fresh monzonite from Turret Hill Quarry site is an extremely strong rock with a point load strength value of about 12 MPa (or uniaxial compressive strength of about 300 MPa using the normal conversion factor of 25) and has very low water absorption and porosity properties. In terms of rock index properties including bulk density, the monzonite has very similar properties to the medium-grained granite occurring in the quarry (Table 3 in Irfan & Nash, 1987). The rock specimens tested were isotropic in nature with no apparent alignment of feldspar megacrysts. The rock type tested was not therefore typical of monzonite occurring in the

32 Territory since the thicker intrusions are generally known to have a welldefined and characteristics feldspar orientation. This usual anisotropy is likely to result in strength differences in directions perpendicular and parallel to the feldspar alignment. Aggregate mechanical properties are also likely to be influenced by this anisotropy and also the presence of feldspar megacrysts. A comparison of the aggregate test results on the monzonite (Table 5) with those of medium-grained granite from the same locality (Table 6) show that the monzonite has lower and hence more desirable aggregate properties in terms of aggregate crushing value, aggregate impact value and Los Angeles abrasion value. The results in terms of water absorption, flakiness and elongation indices are similar in being better than granite. No test results are available from the Quarry (or elsewhere in the Territory) to make a comparison between the aggregate properties of laboratory crushed and plant crushed rocks. 5.2 Suitability of Rock as Aggregate The existing aggregate quarries in Hong Kong are all in granite. No commercial monzonite aggregate test results are available and the in-service performance of this aggregate is not known. Aggregate test results and inservice performance records from overseas sources are also not readily available to make a general assessment of the suitability of monzonite as an aggregate source rock. However, monzonite is similar to granite in terms of composition and grain size, except it has a lower quartz content of less than 20$. The monzonite has similar mechanical and physical properties to those of granite and is therefore expected to have similar aggregate properties. Monzonite aggregates may, however, have lower resistance to abrasion due to a lower free silica content. Acid crystalline rocks including monzonite generally show relatively poor performance in relation to adhesion properties with bitumen (p. 170, Collis & Fox, 1985). In Hong Kong, both the test methods and the acceptance values for aggregates to be used in concrete and as roads tone are generally those recommended in the British Standards (Government of Hong Kong, 1977). A comparison of the test results in Table 5 with typical UK aggregate acceptance values (Table 7) indicates that the aggregates produced from the monzonite in the Quarry are well within the acceptable limits for use in concrete and as roadstone as far as the properties determined in Table 5 are concerned. They are also comparable to those of granite aggregates which are commonly used in Hong Kong. No polished stone values, PSV, were determined. Soundness tests were not carried out to determine the durability of the aggregate because of the fresh state of the rock. Chemical decomposition generally results in higher PSV's in igneous rocks (Collis & Fox, 1985). However, a considerable degree of resistance to weathering including resistance to disintegration with cycles of wetting and drying or freezing and thawing, during the service lifetime is required for both roadstone and concrete aggregates. Some of the severest cases of failure of roadstone in unbound bases have been associated with physical breakdown of rock already subjected to some degree of chemical weathering (Turner & Wilson, 1956; Day, 1962). Monzonite contains a higher percentage of feldspars (lower quartz) compared to granites and is likely to be more susceptible to further decomposition and disintegration if the rock

33 has already weathered to some degree. It is, therefore, recommended that soundness tests should be carried out and abrasion and polished stone properties be determined if anything but fresh monzonite is to be used as aggregate. 6. CONCLUSIONS The laboratory test results carried out on aggregate produced from fresh quartz-monzonite collected from Turret Hill Quarry are well within the commonly accepted limiting values for general use in concrete and as roadstone. In terms of certain properties such as aggregate impact value, aggregate crushing values and Los Angeles abrasion value, the monzonite aggregates have lower and hence slightly more desirable properties than those of medium-grained granite from the same quarry. The polished stone values were not determined. Although the mechanical and physical test results indicate that monzonite may be suitable for aggregate production, the monzonite intrusion at this site, however, is not considered as a suitable source rock since it occurs as a very thin sheet-like form of less than 1.5 m thickness and under considerable overburden of granitic rock. The rock tested in this investigation is also atypical of monzonitic intrusions occurring in the Shatin area and elsewhere in the Territory. It does not show the typical and characteristic fabric anisotropy resulting from the alignment of feldspar megacrysts. Further testing is therefore required on samples collected from other parts of the Territory, particularly from the more common anisotropic variety to determine the overall aggregate potential of monzonite in Hong Kong. The tests in this investigation were carried out on laboratory crushed fresh rock samples. No test results are available on plant crushed monzonite aggregates for a comparison, since monzonite is rarely used as an aggregate in Hong Kong. In-service performance of monzonite aggregates from outside Hong Kong is also not readily available to the author. They are, however, expected to show similar performance records to those of granites being of similar composition and grain size, except that due to lower quartz contents, the aggregates produced from monzonite may have higher and hence more desirable PSV f s but lower resistance to abrasion. 7. REFERENCES Addison, R. (1986). Geology of Sha Tin, 1 ;20 OOP Sheet 7, Geotechnical Control Office, Hong Kong, 85 p. (Hong Kong Geological Survey Memoir No. 1). American Society for Testing Materials (1981). Specification for Concrete Aggregates (ASTM C33-8O. American Society for Testing Materials. American Society for Testing Materials (1981). Test for resistance to abrasion of small size coarse aggregate by use of the Los Angeles machine. Test Designation C American Society for Testing Materials. British Standards Institution (1983). British Standard Specification for

34 Aggregates from Natural Sources for Concrete (BS 882 : 1983). Standards Institution, London, 7 p. British British Standards Institution (1975). Methods for Sampling and Testing of Mineral Aggregates, Sands and Fillers (BS 812 : Parts 1 to 3). British Standards Institution, British Standards Institution (1976)- Code of Practice for the Structural Use of Concrete for Retaining Aqueous Liquids (BS 5337 : 1976), British Standards Institution. British Standards Institution (1981). Code of Practice of Site Investigations (BS 5930 : 1981). British Standards Institution, London, 147 p. Collis, L. & Fox, R.A. (1985). Aggregates : Sand, Gravel and Crushed Rock Aggregates for Construction Purposes. Geological Society Engineering Geology Special Publication No. 1. The Geological Society, London, 220 p. Day, H.L. (1962). A progress report on studies of degrading basalt aggregate bases. Highway Research Board Bulletin No. 334, p Department of Transport (1976). Edition. H.M.S.O., London. Specification for Road and Bridgeworks, 5th Government of Hong Kong (1976). General Specifications for Civil Engineering Works, Public Works Department. Hong Kong Government Printer. Higginbdttom, I.E. (1976). Section General requirements for rocks and aggregates. In Applied Geology for Engineers, H.M.S.O., 378 p. Hosking, J.R. & Tubey, L.W. (1969). Research on Low Grade and Unsound Aggregates. Road Research Laboratory Report L.R. 293, Road Research Laboratory, Crowthorne, 30 p. International Society for Rock Mechanics (178). Rock Characterization Testing and Monitoring. ISRM Suggested Methods (edte.t. Brown). Commission on Testing Methods, International Society for Rock Mechanics, Pergamon Press, 211 p. International Society for Rock Mechanics (1985). Suggested method for determining point load strength. International Society for Rock Mechanics Commission on Testing Methods. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, vol. 22, No. 2, pp ' ~~"~ " Irfan, T.Y. & Purser, p.j. (1985). Laboratory Characterization Testing of Fresh Rock. Unpublished Technical Note, Irfan, T.Y. & Nash, J.M. (1987). Aggregate Properties of Medium-Grained Granite from Turret Hill Quarry. GCO Report No. TN 2/ p. Standards Association of Australia (1985). Aggregates and Rock for Engineering Purposes. Part t - Concrete Aggregates (Australian Standard" ' ). Standards Association of Australia, 16 p. ' ~ ' "" Turner, R.s. & Wilson, J.D. (1956). Degradation study of some Washington

35 aggregates. Washington State Institute Technical Bulletin No. 232.

36 LIST OF TABLES Table No. Page No. 1 Modal Analysis of Monzonite 35 2 Description and Classification of Monzonite 36 Aggregate by the CADAM System 3 Petrographic Evaluation of Monzonite Aggregate 37 4 Rock Index Properties of Monzonite from Turret 38 Hill 5 Test Results on Laboratory Crushed Monzonite 39 Aggregates from Turret Hill 6 Test Results on Laboratory Crushed Monzonite 40 from Turret Hill 7 British Standard and Other Acceptance Values for 41 Test Results on Roadstone and Concrete Aggregates

37 Table 1 - Modal Analysis of Monzonite Mineral Feldspars Quartz Biotite Hornblende Others % Note : Modal analysis carried out on one thin section.

38 Table 2"- Description and Classification of Monzonite Aggregate by the. CADAM System (Collis & Fox, 1985) AGGREGATE FORM Cmuhed Rock G*l LV* Neub^hsJt G*n*htd Sand ~L' Lnd.~tVOTl CLASS [OK MISCELLANEOUS) Pz&iologJjiaZ name [<ii known) GEOLOGICAL AGE/ COLOUR/ GRAIN SHE FISS1LITV Conmejtt [11 any) GRANITE Ignzou6 SltlaaXe Clcu6 [cofiatct name to be qiven betocv) Mesozoic/Medium grey/fresh/medium to coarse-grained, porphyritic/no fissibility (see note). Large crystals up to 30mm in a medium- to coarse-grained matrix. CompUZed by : T. Y. Irfan Vote : SGE/EG I CADAM - CLASSIFICATION and DESCRIPTION of AGGREGATE MATERIAL LOCATION ANV SAMPLE VET AILS QuaAAij/PJJ: add*&64> : Turret Hill Quarry, Shatin, N.T. QpehaioK.'Disused (Contract Qu.) Sample : Type Blocks Size 50 k^?kepaaa u)n Lab. crushed Suppded bif E.G. Section GrUd Re{. Vote Redd Vote oi 6ajnpLLnq " Samp&jxq CeAX. No EG002

39 Table 3 - Petrographic Evaluation of the Monzonite Aggregate PETROGRAPHIC EVALUATION OF AGGREGATES SAMPLE REF LOCATION/GRID REF SAMPLING DATE AGGREGATE PROPERTIES Particle Shape (BS 812:1975) Surface Texture (BS 812:1975) Coating Cleanliness (Dust etc) GEOLOGICAL PROPERTIES Rock Type (GSS Classification) Mineralogy Cementing Materials Major Constituents Minor Constituents HK3662 EG002 SAMPLE SIZE/WEIGHT Turret Hill Quarry, Shatin Bulk sample 50 kg aggregate 84020E 82T6ON sub-sample 1 kg (10-14 mm) Mainly irregular to angular with sharp corners, some percentage of elongated particles Crystalline None Clean Quartz-MONZONITE (mq) Plagioclase feldspars and alkali feldspars in equal proportions (total 81%), biotite Quartz (13%), hornblende Crystalline, no cementing materials I Expansive Minerals Weathering of Particles Organic Material Content GENERAL COMMENTS ADDITIONAL INFORMATION None Fresh, no staining None Rock in the quarry occurs as a thin sill. Very low quartz content. The texture is porphyritic with feldspar crystals up to 20 mm, set in a medium-grained (less than 2 mm) groundmass. Compiled by TYI/JMN Date

40 Table 4 - Rock Index Properties of Monzonite from Turret Hill Rock Index Property Average Range Mineral Grain Specific Gravity (g/cm3) 2, Bulk Density Dry (g/cm3) Saturated (g/cm3) 2, Water Absorption (%) Porosity Total (%) Effective {$) Point Load Strength (MPa) Legend : + Limited test results on 6 irregular lumps

41 Table 5 - Test Results on Laboratory Crushed Monzonite Aggregate from Turret Hill Aggregate Property Test Value Aggregate Crushing Value, ACV 18 Aggregate Impact Value, AIV ««12 Los Angeles Abrasion Value, LAAV (21.5) Water Absorption (*) 0.5 (0.4) Flakiness Index, IF (%) 20 (25) Elongation Index, IE (%) 39 (36) Note : Numbers in brackets for mm aggregate.

42 Table 6 - Test Results on Laboratory Crushed Medium-Grained Granite Aggregates (10-14 mm) from Turret Hill Aggregate Property Test Value Aggregate Crushing Value, ACV (*) 23 Aggregate Impact Value, AIV (3) 24 Los Angeles Abrasion Value, LAAV (*) 29 Water Absorption (*) 0.5 Flakiness Index, IF (*) (20)* Elongation Index, IE (%) 41 (30)* Legend : mm aggregate

43 Table 7 - British Standard and Other Acceptance Values for Test Results on Roadstone and Concrete Aggregates Test Test Value Use Authority Aggregate Crushing Value, ACV (JO Maximum 30 C.R. Higginbottom (1976) Aggregate Impact Value, AIV (JO Maximum 45 + Maximum 30* C.R. BS 882: $ Fines Value (kn) Minimum 50 + More than 100* More than 150* R.C. R. C. Hosking & Tubey (1969) BS 882:1983 BS 882:1983 Aggregate Abrasion Value, Los Angeles Abrasion Value, (ASTM C-131) AAV (50 LAAV Maximum 10 (diff. cond i j Maximum 12 (av. cond.) Maximum 30 (diff. cond») Maximum 40 (av. cond.) Maximum 35* R. C. C. R. DOT (1976) Australian Standard (1985) Shergold (1948) I -fcr Water Absorption (Porosity) (50 Less than 3 + C.R. Higginbottom (1976) BS 5337:1976 Bulk Density (g/cm3) More than 2.60 C.R. Higginbottom (1976) Flakiness Index, I F (JO Less than 35*** C.R. BS 882:1983 Magnesium Sulphate Soundness {%) Maximum 18 (5 cycles) C.R. ASTM C33-81 Sodium Sulphate Soundness (JO Maximum 12 (5 cycles) Maximum 12 (5 cycles) C.R. C. ASTM C33-81 Australian Standard (1985) Legend : R Road aggregates C - * For wearing surfaces ** Concrete aggregates For heavy duty concrete floor *** General use For C20 and over concrete grade

44 LIST OF FIGURES Figure No. Page No. 1 Locatioi* Map Showing Geology of the Site 43 and the Adjacent Areas

45

46 LIST OF PLATES Plate No. Page No. 1 General View of. Turret Hill Quarry 45 2 Sampling Locality on Quarry Bench 45 3 Photomicrograph of Monzonite Showing 46 Inequigranular and Porphyritic Texture 4 Crushed Rock Aggregate from Monzonite 46

47

48

49 SECTION 3 : AGGREGATE PROPERTIES OF COARSE-GRAINED GRANITE FROM LAI KING T.Y. Irfan This report was originally produced as GCO Technical Note No. TN 4/87

50 FOREWORD In order to help provide the Materials Division and the Hong Kong Geological Survey with much needed data on the characterization and possible usage of each of the Territory's major rock types the Office initiated the Fresh Rock Testing Programme in This report forms part of the Fresh Rock Testing Programme and is one of a series of reports which presents the results of selected aggregate and index laboratory testing carried put on fresh block samples of discrete rock types. The rock type described in this report is a coarsegrained granite from Lai King, The author wishes to acknowledge the role played in the field sampling and sample preparation by GE J. M. Nash and TO's W, C. Lee and M* K. Chan and in the laboratory testing by GE K. H. Lee and other laboratory staff. The cooperation and assistance of the Materials Division is also acknowledged. (A.D. Burnett) Chief Geotechnical Engineer/Planning

51 CONTENTS Title Page 47 FOREWORD 48 CONTENTS INTRODUCTION SITE DESCRIPTION AND SAMPLING GEOLOGY Site Geology Description of Test Sample AGGREGATE TESTING AND CHARACTERIZATION Sample Preparation and Testing Methods Classification and Characterization of Aggregate Test Results DISCUSSION ON TEST RESULTS Rock Index and Aggregate Properties Suitability of Rock as an Aggregate CONCLUSIONS REFERENCES 53 LIST OF TABLES 55 LIST OF FIGURES 63 LIST OF PLATES ' 65 Page No,

52 INTRODUCTION This Technical Note on the aggregate properties of fresh, coarse-grained granite from the Lai King area forms the third report in the series of aggregate properties of selected Hong Kong rocks. The report presents the results of selected laboratory physical index and aggregate testing on fresh granite samples collected from a road cutting at Ha Kwai Chung, Lai King, and discusses the results and suitability of coarse-grained granite from this locality as aggregate in comparison with the typical aggregate acceptance values. The suitability of the rock is only assessed on the basis of a narrow range of selected rock properties in this report. 2. SITE DESCRIPTION AND SAMPLING The sampling site is a 30 m high road cutting (cut slope no. 11NW-A/C29) along Wah Yiu Road opposite Kwai Chung Methodist College, Ha Kwai Chung, Lai King, Kowloon (Figure 1 and Plate 1). The location from which the sample was taken is situated in the central portion of the cutting about 2 m above the toe (Plate 2). Three block samples were collected from the fresh granite for testing (Plate 3). While this outcrop of coarse-grained granite is not of sufficient size to form an economic source for aggregate, it does provide a typical representative of this rock type in the Territory for testing and assessment. 3. GEOLOGY 3.1 Site Geology The rock type exposed and sampled in the road cutting is coarse-grained granite (gc). It is intruded by thin aplite dykes and a 3 m wide feldsparphyric rhyolite (rf) dyke trending in an east-northeast direction. The contact between the coarse-grained granite and a fine-grained granite can be observed round the corner along Lai Chi Ling Road (Figure 1). At the sampling station, the granite is slightly weathered and moderately to widely jointed (0,3-1.0 m). This is overlain by moderately to highly weathered granite in the upper portion of the slope. The rock is dissected by four sets of joints forming a blocky to tabular fabric with mean joint orientations of 60/350, 75/066, 67/156 and 10/085. 3*2 Description of Test Sample Engineering geological description (BS 5930:1981). The rock is very strong, light grey with pinkish patches, crystalline, fresh with slight staining along joint planes, coarse-grained GRANITE with inequigranular and porphyritic texture. Detailed description. The rock consists of subhedral grains of quartz, alkali feldspar, plagioclase feldspar and biotite. Alkali feldspars are generally light pink in colour and form the larger grains, up to 20mm in size, ma groundraass of mainly quartz and plagioclase feldspars with an average grain size of 6 to 8 mm. Biotite generally occurs as pods, up to 6 mm m size. Modal analysis carried out on three thin sections (Table 1) gave a mmeralogical composition of 36.3? quartz, 60.2* feldspars, and 3.0$ biotite.

53 Detailed description of coarse-grained granite occurring in Sheet 11 area is given in Strange & Shaw (1986). 4. AGGREGATE TESTING AND CHARACTERIZATION 4.1 Sample Preparation and Testing Methods 75 mm diameter cores were drilled from the block samples using a concrete coring machine and diamond bit in the Public Works Central Laboratory. Selected physical and rock index tests were performed on the cores. The remainder of the samples were broken into smaller pieces using a sledge hammer and a laboratory rock breaker. Point load testing was carried out on irregular lumps of rock using ISRM recommended methods (ISRM, 1985). Standard (10-14 mm) and nominal 20 mm size aggregates (Plate 4) were prepared from the smaller pieces of rock using a laboratory jaw crusher. The rock index tests undertaken included the determination of bulk density, porosity, water absorption and sonic velocity using the PUNDIT (ISRM, 1978). The aggregate tests included aggregate crushing value, aggregate impact value, water absorption, flakiness and elongation indices (BSI, 1975) and Los Angeles abrasion value (ASTM, 1981). 4.2 Classification and Characterization of Aggregate The CADAM scheme recommended by the Geological Society Working Party on Aggregates (Collis & Fox, 1985) is used to describe and classify the aggregate (Table 2). A more detailed petrographic evaluation of the aggregate is given in Table Test Results The results of rock index tests on cores are given in Table 4. The test results on laboratory crushed coarse-grained granite aggregate are tabulated in Table DISCUSSION ON TEST RESULTS 5.1 Rock Index and Aggregate Properties The rock index tests given in Table 4 show that the fresh coarse-grained granite from Lai King is a very strong rock with a point load strength value of about 9 MPa (or uniaxial compressive strength of about 225 MPa using the normal conversion factor of 25) and has very low water absorption and porosity properties. In terms of rock index properties, the coarse-grained granite from this locality has very similar properties to the medium-grained granite from Turret Hill quarry (Table 3, in Irfan & Nash, 1987) having slightly higher dry bulk density (2.62 g/cm3), lower water absorption (0.21 %) and effective porosity ( values and lower point load strength (8.9 MPa). The test values for the medium-grained granite are 2.60 g/c 3, 0.52 %, 1.34 % and 10.1 MPa respectively. A comparison of the aggregate test results on the coarse-grained granite

54 (Table 5) with those of medium-grained granite (Table 6) shows slightly higher and hence less desirable properties for the former rock type in terms of aggregate impact and Los Angeles abrasion values and flakiness index. The rock index and aggregate values presented in Tables 4, 5 and 6 are those of limited tests carried out on a few block samples chosen from particular single localities for each rock type. Their test values may not therefore be typically representative of the whole rock types occurring in the Territory* 5.2 Suitability of Rock as Aggregate The existing aggregate quarries in Hong Kong are all in fine- to mediumgrained and medium-grained granites (Strange & Shaw, 1986; Choy & Irfan, 1986 a, b). Commercial test results on coarse-grained granite are therefore not available to make a general assessment of the suitability of this rock type as an aggregate source rock. Coarse-grained granites, particularly porphyritic types, are generally less sought after for sources of aggregate because of their relatively low crushing strength which arises from fracturing along cleavages or boundaries of coarse crystalline constituents* A comparison of the limited laboratory test results in Table 5 with typical, mainly UK, acceptance values (Table 7) indicates that the aggregates produced from the coarse-grained granite at Lai King are just within the acceptable limits for general use in concrete and as roadstone as far as the aggregate properties determined in this study are concerned. In terms of Los Angeles abrasion value, the test value of 31? although acceptable for general concrete purposes, is just outside the maximum value specified by the Australian Standard AS for concrete exposed to severe conditions. Aggregate crushing-value (or aggregate impact value) of the rock is also relatively high, making the aggregate from this type of granite less desirable as compared to the fine-grained granite for some special uses such as wearing course or heavy duty concrete floor. Soundness tests, which are generally executed to determine the durability of aggregate to salt attack, have not been carried out because of the fresh state of the rock tested. It is, however, recommended that soundness tests are carried out if anything but fresh rock is to be used as aggregate. Polished stone values were not determined in this investigation* 6. CONCLUSIONS The laboratory test results carried out on aggregate produced from the fresh coarse-grained granite collected from a road cutting at Lai King are just within the commonly accepted limiting values for general use in concrete and as roadstone. The aggregate impact value (or crushing value) and Los Angeles abrasion value test results are rather high and near or just above the specified limiting values. This makes the aggregate from this rock type less desirable for special uses such as wearing courses and heavy duty concrete floors compared to aggregates from fine-grained granites or basaltic rocks. No currently operating quarries in Hong Kong are extracting this type of granite and comparative test results are hence not available on plant-crushed aggregates. In-service performance of this granite type is therefore not known. Coarse-grained granites are, however, generally less sought after elsewhere in the world as an aggregate source because of their less desirable

55 properties 7- REFERENCES American Society for Testing Materials (1981). Specification for Concrete Aggregates (ASTM C33-8D. American Society for Testing Materials. American Society for Testing Materials (1981). Test for resistance to abrasion of small size coarse aggregate by use of the Los Angeles machine. Test Designation C American Society for Testing Materials. British Standards Institution (1983). British Standard Specification for Aggregates from Natural Sources for Concrete (BS 882 : 1983). British Standards Institution, London, 7p* British Standards Institution (1975). Methods for Sampling and Testing of Mineral Aggregates, Sands and Fillers (BS 812 : Parts 1 to 3). British Standards Institution. British Standards Institution (1976). Code of Practice for the Structural Use of Concrete for Retaining Aqueous Liquids (BS 5337 : 1976). British Standards Institution. British Standards Institution (1981). Code of Practice for Site Investigations (BS 5930 :1981). British Standards Institution, London, 147 p. Choy, H.H. & Irfan, T.Y. (1986a). Engineering Geology Studies for the Extension of the Anderson Road Quarries. GCO Report No. ADR 12/86, 71 p. Choy, H.H. & Irfan, T.Y. (1986b). Engineering Geology Studies for the Extension of Pok Tung Wan Quarry, Lamma Island. GCO Report No. ADR 18/86, 60 p. Collis, L. & Fox, R.A. (1985). Aggregates : Sand, Gravel and Crushed Rock Aggregates for Construction Purposes. Geological Society Engineering Geology Special Publication No. 1. The Geological Society, London, 200 p. Department of Transport (1976). Edition. H.M.S.O., London. Specification for Road and Bridgeworks, 5th Higginbottom, I.E. (1976). Section General requirements for rocks and aggregates. In Applied Geology for Engineers,, H.M.S.O., 378 p. Hosking, J.R. & Tubey, L.W. (1969). Research on Low Grade and Unsound Aggregates. Road Research Laboratory Report L.R. 293, Road Research Laboratory, Crowthorne, 30 p. International Society for Rock Mechanics (1978). Rock Characterization Testing and Monitoring. ISRM Suggested Methods (ed. E.T. Brown). Commission on Testing Methods, International Society for Rock Mechanics, Pergamon Press, 211 p.

56 . 5H - International Society for Rock Mechanics (1985). Suggested method for determining point load strength. International Society for Rock Mechanics Commission on Testing Methods. International Journal of Rook Mechanics and Mining Sciences and Geomechanics Abstracts, vol. 22, No," 2, pp Irfan, T.Y. & Nash, J.M. (1987). Aggregate Properties of Medium-Grained Granite from Turret Hill Quarry. GCO Report No. TN 2/81, 23 p. Shergold, F.A. (1948). A review of available information on the significance of roadstone tests. Road Research Technical Paper 10. DSIR, H.M.S.O., London. Standards Association of Australia (1985). Aggregates and Rock for Engineering Purposes. Part 1 -Concrete Aggregates (Australian Standard ). Standards Association of Australia, 16 p. Strange, P.J. & Shaw, R. (1986). Geology of Hong Kong Island and. Kowloon. Geotechnical Control Office, Hong Kong, 134 p. (Hong Kong Geological Survey Memoir No. 2).

57 LIST OF TABLES Table No. Page No. 1 Modal Analysis of Coarse-Grained Granite from 56 Lai King 2 Description and Classification of Coarse-Grained 57 Granite Aggregate by the CADAM System 3 Petrographic Evaluation of Coarse-Grained 58 Granite Aggregate 4 Rock Index Properties of Coarse-Grained Granite 59 5 Test Results on Laboratory Crushed Coarse-Grained 60 Granite Aggregate 6 Test Results on Laboratory Crushed Medium-Grained 61 Granite Aggregate from Turret Hill 7 British Standard and Other Acceptance Values for 62 Test Results on Roadstone and Concrete Aggregates

58 Table 1 - Modal Analysis of Coarse-Grained Granite from Lai King Mineral Feldspars Quartz Biotite Others Thin Section Thin Section Thin Section Average

59

60 Table 3 - Petrographic Evaluation of Coarse-Grained Granite Aggregate PETROGRAPHIC EVALUATION OF AGGREGATES SAMPLE REF LOCATION/GRID REF SAMPLING DATE AGGREGATE PROPERTIES Parttete Shape (BS 812:1975) Surface Texture (BS 812:1975) Coaling 3675 EG 015 Wan Yiu Road Cutting, Lai King, Kowloon E N Mainly angular to irregular Crystalline None SAMPLE SIZE/WEIGHT Bulk sample : 50 kg Sub-sample : 1 kg (10-14 mm) CJeanRness (Dust etc) GEOLOGICAL PROPERTIES Rock Type (GSS Classification) Mineralogy Major Constituents Minor Constituents Cementing Materials Some dust resulting from aggregate crushing Coarse-grained GRANITE (gc) Quartz (36.3%), Feldspars (60.2%), Biotite (3-0%) Magnetite, chlorite, zircon Crystalline, no cementing minerals CD I Expansrve Minerals Weathering of Particles Organic Material Content GENERAL COMMENTS ADDITIONAL INFORMATION None Fresh, very few particles show slight staining None Granite is inequigranular and porphyritic with grain size 1 to 10 mm, occasionally 30mm Compiled by Date

61 Table 4 - Rock Index Properties of Coarse-Grained Granite from Lai Kins Rock Index Property Average Value Range Mineral Grain Specific Gravity (g/cm3) n.d. n.d. Bulk Density Dry Saturated (g/cm3) (g/cm3) Water Absorption {%) Porosity Total {%) Effective {%) n.d n.d Sonic Velocity (m/s) 5008* Point Load Strength (MPa) Legend : n.d. Not determined + Mean of 16 tests on irregular lumps (ISRM, 1985) * Determined on 75 mm diameter cores (ISRM, 1978)

62 Table 5 - Test Results on Laboratory Crushed Coarse-Grained Granite Aggregate (10-14 mm) from Lai King Aggregate Property Test Value 4 - Aggregate Crushing Value, ACV (50 23 Aggregate Impact Value, AIV (51) 25 Los Angeles Abrasion Value LAAV (%) 31 Water Absorption <» 0.3 Flakiness Index, IF (?) 11 Elongation Index, IE (?) 3* Legend : + Mean of two test results

63 Table 6 - Test Results on Laboratory Crushed Medium-Grained Granite Aggregates (10-14 ram) from Turret Hill Aggregate Property Test Value Aggregate Crushing Value, ACV {%) 23 Aggregate Impact Value, AIV Cjf) 24 Los Angeles Abrasion Value, Water Absorption Flakiness Index, Elongation Index, LAAV (55) i P <» IE ($) (20)* 41 (30)* Legend : * mm aggregate

64 Table 7 - British Standard and Other Acceptance Values for Test Results on Roadstone and Concrete Aggregates Test Test Value Use Authority Aggregate Crushing Value, ACV (%) Maximum 30 C.R. Higginbottom (1976) Aggregate Impact Value, AIV (%) Maximum 45 + Maximum 30* C.R. BS 882: % Fines Value (kn) Minimum 50+ More than 100* More than 150* R.C. R. C. Hosking & Tubey (1969) BS 882:1983 BS 882:1983 Aggregate Abrasion Value, AAV (%) Maximum 10 (diff. cond.) Maximum 12 (av. cond.) R. DoT (1976) Los Angeles Abrasion Value, LAAV (ASTM C-13D Maximum 30 (diff. cond.) Maximum U0 (av. cond.) Maximum 35* C. C. R. Australian Standard (1985) Shergold (1948) i Water Absorption (Porosity) {%) Less than 3 + C.R. Higginbottom (1976) BS 5337:1976 Bulk Density (g/cm3) More than 2.60 C.R. Higginbottom (1976) Flakiness Index, Ip Less than 35*** C.R. BS 882:1983 Magnesium Sulphate Soundness {%) Maximum 18 (5 cycles) C.R. ASTM C33-81 Sodium Sulphate Soundness {%) Maximum 12 (5 cycles) Maximum 12 (5 cycles) C.R. C. ASTM C33-81 Australian Standard (1985) Legend : R Road aggregates < 2 Concrete aggregates * For wearing surfaces ** For heavy duty concrete jfloor + General use *** For C20 and over concrete grade

65 LIST OF FIGURE Figure No. Page No. 1 Location Map Showing Geology of the Site and 64 the Adjacent Areas

66 1:20000 LEGEND: SOUD GEOLOGY I QG [ I Qb ; Qd I ms JHHH I b I rf I rq Quaternary Superficial Deposits (Onshore) Quaternary Superficial Deposits (Offshore) Basalt Feldsparphyric Rhyolite Quartzphyric Rhyolite Aplite Pegmatite Coarse-grained Granite, > 6mm Fine-grained Granite, <2mm Medium-grained Granite, 2-6mm GEOLOGICAL LINES Megacrystic Geological Boundary, Superficial Deposits Geological Boundary, Solid Rock Fault STRUCTURAL SYMBOLS Jointing Photogeological Lineament Horizontal -L. Inclined 20 Vertical NOTE : The geological map is extracted from the published sheet 11 of the 1 : geological map series of Hong Kong, Not all the geological symbols are given in the legend. Figure 1 - Location Map Showing Geology of the Site and the Adjacent Areas

67 LIST OF PLATES Plate No. 1 General View of Wah Yiu Road Cutting 66 2 Sampling Locality 66 3 Block Sample 67 H Crushed Rock Aggregate from Coarse-Grained Granite 67

68 SLOV Plate 1 - General View of Wah Yiu Road Cutting Plate 2 - Sampling Locality

69

70

71 SECTION 4 : AGGREGATE PROPERTIES OF FINE-TO MEDIUM-GRAJ GRANITE FROM MA YAU TONG T.Y. Man This report was originally produced as GCO Technical Note No. TN 9/87

72 FOREWORD In order to help provide the Materials Division and the Hong Kong Geological Survey with much needed data on the characterisation and possible usage of each of the Territory's major rock types the Office initiated the Fresh Rock Testing Programme in This report forms part of the Fresh Rock Testing Programme and is one of a series of reports which presents the results of selected aggregate and index laboratory testing carried out on fresh block samples of discrete rock types. The rock type described in this report is a fine-tomedium-grained granite from Ma Yau Tong. The author wishes to acknowledge the role played in the field sampling and sample preparation by GE J. M. Nash and TO's W. C. Lee and M. K. Chan and in the laboratory testing by GE K. H. Lee and other laboratory staff. The cooperation and assistance of the Materials Division is also acknowledged. (Dr A,D. Burnett) Chief Geotechnical Engineer/Planning

73 CONTENTS Title Page 69 FOREWORD 70 CONTENTS INTRODUCTION SITE DESCRIPTION AND SAMPLING GEOLOGY Site Geology Description of Test Sample AGGREGATE TESTING AND CHARACTERIZATION Sample Preparation and Testing Methods Classification and Characterization of Aggregate Test Results DISCUSSION ON TEST RESULTS Rock Index and Aggregate Properties Suitability of Rock as an Aggregate CONCLUSIONS REFERENCES. 75 LIST OF TABLES 77 LIST OF FIGURES 85 LIST OF PLATES 87 Page No.

74 INTRODUCTION This Technical Note on the aggregate properties of fine- to mediumgrained granite from Ma Yau Tong area forms the fourth report in the series of aggregate properties of selected Hong Kong rocks. The report presents the results of selected laboratory physical index and aggregate testing on fresh granite samples and discusses the results and suitability of fine- to mediumgrained granite as aggregate in comparison with typical aggregate acceptance values. The suitability of the rock is only assessed on the basis of a narrow range of selected rock properties in this study. 2. SITE DESCRIPTION AND SAMPLING The sampling site is a new road cutting, northeast of Lam Tin Estate, Phase II and below Ma Yau Tong Controlled Tip, Kowloon (Figure 1 and Plates 1 and 2) The rectangular shaped granite samples were collected from the rock excavated during the construction of the new road. Four fresh granite block samples were selected for testing (Plate 3). While this outcrop of fine- to medium-grained granite is not a suitable site to form an economic source for aggregate because of its location, it is, however, of the same rock type as. that being quarried in the lower faces of the Anderson Road quarries (Choy & Irfan, 1986). The granite outcropping in this area is considered typical and representative of fine- to medium-grained granite in the Territory except for its counterpart cropping out in Central and Northern Lamma Island which has a distinctly modified texture (Strange & Shaw, 1986). 3. GEOLOGY 3.1 Site Geology The road cutting is dominantly composed of fine- to medium-grained granite (gfm) with fine-grained granite (gf) occupying a small portion of the western end of the slope. The contact between the two types of granite is shown to be passing just below the controlled tip, east of the road cutting on the recently published geological map of Hong Kong and Kowloon (GCO, 1986). A number of basalt dykes, each approximately 1.0 to 1.5 ra wide, cross the road cutting in a ENE-WSW direction. The granite exposed in the cutting is typical of the fine- to medium-grained granite type cropping out in East Kowloon having a generally equigranular texture and uniform character. The road cutting is in mainly fresh to slightly weathered granite with more weathered granite zones near the crest and southern end of the cut face. The basalt dykes are parallel to the most dominant subvertical joint set in the granite, and trending ENE-WSW. Sub-horizontal sheeting joints are also present in the cut slope. The joint spacing as displayed on the cut face varies from widely spaced (0.6-2 m) to medium spaced ( m). 3-2 Description of Test Sample (1). Engineering geological description. The rock is an extremely PW?; ^ t Pinkish grey, crystalline, fresh, fine- to medium-grained GRANITE with equigranular texture.

75 (2) Detailed description. The major granite constituents are quartz, plagioclase and alkali feldspars and biotite. Quartz forms about 30% of the rock and biotite less than 5%. The results of modal analysis on three sections is given in Table 1, Small amounts of muscovite are also present. Alkali feldspars are generally light pink in hand specimen while some plagioclases show slight greenish discoloration at their centres indicating slight alteration. The rock is equigranular and non-megacrystic with an average grain size of 1 to 2 mm. Occasional quartz and feldspar grains up to 4 mm in diameter are also present. In thin section (Plate 5), some of the plagioclases show slight alteration in the form of either partial replacement by or growth of individual muscovite flakes (hydrothermal alteration?). In addition, some plagioclases show slight alteration to minute kaolinite-like minerals at their centres. The amount of feldspar alteration is about 3.3$ of the rock (Table 1). A few tight microcracks are present traversing quartz and feldspars grains. 4. AGGREGATE TESTING AND CHARACTERIZATION 4.1 Sample Preparation and Testing Methods 75 mm diameter cores were drilled from the block samples using a concrete coring machine and diamond bit in the Public Works Central Laboratory. Selected physical and rock index tests were performed on the cores. The remainder of the sample were broken into smaller pieces using a sledge hammer and a laboratory rock- breaker. Point load testing was carried out on irregular lumps of rock using ISRM recommended methods (ISRM, 1985). Standard (10-14 mm) and nominal 20 mm size aggregates (Plate 4) were prepared from the smaller pieces of rock using a laboratory jaw crusher. The rock index tests undertaken included the determination of bulk density, porosity, water absorption, and sonic velocity using the PUNDIT equipment (ISRM, 1978). The aggregate tests included aggregate crushing value, aggregate impact value, water absorption, flakiness and elongation indices (BSI, 1975) and Los Angeles abrasion value (ASTM, 1981). 4.2 Classification and Characterization of Aggregate The CADAM scheme recommended by the Geological Society Working Party on Aggregates (Collis & Fox, 1985) is used to describe and classify the aggregate (Table 2). A more detailed petrographic evaluation of the aggregate is given in Table Test Results ;.. '. ' :. -'. The results of the rock index tests on cores are given in Table 4. The test results on laboratory crushed fine- to medium-grained granite aggregate are tabulated in Table *5,.

76 DISCUSSION ON TEST RESULTS 5.1 Rock Index and Aggregate Properties The fresh fine- to medium-grained granite from Ma Yau Tong is a very strong rock with a point load strength value of about 8.2 MPa (or uniaxial compressive strength of about 210 MPa using the normal conversion factor of 25) and has very low water absorption and porosity properties (Table k). Although the density, water absorption, porosity values of this rock type is very similar to the coarse-grained granite from Lai King (Irfan, 1987a), and the medium-grained granite and monzonite from Turret Hill (Irfan, 1987b; Irfan & Nash, 1987), it has a lower strength than all the rocks tested so far in this project. The sound velocity is also very much lower than the value obtained on the coarse-grained granite; 3585 m/s against 5008 m/s for the latter. A comparison of the aggregate test results of the fine- to medium-grained granite (Table 5) with those of medium- and coarse-grained granites and monzonite (Table 6) show significantly higher and hence less desirable properties for the former rock type in terms of aggregate impact value (AIV = 31), aggregate crushing value (ACT = 27) and Los Angeles abrasion value (LAAV = 41). This result is rather unexpected since finer grained granites generally have more favourable aggregate properties when compared with coarser grained equivalents. The lower than expected strength and velocity values determined on intact rock and the slightly poorer aggregate strength properties of this rock type from Ma Yau Tong road cutting may be the result of slight hydrothermal alteration it has undergone, which can only be detected in thin section on petrographic examination (see Section 3.2). The lower production platforms of both Pioneer and particularly K. Wah quarries are in fine- to medium-grained granite passing into more finer grained granite near the contact with the volcanics. A comparison of the test results-on samples from Ma Yau Tong (Table 5) is therefore made with the test results available ( ) on the quarry run material from both these quarries (Table 7). The results are similar in terms of aggregate crushing value, aggregate impact value, water absorption, density, flakiness and elongation indices. No Los Angeles abrasion values were determined for the Anderson Road quarry materials. 5.2 Suitability of Rock as an Aggregate A comparison of the limited laboratory test results with typical, mainly UK, aggregate acceptance values (Table 5) indicates that the aggregates produced from the fine- to medium-grained granite at Ma Yau Tong are just within the acceptable limits for general use in concrete and as roadstone, in terms of aggregate crushing and impact values, water absorption value and flakiness index. However, in terms of Los Angeles abrasion value, the test value of 43 is outside the maximum value specified by the Australian Standard AS for concrete exposed to even average conditions. The aggregate impact value of 31 is just outside the maximum value specified by BS 882 which makes the aggregate tested in this study less desirable for special purposes such as wearing surfaces or heavy duty concrete floors. No polished stone values or 10$ Fines values were determined for Ma Yau Tong granite samples.

77 It is to be noted that the rock index and aggregate values presented in Tables 4 to 6 are those of limited tests carried out on few block samples chosen from one particular locality for this rock type, which appears to have undergone slight hydrothermal alteration. The test values may not therefore be fully representative of the fine- to medium-grained granite occurring in Territory. 6. CONCLUSIONS The results of laboratory tests carried out on aggregate produced from fresh fine- to medium-grained granite from a road cutting at Ma Yau Tong are just within the commonly accepted limiting values for general use in concrete and as roadstone, except in terms of Los Angeles abrasion value where a higher than acceptable value of 43 was obtained. This value together with rather high (near or above the specified limiting) aggregate impact and crushing test values make the aggregate from this particular locality less desirable for specific uses such as wearing courses and heavy duty concrete floors compared to finer grained granites and basaltic rocks. The rock appears to have undergone slight hydrothermal alteration. The lower than expected strength and other properties of the intact rock as well as the aggregate properties are therefore attributed to this slight alteration. The aggregate properties of the rock determined on laboratory crushed specimens is very similar to the test values available on quarry run granitic material of similar grain size from the Anderson Road quarries, and the aggregates from these quarries have been satisfactorily used in concrete for general building purposes in the Territory. Further tests on samples from other localities are however necessary to assess more accurately the typical aggregate properties of the fine- to medium-grained granite occurring in the Territory. 7. REFERENCES American Society for Testing Materials (1981). Test for resistance to abrasion of small size coarse aggregate by use of the Los Angeles machine. Test Designation C American Society for Testing Materials. British Standards Institution (1983)- British Standard Specification for Aggregates from Natural Sources for Concrete (BS 882 :1983)» British Standards Institution, London, 7 p. British Standards Institution (1975). Methods for Sampling and Testing of Mineral Aggregates, Sands and Fillers (BS 812 : Parts 1 to 3). British Standards Institution. Choy, H.H. & Irfan, T.Y* (1986). Engineering Geology Studies for the Extension of the Anderson Road Quarries. GCO Report No. ADR 12/86, 71 p* Collls, L. & Fox, R.A. (1985)- Aggregates : Sand, Gravel and Crushed Rock Aggregates for Construction Purposes. Geological Society Engineering Geology Special Publication No. 1. The Geological Society, London, 200 p.

78 Higginbottom, I.E. (1976). Section General requirements for rocks and aggregates. In Applied Geology for Engineers, H.M.S.O., 378 p. International Society for Rock Mechanics (1978)- Rock Characterization Testing and Monitoring. ISRM Suggested Methods (ed. E.T. Brown). Commission on Testing Methods, International Society for Rock Mechanics, Pergamon Press, 211 p. International Society for Rock Mechanics (1985). Suggested method for determining point load strength. International Society for Rock Mechanics Commission on Testing Methods. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, vol. 22, No. 2, pp Irfan, T.Y. (1987a). Aggregate Properties of Monzonite from Turret Hill Quarry. GCO Report No. TN 3/87, 24 p. Irfan, T.Y. (1987b). Aggregate Properties of Coarse-Grained Granite from Lai King. GCO Report No. TN 4/87, 23 p. Irfan, T.Y. & Nash, J.M. (1987). Aggregate Properties of Medium-Grained Granite from Turret Hill Quarry. GCO Report No. TN 2/81, 23 p. Shergold, F.As (1948). A review of available information on the significance of roadstone tests. Road Research Technical Paper 10. DSIR, H.M.S.O., London. Standards Association of Australia (1985). Aggregates and Rock for Engineering Purposes. Part 1 - Concrete Aggregates (Australian Standard ). Standards Association of Australia, 16 p. Strange, P.J. & Shaw, R. (1986). Geology of Hong Kong Island and Kowloon. Geotechnical Control Office, Hong Kong, 134 p. (Hong Kong Geological Survey Memoir No. 2).

79 LIST OF TABLES Table No. No < 1 Modal Analysis of Fine- to Medium-Grained 78 Granite from Ma Yau Tong 2 Description and Classification of Fine- to 79 Medium-Grained Granite by the CADAM System 3 Petrographic Evaluation of the Ma Yau Tong 80 Aggregates i Rock Index Properties of Fine- to Medium- 81 Grained Granite from Ma Yau Tong 5 A Comparison of Aggregate Test Results from 82 Ma Yau Tong with British Standard and Other Acceptance Values 6 Test Results on Laboratory Crushed Granitic 83 Aggregates (10-14 mm) 7 Aggregate Test Results from Anderson Road 84 Quarries, (from Choy & Irfan, 1986)

80 Table 1 - Modal Analysis of Fine- to Medium-Grained Granite from Ma Yau Tong Mineral Feldspars % Quartz % Biotite, Muscovite Chlorite % Others % Thin Section (3.1) (3.4) (3.4) Average 67.3 (3.3) Note : The thin number in brackets section is the percentage of altered feldspars per

81 Table 2 - Description and Classification of Fine- to Medium-Grained Granite by the CADAM System (Collis & Fox, 1985) AGGREGATE FORM CLASS {ox MISCELLANEOUS) Pz&iotogJJicdL name [JLI known) GEOLOGICAL AGE/ COLOUR/ GRAIN SIZE rissllltv [l{ any) CAuAh&d Rock Ccu*iboncut(L> GRANITE NatiLKal Chii^hdd HJYOA Igneous O r-l SJUUXMJUL Cla&i, ^zcumzntaxy hllxtd ii / - MctamoxphsLC Land won [cofiae.ct name, to h.z QAjv<in boxcm) Mesozoic/Light pinkish grey/fresh/medium to Coarse-grained, equigranular/no fissibility CompJJLzd by : T.Y. Irfan VaU : SGE/EG, GCQ CADAM - CLASSIFICATION and DESCRIPTION of AGGREGATE MATERIAL LOCATION ANV SAMPLE VETAILS addh.qj>h : Road Cutting below Ma Yau Tong Controlled Tip, Kowloon Sampla : Typn Blocks kg Slza VKHpaAcvUcn Lab. crushed Supp-tced bu -EG SectioT) GnXd Vata o& complyin VOJL<L Radd Sampling CeAt. No.

82 Table 3 - Petrographic Evaluation of the Ma Yau Tong Aggregate PETROGRAPHIC EVALUATION OF AGGREGATES SAMPLE REF LOCATION/GRO REF SAMPLING DATE AGGREGATE PROPERTIES Particle Shape (BS812;1975) Surface Texture (Bo8i2;1975) Coating CleanRoess (Dust etc) GEOLOGICAL PROPERTIES Rock Type (GSS Classification) 3677EGO17 Road Cutting below Ma Yau Tong Controlled Tip 8**281O 8i9MfON SAMPLE SIZE/WEIGHT Bulk Sample ; 50 kg Sub-sample Mainly angular to irregular, very few flaky and elongated Crystalline None Clean Fine- to Medium-grained GRANITE (gfra) : 1 kg (i0-1*f mm) Mineralogy Major Constituents Minor Constituents Quartz (29-6#) f Feldspars (67.390, Biotite ( 3.0%) Chlorite, muscovite Cementing Materials Expansive Minerals Weathering of Particles Organic Material Content GENERAL COMMENTS ADDITIONAL INFORMATION Crystalline t no cementing minerals None Fresh None Granite is equigranular, with grain size 0,5 to 3.0 mm Compiled by T.Y. Irfan Date

83 Table H - Rock Index Properties of Fine- to Medium-Grained Granite from Ma Yau Tong Rock Index Property Average Value Range Mineral Grain Specific Gravity, g/cnh n.d. n.d. Bulk Density Dry Saturated g/cm^ g/cm^ Water Absorption Porosity Total Effective n.d n. d Sonic Velocity m/s 3585* Point Load Strength MPa Legend : n.d. Not determined. + Mean of 15 tests on irregular lumps (ISRM, 1985). * Determined on 75 mm diameter cores (ISRM, 1978)

84 Table 5 - A Comparison of Aggregate Test Results from Ma Yau Tong with British Standard and Other Acceptance Values Aggregate Property Test Value* Acceptance Value Use Authority Aggregate Crushing Value, ACV % 27 Max. 30 C.R. Higginbottom (1976) Aggregate Impact Value, AIV % 31 Max Max C.R. C.R. BS 882:1983 BS 882:1983 Los Angeles Abrasion Value, LAAV % 43 Max Max * Max. 35"* C. C. R. Australian Standard (1985) (1948) Water Absorption 0.4 Max. 3 1 C.R. Higginbottom (1976) Flakiness Index 13 Max. 35 : C.R. BS 882:1983 Elongation Index 28 Notes : 1 - General use 2 - For wearing surfaces 3.- Difficult conditions 4 - Average conditions 5 - For C20 and over concrete grade + «Average of two test results (10-14 mm) C - Concrete aggregate R - Road aggregate

85 Table 6 - Test Results on Laboratory Crushed Granitic Aggregates (10-14 mm) Aggregate Property Medium-Grained Granite Turret Hill 1 Coarse-Grained Granite Lai King 2 Monzonite Turret Hill 3 Aggregate Crushing % Value Aggregate Impact % Value Los Angeles Abrasion % Value Water Absorption % "0.5 Flakiness Index Elongation Index Notes : 1. Test results from Irfan & Nash (1987) 2. Test results from Irfan (1987a). 3. Test results from Irfan (1987b).

86 Table 1 - Aggregate Test Results from Anderson Road Quarries (from Choy & Irfan, 1986) Aggregate Property K. Wan Quarry Granite Pioneer Quarry- Granite Aggregate Crushing Value, ACV % 30** (24-34) 28** (23-30) Aggregate Impact Value, AIV % 28 (19-33) 29 (25-34) 10? Fines kn 145 ( ) 126 ( ) Water Absorption % 0.6 ( ) 0.7 ( ) Relative Density g/crar 2.60 ( ) 2.60 ( ) Flakiness Index, I % 17 (10-27) 17 (13-22) Elongation Index, I % hi 35 (26-41) 34 (22-42) Na? SGv Soundness % n.d. n.d. Legend : n.d. Not determined, number in parentheses indicate ranges of values. ** Test results from 1975 to 1977, all other test results

87 LIST OF FIGURE Figure No. p f ge No - 1 Location Map Showing Geology of the Site 86 and Adjacent Areas

88 - 86 -

89 LIST OF PLATES plate No. Page No 1 General View of Sampling Locality (Road Cutting 88 below Ma Yau Tong Controlled Tip) 2 Jointing Pattern in Fine- to Medium-Grained 88 Granite 3 Block Sample 89 4 Crushed Rock Aggregate from Fine- to Medium-Grained 89 Granite 5 photomicrograph 90

90 Plate 1 - General View of Sampling Locality (Road Gutting below Ha Yau Tong Controlled Tip) Plate 2 - Jointing Pattern in Fine- to Medium-Grained Granite

91

92

93 SECTION 5 : AGGREGATE PROPERTIES OF FINE- AND FINE-TO MEDIUM- GRAINED GRANITES FROM ANDERSON ROAD T.Y. Man & A. Cipullo This report was originauy produced as GCO Technical Note No. TN 11/87

94 FOREWORD In order to help provide the Materials Division and the Hong Kong Geological Survey with much needed data on the characterisation and possible usage of each of the Territory's major rock types the Office initiated the Fresh Rock Testing Programme in This report forms part of the Fresh Rock Testing Programme and is one of a series of reports which presents the results of selected aggregate and index laboratory testing carried out on fresh block samples of discrete rock types. The rock types described in this report are fineand fine- to medium-grained granites from the Pioneer Quarry, Anderson Road. The authors wish to acknowledge the role played in the field sampling and sample preparation by GE J.M. Nash and TO M,K. Chan, in the laboratory testing by GE K.H, Lee and in the report production by M*W» Yuen (STO/EG). The cooperation and assistance of the Materials Division is also acknowledged. (Dr A.D# Burnett) Chief Geotechnical Engineer/Planning

95 CONTENTS Title Page 91 FOREWORD 92 CONTENTS INTRODUCTION 9*1 2. SITE DESCRIPTION AND SAMPLING GEOLOGY Site Geology Description of Test Sample Fine-Grained Granite Fine- to Medium-Grained Granite AGGREGATE TESTING AND CHARACTERIZATION Sample Preparation and Testing Methods Classification and Characterization of Aggregate Test Results DISCUSSION ON TEST RESULTS Rock Index and Aggregate Properties Suitability of Rock as an Aggregate CONCLUSIONS REFERENCES " LIST OF TABLES 101 LIST OF FIGURES 112 LIST OF PLATES 115 Page No.

96 1. INTRODUCTION This report presents and discusses the results of selected physical Index and aggregate testing on laboratory crushed fine- and fine- to medium-grained granite samples from the Pioneer Quarry, Anderson Road. The results are compared with the routine test values available on quarry run material from the Pioneer Quarry and the suitability of both rock types as aggregate is assessed in comparison with the typical acceptance values for various uses. 2. SITE DESCRIPTION AND SAMPLING The sampling site is at the northwestern part of the Pioneer Quarry along Anderson Road, Kowloon (Figure 1, Plate 1). Quarrying operations at both the Pioneer Quarry and the adjacent Ka Wah Quarry started as a number of permit quarries pre-1960 f s on the southwestern flank of an elongate hill (Tai Sheung Tok) rising up to 420 mpd (Figure 1). Large scale quarry operation started at the western part of the site in 1962 by Ka Wah and the contract for quarrying the eastern part of the site was let to Pioneer in 1974 by the Government. The current combined annual production is 3.0 million tonnes. Fine- and fine- to medium-grained granite block samples were collected from the newly excavated rock stockpile on the 245 mpd platform (Plates 2 and 3). The exact location of the samples on the quarry face is not known, but the majority of the rock in the stockpile is considered to come from the faces above the platform (Plate 2). The samples collected appeared to be typical and representative of both granite types occurring throughout the quarry The currently worked faces of the Pioneer Quarry are dominantly in fine-grained granite (Figure 2) with fine- to medium-grained granite outcropping in the lower faces and the quarry platform. 3. GEOLOGY 3.1 Site Geology A detailed account of the geology and engineering geology of both quarry sites is given in the Advisory Report ADR 12/86 "Engineering Geology Studies for the Extension of Anderson Road Quarries" (Choy & Irfan,^ 1986) The site is underlain by granite with volcanic rocks occupying the summit region of Tai Sheung Tok. The granite-volcanic contact crosses the uppermost quarry face in the Ka Wah Quarry (Figure 2). The granite is grey to pinkish grey, equigranular, and generally of grain size of 1 to 4 ram along the lower reaches of the quarries* It is shown on the new geological map of Hong Kong and Kowloon (GCO, 1986) as fine- to medium-grained granite (gfta). This grades into a finer grained I leas than 2 mm in grain size), inequigranular granite with scattered porphyritic feldspar crystals (fine-grained granite, gf) towards the contact with the pyroclastics. The granite generally contains small amounts of muscovite and less than 5% biotite. Two sets of faults cross the quarry sites in NHW-SSE and NE-SW

97 directions. Kaolin veins and. pyrite mineralization is present along the fault zones which indicates hydrothermal alteration of the granite along these lines of weakness prior to weathering (Choy, Earl, irfan & Burnett, 1987). The joint spacing is variable over the site in the Ka Wah Quarry where the NNW-SSE trending major fault zone passes very close to the current working quarry faces and the spacing is generally 0.5 to 1.5 m. In the Pioneer Quarry, the major faulted zone is well outside the current working limits or to the south and the discontinuity spacing is much wider except along the minor fault/shear zones where the spacing can be less than 0.3 m (Figure 2). At the northwestern corner of the Pioneer Quarry, from where the samples were selected, the rock is generally slightly weathered. Pyrite mineralization was observed along some faults and joints with pyrite crystals also occurring in the rock some distance from the faults. Strange and Shaw (1986) described the geology of both granite types occurring in the Territory. 3.2 Description of Test Sample Fine-Grained Granite (1) Engineering geological description. The rock is a very strong, light grey, crystalline, fresh to slightly decomposed, fine-grained (less than 2 mm) GRANITE with inequigranular and slightly megacrystic texture. (2) Detailed description. The joint surfaces are stained light yellowish brown with some migration of discoloration, up to 10 mm, into the rock from the joint surface. Yellowish brown staining is also present around pyrite crystals scattered throughout the rock indicating slight decomposition of pyrite. The major constituents of the granite are quartz, plagioclase and alkali feldspars. Small amounts of biotite and muscovite and pyrite are also present. Feldspars are milky white except near joint surfaces where they may be light pink in colour. Quartz forms about 32% of the rock and, biotite and muscovite less than 3%. The results of modal analysis carried out on three thin sections are given in Table 1. The rock is inequigranular and slightly megacrystic. The finer groundmass has as grain size of 0.1 to 1.0 mm with quartz and feldspar megacrysts up to 3 mm. Occasional feldspar raegacrysts are up to 8 mm in grain size. In thin section (Plates 4 and 5). some plagioclase and alkali feldspars show slight alteration in the form of either partial replacement by or growth of individual muscovite flakes (muscovite also occurs as a primary constituent). In addition, most plagioclases show slight alteration to minute serieite and clay minerals. Calcite was seen to be forming as decomposition product in one or two plagioclase grains. The total amount of feldspar alteration is about 3.7* of the rock (Table 1). The grain boundaries are tight and interlocking. Occasional quartz-feldspar boundaries show iron-oxide staining. Microcracks are few (less than 1 per 10 mm) single, tight (less than 0.01 m in width) and generally intragranular in quartz and some feldspars. Very few transgranular mlcroeracks of longer length are present.

98 *2 Fine- to Medium-Grained Granite (a) Engineering geological description. The rock is very strong, light grey, crystalline, fresh to slightly decomposed, fine- to medium-grained (1 to 4 mm) GRANITE with equigranular texture. (b) Detailed description. The joint surfaces are stained light yellowish brown with some migration (a few mm) of discoloration into the rock from the joint surface. Slight decomposition of feldspars is evident near the joint surfaces. The feldspars are pink adjacent to one joint surface in one of the block sanples indicating slight hydrothermal alteration. The major rock constituents are quartz, plagioclase, alkali feldspars and biotite. Quartz forms about 3Q% and biotite less than 555 of the rock. The results of modal analyses carried out on three thin sections of granite are given in Table 2. In this section (Plates 6 and 7) a few plagioclases and potash feldspars show slight alteration in the form of either partial replacement by or growth of individual muscovite flakes, but the replacement is much less intense than that of fine-grained granite (see Tables 1 and 2). In addition, most plagioclases show growth of minute flakes of sericite and clay minerals which may have formed as a result of weathering (Plate 7). The total feldspar alteration is about 6% of total feldspar content or 3.6? of the rock. Although most grain boundaries are tight, some quartz-feldspar boundaries are stained indicating movement of iron-oxide from biotite alteration along the slightly open grain boundaries. Transgranular as well as intragranular microcracks exist with microcrack intensity being 2 to 3 per 10 mm. Microcracks are simple, tight and generally less than 0.02 mm in width; most are stained. Two thin micro-quartz veins were observed in one of the thin sections. 4. AGGREGATE TESTING AND CHARACTERIZATION 4.1 Sample Preparation and Testing Methods 75 mm diameter cores were drilled from the block sanples using a coring machine in the Public Works Central Laboratory, Selected physical and rock index tests were performed on the cores. The remainder of the samples were broken into smaller pieces using a sledge hammer and a laboratory rock breaker. Point load testing was carried out on irregular lumps of rock using ISRM recommended method (ISRM, 1985)* Standard (10 to 14 mm) and nominal 20 mm size aggregates (Plates 8 and 9) were prepared from the smaller pieces of rock using a laboratory jaw crusher. The rock index tests undertaken included the determination of bulk density, porosity, water absorption, and sonic velocity using the PUNDIT equipment (ISRM, 1978). The aggregate tests included aggregate crushing value (ACT) aggregate impact value (AIV), water absorption, flakiness (I f ) and elongation indices (I ) (BSI, 1975) and Los Angelas abrasion value (LAAV) (ASTM, 1981). **

99 Classification and Characterization of Aggregate The CADAM scheme recommended by the Geological Society Working Party on Aggregates (Collis & Fox, 1985) is used to describe and classify the aggregates (Tables 3 and 4). A more detailed petrographic evaluation of the aggregates is given in Tables 5 and Test Results The results of the rock index tests on cores and irregular lumps are given in Table 7. The aggregate test results are tabulated in Table DISCUSSION ON TEST RESULTS 5.1 Rock Index and Aggregate Properties The fresh to slightly decomposed fine-grained and fine- to medium-grained granites tested from Anderson Road are both very strong rocks with point load strengths in excess of 7.5 MPa and 7.1 MPa respectively corresponding to uniaxial strengths of MPa and MPa using the normal conversion factor of 25. They both have very low porosity and water absorption properties, less than 1.0/6 and 0.4? respectively (Table 7) and their densities are very similar. The slight difference in their strength properties is also reflected in the seismic velocities where a lower value of 3730 m/s was obtained on fine- to medium-grained granite against 4518 m/s for fine-grained granite. Strength and sonic velocity values of granites are both influenced to a great extent by the degree of microfracturing and decomposition of the rock (Irfan & Dearman, 1978). The fine- to medium-grained granite in this study has more raicrocracks (2 to 3 per 10 mm) compared to the fine-grained granite (about 1 per 10 mm) and consequently lower strength value; the degree of decomposition measured by amount of feldspar alteration being almost the same for both granite types. In terms of selected aggregate properties the fine-grained granite has significantly lower and hence more desirable properties in comparison with those of the fine- to medium-grained granite (Table 8). The aggregate properties of the latter rock are very similar to those of fineto medium-grained granite from Mau lau Tong (Irfan, 1987a) in terms of ACV, AIV, LAAV, I. and water absorption value. The fine-grained granite from the Pioneer Quarry has the lowest and hence most favourable aggregate strength and abrasion properties amongst the granitic rocks tested in this study programme so far except for those of monzonite from Turret Hill where the rock tested was in fresh state (Table 9). A comparison of the laboratory crushed aggregate test results with the mean values of quarterly results available from PWC Laboratory on quarry run material from Anderson Road quarries (Table 10) show that the fine- to medium-grained granite has very similar properties in terms of ACV, AIV, I and water absorption whereas those of the fine-grained granite are superior*,

100 - 98-5,2 Suitability of Rock as an Aggregate A comparison of the limited laboratory test results with typical, mainly UK, aggregate acceptance values (Table 7) indicates that the properties of aggregate produced from the fine-grained granite are well within the acceptable limits for both general use in concrete and as roadstone. The low aggregate test values obtained in terms of AIV and LAAV suggest that this rock type may be suitable for some special purposes such as wearing surface and high strength concrete whereas the fine- to medium-grained granite has marginal values in terms of ACV, AIV and LAAV making it less desirable for special purposes when compared to fine-grained granite or basaltic rocks. A LAAV test value of 44 obtained for this granite type is just outside the maximum value of 40 specified by the Australian Standard AS 2258 for concrete exposed to average conditions. Polished stone values, 10% fines values and chemical reactivity of the aggregates were not determined in this study. The aggregates from Anderson Road quarries have been successfully used for many years for general concrete purposes in Hong Kong, although for some special uses volcanic rocks were considered (e.g. Kai Tak airport runway). The aggregate test values reported in Table 10 are those of the mean values of quarterly tests carried out in the PWC Laboratory for the years from 1975 to In the original data no distinction was made between the various types of granites present in the quarry. Figure 2 suggests that the bulk of the rock excavated for aggregate was from the fine-grained granite in the Pioneer Quarry. The majority of the production faces in the quarry are in the slightly weathered granite zone with some moderately weathered granite along fault zones and higher levels in the quarry (Choy & Irfan, 1986). The quarried material is therefore likely to contain fresh and slightly decomposed granite as well as some moderately decomposed granite (i.e. completely discoloured), which can be suitable if of high strength and low porosity. The rocks tested in this study were fresh to slightly decomposed granite and came from the slightly weathered zone in the quarry. The samples collected from the fine-grained granite had pyrite crystals disseminated throughout the rock. Some forms of pyrites are able to oxidise, with resultant expansion, when situated at or near concrete surfaces. This activity thus leads to the development or surface defects with considerable staining of the surface by iron oxide The surface deterioration is usually of no structural significance, but the unsightly appearance may be undesirable (Collis & Fox, 1985). 6. CONCLUSIONS The laboratory test results on laboratory crushed aggregates from fresh to slightly decomposed fine-grained granite from the Pioneer Quarry are well within the commonly accepted limiting values for general use in concrete and as roadstone, while those of fine- to medium-grained granite from the same locality are marginal in terms of ACV and AIV. The lower values make the fine-grained granite suitable for special uses such as wearing courses and heavy duty concrete floors. While the fine* to medium-grained granite is still suitable for general concrete uses, high

101 aggregate strength test results near to the limiting values and a very high LAAV value of 44 make the aggregates produced" from this rock type rather undesirable for some specific uses. Although the bulk excavation for aggregate came from the fine-grained granite in the quarry, the average values obtained on quarry run material are higher and near to the limiting acceptance values than those determined on the samples chosen from the same granite type in this study. This is attributed to the fresher state of the rock used for laboratory testing in this study than those normally used for producing aggregate in the quarry. There is also variation in grain size even within the rock unit mapped as fine-grained granite in the vicinity of the quarry with grain size becoming finer towards the contact with the volcanic rocks. Field observations indicate that the quality of granite near the fault zones is affected by more intense differential weathering and earlier hydrothermal alteration. Pyrite is present in the rock adjacent to such zones of alteration. Pyrite may cause staining if oxidized at or near concrete free surfaces; the surface deterioration is usually of no structural significance. 7. REFERENCES American Society for Testing Materials (1981). Test for resistance to abrasion of small size coarse aggregate by use of the Los Angeles machine. Test Designation C American Society for Testing Materials. British Standards Institution (1983). British Standard Specification for AggregatesfromNatural Sources for Concrete (BS 882 : 1983)* British Standards Institution, London, 7 p. British Standards Institution (1975). Methods for Sampling and Testing of Mineral Aggregates, Sands and Fillers (BS 812 : Parts 1 to 3). British Standards Institution. Choy, H.H. & Irfan, T.Y. (1986). Engineering Geology Studies for the Extension of the Anderson Road Quarries* GCO Report No. ADR 12/86, 71 p. Choy, H.H,, Earle, Q.G., Irfan, T.Y. & Burnett, A.D. (1987). Studies for the extension of a major urban quarry in Hong Kong. In : Culshaw, M.G., Bell, F.G., Cripps, J.C. & D. O r Hara (eds). Planning and Engineering Geology. Engineering Geology Special Publication of the Geological Society, London, 4 (in press). Collis, L. & Pox, R.A. (1985). Aggregates : Sand, Gravel and Crushed Rock Aggregates for Construction Purposes. ' Geological Society Engineering Geology Special Publication No. 1. The Geological Society, London, 200 p* Geotechnioal Control Office (1986). Hong Kong and Kowloon, Solid and Superficial Geology (1 ; map). Hong Kong Geological Survey Map Series HGM 20, Sheet 11, Geotechnieal Control Office, Hong Kong, 1 map *

102 Higginbottom, I.E. (1976). Section General requirements for rocks and aggregates." In Applied Geology for Engineers, H.M.S.O., 378 p. International Society for Rock Mechanics (1978). Rock Characterization Testing and Monitoring* ISRM Suggested Methods (ed, E.T. Brown). Commission on Testing Methods, International Society for Rock Mechanics, Pergamon Press, 211 p. International Society for Rock Mechanics (1985). Suggested method for determining point load strength. International Society for Rock Mechanics Commission on Testing Methods. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, vol. 22, No. 2, pp Irfan, T.Y. (1987a). Aggregate Properties of Fine- to Medium-Grained Granite from Mau Yau Tong. GCO Report No. TN 9/87, 24 p. Irfan, T.Y. (1987b). Aggregate Properties of Monzonite from Turret Hill Quarry. GCO Report No. TN 3/87, 24 p. Irfan, T.Y. (1987c). Aggregate Properties of Coarse-Grained Granite from Lai King. GCO Report No. TN 4/87, 23 p. Irfan, T.Y. & Dearman, W.R. (1978). The engineering petrography of a weathered granite in Cornwall, England. Quarterly Journal of Engineering Geology, vol. 11, pp Irfan, T.Y. & Nash, J.M. (1987). Aggregate Properties of Medium-Grained Granite from Turret Hill Quarry. GCO Report No. TN 2/81, 23 p. Shergold, F.A. (1948). A review of available information on the significance of roadstone tests. Road Research Technical Paper 10. DSIR, H.M.S.O., London. Standards Association of Australia (1985). Aggregates and Rock for Engineering Purposes, Part 1 - Concrete Aggregates (Australian Standard ). Standards Association of Australia, 16 p. Strange, P.J. 4 Shaw, R. (1986). Geology of Hong Kong Island and Kowloon. Geotechnical Control Office, Hong Kong, 134 p. (Hong Kong Geological Survey Memoir No. 2).

103 LIST OF TABLES Table No. Page No 1 Modal Analysis of Fine-Grained Granite from the 102 Pioneer Quarry 2 Modal Analysis of Fine- to Medium-Grained 103 Granite from the Pioneer Quarry 3 Description and Classification of Aggregate 104 from the Pioneer Quarry by the CADAM System (Fine-Grained Granite) 4 Description and Classification of Aggregate 105 from the Pioneer Quarry by the CADAM System (Fine- to Medium-Grained Granite) 5 Petrographic Evaluation of Granite Aggregates 106 from the Pioneer Quarry (Fine-Grained Granite) 6 Petrographic Evaluation of Granite Aggregates 107 from the Pioneer Quarry (Fine- to Medium-Grained Granite) 7 Rock Index Properties of Fine and Fine- to 108 Medium-Grained Granites from the Pioneer Quarry 8 ' A Comparison of Aggregate Test Results from the 109 Pioneer Quarry with British Standard and Other Acceptance Values 9 Test Results on Laboratory Crushed Granitic 110 Aggregates 10 Aggregate Test Results from Anderson Road 111 Quarries,

104 Table 1 - Modal Analysis of Fine-Grained Granite from the Pioneer Quarry Mineral Feldspars % Quartz % Biotite % Muscovite % Others % Thin Section (2.1) Thin Section (4.1) Thin Section (4.9) Average 64.6 (3.7) Note : The number in brackets is the percentage of altered feldspars (kaolinite, sericite, etc.) per thin section.

105 Table 2 - Modal Analysis of Fine- to Medium-Grained Granite from the Pioneer Quarry ' Mineral Feldspars % Quartz % Biotite % Muscovite % Others % Thin Section (3.7) Thin Section (2.5) Thin Section (4.7) Average 59.9 (3.6) Note : The number in brackets is the percentage of altered feldspars (kaolinite, sericite, etc.) per thin section.

106 Table 3 - Description and Classification of Aggregate from the Pioneer Quarry by thegadam System (Fine- Grained Granite) AGGREGATE FORM CLASS [OK MISCELLANEOUS) 'e /iolog<icaz name [<ll known) GEOLOGICAL AGE/ COLOUR/ GRAIN SIZE FISS1L1TV Comment [i^ any] Cteuhzd Rock Cmuhad Ctu&lted Carbonate GRA1TITB Igneous SUieata Sadimiintan.il Itixtd Mesozoic/Light grey/fresh to slightly weathered/medium grained/l?o fissility Contains pyrite crystals Lrt'J r T(* conatct name to be given CompUed by :. Irfan Vate : ? GCO CADAM - CLASSIFICATION and DESCRIPTION of AGGREGATE MATERIAL LOCATION khffl SAMPLE VETA1LS QuaHAiji Kowloon Qpehakc'* : Pioneer Sample : Typv "Blocks Size 50 kg VKepaKoutwn h & 1 Suppl ledfat/eg ) Section crusned Vote o& Vate Rec'd Sampling CenX. No.

107 Table 4 - Description and Classification of Aggregate from the Pioneer Quarry by the CADAM System (Fineto Medium-Grained Granite) AGGREGATE FORM CLASS MISCELLANEOUS) nam <il known] GEOLOGICAL AGE/ COLOUR/ GRAIW SIZE Cmuhzd Rock Cmshtd CoAbonatt Class GRASTTE Class M-'C'XC.C! SUlcatz Clashed Mesozoic/Light grey/fresh to slightly weathered/coarse grained, equigranular/ Wo fissility X name be givtn below) Comment i ij any) Dhows sign of slight hydrothermal alteration by : T.Y. Irfaai SGE/EG, GCO : 5*11*1987 CADAM - CLASSIFICATION and DESCRIPTION of AGGREGATE MATERIAL LOCATION AhlD SAMPLE PETAHS : rioneer Quarry Redd Anderson Road,.Kowldon 34231OS rioneer Sample. : Sampling Lao, crusnedl samplingcem. Wo. Supplied by EG Section

108 Table 5 -"Petrographio Evaluation of Granite Aggregates from the Pioneer Quarry (Fine-Grained Granite) PETROGRAPHIC EVALUATION OF AGGREGATES SAMPLE REF LOCATION/GRID REF SAMPLING DATE AGGREGATE PROPERTIES Partfcte Shape (BS 812:1975) Surface Texture CBS 812:1975) Coating Cleanliness (Dust etc) 'GEOLOGICAL PROPERTIES Rock Type (GSS Classification) Mineralogy Cementing Material Major Constituents Minor Constituents 3683 EGO23 Pioneer Quany (Anderson Road) S4231OE N Angular to irregular Crystalline Hone Slightly dusty Pine-grained GHA1TITE (gf) Quartz (33#)» Feldspars (6^), Biotite (<1^) I^rite ( 1#), Muscovite Hone SAMPLE SIZE/WEIGHT Bulk sample J 50 kg Sub-sample s T kg (10-14 mm) Expansrve Mine rate Wsaifvering of Particles Organic Material Content GENERAL COMMENTS ADDITIONAL INFORMATION I^rite may be deleterious Generally fresh, some li^itly discoloured (slightly decomposed). Jfone ine^mgranular fabric, grain size 0.1 to 2 mm, occasional megaciysts up to 6 mm. Yellowish brown Compiled by T.Y. Irfan Date

109 TaT)le 6 - Petrographio Evaluation of Granite Aggregates from the Pioneer Quarry (Fine- to Medium-Grained Granite) PETROGRAPHIC EVALUATION OF AGGREGATES SAMPLE REF LOCATtOH/GRK) REF SAMPLING DATE AGGREGATE PROPERTIES Particle Shape (BS 812:1975) Surface Texture {BS 812:1975) Coating CteanKness (Dust etc) GEOLOGICAL PROPERTIES Rock Type (GSS Classification) 3680 BS020 Pioneer Quarry (Anderson &oa&) 84231OS ? Angular to irregular, ^ew Crystalline None Clean elongated Fine- to medium-grained GRANITE (gfm) SAMPLE SIZE/WEIGHT Bulk Sample s 50 kg Sub-sample % 1 kg (10-14 mm) Mineralogy Major Constituents Minor Constituents Quartz (33$), Feldspars (6ofo), Biotite (c 2$>) Muscovite Cementing Materials Expansive Minerals Weathering of Particles Organic Material Content GENERAL COMMENTS ADDITIONAL INFORMATION Ciystalline, no cementing minerals None Generally fresh, a few grains are lightly discoloured (slightly decomposed) A few show signs of slight hvdrothermal alteration ITone Equigranular with grain si me 1 to 4 mm Compiled by T.Y. Irfan Date 5.11»1987

110 Table 7 - Rock Index Properties of Fine- and Fine- to Medium- Grained Granites from the Pioneer Quarry Rock Index Property Fine-Grained Granite (Range) Fine- to Medium- Grained Granite (Range) Mineral Grain Specific Gravity, g/cnr n.d. n.d. Bulk Density Dry g/cnr Saturated g/cnr 2.61 ( ) 2.62 ( ) 2.59 (2.59) 2.60 (2.60) Water Absorption 0.35 ( ) 0.37 ( ) Porosity Total % Effective % n.d ( ) n.d ( ) Sonic Velocity m/s 4518* ( ) 3730* ( ) Point Load Strength MPa *10+ ( ) Legend : n.d. Not determined. + Mean of 15 to 30 tests on irregular lumps (ISRM, 1985). * Determined on 75 mm diameter cores (ISRM, 1978). other index tests - average of 3 to 5 tests on cores*

111 Table 8 - A Comparison of Aggregate Test Results from the Pioneer Quarry with British Standard and Other Acceptance Values Aggregate Property+ Fine- Grained Granite Fine- to Medium- Grained Granite Acceptance Value Use Authority Aggregate Crushing Value, ACV % Max 30 C.R. Higginbottom (1976) Aggregate Impact Value, AIV % Max 451 Max 30 C.R. C.R. BS882 : 1983 BS882 : 1983 Los Angeles Abrasion Value, LAAV % Max 30^ Max 40 Max 35 C. C. R. Australian Standard (1985) Australian Standard (1985) Shergold (1948) Water Absorption % Max 3 1 C.R. Higginbottom (1976) o VO Flakiness Index, I p Max 35 5 CR. Higginbottom (1976) Elongation Index, I p Notes : 1 - General use 2 - For wearing surfaces 3 - Difficult conditions 4 - Average conditions 5 - For C20 and over concrete grade - Average of 2 test results C - Concrete aggregate R - Road aggregate +.

112 Table 9 - Test Results on Laboratory Crushed Granitic Aggregates (10-14 mm) Aggregate Property Fine- to Medium Grained Granite Mau Yau Tong (Irfan, 1987a) Medium- Grained Granite Turret Hill (Irfan & Nash, 1987) Coarse- Grained Granite Lai King (Irfan, 1987c) Monzonite Turret Hill (Irfan, 1987b) Aggregate Crushing Value % Aggregate Impact Value % Los Angeles Abrasion Value % Water Absorption % Flakiness Index Elongation Index

113 Table 10 - Aggregate Test Results from Anderson Road Quarries, (from Choy & Irfan, 1986) Aggregate Property ' Ka Wan Quarry Granite Pioneer Quarry Granite Aggregate Crushing Value, ACV % Aggregate Impact Value, AIV % 10? Fines Value kn Water Absorption, % 30** (24-34) 28 (19-33) 145 ( ) 0.6 ( ) 28** (23-30) 29 (25-34) 125 ( ) 0.7 ( ) Relative Density g/cm 2.60 ( ) 2.60 ( ) Flakiness Index, I_ 17 (10-27) 17 (13-22) Elongation Index, I_ 35 (26-41) 34 (22-42) Na SO. Soundness, % n.d. n.d. Legend : n.d. Not determined, the number in brackets indicates range of values. ** Test results from 1975 to 1977, all other test results

114 Fi f re No - LIST OF FIGURES 1 Location Map Showing Geology of the Site nj and Adjacent Areas 2 Engineering Geological map of the Anderson 114 Road Quarries (from Choy & Irfan, 1986a) Page No.

115

116

117 LIST OF PLATES Plate No. Page No, 1 Anderson Road Quarries The Sampling Locality Block Samples Being Selected From the Stockpile Photomicrograph of Fine-Grained Granite Photomicrograph of Fine-Grained Granite Photomicrograph of Fine- to Medium-Grained 119 Granite 7 Photomicrograph of Fine- to Medium-Grained 120 Granite 8 Fine-Grained Granite Aggregate Fine- to Medium-Grained Granite Aggregate 121

118

119

120

121

122

123

124

125 SECTION 6 : AGGREGATE PROPERTIES OF MEDIUM- GRAINED GRANITE FROM DIAMOND HILL A. Cipullo & T.Y. Man This report was originally produced as GCO Technical Note No. TN 3/88

126 FOREWORD In order to help provide the Materials Division and the Hong Kong Geological Survey with much needed data on the characterization and possible usage of each of the Territory's major rock types, the Office initiated the Fresh Rock Testing Programme in This report forms part of the Fresh Rock Testing programme and is one of a series of reports which presents the results of selected aggregate and index laboratory testing carried out on fresh block samples of discrete rock.types. The rock type described in this report is mediumgrained granite from the Diamond Hill Quarry. The authors wish to acknowledge the role played in the field sampling and sample preparation by J,MU Nash (GE) and M,K. Chan (TO), and in the report production by M.W. Yuen (STO/EG). The cooperation and assistance of the Materials Division is also acknowledged. A.D. Burnett Chief Geotechnical Engineer/Planning

127 CONTENTS Page No. Title Page 123 FOREWORD 124 CONTENTS INTRODUCTION SITE DESCRIPTION AND SAMPLING GEOLOGY 3.1 Site Geology 3.2 Description of Test Sample AGGREGATE TESTING AND CHARACTERIZATION Sample Preparation and Testing Methods Classification and Characterization of Aggregate DISCUSSION ON TEST RESULTS 5.1 Rock Index and Aggregate Properties Suitability of Rock as An Aggregate CONCLUSIONS REFERENCES 129 LIST OF TABLES 131 LIST OF FIGURES 139 LIST OF PLATES

128 INTRODUCTION This report presents and discusses the results of selected physical index and aggregate testing on laboratory crushed medium-grained granite samples from the Diamond Hill Quarry. The results are compared with the routine test values available on quarry run material and the suitability of the rock as aggregate is assessed in comparison with the typical acceptance values for various uses. 2. SITE DESCRIPTION AND SAMPLING The Government quarry site was located on the west facing flank of a northwest-southeast trending hill, rising up to 180 mpd. (Tsuen Shek Shan (Figure 1, Plate 1). Original quarrying operations started in 1952 on the southern side of the hill as a private permit quarry. Government quarry operations at the western end (Plate 2) commenced in 1962 and production of aggregates ceased by the end of The quarry site has since been incorporated in a major redevelopment project which will result in the removal of most of the original hill and the formation of a number of platforms for residential purposes. Production of aggregates from the excavated rock material will continue during site formation works. Medium-grained granite block samples were collected from the newly excavated lower quarry face and were typical and representative of the rock material occurring throughout the quarry (Plate 2). 3. GEOLOGY 3.1 Site Geology The new Sheet 11 of the geological map series of the Hong Kong Geological Survey (GCO, 1986) shows the quarry area to be underlain by medium-grained granite (gfta) of Mesozoic Age (Figure 2). The granite at this site is light grey with average grain size of 3 to 5 mm, comprising subhedral interlocking grains of quartz, alkali feldspars, subordinate white plagioclase grains and with biotite generally making up only 2% to 3% of the rock (Strange & Shaw, 1986). No major faults cross the site and joints are predominantly vertical to subvertical, striking mainly northwest-southeast and generally medium to widely spaced. One large composite basalt dyke, about 7 m wide, cut subvertically through the granite in a ENE direction at the southern end of the site (Plate 1). The mostly subvertical narrow ehloritized veins observed in parts of the quarry faces (Plate 3) are thought to result from hydrothermal alteration which has also affected the basalt dyke. Strange 4 Shaw (1986) give a detailed description of the mineralogical composition and texture of both the medium-grained granite occurring in the" Kowloon area and the basalt intrusion at the quarry site.

129 Description of Test Sample (a) Engineering geological description. The rock is very strong, light grey, crystalline, fresh, medium-grained GRANITE, with average grain size of 3 to 5 mm and inequigranular texture. (b) Detailed description. The major mineral constituents of the granite are quartz, plagioclase and alkali feldspars. Small amounts of biotite and occasional accessory pyrite grains are also present. Alkali feldspars are 2.5 to 5 mm in size, cloudy in polarized light and mostly microperthitic. The sodic plagioclase patches and lenticles are partly chloritized and altered to sericite and clay minerals. Plagioclases are 1.5 to 2 mm in size, cloudy, some with partial alteration to sericite and clay minerals. Quartz grains are, on average, 1.5 to 3 mm in size with occasional individual grains up to 5 mm. Biotite grains are 2 to 4 mm in size, partially chloritized and with alteration rims and minor segregation along cleavage planes. Isolated small (< 1 mm) grains of opaque mineral (magnetite?) were observed in one thin section. Mineral grains are subhedral with tight, mostly unstained and interlocking boundaries. Hairline cracks are limited to quartz grains, mostly intragranular, tight and unstained with occasional, partial extension into adjacent grains. The results of modal analysis carried out on three thin sections are given in Table 1 and show that feldspars and quartz are the predominant minerals forming, respectively, about 57? and 4035 of the rock. Plates 4a and 4b are photomicrographs showing typical mineral texture and extent of alteration. 4. AGGREGATE TESTING AND CHARACTERIZATION 4.1 Sample Preparation and Testing Methods Cores of 50 mm and 75 mm diameter were drilled from the block samples using a coring machine at the Public Works Central Laboratory. Selected physical and rock index tests were performed on the cores. The remainder of the samples were broken into smaller pieces using a sledge hammer and a laboratory rock breaker. Standard (10 to 14 mm) and nominal 20 mm size aggregates were prepared from the smaller pieces of rock using a laboratory jaw crusher* The rock index tests undertaken included the determination of bulk density, porosity and water absorption. Sonic velocity using the PUNDIT equipment (ISHH, 1978) and point load strength testing on irregular lumps of rock (ISRM, 1985) were also carried out. The aggregate tests included

130 the determination of aggregate crushing value (ACV), aggregate impact value (AIV), water absorption, flakiness (Ip) and elongation indices (Ig), ten percent fines value, relative density (BSI, 1975) and Los Angeles abrasion value (LAAV)USTM, 1981). 4.2 Classification and Characterization of Aggregate The CADAM scheme recommended by the Geological Society Working Party on Aggregates (Collis & Fox, 1985) is used to describe and classify the aggregates (Table 2).. A more detailed petrographic evaluation of the aggregates is given in Table DISCUSSION ON TEST RESULTS 5.1 Rock Index and Aggregate properties The results of rock index tests carried out on the selected samples are presented in Table 4 and indicate that the medium-grained granite from Diamond Hill is a strong rock with an average point load strength value of 6.5 MPa (corresponding to uniaxial strength of MPa using a conversion factor of 25) and very low porosity and water absorption properties. The strong nature of the rock is also reflected in the high value of the measured sonic velocity. The"results of tests on laboratory crushed aggregates are presented in Table 5* A comparison of these results with the mean values of results available from Public Works Central Laboratory on quarry run material (Table 6) show that AIV, ACV, Ip, Ig and water absorption determined in the laboratory are slightly lower while relative density and 1056 Fines Values are similar. The PSV (polished stone value) shown in Table 6 refers to one test only and it does not allow for significant comments. In terms of index properties the medium-grained granite from Diamond Hill has similar values to the medium-grained granite from Turret Hill Quarry (Irfan & Nash, 1987) only in terms of bulk density while exhibiting lower porosity and water absorption properties. However in terms of both laboratory and quarry run tests on aggregates the medium-grained granite from Turret Hill Quarry has generally superior characteristics except for relative density and water absorption where the test values are similar. This is probably due to the relatively higher state of hydrothermal decomposition of the feldspars in the Diamond Hill granite, 5#2 Suitability of Rock As An Aggregate A comparison of the limited laboratory test results with typical, mainly UK, aggregate acceptance values (Table 7) indicate that the properties of laboratory produced aggregate are generally within or at the limit of the acceptable values for both general use in concrete and as roadstone. The lower than required 10* Fines Value and AIV suggest that this rock type is not suitable for special purposes such as high strength concrete and heavy duty concrete floor finishes. The LAAV of 41, although just above the required value, may be acceptable for general concrete purposes but it is well outside the maximum values specified for concrete

131 exposed to severe conditions. However as the value is derived from a * single test it would need to be confirmed by additional tests although the AIV would seem to be in agreement with the above limitation. The aggregates from Diamond Hill Quarry have been successfully used for many years for general concrete purposes in Hong Kong. The as/resate test values presented in Table 6 are mean values of tests carried out on quarry run material at the Public Works Central Laboratory over the period from 1972 to The AIV is well below the maximum value acceptable in general use concrete as is the ACV, but just above that for wearing surfaces and well in excess of the maximum required for severe conditions The 10% Fines Value supports this limitation. 6. CONCLUSIONS The laboratory test results on laboratory crushed aggregates from fresh, medium-grained granite from the Diamond Hill Quarry are generally within the commonly accepted limiting values for general use in concrete and as roadstone. The mean values of aggregate tests on quarry run material also indicate the suitability of this rock for general use and confirm the laboratory test results which indicate that the near or above limiting values for ACV and AIV makes the aggregate produced from this rock type less suitable for specific uses such as wearing courses and heavy duty concrete floors. A comparison with the properties of laboratory produced and quarry run aggregates of medium-grained granite from Turret Hill Quarry indicates that the aggregate produced from Diamond Hill Quarry is of slightly inferior quality. This is probably attributable to the relatively higher state of alteration of the Diamond Hill granite and also slightly larger grain size revealed by the petrographic analysis. No soundness tests to determine the durability of the aggregate were carried out, for the reason that the rock tested was basically fresh and the aggregates from fresh granites are known to be durable. However it is recommended that soundness tests be carried out if the proportion of discoloured and/or altered rock in significant. 7. REFERENCES American Society for Testing and Materials (1981). Test for resistance to abrasion of small size coarse aggregate by use of the Los Angeles machine* Test Designation C Annual Book of ASTM Standards..American Society for Testing and Materials. ' British Standards Institution (1983). British Standard Specification for Aggregates from Natural Sources for Concrete (BS 882 : 1983)* British Standards Institution* London, 7 p. British Standards Institution (1975). Methods for Sampling and Testing of Mineral Aggregates, Sands and Filters (BS 812 : Parts 1 to 3), British Standards 'Institution* ' '" ' ' ' ' '

132 Collis, L. & Fox, R.A. (1985). Aggregates : Sand, Gravel and Crushed Rook Aggregates for Construction Purposes. Geological Society Engineering Geology Special Publication No. 1, The Geological Society, London, 200 p. Geotechnical Control office (1986). Hong Kong and Kowloon, Solid and Superficial Geology (1 : map). Hong Kong Geological Survey Map Series HGM 20, Sheet 11, Geotechnical Control office, Hong Kong, 1 map. Higginbottom, I.E. (1976). Section General requirements for rocks and aggregates. In Applied Geology for engineers, H.M.S.O., 378 p. International Society for Rock Mechanics (1978). Rock Characterization Testing and Monitoring. ISRM Suggested Methods" (ed. E.T. Brown). Commission on Testing Methods, International Society for Rock Mechanics, Pergamon Press, 211 p. International Society for Rock Mechanics (1985). Suggested method for determining point load strength. International Society for Rock Mechanics Commission on Testing Methods. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, vol. 22, No. 2, pp Irfan, T.Y. & Nash, J.M. (1987). Aggregate properties of Medium-Grained Granite from Turret Hill Quarry. GCO Report No. TN 2/81, 23 p. Shergold, F.A. (1948). A review of available information on the significance of roadstone tests. Road Research Technical paper 10. DISIR, H.M.S.O., London. Standards Association of Australia (1985). Aggregates and Rock for Engineering Purposes. Part 1 - Concrete Aggregates (Australian Standard ). Standards Association of Australia, 16 p. Strange, P.J. & Shaw, R. (1986). Geology of Hong Kong Island and Kowloon. Geotechnical Control Office, Hong Kong, 134 p. (Hong Kong Geological Survey Memoir No. 2).

133 LIST OF TABLES Table No. Page Mo. 1 Modal Analysis of Medium-Grained Granite 132 from Diamond Hill Quarry 2 Description and Classification of Aggregate 133 from Diamond Hill Quarry by the CADAM System 3 Petrographic Evaluation of Granite Aggregate 134 from Diamond Hill Quarry 4 Rock Index Properties of Medium-Grained Granite 135 from Diamond Hill 5 Test Results on Laboratory Crushed Aggregates 136 from Diamond Hill 6 Aggregate Test Results from Diamond Hill Quarry, A Comparison of Aggregate Test Results from the 138 Diamond Hill Quarry with British Standard and Other Acceptance Values

134 Table 1 - Modal Analysis of Medium-Grained Granite from Diamond Hill Quarry Mineral Feldspars % Quartz % Biotite % Others % Thin Section (5. 8) (0.1) 0.1 Thin Section (8.1) (0.4) 0.2 Thin Section (3.3) (1.2) 0.0 Average 56.7 (5.7) (0.6) 0.1 Note : The number in (sericite and chlorite) brackets is the percentage clay minerals) and altered of altered feldspars biotite (mainly

135 Table 2 Description and Classification of Aggregate from Diamond Hill Quarry try the CADAM System (Collis & Fox, 1985)

136 Table 3 - Petrographic Evaluation of Granite Aggregate from Diamond Hill Quarry P E T R O G R A P H I C E V A L U A T I O N O F A G G R E G A T E S SAMPLE REF LOCATION/GRID REF SAMPLING DATE AGGREGATE PROPERTIES Particle Shape (BS 812:1975) Diamond Hill Quarry/83B8OOE, K May 1966 Kainly angular and irregular, few elongated and flaky SAMPLE SIZE/WEIGHT Bulk bample %) kg Sub-Bample 1 kg (10-14 mm) Surface Texture {BS 812:1975} Coating Crystalline Hone Cleanliness (Dust etc) Clean GEOLOGICAL PROPERTIES Rock Type {GSS Classffication) fcediue - grained (2UKITE (gss) Mineralogy Major Constituents Minor Constituents Alkali and Plagioclose Feldspars (56«7/*)t ^uarts (40.3^)1 Biotite (2.9>) Caaorite, Occasional fin grains of magnetite Cementing Materials Expansive Minerals Weathering of Particles Organic Material Content GENERAL COMMENTS ADDITIONAL INFORMATION Crystalline uo oecieating material None R*#sh, no staining Kone Graaite is inequigxanular with grain size j to 5 21; and occasional individual feldspars up to a maximum 10 mir. Compiled by A. cipuiio Date

137 Table 4 - Rock Index Properties of Medium-Grained Granite from Diamond Hill Rock Index Property Average Value Range Mineral Grain Specific Gravity g/cm3 n.d. n.d. Bulk Density Dry g/cm3 Saturated g/cm Water Absorption % Porosity Total % Effective % n.d Sonic Velocity m/s Point Load Strength, Is(50) ^Pa 6.5* Legend : + Determined on 75 mm diameter cores ( 1SRM, 1978). * Average of 17 tests on irregular lumps (ISRM, 1985). n.d Not determined. Other index tests - Average of three tests on cores.

138 Table 5 - Test Results on Laboratory Crushed Aggregates (10-14 mm) from Diamond Hill Aggregate Property Test Value Aggregate Crushing Value, ACV % 29 Aggregate Impact Value, AIV % 29 Los Angeles Abrasion Value, LAAV* % «, Water Absorption * 0.5 Flakiness Index, i v * % 8 Elongation Index, Fines Value 108 Relative Density (Saturated Surface Dried) and g/cm Legend : * Size fraction tested mm - One Test + One Test

139 Table 6 - Aggregate Test Results from Diamond Hill Quarry, (20 mm aggregate) Aggregate Property Test Value (Range) "\0% Fines Value kn 104 (90-110) Aggregate Impact Value, AIV % 33 (28-36) Aggregate Crushing Value, ACV % 31 (28-36) Aggregate Abrasion Value, AAV % n.d. Water Absorption % 0.73 ( ) Flakiness Index, Ip % 14 (9-19) Elongation Index, Ig % 52 (39-64) Relative Density (Saturated and Surface Dried) g/cm ( ) Polished Stone Value, PSV + % 52 Legend : + One test on 10 mm aggregate n.d. Not determined

140 Table 7 - A Comparison of Aggregate Test Results from the Diamond Hill Quarry with British Standard and Other Acceptance Value Aggregate Property Medium- Grained Granite Acceptance Value Use Authority 10% Fines Value KN 108 Min Min 1503 C. C. BS 882 : 1983 Aggregate Crushing Value, ACV % 29 Max 30 C.R. Higginbottom (1976) Aggregate Impact Value, AIV % 29 Max 45 1 Max 30 2 Max 253 C.R. C.R. BS 882 : 1983 BS 882 : 1983 BS 882 : 1983 Los Angeles Abrasion Value, LAAV % 41 Max 303 Max 40^ Max 35 1 C. C. R. Australian Standard (1985) Australian Standard (1985) Shergold (1948) OO Water Absorption % 0.5 Max 3 1 C.R. Higginbottoffl (1976) BS 5337 : 1976 Flakiness Index, Ip 8 Max 35 5 C.R. BS 882 t 1983 Elongation Index, I E 30 Notes : 1 - General use 2 - For wearing surfaces 3 - Difficult conditions 4 - Average conditions 5 - For C20 and over concrete grade C - Concrete aggregate R - Road aggregate

141 LIST OF FIGURES Figure No. Page No. 1 Location Map Geology of the Site and the Adjacent Areas 141

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144 LIST OF PLATES Plate No. Page No. 1 General View of the Former Quarry Area -j43 Looking Southeast and Showing the Basalt Dyke Intrusion 2 Sampling Locality Showing the General Joints 143 Distribution 3 Close-up View of the Sampling Locality Showing 144 Subvertical Chloritized Veins 4 Photomicrographs of Medium-Grained Granite 145

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149 SECTION 7 : AGGREGATE PROPERTIES OF FINE-, MEDIUM-, AND MEGACRYSTIC GRANITES FROM LAMMA ISLAND T.Y. Man This report was originally produced as GCO Technical Note No. TN 11/89

150 FOREWORD In order to provide industry and Government with reliable and high quality test data concerning the index and aggregate properties and possible uses of each of the Territory's major rock types, the Geotechnical Control Office initiated the Fresh Rock Testing Programme yi This report forms part of the Fresh Rock Testing Programme and is one of a series of reports which presents the results of selected aggregate and index laboratory testing carried out on fresh block samples of discrete rock types. The rock types described in this report are the finegrained, medium-grained and megacrystic granites from the Pok Tung Wan Quarry, Lamma Island. The testing was carried out under the supervision of Dr T.I. Irfan when he was Senior Geotechnical Engineer/Engineering Geology Section and the report was written after he moved to the Special Projects Division in April, The assistance of the technical staff of the Engineering Geology Section with the field sampling and sample preparation and the staff of the Materials Division with the testing is acknowledged. (A.D. Burnett) Chief Geotechnical Engineer/Planning

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163 Table 3 - Classification, Description and Petrographic Evaluation of Aggregate Produced from the Medium-Grained Granite

164 Table 4 - Classification, Description and Petrographic Evaluation of Aggregate Produced from the Megacrytic Granite AGGREGATE FOPM CLASS [on. MISCELLANEOUS) Pz.tAolog.ical name [.Ifi known) GEOLOGICAL AGE/ COLOUR/ GRAIN SIZE F1SS1L1TV j Corme.nl {i& any] Ca,xbonaX:z j Cfa-44 GRANITE QiuuU CZa.64 Giavzt HaXiiAat C-nuAlizd hlixzd Sand Natunat Ciu-ihed Uxzd S-U-ica.Cz CLa.46 Igntoui J Szdbntn-taiu Mitamonphic Land-voon Vizdgzd y.iaczckanilquii Matzxiat icotazct name. to bt qivzn bef owl Mesozoic/Light pinkish grey to dark grey/medium to coarse-grained/megacrystic/ Fresh to plightly Decomposed/No fissi'.ity. Variable texture and grain size, contains over 10% of dark ferromagnesian minerals. Compiled by T.Y. Irfan CADAM - CLASSIFICATION and DESCRIPTION of ACCRECATE.MATERIAL LOCATION AW PETAUS OuaAALj/P.lt adfazu.ypok Tung Wan. Island OptACLtoi : Sample. : Ttjpz Blocks 50 leg b. crushed Section Gtid tempting Vtutz Rcc'rf Sampting C EG042 PETROGRAPHIC EVALUATION O F A G G R E G A T E S SAMPLE REF LOCATION/GRtt) REF SAMPLING DATE AGGREGATE PROPERTIES?artteto$hap«{BS 812:1975) Surface Texture (BS 812:1975) Coating CleanQrmss (Dust etc) /EGO 42 Pok Tung Wan Quarry, Lamma Island 1985 Angular to irregular Crystalline Clean SAMPLE &I2E/WEIGHT About 25 kg of bulk sample - processed to aggregate in laboratory (10-14 mm) GEOLOGICAL PROPERTIES Rock Type (GSS Classification) Mineralogy Major Constituents Minor Constituents Cementing Materials Expansive Minerals Weathering of Particles Drgank: Material Content Megacrystic fine- to medium-grained GRANITE (g w) Megacrysts of feldspars compose 20-30% of the rock Quartz (22 to 31%), Feldspars (65 to 67%), Siotit (2 to 20%) Magnetite, hornblende ( 28), sphere, sericite Generally fresh, some are slightly GENERAL COMMENTS ADDITIONAL INFORMATION InequiciranuJiar and variable fabric with fold«p«r megacrysts (up to 10 mm) set in a finer qraintd Biotite rich areas are dark qrey coloured And in composition Compiled by T\Y. Data fi.*).

165 Table 5 - Rock Index Properties of Granites from Pok Tung Wan Quarry, Lamina Island Rock Index Property Fine- Grained Granite EG040 Medium- Grained Granite EG041 Megacrystic Granite EG042 Mineral Grain Specific Gravity, Mg/m^ n.d. n.d. n.d. Bulk Density Dry Mg/nH Water Absorption Saturated 2.60 ( ) 2.61 ( ) 0.25 ( ) 2.62 ( ) 2.63 ( ) 0.19 ( ) 2.60 ( ) 2.61 ( ) 0.16 ( ) Porosity Sonic Velocity Total % Effective % m/s n.d ( ) 4605 ( ) n.d ( ) 5235 ( ) n.d ( ) 5020 ( ) Schmidt Hammer Value 1 60 (58-61) 57 (57-58) 59 (59-60) Point Load Strength 2 MPa Notes : 1 Determined on blocks 2 Determined on irregular lumps, average of tests ( ) Range of values Other index tests - average of 3 to 5 tests on cores.

166 Table 6 - A Comparison of Aggregate Test Results on Granites from Pok Tung Wan Quarry Other Granites and Acceptance Values Aggregate Property Aggregate Crushing Value, ACV % Aggregate Impact Value, AIV % Los Angeles Abrasion Value, % LAAV 10$ Fines Value kn Water Absorption % Fiaklness Index, Elongation Index, I F I E Fine- Medium- Grained Grained Megacrystic Granite Granite Granite * ** 33** n.d n.d * 17* 21* 38* 26* 145* Other Granites (FRTP) Acceptance Value Max 20 2 Max 30 1 Max 20^' 5 Max 30 2 Max 40 2 Max 45 1 Max 30 5 Max 35* Max 403 Max 35 1 Min 50 1 Min Min Max 3 1 Max 3 Max I^* 5 Max ' 5 Max 35 Max ' 5 Use C. Higginbottom (1976) C.R. Higginbottom (1976) C. C.R. C. C.R. C. C. C. R. C. c. c. C.R. C. C. c. C.R. C. Authority Fookes (1984) BS 882 (1983) ASTM C-131 BS 882 (1983) Notes : C, = Concrete R, = Roadstone n.d, = Not determined * = One test result, others average of two tests ** = On 5-10 mm aggregate, others on 10-1*1 mm aggregate FRTP = Fresh Rock Testing Programme (see references in this report for detailed results) 1. = General use 4. = Moderate exposure 2. = Wearing surfaces 5. = Severe exposure 3. = Protected concrete 6. = Heavy duty concrete Australian Standard (1985) Australian Standard (1985) Australian Standard (1985) Shergold (1948) BS 882 (1983) BS 882 (1983) BS 882 (1983) Higginbottom (1976) BS 5337 (1976) Fookes (1984) Fookes (1984) BS 882 (1983) Fookes (1984)

167 Table 7 - Test Results on Quarry Crushed Aggregate (20 mm Aggregate) from Pok Tung Wan Quarry, Aggregate Property- PW Central Laboratory Contractor's Laboratory^ Aggregate Crushing Value, ACV % n.d. 21 Aggregate Impact Value, AIV % 17 n.d. 10% Fines Value kn 215 ( ) 180 Water Absorption % 0.7 ( ) 0.7 Relative Density Mg/m ( ) 2.63 Flakiness Index, h % 11 (6-16) 15 Elongation Index, h % 30 (22-45) 19 Notes : n.d. not determined 1 6 series of tests, 1981 to Average of 2 series of tests carried out in 1986 ( ) Range of test values

168 LIST OF FIGURES Figure No. p age No, 1 Location Map Showing Geology of the Sampling 167 Site and the Adjacent Areas 2 Engineering Geological Map of the Pok Tung Wan 168 Quarry (from Choy & Irfan, 1986)

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171 LIST OF PLATES Plate Page No. * No. 1 Pok Tung Wan Quarry Hand Specimen of the Fine-Grained Granite Hand Specimen of the Medium-Grained Granite Hand Specimen of the Megacrystic Granite Core Specimens of the Fine-Grained, the 174 Medium-Grained and the Megacrystic Granites 6 photomicrograph of the Fine-Grained Granite Photomicrograph of the Medium-Grained Granite photomicrograph of the Megacrystic Granite 177

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181 SECTION 8 : AGGREGATE PROPERTIES OF VOLCANIC ROCK TYPES FROM 'SPUN' SITES AT MOUNT DAVIS AND CHAI WAN A. D. Burnett This report was originally produced as GCO Technical Note No. TN 5/89

182 FOREWORD In order to help provide the Materials Division and the Hong Kong Geological Survey of the Geotechnical Control Office with much needed data on the charterisation and possible usage of each of the Territory's major rock types the Office initiated the Fresh Rock Testing Programme in This report forms part of the Fresh Rock Testing Programme and is one of a series of reports which presents the results of selected aggregate and index laboratory testing carried out on fresh block samples of discrete rock types. The two sites selected for sampling on this occasion were from the 'SPUN' Project which is investigating the potential use of underground space in Hong Kong. These two potential cavern sites are both very likely to be within volcanic bedrock. The rock types involved and described in this report are fine and coarse ash crystal tuffs and eutaxites from the two 'SPUN 1 sites at Chai Wan and Mount Davis. The author wishes to acknowledge the role played in the field sampling and sample preparation by GE P.G.D. Whiteside and TO C,C. Mak, in the laboratory testing by GE T. Fung and in the report production by M.W. Yuen (STO/EG). The cooperation and assistance of the consultants for the f SPUN f Project, Ove Arup and Partners, is also acknowledged. (A.D. Burnett) Chief Geotechnical Engineer/Planning

183 CONTENTS Title Page 179 FOREWORD 180 CONTENTS INTRODUCTION SITE DESCRIPTION AND SAMPLING Chai Wan Mount Davis GEOLOGY Chai Wan *1 Site Geology 183 3«K2 Description of Bedrock Samples * 184 3*2 Mount Davis Site Geology Description of Bedrock Samples AGGREGATE TESTING AND CHARACTERIZATION Sample Preparation and Testing Methods Classification and Characterization of Aggregate Test Results Page No DISCUSSION ON TEST RESULTS " 5.1 Rock Index and Aggregate Properties 5.2 Suitability of Rocks as Aggregate * 5*3 Recommendations for Further Tests 6. CONCLUSIONS l Q 7. REFERENCES LIST OF TABLES 191 LIST OF FIGURES 205 LIST OF 'PLATES.. ' :.. ;.' 197

184 INTRODUCTION The Geotechnical Control Office initiated the Fresh Rock Testing programme (FRTP) in 1985 in order to produce reliable and much needed high Quality data on the index and aggregate characterisation properties and possible usage of each of the major rock types of the Territory. The Programme, which is ongoing, involves selecting and sampling sites containing typical and representative members of a particular individual or suite of rocktypes. The fresh (unweathered) block samples are then crushed to form aggregate or otherwise prepared for selected laboratory index and aggregate testing, A report is then prepared which presents the results and discusses them in relation to other rock types and typical aggregate acceptance standards. Most of the reports in this Programme have dealt with granites but with the increased usage of local and imported volcanic rocks as concrete aggregates in particular, it has become important to undertake studies of these rocks and their particular problems. Indeed the first report dealing with volcanic rocks has recently been produced in the Planning Division by S.T. Gilbert and T.Y. Irfan. This useful, discussive report is numbered SPR 6/89 and is entitled, "Suitability of Volcanic Rocks for Concrete Aggregates in Hong Kong." The current report is the second to cover volcanic rocks and the opportunity has been taken to link this FRTP work to a 'SPUN' Project requirement. The GCO 'SPUN 7 Project is aimed at investigating the potential use of underground space in Hong Kong where two of the potential project cavern sites are located in volcanic bedrocks The purpose of the current FRTP investigation is to assess whether the rock likely to be produced in cavern excavation would be suitable for processing and sale as aggregate. This report thus presents and discusses the results of selected physical index and aggregate testing on laboratory crushed fine ash and lapilli/coarse ash crystal TUFF samples from cavern sites at Chai Wan and Mount Davis. The results are compared with typical granite values and the suitability of the materials as aggregate is assessed in relation to normal acceptance values for various uses. 2. SITE DESCRIPTION AND SAMPLING 2.1 Chai Wan The sampling at the Chai Wan site took place on the 16th March 1989 and was carried out by staff from both GCO (Burnett and Whiteside) and Ove Arup and Partners (Fowler). The general location of the site near Chai Wan is shown in Figure 1 and the detailed positions of the alternative cavern sites and the actual sampling locations is given in Figure 2. It can be seen from the latter figure and Figure 3 that the possible SPUN underground facilities lie to the south of the new Siu Sai Wan construction platform deep in the hillside beneath Cape Collinson Road at a position midway between Pottinger Peak and Cape Collinson. As the proposed Government Supplies Store facility is likely to be

185 some 100 m underground, the surface outcrop sampling attempted to take into account the known local geological structure and single regional rocktype to obtain samples reasonably representative of the anticipated cavern materials* The general area was already covered by a spread of hand specimen sampling taken for the Hong Kong Geological Survey and which confirmed the presence of a single rocktype. Thus only three extra f SPUN f hand specimen samples were taken (SPUN 1,2,3) plus one bulk sample (SPUN 4) comprising about 40 kg of broken fresh lumps. Figure 2 shows the actual sampling locations and Plates 1 & 2 illustrate the site and the bulk sampling operations which comprised selecting large representative fresh boulders of blasted rock from the site formation works at a portal position and further breaking these by sledgehammer for bagging and labeling. 2.2 Mount Davis The sampling operations at the Mount Davis took place on two separate days, notably, the 16th March and the 6th April 1989 and again involved the same GCO and Ove Arup & partners staff as for the Chai Wan site sampling. Figures 1 and 4 show respectively the general and detailed locations of the sampling and the proposed underground facilities. The elevation of the facilities is planned to be between about +10 and +40 mpd and its position to lie immediately beneath Mount Davis Path between the coast line and Mount Davis. At the Mount Davis locality surface geological mapping by Strange (1986) had shown two volcanic rocktypes to be present in the area of the 'SPUN 1 proposed underground Refuse Transer and Sewage Treatment facilities. On the basis of the Hong Kong Geological Survey surface mapping and existing hand speciman samples it was desided that two bulk samples (SPUN 6 and 7) and four extra hand specimens (SPUN 5,8,9,10) were required and were subsequently taken. Each bulk sample again comprised about kg of sledgehammer broken fresh lumps of rock representative of the two major rocktypes on the site, namely eutaxite and coarse ash crystal tuff. Plate 3 shows the (SPUN 6 bulk sampling location on Victoria Road; Plate 4 shows the Mount Davis Reservior SPUN 7 bulk sample location. 3. GEOLOGY 3-1 Chai Wan, -. " " 3*1*1 Site Geology Description of the geology of the Chai Wan site falls into three categories, namely Lithology, Intrusive History and Structure. Lithologlcally the site comprises Upper Jurassic rocks of the Repulse Bay Volcanic Group which are dominated by tuffs. In this region of the Territory the Group has been divided into four formations, each of which displays specific distinctive characteristics to the skilled observer and which has allowed their recognition and identification in the field. The generalised sequences of the rocks comprising these formations is shown m Figure 6, (Strange & Shaw, 1986)- Essentially the formations comprise considerable thicknesses of structureless fine ash or coarse ash crystal tuff interspersed with minor, laterally impersisterit yet mappable, units of

186 eutaxite, tuff-breccia, siltstone and sandstone. The Shing Mun Formation within which the Chai Wan site falls is characteristically a rather variable formation and on the hill slope to the east of Siu Sai Wan bluish grey fine to coarse ash welded tuff with subhedral plagioclase crystals (1-2 mm) are noted to included dark grey lava lapilli. Southwards towards Cape Collinson Training Centre these very dark tuffs contain an increasing amount of subangular to angular black aphanitic lapilli up to 40mm in size. A strong feature-forming welded tuff (eutaxite) layer forms the approximately east-west trending Pottinger Peak ridge and many boulders of welded tuff and other impersistent layers of the same rocktype indicate that eutaxites should not be unexpected in the proposed underground excavation. There is no evidence of granite intrusion outcrop in the Siu Sai Wan/Pottinger Peak area and this fact together with a consideration of the general disposition of this particular volcanic roof pendant leads to the belief that even at the proposed +5 to +30mPD underground elevations of the works, granite will not be encountered. Structurally while no clear impression of the overall dip of the strata can be ascertained the Shing Mun Formation at this locality is heavily fractured by closely spaced joint sets and probably also faults. The local drainage pattern clearly depicts this structural geological control and illustrates the primary joint set directions of N~S, NW-SE and ESE-WNW Description of Bedrock Samples From an engineering geology viewpoint the main rock (JSM) at this location as represented by the bulk sample SPUN 4 may be described as an extremely strong dark grey crystalline fine- to very fine-grained TUFF occasionally displaying welding and or volcanic lithic lapilli Plate 5 shows a close-up of a typical hand specimen example of this material. The geological petrographic description of bulk sample SPUN 4 and as summarised in Table 5 is as follows : Hand Specimen - dark grey to black, slightly greenish and altered with abundant small (< 2 mm) feldspars and dark greenish grey rounded lithic fragments of < 20mm size. Thin Section - feldspars (< 4 mm), embayed quartz (< 2 mm)and mafic (< 1 mm) crystals set in an aphanitic groundmass. The quartz is often bipyramidal or shardic; a small patch comprising green-brown pleochroic hornblende with elongate crystals of size about 0.7mm exists in a groundmass showing snowflake (devitrified) features. Feldspars, microcline and microperthite are present as is chloritized biotite and zoned oligoclase. Final Identification - crystal coarse ash bearing, vitric TUFF,

187 Mount Davis Site Geology The Mount Davis underground facility site is likely to be more complex than that at Chai Wan because two volcanic rocktypes are mapped at outcrop as stradding the site and in addition the proximity of granite outcrop indicates that it might also be encountered underground in the proposed excavations. Stratigraphically, as can be seen from Figures 4 and 6, the site lies largely within the Upper Jurassic Tai Mo Shan Formation of the Repulse Bay Volcanic Group of rocks. This comprises essentially a coarse ash crystal tuff of remarkably uniform and structureless appearance in outcrop apart from the interspersed occasional presence of dark angular lithic lapilli up to mm in size. Abundant quartz and some biotite crystals can be seen in hand specimen as illustrated in Plate 6. Epiclastic layers appear to be a common characteristic of the formation in this district (Strange & Shaw, 1986). These take the form of moderately steeply dipping sandstone lenses up to 25 m thick and extending laterally for 100 to 300 m. To the west of Victoria Road, the Tai Mo Shan (JTM) rocks in the vicinity of the site are overlain by a thick band of eutaxite (flow banded welded tuff) dipping some to the west. This rocktype is finergrained and more vitric in appearance as shown in Plate 7 and displays a parataxitic fabric and is also thermally metamorphosed due to the proximities of the granite. This eutaxite, although not totally representative of the classic Ap Lei Chau Formation eutaxites was sufficiently distinctive to also warrant being sampled in bulk for testing as the SPUN 6 sample* The likelyhood of encountering the top of the granite pluton in the proposed undergrained excavations cannot be discounted in this facility and should not be overlooked. The structural geology of the site is rather confusing and not easy to predict with any certainty. The schematic sections shown in Figure 5 probably represent a reasonable estimate of the local structure based on the dips of the main rocktypes as mapped (GCO 1986). 3*2.2 Description of Bedrock Samples The engineering geology description of the coarse ash crystal tuff (JTM) at this site and as represented by the SPUN 7 bulk sample is : extremely strong mid to greenish grey equigranular crystalline coarse ash to lapilli TUFF containing occasional well dispersed volcanic lithic lapilli, Plate 6 iullustrates this material in hand specimen. The SPUN 6 bulk sample represents a material which can be described as extremely strong light greenish grey slightly flow banded in places fine ash TUFF* Plate 7 shows a close-up view of a hand specimen of the SPUN b sample.,.. ' " ' ' - ' The petrographie descriptions of both these samples is summarized in Table 5" and a fuller description is.given below. '..

188 SPUN 6 Hand Specimen - Grey with white feldspars (< 3 mm), brown quartz (< 2 mm) and black mafic flakes (< 1 mm). The rock is dominated by crystals in a fine groundmass. Thin Section - Cloudy feldspars of < 3 mm size and quartz of < 4 mm size occur in a fine matrix. Most crystals are subhedral with much dark mineral. Pleochroic biotite flakes of < 1 mm size are noted as are perthitized potassium feldspar and zoned oligoclase. The matrix comprises recrystallised quartz 85%; most quartz shows signs of granulation but is still strained - indicating thermal metamorphism. Final Identification - Thermally metamorphosed ash crystal TUFF. SPUN 7 Hand Specimen - Light grey, speckled white and black, with white feldspars (< 3 mm), thin mafic flakes (< 2 mm) and dominated by crystals. Thin Section - Quartz (< 3 mm), feldspars (< 3 nun) and mafic minerals (about 0.5 mm) in a finely crystalline groundraass. The quartz is subhedral and/or bipyramidal, embayed and shardic. The feldspar is subhedral and cloudy but the plagioclase is zoned and fresh. Zoned serizitised microcline and mircoperthite is present. Muscovite and small pleochroic biotite flakes are present. All are dominated by a fine (about 0.05 mm) crystal groundmass. Final Identification - Ash crystal TUFF * AGGREGATE TESTING AND CHARACTERIZATION 4.1 Sample Preparation and Testing Methods All ten samples taken in this study i.e. both hand specimens and the bulk samples, were given T SPUN f numbers in the field and these temporary numbers were then converted to f HK f numbers for permanent registration and curation in the Hong Kong Rock Collection of the Hong Kong Geological Survey. Nine of the ten samples were submitted for thin sectioning; only SPUN 9 (HK 8510) was not as it was slightly to moderately weathered and hence not representative of the fresh rock anticipated in the proposed underground excavations. All ten hand specimens and the nine thin sections together with the photomicrographs (In plane, crossed polarised, and 1/4 Lambda wavelength light) of the sections are available for inspection and reference in the Hong Kong Geological Survey* The three field collected bulk samples, each comprising about kg of bagged, broken fresh lumps, were converted into aggregate by processing through a small laboratory/field jaw crusher and hand sieving* Plate 11 shows these operations by which standard mm, and mm size aggregates were prepared in preparation for testing.

189 The rock index tests undertaken on each of the three bulk samples (14-10 ram size) included bulk density, grain specific gravity (< 150 mm), water absorption, effective porosity and total porosity. The aggregate physical tests undertaken included aggregate crushing value (ACV), aggregate impact value (AIV), ten per cent fines value, Los Angeles abrasion value (LAAV), flakiness index (I F ), and elongation index (I E ). All the above tests were performed in the North Point Public Works Laboratory of the GCO to full British Standards Institution (BSD(1975) and American Society for Testing Materials (ASTM)(198D standards. In order to make a preliminary assessment of the potential alkali reactivity of the aggregate, Test C289 of ASTM (1981) was also carried out in triplicate on 10 mm aggregate from each bulk sample. 4.2 Classification and Charaterization of Aggregates The CADAM Scheme, as recommended by the Geological Society Working Party on Aggregates (Collis & Fox, 1985), is used to describe and classify the aggregates. In addition, a more detailed petrographic evaluation of the aggregates produced from three bulk samples has also been made. The results of these classification techniques are presented in Tables 1 to Test Results The results of the rock index and aggregate laboratory testing on the aggregates produced from the three representative SPUN bulk samples are summarised in Table 5 which also shows the results of a typical Hong Kong granite and the British Standard and other concrete acceptance values for comparison* 5. DISCUSSION OF TEST RESULTS 5*1 Rock Index and Aggregate Properties Table 4 shows that the grain specific gravities of all three SPUN samples volcanic rocktypes is consistant and dense and averages about 2.70 with a range 2.69 to 2,71 v The oven-dried density of these tuffs averages 2.65 and varies between 2*63 and 2.65 g/cc. These values are notically up on equivalent values for granites which tend to average 2.60 g/cc. The considerable strength and density of the tuffs lead to very low and uniform water absorption and effective porosity values of 0A% and 1.irrespectively. While these values are possibly only marginally better than equivalent fresh granite values they are very well within the 3% maximum usually specified for concrete aggregate. As far as the flakiness and elongation indices are concerned the normally required acceptance criteria are 35 and 30$ maximum respectively. The average values for the three tuff samples of about 19 and 24 for flaklneas and elongation respectively are thus well within the usually specified values, even bearing in mind the fact that the samples were "artificially*' produced using a small field/laboratory jaw crusher - the type of which are thought to increase flakiness/elongation in comparison to : competent full scale quarry crushing.. ' *

190 Each of the mechanical test properties of the SPUN volcanic aggregates are consistantly and tightly grouped, better than the normal granite spread of values and well within the general purpose concrete specification and even the heavy duty/wearing surface concrete acceptance criteria as shown in Table 5. These favourable mechanical test results as defined by the aggregate crushing, impact, 10% fines value and Los Angeles abrasion values are not unexpected bearing in mind the high strengths determined by Irfan (1985) for the entire volcanic group of rocks, Irfan reported, after a reasonably comprehensive point load testing programme, that for fresh, mainly pyroclastic, volcanic rocks an average (from 154 tests) point load strength of 10.2 mpa with a standard deviation of 2,6 mpa resulted. It is clearly concluded that the volcanic tuffs are distinctly mechanically superior to their typical granite equvalents and equally clearly will provide very suitable concrete (and other) aggregates from the mechanical property viewpoint. No polished stone value tests were undertaken on the three SPUN samples in this study but other sources (Gilbert & Irfan, 1989) indicate that volcanic rocks are slightly superior to Hong Kong granites in this respect. This data source also indicates that local volcanic rocks are also far more resistant, i.e. sound to chemical attack weathering than local granites and fall very well within the usual MgSOij and NaSOjj soundness criteria. The durability of the volcanic tuffs thus appears to be very favourable based on the results of the present and other laboratory tests undertaken to date. Despite the fact that no clearly deleterious mineral phases or minerals appear to be present in the three SPUN tuffs tested it is well known that some doubt hangs over these volcanic rock types for reasons of their potential alkali-aggregate reactivity. For this reason the American Society of Testing Materials Potential reactivity of aggregate (Chemical Method) Test C289 was called for and undertaken. Table 4 presents the results of this indicative chemical test which are also plotted on the usual dissolved silica (Sc) versus reduction xtx alkalinity (Re) graph in Figure 7. The three SPUN sample results plot on the "innocuous aggregate" side of the graph and thus provide an initial indication that the aggregates are not deleterious. The few previous volcanic rock test results all plot in the same general vicinity of the graph, thus apparently showing a considerable degree of consistancy throughout the volcanic suite of rocks. ^ 2 Suitability of Rocks as Aggregate The test results and petrographic examinations described above tend to indicate that the rock types sampled as being representative of the materials likely to be excavated in the 'SPUN 1 sites should be satisfactory as normal or even special purpose concrete aggregates. The physical and mechanical tests are clearly very satisfactory with only a slight query hanging over the brittleness and hence crushed rock particle shape of any future aggregate. The soundness (to salt attack) of the materials is also very good.

191 Regarding the alkali silica reactivity potential of the rock types tested, while the ASTM C289 quick chemical test results were encouraging it is known that no single test taken in isolation is foolproof or a substitute for long term servicibility experience. These tuff rocks are also known to contain (or certainly originally contained) the potentially deleterious substances of volcanic glass, crypto- to microcr ys talline silica and strained quartz While most of the former glass and silica appear to have devitrified this is interpreted by difficult and imperfect observational methods only (petrographic examination) and hence some doubts must remain, however slight, regarding the aggregate suitability. Reference is made for a relevent and fuller discussion on alkali reactivity to the Gilbert and Irfan (1989) report. 5.3 Recommendations for Further Tests In the light of the importance of the use of volcanic rock aggregates in general and from these samples/sites in particular, it is suggested that it would be worthwhile for parties interested in the use of these materials to arrange for the remaining, and thus far untried, long term mortar bar tests (ASTM C227) to be undertaken on these three SPUN samples. Confirmatory expert petrographic examination, as far as this pertains to appraisal of aggregate suitability, would also be prudent. 6. CONCLUSIONS The three SPUN tuff rock types sampled and relatively thoroughly tested have given everjr indication thus far of producing a perfectly suitable aggregate for concrete purposes. Confirmatory and additional testing and evaluation, in the form of mortar bar testa and expert aggregate petrographic examination, should provide the necessary confidence for full-scale use of these materials, whereafter long term, in-service monitoring will provide the final conclusive proof of the materials suitability. 7. REFERENCES American Society for Testing Materials (1981). Test for resistance to abrasion of small size coarse aggregate by use of the Los Angeles machine. Test Designation C American Society for Testing Materials, British Standards Institution (1983). British Standard Specification for Aggregates from,natural Sources for Concrete (BS 882 : 1983)*British Standards Institution, London, 7 p. British Standards Institution (1975). Methods for Sampling and Testing of Mineral Aggregates, Sands and Fillers (BS 812 : parts 1 to 3). British' Standards Institution, '. Collie, U & Pox, R.A.- (1985). Aggregates : Sand, Gravel and Crushed Rock Aggregates for Construction Purposes. Geological Society Engineering Geology "Special Publication No, 1. The Geological. Society, London, 200 p.

192 Fookes, P.G. (1984). An introduction to concrete in the Far East - Part 2. Concrete, July Edition, pp Geotechnical Control Office (1986) Hong Kong and Kowloon, Solid and Superficial Geology (1 : mapfl Hong Kong Geological Survey Map Series HGM 20, Sheet 11, Geotechnical Control Office, Hong Kong, 1 map. Higginbottom, I.E. (1976). Section General requirements for rocks and aggregates. In Applied Geology for Engineer, H.M.S.O., 378 p. Hindley, T. (1984). Quarrying in Hong Kong. Hong Kong Contractor. October Edition, pp International Society for Rock Mechanics (1978). Rock Characterization Testing and Monitoring. ISRM Suggested methods (led. E.T. Brown). Commission on Testing Methods, International Society for Rock Mechanics, Pergamon Press, 211 p. Irfan, T.Y. (1985). Point Load Strength of Common Hong Kong Rocks. GCO Report No. TN 1/85, 49 p. Shergold, F.A. (1948). A review of available information on the significance of roadstone tests. Road Research Technical Paper 10. DSIR, H.M.S.O., London. Standards Association of Australia (1985). Aggregates and Rock for Engineering Purposes. Part 1 - Concrete Aggregates (Australian, Standard ). Standards Association of Australia, 16 p. Strange, P.J. & Shaw, R. (1986). Geology of Hong Kong Island and Kowloon. Geotechnical Control Office, Hong Kong, 134 p. (Hong Kong Geological Survey Memoir No. 2). Property Services Agency (PSA)(1979), Standard Specification Clauses for Airfield Pavements and Works Part 3, Concrete Appendix 3A. Property Services Agency, Department of the Environment. Gilbert, S.T. & Irfan, T.Y. (1989)* Suitability of Volcanic Rocks for Concrete Aggregates in Hong Kong. GCO Report No. SPR 6/89, 54 p.

193 LIST OF TABLES Table No. Page No. 1 Classification, Description and Petrographic 192 Evaluation of Aggregate Produced from the SPUN 4 Bulk Sample 2 Classification, Description and Petrographic 193 Evaluation of Aggregate Produced from the SPUN 6 Bulk Sample 3 Classification, Description and Petrographic 194 Evaluation of Aggregate Produced from the SPUN 7 Bulk Sample Aggregate 4 Petrographic Description of -Samples SPUN 4, 195 SPUN 6 and SPUN 7 5 Laboratory Test Results for the SPUN Bulk 196 Samples (Together with Typical Granite Results and Normal Concrete Acceptance Criteria for Comparison)

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197 Table 4 - Petrographic Description of Sample SPUN 4, SPUN 6 and SPUN 7 SPECIMEN NUMBER Thin Section Photomicrograph Modal Analysis Silicate Analysis Partial Analysis Normative Analysis Palaeontology FINAL IDENTIFICATION Vitric Tuff GEOLOGIST'SLOCALITYREF. Crystal Coarse Ash-bearing DATE S j P/L j D,f4 j Chai Wan, HK 1 [1 I 6l 0J3 8Ti 1: HKGRIDEAST NORTH AERIALPHOTO YEAR 11 4 j 3j 9 Qj Ol I 1J3 JS J3JO I [ FIELD NAME ROCK UNIT FIELDOCCURRENCE: Blast boulders from cut slope formation works. Bulk sample also taken for SPUN project. HANDSPECIMEN: Dark grey - black; slightly greenish altered, white fd<2 mm, abundant; rounded lithic< 20 mm, dark greenish grey; PETROGRAPHIC DESCRIPTION St«back for details Feldspar < 4 mm; embayed quartz K 2 mm; maficrsi mm; set in aphanitiz groundmass; qz bipyramidal or shardic; small patch comprising green-brown pleochroic hornblende; elongate crystals <v 0,7 mm; some snowflake texture; feldspar microcline microperthxte; chloritized biotite; zoned oligoclase GEOLOGICAL SURVEY 48 JSM SPECIMEN NUMBER Thin Section Photomicrograph Modal Analysis Silicate Analysis Partial Analysts Normative Analysis Palaeontology FINAL Thermally Metamorphosed IDENTIFICATION Ash Crystal Tuff GEOLOGIST'S LOCALITY REF. DATE Lj C/6 [Victoria Road, HK _J M 16 O [3T 9 1: HK GRID EAST NORTH - AERIALPHOTO YEAR 11 1 SW 1 3»OJ1 j6 jo] [I j 5j 2J3J0] [_ FIELD NAME ROCK UNIT me tamorphos ed entaxite FIELDOCCURRENCE: Rock,,,jn road cutting, east; side of Victoria Road. Bulk sample also taken for SPUN project HAND SPECIMEN: Grey? white fd < 3 mm; brown qz < 2 mm; mafic black, "^ 1 mm; dominated by crystals in fine ground JBflJ&SL PETROGRAPHIC DESCRIPTION Sea back for rf»t a ii«cloudy fd < 3 mm; Qz < 4 mm; fine matrix; most crystals subhedral; much dark mineral; light-dark brown bi flakes < 1 mm; perthitiz K-fd; o^jgoc^ase; matrix recryst qz & bi mm; most fd cloudly; most qz showing signs of granulation; but still..strained; thermal metamorphism? greizenization GEOLOGICALSURVEY 48 SPECIMEN NUMBER Thin Section Photomicrograph Modal Analysts Silicate Analysts Partial Analysis Normative Analysis Palaeontology 8507 FINAL Ash Crystal Tuff IDENTIFICATION GEOLOGIST'SLOCALITY REF, DATE S jp/fc C/ 7 i I Mt. Davies, HK l2j6[0 3 1: HKGRIDEAST NORTH AERIALPHOTOYEAR iv pit] 1_31 o j e j o o 1 h j sj oj 5j o 19 FIELDNAME ROCKUNIT FIELDOCCURRENCE* Rock cutting forming part of west end of Mt. Paving Reservoir. Bulk sample also taken to SPUN project. HAND SPECIMEN: Light grey, speckled white and black; white fd '< 3 mmy thin mafic flakes < 2 mm; greenish fd < 3 mm; damiaat<fcd by, r crystals PETROGRAPHIC DESCRIPTION Sit back lor < «... < _ 3 _ td < 3 **' - nz 0 5 mmi finely crystalline groundmass; some muscovxte qz embayed or shardic; fd subhedral, fresh; y.oned serizitized microcline ~ ' 7 : zz r^ ~_^-, T. muscovite 6 pieochroic bi flakes, small, domi rpundma mm; some opaque 005 GEOIOGICAL e opasurvey JTM

198 196 Table 5 - Laboratory Test Results for SPUN Bulk Samples (Together With Typical Granite Results and Normal Concrete Acceptance Criteria for Comparison) Aggregate property Chai SPUN Volcanic Rocks Mount SPUN 6 (Victoria Rd Site) Wan 4 Davis SPUN 7 (Reservoir Site) Typical Granite" (FRTP) Acceptance Criteria for Concrete Reference Mechanical Properties Aggregate Crushing Value (ACV) % Max Max 20 Higginbottom (1976) Aggregate Impact Value (AIV) % Max Max Max 25 C OQC jjcd BS : 88 2 (1983) Los Angeles Abrasion Value (LAAV) % Max Max Max Max 40 c 30f 25S 35 d ASTM C131 A u s t ralian Standard (1985) Shergold (1948) 10$ Fines Value kn Min Min Min 100 c 150 e 50 d BS 882 (1983) Polished Stone Value (PSV) Q b - - Physical Properties Water Absorption * Max 3 Higginbottom (1976) BS5337 : 1976 Effective Porosity * Flakiness Index (Ip) % Max 35 BS882 (1983) Elongation Index (Ig) % Max 30 Fookes (1984) Density (Oven dried) g/cc Grain Specific Gravity Chemical properties Soundness with MgSOj, G-I5 b Max Max I8 h PSA (1979) ASTM C33 % loss (5 cycles) with NaSOj, ** Max Max Max Max 12 io* 6^ ASTN C33 Australian Standard (1985) Reactivity Aggregate Reactivity (AAR) m (millinoles/litre) Dissolved Silica S c ,3 * - ( Seo Figure 7 ASTM C 289 Reduction in Alkalinity R c ( See Figure 7 Note : a. Tests carried out by PWDTL. b. Results from Hindley (1984) c. Wearing surfaces, d. General purpose ooncrete. e. Heavy duty ooncrete. f. Protected ooncrete. g. Moderate exposure. h. Airfield pavements. (Coarse and fine aggregate). 1, Vim aggregates, j. Coarse aggregatea. k* Severe exposure, ttu Triplicate analyses n, 3«Gilbert & Irfan (1989)

199 LIST OF FIGURES Figure ' Page No. No. 1 General Location and Geology Map Geology and Sample Location Plan Proposed Chai Wan Underground Facilities 3 Cross-sections - Proposed Chai Wan Underground 200 Facilities 4 Geology and Sample Location Plan - Proposed 201 Mount Davis Underground Facilities 5 Cross-sections - Proposed Mount Davis 202 Underground Facilities 6 Generalized Sequences of Repulse Bay Volcanic 203 Group Rocks 7 Potential Reactivity of the SPUN Sample 204 Aggregates by the ASTM C28 Chemical Method

200 Granitic rocks Volcanic / granite contact* SPUN Sampio Site Figure 1 - General Location and Geology Map (After Strange 4 Shaw, 1986)

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207 LIST OF PLATES Plate No. Page No. 1 General View of SPUN 4 Bulk Sample Location 206 at the Chai Wan Site 2 Sampling Operations for the SPUN 4 Bulk Sample; 206 Chai Wan Site 3 General View of the SPUN 6 Bulk Sample Location 207 on Victoria Road, Mount Davis 4 General View of the SPUN 7 Bulk Sample Location 207 at Mount Davis Reservoir 5 Production of Aggregate for Testing by Field 208 Crushing and Hand Sieving 6 Close-up of SPUN 4 Bulk Sample Fine Ash Tuff 208 Lithology (HK 8504) 7 Close-up of SPUN 7 Bulk Sample Coarse Ash 209 Tuff Lithology (HK 8507) 8 Close-up of SPUN 6 Bulk Sample Fine Ash/Eutaxite 209 Tuff Lithology (HK 8506) 9 Photomicrographs of SPUN 4 Lithology.- Fine 210 Ash Tuff (HK 8504) 10 Photomicrographs of SPUN 4 Lithology - Fine 211 Ash Tuff (HK 8507) 11 Photomicrographs of SPUN 4 Lithology - Fine 212 Ash Tuff/Eutaxite (HK 8506)

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215 GEOTECHNICAL ENGINEERING OFFICE PUBLICATIONS Geotechnical Manual for Slopes, 2nd edition (1984), 306 p. (Reprinted, 1994). Guide to Retaining Wall Design, 2nd edition (1993), 268 p. (Reprinted, 1994). Guide to Site Investigation (1987), 368 p. (Reprinted 1993). Guide to Rock and Soil Descriptions (1988), 195 p. (Reprinted, 1994). Guide to Cavern Engineering (1992), 159 p. (Reprinted, 1994). Model Specification for Prestressed Ground Anchors, 2nd edition (1989), 168 p. Model Specification for Reinforced Fill Structures (1989), 140 p. Mid-levels Study : Report on Geology, Hydrology and Soil Properties (1982), 265 p. plus 54 drgs. Prediction of Soil Suction for Slopes in Hong Kong, by M.G. Anderson (1984), 243 p. (Superseded by GCO Publication No. 1/85) (Superseded by Geospec 1) Review of Superficial Deposits and Weathering in Hong Kong, by J.D. Bennett (1984), 58 p. (Reprinted, 1993). Review of Hong Kong Stratigraphy, by J.D. Bennett (1984), 86 p. Review of Tectonic History, Structure and Metamorphism of Hong Kong, by J.D. Bennett (1984), 63 p. (Superseded by GCO Publication No. 1/88) Groundwater Lowering by Horizontal Drains, by D.J. Craig & I. Gray (1985), 123 p. (Reprinted, 1990). Geoguide 1 Geoguide 2 Geoguide 3 Geoguide 4 Geospec 1 Geospec 2 - GCO Publication No. 1/84 GCO Publication No. 2/84 GCO Publication No. 3/84 GCO Publication No. 4/84 GCO Publication No. 5/84 GCO Publication No. 6/84 GCO Publication No. 1/85 GCO Publication No. 2/85 HK$74 (US$21.5) HK$48 (US$16.5) HK$83 (US$28) HK$58 (US$18) HK$36 (US$13.5) HK$25 (US$5.5) HK$25 (US$5.5) HK$200 (US$34) HK$50 (US$9) HK$40 (US$8) HK$25 (US$5.5) HK$20 (US$5) HK$74 (US$12)

216 (Superseded by GEO Report No. 9) Review of Design Methods for Excavations (1990), 193 p. (Reprinted, 1991). Foundation Properties of Marble and Other Rocks in the Yuen Long - Tuen Mun Area (1990), 117 p. Review of Earthquake Data for the Hong Kong Region (1991), 115 p. Review of Granular and Geotextile Filters (1993), 141 p. Report on the Kwun Lung Lau Landslide of 23 July 1994, 2 Volumes, 400 p. (Also available in Chinese) (Hong Kong) Rainfall and Landslides in 1984, by J. Premchitt (1991), 91 p. plus 1 drg. (Reprinted, 1995). (Hong Kong) Rainfall and Landslides in 1985, by J. Premchitt (1991), 108 p. plus 1 drg. (Reprinted, 1995). (Hong Kong) Rainfall and Landslides in 1986, by J. Premchitt (1991), 113 p. plus 1 drg. (Reprinted, 1995). Hong Kong Rainfall and Landslides in 1987, by J. Premchitt (1991), 101 p. plus 1 drg. (Reprinted, 1995). Hong Kong Rainfall and Landslides in 1988, by J. Premchitt (1991), 64 p. plus 1 drg. (Reprinted, 1995). Hong Kong Rainfall and Landslides in 1989, by K.L. Siu (1991), 114 p. plus 1 drg. (Reprinted, 1995). Aggregate Properties of Some Hong Kong Rocks, by T. Y. Man, A. Cipullo, A.D. Burnett & J.M. Nash (1992), 212 p. (Reprinted, 1995). Foundation Design of Caissons on Granitic and Volcanic Rocks, by T.Y. Man & G.E. Powell (1991), 85 p (Reprinted, 1995). Bibliography on the Geology and Geotechnical Engineering of Hong Kong to December 1991, by E.W. Brand (1992), 186 p. (Superseded by GEO Report No.39) Bibliography on Settlements Caused by Tunnelling by E.W. Brand (1992), 50 p. (Reprinted, 1995). GCO Publication No. 1/88 GCO Publication No. 1/90 GCO Publication No. 2/90 GCO Publication No. 1/91 GEO Publication No. 1/93 GEO Report No. 1 GEO Report No. 2 GEO Report No. 3 GEO Report No. 4 GEO Report No. 5 GEO Report No. 6 GEO Report No. 7 GEO Report No. 8 GEO Report No. 9 GEO Report No. 10 HK$40 (US$12) HK$58 (US$10) HK$42 (US$11.5) HK$32 (US$19) Free HK$118 (US$17.5) HK$126 (US$20) HK$126 (US$20) HK$122 (US$19.5) HK$106 (US$16) HK$126 (US$20) HK$120 (US$19.5) HK$62 (US$10.5) HK$48 (US$8.5)

217 Direct Shear Testing of a Hong Kong Soil under Various GEO Report Applied Matric Suctions, by J.K. Gan & D.G. Fredlund No. 11 (1992), 241 p. (Reprinted, 1995). Rainstorm Runoff on Slopes, by J. Premchitt, T.S.K. GEO Report Lam, J.M. Shen and H.F. Lam (1992), 211 p. (Reprinted, No ). HK$136 (US$21.5) HK$121 (US$19.5) Mineralogical Assessment of Creep-type Instability at Two Landslip Sites, by T.Y. Man (1992), 136 p. (Reprinted, 1995). Hong Kong Rainfall and Landslides in 1990, by K.Y. Tang (1992), 78 p. plus 1 drg. (Reprinted, 1995). Assessment of Stability of Slopes Subjected to Blasting Vibration, by H.N. Wong & P.L.R. Pang (1992), 112 p. (Reprinted, 1995). Earthquake Resistance of Buildings and Marine Reclamation Fills in Hong Kong, by W.K. Pun (1992), 48 p. (Reprinted, 1995). Review of Dredging Practice in the Netherlands, by S.T. Gilbert & P.W. To (1992), 112 p. (Reprinted, 1995). Backfilled Mud Anchor Trials Feasibility Study, by C.K. Wong & C.B.B. Thorley (1992), 55 p. (Reprinted, 1995). A Review of the Phenomenon of Stress Rupture in HDPE Geogrids, by G.D. Small & J.H. Greenwood (1993), 68 p. (Reprinted, 1995). Hong Kong Rainfall and Landslides in 1991, by N.C. Evans (1992), 76 p. plus 1 drg. (Reprinted, 1995). Horizontal Subgrade Reaction for Cantilevered Retaining Wall Analysis, by W.K. Pun & P.L.R. Pang (1993), 41 p. (Reprinted, 1995). Report on the Rainstorm of 8 May 1992, by N.C. Evans (1993), 109 p. plus 2 drgs. (Reprinted, 1995). Effect of the Coarse Fractions on the Shear Strength of Colluvium, by T.Y. Man & K.Y. Tang (1993), 223 p. (Reprinted, 1995). The Use of PFA in Reclamation, by J. Premchitt & N.C. Evans (1993), 59 p. (Reprinted, 1995). GEO Report No. 13 GEO Report No. 14 GEO Report No. 15 GEO Report No. 16 GEO Report No. 17 GEO Report No. 18 GEO Report No. 19 GEO Report No. 20 GEO Report No. 21 GEO Report No. 22 GEO Report No. 23 GEO Report No. 24 HK$87 (US$15) HK$112 (US$17) HK$75 (US$12) HK$48 (US$8.5) HK$76 (US$12) HK$50 (US$9) HK$56 (US$9.5) HK$111 (US$16.5) HK$44 (US$8) HK$126 (US$20) HK$126 (US$20) HK$52 (US$9)

218 Report on the Rainstorm of May 1982, by M.C. Tang (1993), 129 p. plus 1 drg. (Reprinted, 1995). Report on the Rainstorm of August 1982, by R.R. Hudson (1993), 93 p. plus 1 drg. (Reprinted, 1995). Landslips Caused by the June 1983 Rainstorm, by E.B. Choot (1993), 124 p. (Reprinted, 1995). Factors Affecting Sinkhole Formation, by Y.C. Chan (1994), 37 p. (Reprinted, 1995). Classification and Zoning of Marble Sites, by Y.C. Chan (1994), 37 p. (Reprinted, 1995). Hong Kong Seawall Design Study, by P.M. Aas & A. Engen (1993), 94 p. (Reprinted, 1995). Study of Old Masonry Retaining Walls in Hong Kong, by Y.C. Chan (1995), under preparation. Karst Morphology for Foundation Design, by Y.C. Chan & W.K. Pun (1994), 90 p. plus 1 drg. (Reprinted, 1995). An Evaluation of the Suitability of Decomposed Granite as Foundation Backfill for Gravity Seawalls in Hong Kong, by E.B. Choot (1993), 34 p. (Reprinted, 1995). A Partial Factor Method for Reinforced Fill Slope Design, by H.N. Wong (1993), 55 p. (Reprinted, 1995). Hong Kong Rainfall and Landslides in 1992, by P.K.H. Chen (1993), 201 p. plus 2 drgs. (Reprinted, 1995). Methods of Test for Soils in Hong Kong for Civil Engineering Purposes (Phase I Tests), by P.Y.M. Chen (1994), 91 p. Creep, Stress Rupture and Hydrolysis of Polyester Reinforced Geogrids, by J.H. Greenwood (1995), under preparation. Skin Friction on Piles at the New Public Works Central Laboratory, by J. Premchitt, I. Gray & K.K.S. Ho (1994), 158 p. (Reprinted, 1995). Bibliography on the Geology and Geotechnical Engineering of Hong Kong to May 1994, by E.W. Brand (1994), 202 p. (Reprinted, 1995). GEO Report No. 25 GEO Report No. 26 GEO Report No. 27 GEO Report No. 28 GEO Report No. 29 GEO Report No. 30 GEO Report No. 31 GEO Report No. 32 GEO Report No. 33 GEO Report No. 34 GEO Report No. 35 GEO Report No. 36 GEO Report No. 37 GEO Report No. 38 GEO Report No. 39 HK$135 (US$21) HK$118 (US$17.5) HK$83 (US$13) HK$40 (US$7.5) HK$40 (US$7.5) HK$68 (US$11) HK$118 (US$17.5) HK$38 (US$7) HK$50 (US$9) HK$167 (US$25.5) HK$97 (US$16.5) HK$118 (US$19)

219 Hydraulic Fill Performance in Hong Kong, by C.K. Shen & K.M. Lee (1995), under preparation. Mineralogy and Fabric Characterization and Classification of Weathered Granitic Rocks in Hong Kong, by T.Y. Man (1995), under preparation. Performance of Horizontal Drains in Hong Kong, by R.P. Martin, K.L. Siu & J. Premchitt (1995), under preparation. Hong Kong Rainfall and Landslides in 1993, by W.L. Chan (1995), under preparation. General Report on Landslips on 5 November 1993 at Man-made Features in Lantau, by H.N. Wong & K.K.S. Ho (1995), under preparation. Gravity Retaining Walls Subject to Seismic Loading, by Y.S. Au-Yeung & K.K.S. Ho (1995), under preparation. Direct Shear and Triaxial Testing of a Hong Kong Soil under Saturated and Unsaturated Conditions, by J.K.M. Gan & D,G. Fredlund (1995), under preparation. Stability of Submarine Slopes, by N.C. Evans (1995), under preparation. Strength Development of High PFA Content Concrete, by W.C Leung & WX. Tse (1995), under preparation. AAR Potential of Volcanic Rocks from Anderson Road Quarries, by W.C. Leung, W.L. Tse, C.S. Mok & S.T. Gilbert (1995), under preparation. GEO Report No. 40 GEO Report No. 41 GEO Report No. 42 GEO Report No. 43 GEO Report No. 44 GEO Report No. 45 GEO Report No. 46 GEO Report No. 47 GEO Report No. 48 GEO Report No Geotechnical Area Studies Programme - Hong Kong and Kowloon (1987), 170 p. plus 4 maps, Geotechnical Area Studies Programme - Central New Territories (1987), 165 p. plus 4 maps. Geotectmical Area Studies Programme - West New Territories (1987), 155 p. plus 4 maps.. Geotechnical Area Studies Programme - North West New Territories (1987), 120 p. plus 3 maps. Geotechnical Area Studies Programme - North New Territories (1988), 134 p. plus 3 maps. GASP I GASP II GASP III GASP IV GASP V HK$240 (US$40) HK$150 (US$25) HK$150 (US$25) HK$150 (US$25) HK$150 (US$25)

220 Geotechnical Area Studies Programme - North Lantau (1988), 124 p. plus 3 maps. Geotechnical Area Studies Programme - Clear Water Bay (1988), 144 p. plus 4 maps. Geotechnical Area Studies Programme - North East New Territories (1988), 144 p. plus 4 maps. Geotechnical Area Studies Programme - East New Territories (1988), 141 p, plus 4 maps. Geotechnical Area Studies Programme - Islands (1988), 142 p. plus 4 maps. Geotechnical Area Studies Programme - South Lantau (1988), 148 p. plus 4 maps. Geotechnical Area Studies Programme - Territory of Hong Kong (1989), 346 p. plus 14 maps. Geology of Sha Tin, by R. Addison (1986), 85 p. Geology of Hong Kong Island and Kowloon, by P.J. Strange & R. Shaw (1986), 134 p. Geology of the Western New Territories, by R.L. Langford, K.W. Lai, R.S. Arthurton& R. Shaw (1989), 140 p. Geology of Sai Kung and Clear Water Bay by P.J. Strange, R. Shaw & R. Addison (1990), 111 p. Geology of the North Eastern New Territories, under preparation. Geology of Lantau, under preparation. Geology of Yuen Long by D.V. Frost (1992), 69 p. Geology of Chek Lap Kok by R.L. Langford (1994), 61p. San Tin : Solid and Superficial Geology (1: map) (1989), 1 map. GASP VI GASP VII GASP VIII GASP IX GASPX GASP XI GASP XII Geological Memoir No. 1 Geological Memoir No. 2 Geological Memoir No. 3 Geological Memoir No. 4 Geological Memoir No. 5 Geological Memoir No. 6 Sheet Report No. 1 Sheet Report No. 2 Map HGM 20, Sheet 2 HK$150 (US$25) HK$150 (US$25) HK$150 (US$25) HK$150 (US$25) HK$150 (US$25) HK$150 (US$25) HK$150 (US$25) HK$50 (US$9) HK$78 (US$12.5) HK$97 (US$17) HK$87 (US$13) Free Free HK$45

221 Sheung Shui : Solid and Superficial Geology (1: map) (1992), 1 map. Kat O Chau : Solid and Superficial Geology (1: map) (1993), 1 map. Tsing Shan (Castle Peak) : Solid and Superficial Geology (1: map) (1988), 1 map. Yuen Long : Solid and Superficial Geology (1: map) (1988), 1 map. Sha Tin : Solid and Superficial Geology (1: map) (1986), 1 map. Sai Kung Peninsula : Solid and Superficial Geology (1: map) (1989), 1 map. Tung Chung : Solid and Superficial Geology (1: map) (1994), 1 map. Silver Mine Bay : Solid and Superficial Geology (1: map) (1992), 1 map. Hong Kong and Kowloon : Solid and Superficial Geology (1: map) (1986), 1 map. Clear Water Bay : Solid and Superficial Geology (1: map) (1989), 1 map. Shek Pik : Solid and Superficial Geology (1: map), under preparation. Cheung Chau : Solid and Superficial Geology (1: map), under preparation. Hong Kong South and Lamma Island : Solid and Superficial Geology (1: map) (1987), 1 map. Waglan Island : Solid and Superficial Geology (1: map) (1989), 1 map. San Tin : Solid Geology (1 : map) (1994), 1 map. Lo Wu : Superficial Geology (1:5 000 map) (1990), 1 map. Lo Wu : Solid Geology (1:5 000 map) (1990), 1 map. Map HGM 20, Sheet 3 Map HGM 20, Sheet 4 Map HGM 20, Sheet 5 Map HGM 20, Sheet 6 Map HGM 20, Sheet 7 Map HGM 20, Sheet 8 Map HGM 20, Sheet 9 Map HGM 20, Sheet 10 Map HGM 20, Sheet 11 Map HGM 20, Sheet 12 Map HGM 20, Sheet 13 Map HGM 20, Sheet 14 Map HGM 20, Sheet 15 Map HGM 20, Sheet 16 Map HGM20S MapHGP5A, Sheet 2-NE-D MapHGP5B, Sheet 2-NE-D HK$45 HK$45 HK$45 HK$45 HK$45 HK$45 HK$45 HK$45 *HK$45 HK$45 HK$45 HK$45 HK$45 HK$30 HK$30

222 Mai Po : Superficial Geology (1:5 000 map) (1990), Map HGP 5A, HK$30 1 map. Sheet 2-SE-A Mai Po : Solid Geology (1:5 000 map) (1990), 1 map. Map HGP 5B, HK$30 Sheet 2-SE-A Lok Ma Chau : Superficial Geology (1:5 000 map) Map HGP 5A, HK$30 (1990), 1 map. Sheet 2-SE-B Lok Ma Chau : Solid Geology (1:5 000 map) (1990), Map HGP 5B, HK$30 1 map. Sheet 2-SE-B Deep Bay : Superficial Geology (1:5 000 map) (1989), Map HGP 5A, HK$30 1 map. Sheet 2-SW-C Deep Bay : Solid Geology (1:5 000 map) (1989), 1 map. Map HGP 5B, HK$30 Sheet 2-SW-C Shan Pui : Superficial Geology (1:5 000 map) (1989), Map HGP 5A, HK$30 1 map. Sheet 2-SW-D Shan Pui : Solid Geology (1:5 000 map) (1989), 1 map. Map HGP 5B, HK$30 Sheet 2-SW-D Man Kam To : Superficial Geology (1:5 000 map) (1990), Map HGP 5A, HK$30 1 map. Sheet 3-NW-C Man Kam To : Solid Geology (1:5 000 map) (1990), Map HGP 5B, HK$30 1 map. Sheet 3-NW-C Tin Shui Wai: Superficial Geology (1:5 000 map) (1989), Map HGP 5A, HK$30 1 map. Sheet 6-NW-A Tin Shui Wai : Solid Geology (1:5 000 map) (1989), Map HGP 5B, HK$30 1 map. Sheet 6-NW-A Yuen Long.:'Superficial Geology (1:5 000 map) (1989), Map HGP 5A, HK$30 1 map. Sheet 6-NW-B Yuen Long : Solid Geology (1:5 000 map) (1989), 1 map. Map HGP 5B, HK$30 Sheet 6-NW-B Hung Shui Kiu : Superficial Geology (1:5 000 map) Map HGP 5A, HK$30 (1989), 1 map. Sheet 6-NW-C Hung Shui Kiu : Solid Geology (1:5 000 map) (1989), 1 Map HGP 5B, HK$30 ma P- Sheet 6-NW-C

223 Muk Kiu Tau : Superficial Geology (1:5 000 map) (1990), Map HGP 5A, HK$30 1 map. Sheet 6-NW-D Muk Kiu Tau : Solid Geology (1:5 000 map) (1990), Map HGP 5B, HK$30 1 map. Sheet 6-NW-D Chek Lap Kok : Solid and Superficial Geology (1:5 000 Map HGP 5, HK$30 map) (1993), 1 map. Sheet 9-NE-C/D Yam O Wan : Solid and Superficial Geology (1:5 000 Map HGP 5, HK$30 map) (1995), 1 map. Sheet 10-NW-B Siu Ho : Solid and Superficial Geology (1:5 000 map) Map HGP 5, HK$30 (1994), 1 map. Sheet 10-NW-C Ma Wan : Solid and Superficial Geology (1:5 000 map) Map HGP 5, HK$30 (1994), 1 map. Sheet 10-NE-A Tsing Yi : Solid & Superfical Geology (1:5 000 map) Map HGP 5, HK$30 (1995), 1 map. Sheet 10-NE-B/D Pa Tau Kwu : Solid and Superficial Geology (1:5 000 Map HGP 5, HK$30 map) (1994), 1 map. Sheet 10-NE-C ORDERING INFORMATION IS GIVEN ON THE NEXT PAGE

224 Copies of GEO publications (except Sheet Reports, 1:5 000 maps and other reports which are free of charge) may be ordered by writing to : Publications (Sales) Office, Information Services Department, 28th Floor, Siu On Centre, 188 Lockhart Road, Wan Chai, Hong Kong. The Information Services Department will issue an invoice upon receipt of a written order. In Hong Kong, publications may be directly purchased from : Government Publications Centre, Ground Floor, Low Block, Queens way Government Offices, 66 Queens way, Hong Kong. Requests for copies of Geological Survey Sheet Reports and other reports which are free of charge should be directed to : Chief Geotechnical Engineer/Special Projects, Geotechnical Engineering Office, Civil Engineering Department, Civil Engineering Building, 101 Princess Margaret Road, Homantin, Kowloon, Hong Kong. 1:5 000 maps may be purchased from : Map Sales Centre, Survey & Mapping Office, Lands Department, 14th Floor, Murray Building, Garden Road, Hong Kong. All prices given in this List are for information only and may be changed without notice. The US$ prices shown are for overseas orders and are inclusive of surface postage to anywhere in the world. An additional bank charge of HK$50 or US$6.50 is required per cheque made in currencies other than Hong Kong dollars. Cheques, bank drafts or money orders must be made payable to HONG KONG GOVERNMENT.

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