International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol:12 No:6 13 The Effects of Water Contents on Free Swelling of Expansive Agus Tugas Sudjianto 1), M. Cakrawala 1) and Candra Aditya 1) 1) Civil Engineering Department, University of Widyagama Malang, East Java, Indonesia E-mail : ats_23@yahoo.com Abstract-- The expansive soil will be swelling upon wetting and shrinnking to drying. This behavior can damage of construction structures, particularly, light buildings and roads. The phenomenom is very interesting to be researched, how far the effect of water contents is towards the behavior of free swelling of expansive soil. The material of expansive soil are selected from Karang Ngawi region East Java Province. The expansive soils result in a variation of plasticity index and activity in the soil from Karang (Ngawi) mixed with Nabentonite. The research on free swelling is done by being remolded with diameter 6.35 cm and 1.7 cm, with initial water content of 32% and dry density of 1.26 g/cm 3. An electronic digital caliper is used to measure free swelling. Results of the research indicate that the water contents have a linear relation with free swelling. Index Term-- The expansive soil, Na-bentonite, water content, free swelling. I. INTRODUCTION An expansive clay is one type of fine-grained soil that is formed from expansive minerals with the size of colloidal. In general, expansive clay minerals are formed from montmorilonite, illite, kaolinite, halloysite, chlorite, vermiculite, and attapulgite [1]. Expansive clays have properties which are typical of the expansive mineral content with a ion exchange capacity, resulting in expansive clays having a shrinkage potential development, if there is a change in water content. If the water content increases, expansive soil will swell accompanied by an increase in pore water pressure and the incidence and development pressures. When the water content is reduced to the extent, a shrinkage will occur. The nature and development of such shrinkage can cause damage to the buildings [2]. It is stated [3]that the order of sensitivity to development is the shrinkage of the expansive mineral montmorillonite having the est level of development, and these minerals are divided into Na-montmorillonite and Ca - montmorillonite. Expansive clay soil can be found in many places in the world [1], namely Argentina, Saudi Arabia, South Africa, the United States, Australia, Canada, China, Ethiopia, Ghana, India, Indonesia, Iran, Israel, Kenya, Mexico, Morocco, Myanmar, Jordan, Sudan, Ethiopia, Spain, Turkey and Venezuela.. The phenomenon of swelling - shrinkage can cause damage to the building. It is resported [4] that in the United States, losses caused by expansive soil problem turned out exceeding other natural disasters, including losses caused by earthquakes and tornadoes. According to data from the Federal Emergency Agency (FEMA) in 1982, losses due to expansive soil in 197 reached $ 798,1, [5]. Every year building damage, the structure of buildings and roads caused by expansive soils are predicted approximately $ 15,, in the UK, approximately $ 1,, in the USA, and even billions of dollars around the world [6]. In Indonesia, in terms of incidence of the soil, expansive clay problems are almost found all over Indonesia, from North Sumatra to Papua. Total losses have not been reported, but from research and surveys that have been made by the Highways and Road Development Research Center and Department of General Construction, a lot of damages that occur in several roads on the island of Java are caused by expansive clay soil problems [7]. Some researches show that the consistency of expansive clay soil is strongly influenced by soil water content. According to [8], plasticity index (PI) and liquid limit (LL) can be used to determine the swelling characteristics of expansive clays in general. Tthe only plasticity index (PI) alone can be used to estimate the swelling characteristics of expansive clays in general [9]. According [1], [1[, [11[ and [12], the er the plastic index (PI) in an expansive clay minerals is, the er the potential for development will be. Expansive soils in Indonesia make logical problems become more complex, because our country is located in the tropics, where wetting and drying cycles always happen due to the rainy and dry seasons. The result is that in areas where expansive soils become swelling - shrinkage is due to changes in water content and suction. Based on this phenomenon, this research is conducted separately to determine the severity of such influences as how far does the change in water content affect the behavior of free swelling of expansive soil. II. EXPERIMENTAL PROGRAM A. Material and Sample Preparation The soil samples for this study were brought from Karang, Ngawi region, East Java Province, of which its map is shown in Fig. 1. The region experiences some of the largest diferential ground movement in East Java. Samples were obtained from a test pit with a depth of two meters. The pit was
International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol:12 No:6 14 escavated in ± 1 ms from the shoulder of the road. Undisturbed samples were taken using a sample tube with a length dimension of cms and a diameter of 7 cms. Undisturbed samples will be kept to water content change and vibration, as well as clean from the roots of plants. The expansive formation at the site is a grey-green to yellowish weathered clayey shale. In this study to vary the plasticity index and activity, then Karang soil was mixed with Nabentonite. Mixing methods as practiced by [9] is a composition of 1% to % of the dry weight of expansive soil, respectively. Examples of Na-bentonite ares used presented in Fig. 2. Na-bentonite were bought in a chemical shop in Surabaya city (East Java). mixture are made in 3 variations, the composition of the mixture are shown in Table I. The test method according ASTM D4546-96 [13] with a method based on [9]. Dimension of soil samples with a diameter of 6.35 Cms and of 1.7 Cms, with initial water content of 32 % and dry density of 1.26 g/cm 3, as based on the standard Proctor test. The samples of free swelling test are shown in fig. 4. Fig. 3. Electronic digital caliper. Fig Fig. 1. The map Karang, region Ngawi, East Java. Fig. 4. The samples free swelling test.. To calculate vertical and horizontal swelling from Electronic digital caliper, formula 1 and 2 are used. For the calculation of volumetric swelling by using formula 3. Sz Sx Sv final final diameter final volume initial H 1% 1% H initial initial diameter D 1% 1% D initial diameter initial volume V 1% 1% V initial volume (1) (2) (3) Fig 2. The samples Na-Bentonite. T ABLE I COMPOSITION OF MIXED SOIL MATERIAL Expansive soil Karang Clay 1. 61.6 54.27 47.49 Na-bentonite. 6.78 13.57 2.35 B. Test Procedure of Free Swelling Test In this study, to measure the free swelling deformation, anelectronic digital caliper was employed. The electronic digital caliper is shown in Fig 3. IV. RESULTS AND DISCUSSION A. Properties Test properties of clay Karang (Ngawi) and mix of soil are intended to obtain information about swelling potential from soil properties, especially soil consistency limits, chemical and mineral compositions of soil. When observed visually, the clay sample has a grayish black color. The results of properties, chemical and mineral compositions of clay expansive of Karang, Ngawi (East Java) and mix of soil are shown from Table II to Table IV and Fig. 5 shows the results of X-ray difraction.
Dry Density, γd (g/cm3) International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol:12 No:6 15 T ABLE II GENERAL SOIL PROPERTIES KARANG JATI (NGAWI) AND MIX OF SOIL PROPERTY Karang Water Content, w c (%) 63.59 54.8 5.81 46.77 Unit weight, γ (t/m 3 ) 1.51 1.51 1.51 1.51 Specific Gravity, G s 2.62 2.59 2.56 2.53 Plastic Limit, PL (%) 29.77 31.92 36.21 41.25 Liquid Limit, LL (%) 11. 119.7 5 Plasticity Index, PI (%) Shrinkage Limit, SL (%) 136.66 164.3 71.23 87.83 1.44 122.8 1.7 13.49 16.24 18.98 Clay content (%) 95.6 94.53 94.87 95.13 Classification Unified CH CH CH CH Classification AASHTO A-7-5 A-7-5 A-7-5 A-7-5 T ABLE III CHEMICAL COMPOSITION KARANG JATI (NGAWI) AND MIXED OF PROPERTY SOIL Karang SiO 2 64.98 62. 62.54 62.63 Al 2 O 3 2.67 23.4 22.73 22.69 Fe 2 O 3 5.39 1.27 9.74 9.38 TiO 2.24.26.25,25 CaO 3.55 1.27 1. 1.34 MgO 3.57 1.67 1.69 1.74 Na 2 O 1.5 1.15 1.43 1.65 K 2 O.55.34.32.32 T ABLE IV MINERAL COMPOSITION OF SOIL KARANG JATI AND MIXED OF PROPERTY SOIL Karang Montmorilonite (%) 76.1 5,11 5,48 5,94 Feldspar (%) 16.2 16,3 16,67 17,9 Alpha Quartz (%) 5. 6,8 6,63 6,47 Halloysite (%) 4. 13,3 12,89 12,1 Cristobalite (%).9 14,3 13,33 12,59 The results of soil properties fom Karang (Ngawi) and mix of soil especially soil consistency limits (Atterberg limits) at the liquid limit (LL) are from 11% to 164,3% and plasticity index (IP), from 71.32% to 122,8%. The test of clay composition in mineral Karang and mix of soil shows that the most dominant are the montmorillonite of 49.74% to 5,94%, this soil has a very swelling potential. This procedure as done by previous researchers include, [8], [9], [1], [15] and [16] who state that the expansive clay soil is classified as a very swelling potential if the liquid limits (LL) is er than 6% and plasticity index (IP) is er than 35% and the amount of mineral montmorillonite is over 35% of the total mineral content. B. Swelling Potential Variaous investigations have developed charts and tables to asses the degree of expansiveness of expansive soils using simple index tests. Only a few are tested here, depending on simplicity and wide aceptance. The summary of swelling potential of expansive soils is shown is Table V. Ii is obseved that expansiveness of all in the summry in Table V, the soils vary from to very according to [8], [9], [1], [15], and [16] T ABLE V SUMMARY SELLING POTENTIAL OF EXPANSIVE CLAY METNOD OF Soko Mix PREDICTION SWELLING 3 POTENTIAL Cassagrande Merwe Mitchell (1976) High Seed, dkk. (1962) High Holtz and Gibbs (1956) High Extr a C. The Results of swelling vertical Test The Swelling test in Karang (Ngawi) clay and mix of soil is based on with initial water content of 32 % and dry density 1.26 g/cm 3. as based on standard Proctor test as shown fig. 5. The swelling test results swelling are shown in Table VI and Fig. 6. The fig. shows the relationship between time (minute) and strain (ε) of soil Karang (Ngawi) and mix of soil. The swelling vertical are greater with the increas in Na-bentonite in the Karang clay. 1.36 1. 1.24 1.18 1.12 1.6 1. 15 2 25 35 4 45 5 55 Water Content, w (%) Fig. 5. Curve Proctor standard test [14].
International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol:12 No:6 16 Samples T ABLE VI SWELLING VERTICAL OF EXPANSIVE SOIL W Sr Initial Swelling W Final Initial (Sr), % vertical (wf), % (wi), % Sr Final (Sr), % Karang 32. 82.57 24.87 57.89 1 32. 83.53 32.2 62.94 1 Mix 2 32. 84.52 37.94 67.4 1 32. 85.57 43.82 71.1 1 5 4 2 1 Karang (Ngawi) Ssoil Mix 2 2 4 5 6 Fig. 8. Curve relation of water content and free swelling of mix 1 soil [14]. 7 6 5 4 2 Fig. 6. Relationships between time and strain of soil Karang (Ngawi) and mix of soils. The Relationship between swelling vertical (strain) and time (minute) shows that the greater the time (minute) is, the greater swelling vertical (strain) expansive clay soil that occur as shown in Fig. 6. The Results of free swelling One of the parameters in relations of the swelling expansive soil is to know the value of water content (w) ([1], ([9] and [12]). The relationship between the water content (w) and free swelling in Karang soil is shown in Fig. 7. For mixed soil 1, 2 and 3, it is as shown in fig 8 to fig. 1 below. 1 2 4 5 6 7 8 Fig. 9. Curve relation of water content and free swelling of mix 2 soil [14]. 7 6 5 4 5 4 2 1 2 2 4 5 6 7 8 1 2 4 5 6 Fig. 7. Curve relation of water content and free swelling of Karang soil [14]. Fig. 1. Curve relation of water content and free swelling of mix 3 soil [14]. Fig 7 to fig. 1 and Table VII, show the relationship between the free swelling ND water content (w). In that fig., the greater the value water content (w) is, the greater the free swelling occurs. The results also showed that the difference between vertical swelling and horizontal swelling in free swelling is not very large, only about 1.22. But the volumetric swelling is large because of the combined results of the calculation of vertical swelling and horizontal swelling, as in formula 3. Ratio of
International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol:12 No:6 17 volumetric deformation swelling with vertical deformation swelling is as as 2,98 and the ratio of volumetric deformation swelling and horizontal deformation swelling is as as 3,63. The value of plasticity index Karang (Ngawi) soil and soil mixture on the Table II, showed the greater the percentage of Na-bentonite is in clay Karang (Ngawi), the greater the value plasticity index (PI) is. With the increae in the value of plasticity index (IP) and activity (A), free swelling Krang soil and mixed soil is greater, as shown in Table VII below. Samples T ABLE VII FREE SWELLING OF EXPANSIVE SOILS W Initial Swelling Swelling Swelling (wi), % horizontal vertical volumetric Karang 32. 6.7 9.21 24.34 32. 9.5 11.58 33.78 Mix 2 32. 11.73 14.74 43.24 32. 15.8 16.84 54.75 The results of free swelling test on the fig. 7 to fig. 1 and Table VII show the behaviour of swelling of expansive soils as presented by [8], [9], [1], [15] and [16]. V. CONCLUSION Based on research results, some conclusions are drawn as follows. 1. The behavior of swelling vertical, swelling horizontal and swelling volumetric in free swelling test with initial water content and density is similar to the expansive soil of Karang (Ngawi) and soil mix which are strongly influenced by water content changes, the swelling vertical, swelling horizontal and swelling volumetric linearly increase with increasing water content. 2. The vertical deformation swelling with horizontal deformation swelling is not much different, the ratio vertical deformation swelling and horizontal deformation swelling is as as 1,22. 3. The vertical deformation swelling with volumetric deformation swelling is much different, the ratio of volumetric deformation swelling with vertical deformation swelling is as as 2,98. 4. The horizontal deformation swelling with volumetric deformation swelling is too much different, the ratio of volumetric deformation swelling with horizontal deformation swelling is as as 3,63. 5. Na-bentonite can be used for a variety of plasticity index (PI) and activity (A) in expansive soils. Plasticity index (PI) and Activity (A) parameter to be influenced is significant to free swelling of expansive soils, the swelling vertical, swelling horizontal and swelling volumetric linearly increase with increasing plasticity index (PI) and Activity (A). ACKNOWLEDGMENT This research was carried out by the financial support of Directorate of Research and Community Service (DP2M) Directorate Jenderal of Higher Education, Ministry of National Education, Republic of Indonesia through a Research Grant Hibah Penelitian Hibah Bersaing in the 212 fiscal year with Number of Contract: 36/SP2H/PP/K7/KL/II/212, in 9 th February 212, All contributions are acknowledged. REFERENCES [1] Chen, F.H., Foundation on Expansive s, Developments in Geotechnical Enginering, Elseveier Scientific Publication Company, New York, 1975. [2] Hardiyatmo, H.C., Mekanika Tanah 1, edisi 4, Gadjah Mada University,Yogyakarta, 26. [3] Holtz, W, G., and Kovacs, Expansive s The Hidden Disaster, Civil Engineering, Vol 4, 1973. [4] Jones, D, E., and Holtz, W, G., Expansive s The Hidden Disaster, Civil Engineering, Vol 4, 1973 [5] Nelson, J.D., and Miller, D.J., Expansive s Problem and practice in Foundation and Pavement Engineering, John Wiley and Sons, New York, 1992. [6] Gourly, C.S., Newill, D., and Schreiner, H.D., Expansive, TRL s Research Strategy, Proc. Ist Inc. Symp. Engineering Characteristics of Arid s, London, 1993. [7] Mochtar, I. B., Improvement and Alternative Technology Planning at the Problematic, Civil Engineering Department, Faculty of Civil Engineering and Planning, Institute of T echnology Sepuluh November (ITS), Surabaya, 2. [8] Holtz, R.D., and Gibbs, H.J., Prediction on Swelling Potential for Compacted Clay, Journal of the mechanics and Foundation devision, ASCE, Discussion, Vol 88, No.SM4, 1956. [9] Seed, H.B., Woodward R.J., Lundgren R., Prediction of Swelling Potential for Cpmpacted Clays, Journal of the Mechanics and Foundation Division, ASCE, Vol.88. No. SM3. Proc. Paper 3169, 1962. [1] Dakhshanamurthy, V. and Raman, V., Review of Expansive s, Discusion, Journal of Geotechnical Enggineering Division, ASCE, Volume 11,, No. GT 6, 1975. [11] Mitchell, J.K., 1992, Fundamentals of Behavior, Second edition, Jhon Wiley & Sons, Inc., New York, USA. [12] Das, B.M, 28, Advanced Mechanic, Third Edition, Taylor & Francis Group, London, UK. [13] ASTM, Annual Books of ASTM Standards Section 4 Volume 4.8 and Rock (I): D42-D4914, 23. [14] Sudjianto, A.T., Cakrawala, M., and Aditya, C., 212, Pengembangan Model dan Prediksi Swelling Tiga Dimensi Tanah lempung Ekspansif menggunakan Uji kembang Bebas, Laporan Akhir Penelitian Hibah Bersaing Tahun I, Directorate of Research and Community Service (DP2M) Directorate general of Higher Education, Ministry of National Education, Republic of Indonesia, unpublished. [15] Van Der Merwe, D.H., The Prediction of heave from the Plasticity Index and percentage Clay Fraction of s, Civil Engineers in south Africa, 6(6):pp 13-17, 1964. [16] Sahu, B.K., 2, Engineering Characteristic of Block Cotton s in francistown, Unsaturated s for Asia, Rahardjo, Toll & Leong, A.A Balkema, Rotterdam, pp 715 719.