Bruk av Lokale Materialer for Veibygging

Transcription

1 Department of Civil and Environmental Engineering Ph.D. project: Use of Local Materials for Road Construction Trondheim, 10 November 2017 Bruk av Lokale Materialer for Veibygging Diego Maria Barbieri, Ph.D. student

2 Ph.D. OPEN LECTURE OVERVIEW A. Mission of the Ph.D. Project B. Crushed Rocks for Road Construction C. Field and Laboratory Material Testing D. Enhancing Weak Rocks

3 MISSION OF THE Ph.D. PROJECT 1. The extended E39 highway tunnelling system generates a surplus of blasted rocks. Do we have better solutions than throwing material in the fjords? A. Lærdalstunnelen, Norsk versjon, Statens Vegvesen Presenterer

4 MISSION OF THE Ph.D. PROJECT 1. The extended E39 highway tunnelling system generates a surplus of blasted rocks. 2. Use the crushed rocks in the unbound layers of the highway (and roads). A. Design manual N200 sets requirements for pavement layers. Limit requirements for base Flakiness index FI 35 Los Angeles value LA 30 Micro Deval value 15 M DE Limit requirements for subbase Los Angeles value LA Micro Deval value M DE Statens Vegvesen. Håndbok N200. Vegbygging. Vegdirektoratet; Statens Vegvesen. Håndbok N200. Vegbygging. Vegdirektoratet; 2014.

5 MISSION OF THE Ph.D. PROJECT 1. The extended E39 highway tunnelling system generates a surplus of blasted rocks. 2. Use the crushed rocks in the unbound layers of the highway (and roads). 3. Map the geology encountered locally along the E39 alignment. the major part: igneous and supracrustal rocks (pink) granite and granodiorite, granitic to dioritic gneiss there are also smaller zones: igneous and metamorphic rocks (brown, green) gabbro, augen gneiss, mica schist A. Norges Geologiske undersøkelse

6 MISSION OF THE Ph.D. PROJECT 1. The extended E39 highway tunnelling system generates a surplus of blasted rocks. 2. Use the crushed rocks in the unbound layers of the highway (and roads). 3. Map the geology encountered locally along the E39 alignment. 4. The igneous strong rocks generally satisfy the code requirements. How is it possible to enable the local use of the other weak rocks? The transport distance should be within km to be a competitive solution. A. Provide better economy and less environmental impact Neeb P.R. Byggeråstoffer. Tapir; 1992.

7 N200: CRUSHED ROCKS IN UNBOUND LAYERS BASE paved crushed rocks B Statens Vegvesen. Håndbok N200. Vegbygging. Vegdirektoratet; 2014.

8 N200: CRUSHED ROCKS IN UNBOUND LAYERS SUBBASE crushed rocks B Statens Vegvesen. Håndbok N200. Vegbygging. Vegdirektoratet; 2014.

9 N200: CODE REQUIREMENTS BASE flakiness index FI 35 Los Angeles value LA 30 Micro Deval value M DE 15 B Statens Vegvesen. Håndbok N200. Vegbygging. Vegdirektoratet; 2014.

10 N200: CODE REQUIREMENTS SUBBASE The most relevant gradings of crushed rock in the subbase are: - crushed rock, bigger size 22/120 22/180 - crushed rock, smaller size 22/90 - unsorted crushed rock 0/63 0/90 Los Angeles value LA 35 Micro Deval value M DE 15 B Statens Vegvesen. Håndbok N200. Vegbygging. Vegdirektoratet; 2014.

11 EXAMPLE ABOUT THE IMPACT Twin-tube tunnel length: 4 km tunnel profile: T10,5 excavated cross area: 75 m 2 assumed specific weight: 1.6 t/m 3 o TOTAL EXCAVATED VOLUME: m 3 WEIGHT: t B. Vedlegg 1. Statens Vegvesen. Håndbok N500. Vegtuneller. Vegdirektoratet; 2016.

12 EXAMPLE ABOUT THE IMPACT Class H9 road (highway) traffic class: F number of lanes: 4 design period: 20 years B. total width of the road: 23 m C.1 Statens Vegvesen. Håndbok N100. Veg- og gateutforming. Vegdirektoratet; 2014.

13 EXAMPLE ABOUT THE IMPACT - USE SCENARIO SA. GOOD SUBGRADE MOUNTAIN CUT SCENARIO SB. POOR SUBGRADE SILT thickness of the base layer, paved crushed rocks: 25 cm thickness of the subbase layer, crushed rocks: 30 cm thickness of the base layer, paved crushed rocks: 25 cm thickness of the subbase layer, crushed rocks: 120 cm B. Chapter 5. Statens Vegvesen. Håndbok N200. Vegbygging. Vegdirektoratet; 2014.

14 EXAMPLE ABOUT THE IMPACT - USE SCENARIO SA. GOOD SUBGRADE MOUNTAIN CUT unbound layers total thickness: 55 cm SCENARIO SB. POOR SUBGRADE SILT unbound layers total thickness: 145 cm unbound layers cross section area: 13 m 2 ESTIMATE OF ROAD LENGTH TO USE UP THE EXCAVATED MATERIALS 50 km unbound layers cross section area: 34 m 2 ESTIMATE OF ROAD LENGTH TO USE UP THE EXCAVATED MATERIALS 20 km B. Chapter 5. Statens Vegvesen. Håndbok N200. Vegbygging. Vegdirektoratet; 2014.

15 EXAMPLE ABOUT THE IMPACT 1 Sandvik UJ 440 mobile jaw crusher cost new machine: NOK throughput capacity: 400 t/hour diesel consumption: 50 l/hour USE OF MOBILE CRUSHERS 1 Sandvik US 440 mobile cone crusher B. cost new machine: NOK throughput capacity: 500 t/hour diesel consumption: 50 l/hour

16 EXAMPLE ABOUT THE IMPACT COST SCENARIO S1. NO USE OF LOCAL CRUSHED ROCKS price at the quarry: 80 NOK/t SCENARIO S2. USE OF LOCAL CRUSHED ROCKS mobile crushing line NOK transport (20 km) 40 NOK/t 2 workers (300 NOK/ hour; 2500 hours) NOK B. get rid of crushed rocks 40 NOK/t 160 NOK/t l fuel (fuel 13 NOK/l; 2500 hours) NOK 13 NOK/t

17 SUPPLY FOR THE MATERIAL current tunnelling operations at E39 Svegatjørn Rådal (Bergen) supply for the material C.

18 SUPPLY FOR THE MATERIAL current tunnelling operations at E39 Svegatjørn Rådal (Bergen) supply for the material «strong» rocks «weak» rocks C. material M1 mafic igneous origin, modified by metamorphism Los Angeles value: 17.2 micro-deval value: 10.2 material M2 metamorphic origin, fine-grained felsic rocks Los Angeles value: 30.0 micro-deval value: 23.6 material M3 metamorphic origin, very fine-grained felsic rocks Los Angeles value: 29.8 micro-deval value: 26.3 EN Tests for Mechanical and Physical Properties of Aggregates. Part 2: Methods for the Determination of Resistance to Fragmentation. Brussels: CEN EN Tests for Mechanical and Physical Properties of Aggregates. Part 1: Determination of the Resistance to Wear (micro-deval). Brussels: CEN 2011.

19 REPEATED TRIAXIAL LOAD TEST (RTLT) PRINCIPLE ii. stiffness and deformation properties of unbound materials are connected to i. geology grain size distribution curve iii. stress level iv. water content v. density M1, M2, M3 average for base layer (see below) EN stress path w = 1% - 5% (OMC) compression time t c = 30 s C. M1, M2, M3 base layer gradation («average» line) tested with RTLTs Barbieri D. M., I. Hoff and H. Mork. Laboratory Investigation on Unbound Materials Used in a Highway with Premature Damage. Bearing Capacity of Roads, Railways and Airfields. 2017, pp

20 REPEATED TRIAXIAL LOAD TEST (RTLT) PRINCIPLE Multi-stage Low Stress Procedure 5 sequences 6 steps for each sequence both σ t and σ d gradually increase stop: if axial permanent deformation reaches 0.5% (or last step) C. triaxial stress (σ t ), pressurized water: constant deviatoric stress (σ d ), hydraulic jack: sinusoidal pattern EN Unbound and Hydraulically Bound Mixtures. Part 7: Cyclic Load Triaxial Test for Unbound Mixtures. Brussels: CEN 2004.

21 RESULTS FROM RTLT: RESILIENT MODULUS Resilient Modulus M R describes the unbound materials stiffness Test results M R = Δσ dyn d el ε a Δσ dyn d change in the dynamic deviatoric stress ε el a axial resilient strain K-θ model (regression curve) C. 5 sequences 6 steps for each sequence repetitions for each step M R = k 1 σ a θ σ a k 2 θ bulk stress σ a reference stress (100 kpa) k 1, k 2 model parameters Hicks, R.G. & Monismith, C.L Factors influencing the resilient response of granular materials. Highway Research Record 345: Washington DC: Highway Research Board.

22 MATERIALS PERFORMANCE RESILIENT MODULUS Material k 1 k 2 M M M Material k 1 k 2 M M M C. water content w=1% water content w=5% (OMC) Resilient moduli as standard tests (LA, M DE ) as well - highlight a difference between M1 and M2, M3.

23 standard tests (LA, M DE ) MATERIALS PERFORMANCE CRUSHING - VARIATION IN GRAIN SIZE crushing taking place in road life (unbound subbase layer is studied) A. during construction phase field test Los Angeles test (LA) micro-deval test (M DE ) B. during service life phase simulated with RTLT check if both the approaches agree when it comes to M1, M2, M3 «crushability» C. Barbieri D. M., I. Hoff and M. B. E. Mørk. Mechanical Assessment Of Crushed Rocks Derived From Tunnelling Operations

24 MATERIALS PERFORMANCE MODELLING SUBBASE LAYER LIFE PHASES A. during construction phase - 30 cm thick - 3 m wide m long m drum length - M R non-linear law (from w=1%) - symmetric problem B. during service life phase - add 20 cm unbound layer - add 10 cm bound layer - M R non-linear law (from w=1%) - symmetric problem C. roller 1 DOF scheme - load drum roller compactor - contact width 2.5 cm cm cm - load 10-ton standard axle load - contact radius 13 cm - 15 cm 17 cm

25 MATERIALS PERFORMANCE MODELLING SUBBASE LAYER LIFE PHASES results are similar for all M1, M2, M3 resilient modulus M R laws very different stress levels associated to the two life phases different amounts of crushing are expected in the two life phases C.

26 MATERIALS PERFORMANCE: CRUSHING A. CONSTRUCTION LIFE PHASE quantifying the crushing under a steel roller drum: comparing sieving curves before and after compaction 1. site preparation materials size: 20/120 mm 2. compaction C. 3. material collection

27 MATERIALS PERFORMANCE: CRUSHING B. SERVICE LIFE PHASE quantifying the crushing under 10-ton standard wheel load: comparing sieving curves before and after testing σ t and σ d reflect the stresses of the wheel load (from the modelling) repetitions Repeated Triaxial Load Test (RTLT) σ t : triaxial stress (pressurized water) σ d : deviatoric stress (hydraulic jack) σ t materials size: 20/30 mm C. σ d

28 A MATERIALS PERFORMANCE: CRUSHING COMPARISON SIEVING CURVES B C. before (solid) VS after (dashed) compaction before (solid) VS after (dashed) wheel action Significative crushing happens during construction phase, not during road life. M1 performs better (= crushes less) than M2 and M3.

29 MATERIALS PERFORMANCE: CRUSHING FURTHER OUTCOMES - change in coefficient of uniformity A C u = D 10 D 60 C c = D 30 D 10 D 60 B - change in coefficient of curvature 2 A B C.

30 MATERIALS PERFORMANCE: CRUSHING FURTHER OUTCOMES A correlation between - particle breakage factor B 10 = 1 D 10,f standard tests (LA, M DE ) particle breakage factor (B 10 ) during construction life phase D 10,i B LA = α B 10 M DE = β B 10 C. for M1, M2, M3 the best fitting values are α = 0.95, β = 0.69 Lade P.V., J. A. Yamamuro and P. A. Bopp. Significance of Particle Crushing in Granular Materials. Journal of Geotechnical Engineering, Vol. 122, No. 4, 1996, pp

31 (HOW) CAN WE USE WEAK ROCKS? D.

32 MAKING WEAK ROCKS USABLE: 0 approach TRANSPORT STRONG ROCKS D. The transport distance should be within km to be a competitive solution. Neeb P.R. Byggeråstoffer. Tapir; 1992.

33 MAKING WEAK ROCKS USABLE: 1 st approach STRONG AND WEAK MIX M2 and M1 mixture M DE,i+j = M DE,i m i m i + m j + M DE,j m j m i + m j M3 and M1 mixture The increase in micro-deval and Los Angeles values follows a linear trend. D. LA i+j = LA i m i m i + m j + LA j m j m i + m j

34 MAKING WEAK ROCKS USABLE: component C1 acrylic co-polymer emulsion (acetic acid and methanol) particle size lower than 90 nm 2 nd approach ADDITIVE water soluble - non-leachable - UV, heat stable made of two components component C2 polymeric dispersion silanol groups into alkyl siloxane groups (on the rocks surface, 4-6 nm coating) D. particle surface 4-6 nm alkyl siloxane groups water vapor comes out, but not in internal siloxane bonds

35 MAKING WEAK ROCKS USABLE: 2 nd approach ADDITIVE w = 5% (OMC) and add%a = 2 kg additive : 100 l water add%b = 20 kg additive : 100 l water enhanced stiffness better lubrication for compaction water resistance D.

36 MAKING WEAK ROCKS USABLE: 2 nd approach ADDITIVE standard tests (LA, M DE ) with weak materials soaked with additive and then dried at room temperature D.

37 MAKING WEAK ROCKS USABLE: 3 rd approach OVERHEATING 175 C and 250 C temperatures condition «weak» rocks for 24h and 48h M2 M3 No significative change, micro-deval values remain approximately the same. D. Simpson D., J. H. Fergus Jr. The Effect of Water on the Compressive Strength of Diabase. Journal of Geophysical Research, Vol. 73, No. 20, 1968, pp

38 FINAL REMARKS Use of rock masses locally: economic and environmental benefits. Three different rock materials: M1 («strong») fulfills code requirements, M2 and M3 («weak») do not do so. Improve the performance of the «weak» rocks: materials mixture and additive use are effective methods.

39 THANK YOU! TAKK FOR OPPMERKSOMHET! 谢谢您的注意! GRAZIE DELL ATTENZIONE! Ph.D. candidate: Diego M. Barbieri / NTNU diego.barbieri@ntnu.no Supervisor: Inge Hoff / NTNU inge.hoff@ntnu.no Co-supervisor: Lillian M. Uthus/ Veidekke lillian.uthus.mathisen@veidekke.no Contact partner: Nils S. Uthus / NPRA nils.uthus@vegvesen.no