Shear strength characteristics of a thermally cured sand-bentonite mixture

Document Type : Article

Authors

1 Department of Civil Engineering, School of Engineering, Kharazmi University, Tehran, Iran

2 Department of Civil Engineering, Sharif University of Technology, Tehran, Iran

Abstract

An experimental program was conducted to investigate the effects of curing time and curing temperature on shear behavior of a sand-bentonite mixture. The specimens were cured at temperatures of 40°C, 60°C and 80°C for 1, 3 and 5 days under 100kPa, 500kPa and 1000kPa confinements. The results of consolidated undrained triaxial shear tests showed that an increase in temperature from 40°C to 80°C at 1, 3 and 5 days of curing increased the shear strength by 25%, 24% and 23%, respectively. Also, the increase in curing time from 1 to 3 and from 1 to 5 days at 80°C increased the shear strength of samples 12% and 24%, respectively. The failure of pre-cured samples occurred in lower strains as a result of more induced brittleness. Moreover, the secant modulus as well as the size of yield loci and critical state line’s slope increased by pre-curing. The application of thermal cycles resulted in increasing shear strength and experiencing a negative pore water pressure which shows a transition towards the quasi-structured behavior. The results of scanning electron microscopy (SEM) studies confirmed the increase in void ratio during thermal curing.

Keywords


  1. References

    1. Ghaebi. H., Bahadori, M.N., Saidi, M.H. “Different operational alternatives of aquifer thermal energy storage system for cooling and heating of a residential complex under various climatic conditions in Iran”, Scientia Iranica, 26(3), pp.1281-1292 (2019).
    2. Chen, W.Z., Ma, Y.S., Yu, H.D. et al. “Effects of temperature and thermally-induced microstructure change on hydraulic conductivity of Boom Clay”, Journal of Rock Mechanics and Geotechnical Engineering, 9(3), pp. 383–395 (2017).
    3. Tsuchida, T., Kobayashi, M., and Mizukami, J. “Effect of aging of marine clay and its duplication by high temperature consolidation”, Soils and Foundations, 31(4), pp. 133–147 (1991).
    4. Towhata, I., Kuntiwattanaku, P., Seko, I. et al. “Volume change of clays induced by heating as observed in consolidation tests”, Soils and Foundations, 33(4), pp. 170–183 (1993).
    5. Pusch, R. and Guven, N. “Electron microscopic examination of hydrothermally treated bentonite clay”, Engineering Geology, 28, pp. 303-314 (1990).
    6. Attah, I.C., Etim, R.K. “Experimental investigation on the effects of elevated temperature on geotechnical behaviour of tropical residual soils”, SN Applied Sciences, 2, 370, https://doi.org/10.1007/s42452-020-2149-x (2020).
    7. Shirasb, A., Hamidi, A. and Ahmadi, M.M. “Consolidation characteristics of a thermally cured sand–bentonite mixture”, SN Applied Sciences, 2(6), https://doi.org/10.1007/s42452-020-2932-8 (2020).
    8. Tabarsa, A., Lashkarbolok, M. “A numerical investigation of the effect of the temperature on the seepage calculation”, Scientia Iranica, 25(4), pp. 1907-1915 (2018).
    9. Avci, E. “The effect of different curing temperatures on engineering properties of chemically grouted sands”, Scientia Iranica, 27(3), pp. 1144-1161 (2020).
    10. Gens, A., Vaunat, J., Ggaritte, B. et al. “In situ behaviour of a stiff layered clay subject to thermal loading: observations and interpretation”, Geotechnique, 57(2), pp. 208-227 (2007).
    11. Ajdari, M. and Bahm Yari, H. “Oedometric response of an artificially prepared sand-bentonite mixture improved by potassium silicate”, Scientia Iranica A, 22(2), pp. 367-372 (2015).
    12. Cabalar, A.F. “Influence of grain shape and gradation on the shear behavior of sand mixtures”, Scientia Iranica, 25(6), pp. 3101-3109 (2018).
    13. Liu, J.F., Song, S.B., Ni. H.Y. et al. “Research on the gas migration properties in a saturated bentonite/sand mixture under flexible boundary condition”, Soils and Foundations, 58(1), pp. 97–109 (2018).
    14. Li, H.F., Chen, M.Q., Fu, B.A. et al. “Evaluation on the thermal and moisture diffusion behavior of sand/bentonite”, Applied Thermal Energy, 151, pp. 55–65 (2019).
    15. Dixon, D.A., Gray, M.N., and Thomasa, W. “A study of the compaction properties of potential clay-sand buffer mixtures for use in nuclear fuel waste disposal”, Engineering Geology, 21, pp. 247–255 (1985).
    16. Rawat, A., Baille, W., Tripathy, S. “Swelling behavior of compacted bentonite-sand mixture during water infiltration”, Engineering Geology, 257, 105141 (2019). https://doi.org/10.1016/j.enggeo.2019.05.018.
    17. Jarad, N., Cuisinier, O., and Masrouri, F. “Effect of temperature and strain rate on the consolidation behavior of compacted clayey soils”, European Journal of Environmental and Civil Engineering, 23(7), pp. 789–806 (2017).
    18. White, R.E. “Principles and practice of soil science”, Blackwell Publishing, (2006).
    19. Fookes, P.G. “Tropical residual soils”, The Geological Society, London (1997).
    20. de La Fuente, S., Cuadros, J., Fiore, S. et al. “Electron microscopy study of volcanic tuff alteration to illite-smectite under hydrothermal conditions”, Clays and Clay Minerals, 48(3), pp. 339–350 (2000).
    21. Wersin, P., Johnson, L.H., McKinley, I.G. “Performance of the bentonite barrier at temperatures beyond 100°C: a critical review”, Physics and Chemistry of the Earth, 32(8), pp.780–788 (2006).
    22. Estabragh, A.R., Khosravi, F., Javadi, A.A, “Effect of thermal history on the properties of bentonite”, Environmental Earth Sciences, 75 (2016).
    23. ASTM D-4546, Annual Book of ASTM Standards, Soils and Rock Division, West Conshohocken, USA (2003).
    24. Erzin, Y. and Erol, O. “Correlations for quick prediction of swell pressures”, Electronic Journal of Geotechnical Engineering, 9(1): 476 (2004).
    25. Komine, H., and Nobuhide, O. “Experimental study on swelling characteristics of sand-bentonite mixture for nuclear waste disposal”, Soils and Foundations, 39(2), pp. 83–97 (1999).
    26. Lingnau, B.E., Graham, J., Yarechewski, D. et al. “Effects of temperature on strength and compressibility of sand-bentonite buffer”, Engineering Geology, 41, pp. 103–115 (1996).
    27. ENERSA. “Full-scale engineered barriers experiment for a deep geological repository for high-level radioactive waste in crystalline host rock (FEBEX project)” EUR 19147, Nuclear Science and Technology series, Luxembourg (2000).
    28. Mukherjee, K. and Mishra, A.K. “Evaluation of hydraulic and strength characteristics of sand–bentonite mixtures with added tire fiber for landfill application liner”, Journal Environmental Engineering, 145(6), https://doi.org/10.1061/(ASCE)EE.1943-7870.0001537 (2019).
    29. ANDRA, Re´fe´rentiel du site Meuse/Haute Marne, Report CRPADS040022_B. Chatenay-Malabry, 2, ANDRA (2005).
    30. Knellwolf, C., Peron, H., and Laloui, L. “Geotechnical analysis of heat exchanger piles”, Journal of Geotechnical and Geoenvironmental Engineering, 137(10), pp. 890–902 (2011).
    31. Oclon, P., Taler, D., Cisek, P. et al. “FEM-based thermal analysis of underground power cables located in backfills made of different materials”, Strength of Materials, 47(5), pp. 770–780 (2015).
    32. Tanaka, N., Graham, J., and Crilly, T. “Stress-strain behavior of reconstituted illite clay at different temperature”, Engineering Geology, 47, pp. 339–350 (1997).
    33. Abuel-Naga, H.M., Bergado, D.T., Ramana, G.V. et al. “Experimental evaluation of engineering behavior of soft Bangkok clay under elevated temperature”, Journal of Geotechnical and Geoenvironmental Engineering, 132(7), pp. 902–910 (2006).
    34. Marques, M.E.S., Strain-rate and temperature effect on consolidation of natural clays, MSc Thesis, Federal University of Rio de Janeiro, Brazil (1996).
    35. Horpibulsuk, S., Analysis and assessment of engineering behavior of cement stabilized clays, PhD Dissertation, Saga University, Japan (2001).
    36. Rios, S. and Baudet, B.A. “On the shearing behaviour of an artificially cemented soil”, Acta Geotechnica, 9, pp. 215–226 (2013).
    37. Amini, Y., Hamidi, A., and Asghari, E. “Shear strength–dilation characteristics of cemented sand–gravel mixtures”, International Journal Geotechnical Engineering, 8(4), pp. 406–413 (2014).
    38. Mollamahmutoglu, M., Avci, E. “Effect of cement grain size on the geotechnical properties of stabilized clay”, Scientia Iranica, 26(6), pp. 3196-3206 (2019).
    39. Bushra, I., Robinson, R.G. “Shear strength behavior of cement treated marine clay”, International Journal of Geotechnical Engineering, 6, pp. 455-465 (2012).
    40. Hamidi, A., Tourchi, S., and Khazaei, C. “Thermomechanical constitutive model for saturated clays based on critical state theory”, International Journal of Geomechanics, 15(1), https://doi.org/10.1061/(ASCE)GM.1943-5622.0000402 (2015).
    41. Wang, M.C., Benway, J.M., and Arayssi, A.M. “The Effect of Heating on Engineering Properties of Clays, ASTM Special Technical Publication, pp. 139-158 (1990).