Abstract
Bentonite pellet mixture emplaced in a high-level radioactive waste (HLW) repository may suffer decay heat released by nuclides and alkaline solutions produced by concrete degradation, leading to complex hydro-mechanical behaviours different to those of compacted bentonite blocks. In this paper, swelling pressure and hydraulic conductivity tests were conducted on bentonite pellet mixtures infiltrated with distilled water and NaOH solutions (0.1, 0.5 and 1.0 M) at different temperatures (20, 40 and 60 °C). At selected hydration times, water contents, dry densities, pore size distributions of lower, middle and upper layers of the specimens were measured. Mineralogies and microfabrics of the bottom part of the specimens were also studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that with increasing NaOH concentration (0–0.5 M) and temperature, more montmorillonites were dissolved and more large pores or even cracks generated in the specimen, leading to deteriorated swelling pressure and increased hydraulic conductivity. As the NaOH concentration further increased to 1.0 M, large pores and cracks were clogged by precipitates generated during dissolution of montmorillonite, resulting in decreased hydraulic conductivity. The migration of water/solution was significantly retarded by combinedly increasing NaOH concentration and temperature, due to the reduced adsorption and capillary ability of the bentonite, pore clogging near the specimen bottom as well as chemical consumption of pore water during the dissolution of montmorillonite and other minerals.
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References
Bensch JJ, Brynard HJ (1972) New approach to density measurements using Archimedes’s principle. Nat Phys Sci 239(93):96. https://doi.org/10.1038/physci239096a0
Benson C, Ören AH, Gates WP (2010) Hydraulic conductivity of two geosynthetic clay liners perrmeated with a hyperalkaline solution. Geotext Geomembr 28(2):206–218. https://doi.org/10.1016/j.geotexmem.2009.10.002
Castellanos E, Villar MV, Romero E, Lloret A, Gens A (2008) Chemical impact on the hydro-mechanical behaviour of high-density FEBEX bentonite. Phys Chem Earth 33:S516–S526. https://doi.org/10.1016/j.pce.2008.10.056
Chen B, Guo JX, Zhang HX (2016) Alteration of compacted GMZ bentonite by infiltration of alkaline solution. Clay Miner 51:237–247. https://doi.org/10.1180/claymin.2016.051.2.10
Chen YG, Liu LN, Ye WM, Cui YJ, Wu DB (2019) Deterioration of swelling pressure of compacted Gaomiaozi bentonite induced by heat combined with hyperalkaline conditions. Soils Found 59:2254–2264. https://doi.org/10.1016/j.sandf.2019.12.008
Cui LY, Masum SA, Ye WM, Thomas HR (2022) Investigation on gas migration behaviours in saturated compacted bentonite under rigid boundary conditions. Acta Geotech 17:2517–2531. https://doi.org/10.1007/s11440-021-01424-1
Dixon D, Sandén T, Jonsson E, Hansen J (2011) Backfilling of deposition tunnels: use of bentonite pellets. SKB P-11-44, Stockholm, Sweden. http://www.skb.se/upload/publications/pdf/P-11-44.pdf
Fernández R, Cuevas J, Sánchez L, de la Villa V, Leguey S (2006) Reactivity of the cement–bentonite interface with alkaline solutions using transport cells. Appl Geochem 21:977–992. https://doi.org/10.1016/j.apgeochem.2006.02.016
Ferrari A, Bosch JA, Baryla P, Rosone M (2022) Volume change response and fabric evolution of granular MX80 bentonite along different hydro-mechanical stress paths. Acta Geotech. https://doi.org/10.1007/s11440-022-01481-0
García-Siñeriz JL, Villar MV, Rey M, Palacios B (2015) Engineered barrier of bentonite pellets and compacted blocks: State after reaching saturation. Eng Geol 192:33–45. https://doi.org/10.1016/j.enggeo.2015.04.002
Gates WP, Bouazza A (2010) Bentonite transformations in strongly alkaline solutions. Geotext Geomembr 28:219–225. https://doi.org/10.1016/j.geotexmem.2009.10.010
Imbert C, Villar MV (2005) Hydro-mechanical response of a bentonite pellets/powder mixture upon infiltration. Appl Clay Sci 32:197–209. https://doi.org/10.1016/j.clay.2006.01.005
Karnland O, Olsson S, Nilsson U, Sellin P (2007) Experimentally determined swelling pressures and geochemical interactions of compacted Wyoming bentonite with highly alkaline solutions. Phys Chem Earth 32:275–286. https://doi.org/10.1016/j.pce.2006.01.012
Lee JO, Lim JG, Kang IM, Kwon S (2012) Swelling pressures of compacted Ca-bentonite. Eng Geol 129:20–26. https://doi.org/10.1016/j.enggeo.2012.01.005
Liu LN, Chen YG, Ye WM, Cui YJ, Wu DB (2018) Effects of hyperalkaline solutions on the swelling pressure of compacted Gaomiaozi (GMZ) bentonite from the viewpoint of Na+ cations and OH– anions. Appl Clay Sci 161:334–342. https://doi.org/10.1016/j.clay.2018.04.023
Liu ZR, Ye WM, Zhang Z, Wang Q, Chen YG, Cui YJ (2019) Particle size ratio and distribution effects on packing behaviour of crushed GMZ bentonite pellets. Powder Technol 351:92–101. https://doi.org/10.1016/j.powtec.2019.03.038
Liu ZR, Ye WM, Cui YJ, Zhu HH, Wang Q, Chen YG (2021) Insights into the water retention behaviour of GMZ bentonite pellet mixture. Acta Geotech 16:3145–3160. https://doi.org/10.1007/s11440-021-01249-y
Liu ZR, Ye WM, Cui YJ, Zhu HH, Wang Q, Chen YG (2021) Development of swelling pressure for pellet mixture and compacted block of GMZ bentonite. Constr Build Mater 301:124080. https://doi.org/10.1016/j.conbuildmat.2021.124080
Liu ZR, Ye WM, Cui YJ, Zhu HH, Wang Q (2022) Water infiltration and swelling pressure development in GMZ bentonite pellet mixtures with consideration of temperature effects. Eng Geol 305:106718. https://doi.org/10.1016/j.enggeo.2022.106718
Liu ZR, Ye WM, Cui YJ, Zhu HH, Wang Q (2022) Temperature effects on water retention behaviour and structural evolution of GMZ bentonite pellet mixtures. Appl Clay Sci 222:106492. https://doi.org/10.1016/j.clay.2022.106492
Liu ZR, Ye WM, Zhu HH, Wang Q, Chen YG (2023) Effect of super-absorbent polymer on swelling pressure of compacted bentonite infiltrated by alkaline solutions. Appl Clay Sci 233:106816. https://doi.org/10.1016/j.clay.2023.106816
Meng YH, Wang Q, Su W, Ye WM, Chen YG (2022) Effect of sample thickness on the self-sealing and hydration cracking of compacted bentonite. Eng Geol. https://doi.org/10.1016/j.enggeo.2022.106792
Molinero-Guerra A, Mokni N, Delage P, Cui YJ, Tang AM, Aimedieu P, Bernier F, Bornert M (2017) In-depth characterisation of a mixture composed of powder/pellets MX80 bentonite. Appl Clay Sci 135:538–546. https://doi.org/10.1016/j.clay.2016.10.030
Molinero-Guerra A, Aimedieu P, Bornert M, Cui YJ, Tang AM, Sun Z, Mokni N, Delage P, Bernier F (2018) Analysis of the structural changes of a pellet/powder bentonite mixture upon wetting by X-ray computed microtomography. Appl Clay Sci 165:164–169. https://doi.org/10.1016/j.clay.2018.07.043
Molinero-Guerra A, Cui YJ, He Y, Delage P, Mokni N, Tang AM, Aimedieu P, Bornert M, Bernier F (2019) Characterization of water retention, compressibility and swelling properties of a pellet/powder bentonite mixture. Eng Geol 248:14–21. https://doi.org/10.1016/j.enggeo.2018.11.005
Nakayama S, Sakamoto Y, Yamaguchi T, Akai M, Tanaka T, Sato T, Iida Y (2004) Dissolution of montmorillonite in compacted bentonite by highly alkaline aqueous solutions and diffusivity of hydroxide ions. Appl Clay Sci 27:53–65. https://doi.org/10.1016/j.clay.2003.12.023
Ramirez S, Cuevas J, Vigil R, Leguey S, (2002) Hydrothermal alteration of ‘“La Serrata”’ bentonite (Almerı´a, Spain) by alkaline solutions. Appl Clay Sci 21:257–269. https://doi.org/10.1016/S0169-1317(02)00087-X
Sánchez L, Cuevas J, Ramírez S, Riuiz De Leon D, Fernández R, Vigi Dela Villa R, Leguey S (2006) Reactions of FEBEX bentonite in hyperalkaline conditions resembling the cement-bentonite interface. Appl Clay Sci 33:125–141. https://doi.org/10.1016/j.clay.2006.04.008
Taubald H, Bauer A, Schäfer T, Geckeis H, Satir M (2000) Experimental investigation of the effect of high-pH solutions on the Opalinus shale and the Hammerschmiede smectite. Clay Miner 35:515–524. https://doi.org/10.1180/000985500546981
Tripathy S, Sridharan A, Schanz T (2004) Swelling pressures of compacted bentonites from diffuse double layer theory. Can Geotech J 41(3):437–450. https://doi.org/10.1139/t03-096
Van Geet M, Volckaert G, Roels S (2005) The use of microfocus x-ray computed tomography in characterising the hydration of a clay pellet/powder mixture. Appl Clay Sci 29(2):73–87. https://doi.org/10.1016/j.clay.2004.12.007
Villar MV, Iglesias RJ, Gutiérrez-Álvarez C, Carbonell B (2021) Pellets/block bentonite barriers: Laboratory study of their evolution upon hydration. Eng Geol 292:106272. https://doi.org/10.1016/j.enggeo.2021.106272
Wang Q, Cui YJ, Tang AM, Li XL, Ye WM (2014) Time-and density-dependent microstructure features of compacted bentonite. Soils Found 54(4):657–666. https://doi.org/10.1016/j.sandf.2014.06.021
Xu YS, Zhou XY, Sun DA, Zeng ZT (2022) Thermal properties of GMZ bentonite pellet mixtures subjected to different temperatures for high-level radioactive waste repository. Acta Geotech 17:981–992. https://doi.org/10.1007/s11440-021-01244-3
Yamaguchi T, Sakamoto Y, Akai M, Takazawa M, Iida Y, Tanaka T, Nakayama S (2007) Experimental and modeling study on long-term alteration of compacted bentonite with alkaline groundwater. Phys Chem Earth 32:298–310. https://doi.org/10.1016/j.pce.2005.10.003
Ye WM, Chen YG, Chen B, Wang Q, Wang J (2010) Advances on the knowledge of the buffer/backfill properties of heavily-compacted GMZ bentonite. Eng Geol 116(1–2):12–20. https://doi.org/10.1016/j.enggeo.2010.06.002
Ye WM, Zheng ZJ, Chen B, Chen YG, Cui YJ, Wang J (2014) Effects of pH and temperature on the swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite. Appl Clay Sci 101:192–198. https://doi.org/10.1016/j.clay.2014.08.002
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The authors are grateful to the National Natural Science Foundation of China (42030714, 42002291) and the China Postdoctoral Science Foundation (2020M671217) for the financial supports.
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Liu, ZR., Ye, WM., Zhu, JC. et al. Temperature and alkaline solution effects on the hydro-mechanical behaviours of GMZ bentonite pellet mixtures. Acta Geotech. 18, 6097–6110 (2023). https://doi.org/10.1007/s11440-023-02044-7
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DOI: https://doi.org/10.1007/s11440-023-02044-7