Swelling Properties and Permeability of GMZ Bentonite-Sand Mixtures during Different Solutions Infiltration

Yu-Ping Wang, Zhe Wang, Yu Zhao, Fa-Cheng Yi and Bao-Long Zhu
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Yu-Ping Wang: School of Environment and Resource, Southwest University of Science and Technology, Mianyang 621010, China
Zhe Wang: School of Environment and Resource, Southwest University of Science and Technology, Mianyang 621010, China
Yu Zhao: School of Environment and Resource, Southwest University of Science and Technology, Mianyang 621010, China
Fa-Cheng Yi: School of Environment and Resource, Southwest University of Science and Technology, Mianyang 621010, China
Bao-Long Zhu: School of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China

Sustainability, 2021, vol. 13, issue 4, 1-12

Abstract: In China, Gaomiaozi (GMZ) bentonite is recognized as a barrier material for isolating nuclear waste. Different chemical solutions may change the hydraulic conductivity and swelling capacity of bentonite. Consequently, a series of swelling pressure and permeability experiments was carried out on bentonite-sand mixtures with various dry densities and infiltrating solutions. X-ray diffraction (XRD) and the field emission scanning electron microscope (FESEM) were carried out on the samples experiencing the tests to identify the influence of chemistry pore solutions upon the mineralogical and microstructure changes. The results show that the swelling pressure experienced rapid swelling, slow expansion, and the stable expansion stage for the specimens of infiltrating solutions except for NaOH. For the specimens infiltrated with NaOH solutions, the swelling pressure experienced rapid increases, slow decreases, and a stable development stage. With hyper-alkaline and hyper-salinity infiltration, the swelling pressure decreased, and the permeability increased. In addition, swelling pressure attained stability more quickly on contact with hyper-alkaline and hyper-salinity solutions. Comparing the test results, the results indicate that the influence of NaOH on the expansion and permeability was higher than NaCl-Na 2 SO 4 at the same concentration.

Keywords: bentonite-sand mixture; dry density; infiltrating solution; expansion pressure; permeability coefficient; FESEM (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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