@article{ZENG2025, 
author = {Zhaotian ZENG and Hanbin ZHANG and Haibo LV and Dongze CHE and Bin PAN},
title = {Aging effect on physical properties of bentonite under high temperature-strong alkaline conditions},
year = {2025},
journal = {Journal of Civil and Environmental Engineering},
volume = {47},
number = {2},
pages = {49-56},
keywords = {bentonite, high temperature-strong alkaline conditions, physical property, aging effect, montmorillonite dissolution},
url = {https://www.sciopen.com/article/10.11835/j.issn.2096-6717.2023.005},
doi = {10.11835/j.issn.2096-6717.2023.005},
abstract = {During the operation of deep geological repository, the bentonite as a buffer material would be in a high temperature-strong alkaline environment for a long time, and its physical properties would deteriorate with time. Aging effect on physical property of MX-80 bentonite powder at high temperature and strong alkali conditions was investigated in this paper. MX-80 bentonite was subjected to alkali-heat conditions, i. e., T=90 ℃ and CNaOH=0.5 mol/L for duration of 0, 15, 30, 45, 60, 90 days, respectively. The variation of physical properties such as the specific gravity, specific surface area and swell index of MX-80 bentonite was studied through laboratory experiments. Some representative specimens were selected for X-ray diffraction (XRD) tests and thermogravimetric analysis (TGA) tests to provide a reasonable explanation from microscopic perspective. The results showed that the specific gravity, specific surface area and swell index of bentonite decreased sharply from 0 to 45 days, gradually levelling off after then, finally, the reduction amplitudes were 13.6%, 18.5% and 58.1% after 90 days, respectively. Montmorillonite content decreased and albite content increased. The changes of montmorillonite and albite were -23.3% and +3.7% after 90 days. The content of free water, weakly bound water and strongly bound water decreased, and the content of the three decreased by 2.84%, 0.13% and 0.24% respectively after 90 days. The fundamental reason for the deterioration of bentonite physical properties over time under high temperature and strong alkali conditions was the dissolution of montmorillonite.}
}