Anti-seepage performance and underlying mechanism of carboxymethyl cellulose sodium-modified bentonite in hydraulic engineering applications

Abstract

Bentonite is widely utilized in hydraulic engineering projects. However, its performance may deteriorate under extreme environmental conditions. Hence, we aim to develop a sodium carboxymethyl cellulose (CMC)-modified bentonite and investigate its anti-seepage performance. The results showed that the 10% CMC-modified bentonite exhibited the best performance. Compared with unmodified bentonite, the expansion index of 10% CMC-modified bentonite significantly increased to 40 mL/2 g, indicating a high water absorption capacity and expansion property. Moreover, it showed a significant decrease in permeability coefficient (3.72×10−11 m/s) and an increase in porosity (1.90), indicating its excellent anti-seepage effect. Furthermore, under unconventional environmental conditions and long-term performance tests, the 10% CMC-modified bentonite shows improved stability compared to the unmodified bentonite. Therefore, it can be concluded that this study provides support for the utilization of CMC-modified bentonite in anti-seepage engineering and hydraulic engineering applications.