# Compression Behavior of Rubber-Bentonite Mixture under Different Salinities
## 1 Introduction
### Test Methods and Working Conditions  
During the experimental process, this study conducted one-dimensional consolidation tests on the mixture of bentonite and rubber particles. Different mass ratios were used, including pure bentonite (B10), bentonite-rubber mass ratio of 8:2 (BST2), bentonite-rubber mass ratio of 6:4 (B6T4), and bentonite-rubber mass ratio of 4:6 (B4T6). The specific mix ratio design of the experiment is shown in Table 1. The moisture content of each mixture was maintained at 40%. The mixed materials were immersed in a NaCl solution of 0-1 mol/L to simulate groundwater conditions. The steps of the one-dimensional consolidation test followed the relevant provisions specified in the \"Standard Test Methods for Geotechnical Testing\" (GB/T 50123-2019) [31]. After the preparation of the specimens, they were transferred to a consolidation apparatus for installation. The corresponding components were sequentially placed on the consolidation apparatus, including the external ring, permeable stones at the bottom, and filter paper. Then, the sample with a cutting ring was carefully placed into the protective ring and inserted into the external ring. A piece of filter paper was placed on the surface of the sample, followed by an upper layer of permeable stones. Finally, a pressure cap was placed, and the consolidation container was positioned under the displacement gauge frame, aligning it at the center of the displacement gauge frame. A dial gauge for recording displacement was installed. To ensure sufficient contact between the components of the consolidation apparatus during the experiment, an initial preloading pressure of 1 kPa was applied. Then, the range on the displacement gauge above was adjusted to read zero. Subsequently, an initial pressure of 50 kPa was applied to correct the errors in manual specimen preparation and ensure consistent initial conditions among specimens with different ratios. The loading time was 24 h. Then, a sodium chloride solution with concentrations of 0 mol/L, 0.1 mol/L, 0.5 mol/L, or 1 mol/L was added to the consolidation container. The samples were allowed to expand for 48 h in environments with different concentrations of saline solution. Then, the weights of weights to be added for each load level were determined according to the experimental design requirements. After applying the first load level, the consolidation compression was maintained for 24 h or until the change in dial gauge reading within 1 h did not exceed 0.01 mm to ensure stability under this load level. Once the reading on the dial gauge no longer changed, the reading on the dial gauge was recorded. The next load level was then applied, following this process until reaching the maximum applied load. After reaching the maximum experimental design load of 400 kPa, rebound tests were conducted until unloading reached the initial pressure load of 50 kPa. The stability requirements during unloading for each load level were consistent with the stability requirements during loading.  
The aim of this investigation was to assess the deformation and compression capabilities of bentonite/rubber mixtures with different mass ratios under varying concentrations of salt solution. By analyzing the compression deformation characteristics, we investigated the influence of different variables on the behavior of the mixture to better understand its performance in different salt solution environments. This provides valuable insights into managing and predicting compression-related deformation in practical applications.