Analysis of the Synergistic Effect on the Strength Characteristics of Modified Red Mud-Based Stabilized Soil

Based on the existing research results, this research team developed roadbed stabilized soil materials using nano-SiO₂ synergistically modified red mud in order to study whether the strength of the stabilized soil materials meets the strength requirements of the roadbed materials, and at the same time, analyze its strength characteristics to make the feasibility of it being used as a roadbed material clear. Through different combination schemes, the effects of different nano-SiO₂ and cement contents on the strength of the stabilized materials were explored. The test results show the following: In the synergistic modification of nano-SiO₂ and cement, nano-SiO₂ can significantly improve the early unconfined compressive strength of red mud-based stabilized soil. In the synergistic modification of nano-SiO₂, gypsum, and cement, the 7 d unconfined compressive strength of red mud-based stabilized soil is greater than 2 MPa, which meets the strength requirements of road base materials and shows the superiority of synergism. The nominal stress-strain curves are divided into five stages: compressed and compacted stage, elastic deformation stage, plastic deformation stage, damage deformation stage, and residual deformation stage. The macroscopic compressive damage pattern of the specimens shows that the modified red mud-based stabilized soil mostly exhibits brittle damage. Tests have shown that the strength of modified terracotta-based stabilized soil meets the requirements of roadbed strength.