Study on physical and mechanical properties of calcium carbide residue stabilized waste clay

Calcium carbide residue (CCR) is a strongly alkaline industrial waste slag dominated by Ca(OH)₂, and it has high potential and economic advantages of being a soil solidifying agent due to its cementitious characteristic. The results indicate that dosage of hardener ( a ccr ) has a notable effect on improving the physical and mechanical properties of CCR stabilized soil than H (carbonation time). After adding CCR, the plasticity index( I p ) of the soil decreased continuously from an initial value of 16.1 to 10.2, a decrease of approximately 37%, indicating a reduction in the plasticity of the soil. Within 2 hours of carbonation, the strength of CCR-stabilized carbonated soil increases continuously with increasing amount of a ccr , reaching a maximum UCS strength of 1271.6 kPa, i.e., a 472% increase in strength compared to the minimum UCS value (221.92 kPa) among all test groups. E 50 (elastic modulus) is notably affected by a ccr , with the maximum increment of E 50 reaching 98%. Accelerating the carbonation reaction not only accelerates the formation of CaCO 3 , but also increases the volume of carbonation products as H increases, forming a complex mixed structure that facilitates pore filling and improves strength. This study provides a theoretical basis and experimental reference for the engineering application of solidification-carbonation improvement technology for shield tunnel waste clay under laboratory conditions.