Abstract: Excessive stockpiling of copper slag, an industrial solid waste, has caused a series of land occupation and environmental pollution problems in the process of urbanization. In this paper, copper slag combined with traditional stabilizer lime was used to treat expansive soil. The engineering properties and microstructure of modified expansive soil were investigated by a series of macroscopic and microscopic tests, and the stabilization mechanism was illustrated. The evaluation of environmental effects was made in combination with the Hakanson potential ecological risk index method. Results show that copper slag can effectively reduce the swelling and compressibility of expansive soil and significantly improve its strength. Compared with the specimen without copper slag, the strength of the specimen with 6% copper slag can reach 1.2 MPa, which meets the road standard. Microscopic test results reveal the process of densification of soil structure through a series of physicochemical effects such as physical filling, cation exchange and pozzolanic reaction. Meanwhile, the interaction mechanism between lime-copper slag composite cementitious material and expansive soil is divided into the following three stages: physical filling stage, initial hydrolysis and hydration stage, and secondary hydration stage. The environmental effect evaluation results prove the environmental harmlessness of lime-copper slag in the process of stabilizing expansive soil. The study demonstrates that copper slag is highly effective as a soil stabilizer and has a broad application prospect in resource utilization.
Keywords: copper slag; expansive soil; engineering properties; microstructure; environmental effects
合肥工业大学学报自科版