Investigation of the Influences of Utilizing Industrial Solid Waste in All-Solid Waste Controlled Low-Strength Material

Given that controlled low-strength material (CLSM) requires low strength, it has the potential to be entirely developed by industrial solid waste. In this study, all-solid waste CLSM was prepared with ground granulated blast-furnace slag (GGBS), carbide slag (CS), fly ash (FA), solid NaOH, and iron tailing sand. The engineering properties, microstructure, and environmental impact of all-solid waste CLSM were characterized by conducting a series of tests. The experimental results demonstrated that all-solid waste CLSM offers high flowability (≥205 mm), low bleeding (≤4.8%), and faster setting time (4.1–13 h). The increase in CS content decreased the flowability, whereas the increase in NaOH content slightly decreased the flowability significantly reduced the bleeding by 60.87%, and shortened the setting time by 75.37%. Meanwhile, increasing the content ratio of GGBS to CS was conducive to improving flowability and strength as well as shortening the setting time. Based on the experimental data, empirical formulas were established among flowability, bleeding, setting time, strength, and cementitious material components. The hydration products of all-solid waste CLSM were mainly calcium alumina silicate hydrate (C─ A─ S─ H), calcium aluminum iron silicate hydrate (C─ F─ A─ S─ H), and tricalcium aluminate hexahydrate (C3AH6), improving the structural strength of all-solid waste CLSM. The environmental impact assessment showed that the all-solid waste CLSM showed acceptable corrosion after 7 days, and the leaching concentration of heavy metals in leachate meets the requirements. In addition, the cementitious materials in all-solid waste CLSM can reduce carbon emissions by 23.4% to 68.8%.