Study on mix proportion optimization and durability of concrete prepared from mining and metallurgical solid waste.

Purpose: In order to solve the environmental pollution problem caused by the large amount of industrial solid waste stockpiling and land occupation,and to improve the comprehensive utilization efficiency of industrial solid waste. Method: we prepared low-carbon concrete with C30 strength grade, which is prepared by mixing solid waste-based cementitious materials with cement and fly ash in different proportions, and then using iron tailing sand and iron tailing gravel as aggregates. Among them, solid waste-based cementitious materials consist of typical process solid wastes such as steel slag,slag,and desulfurization gypsum. The experiments investigated the effects of cement substitution rate and fly ash admixture on the compressive strength of low-carbon concrete,analyzed the durability performance of all-solid-waste low-carbon concrete, and explored the hydration products and processes of solid-waste-based cementitious materials using XRD, TG-DSC, and SEM. Result; The results show that; under the condition of 80 kg/m3 of fly ash mixing,the replacement rate of cement by solid waste-based cementitious materials could reach 50% -- 70%, and it was appropriate to use solid waste-based cementitious materials as a single cementitious material when they completely replace cement. The all-solid-waste low-carbon concrete had good [ABSTRACT FROM AUTHOR]