Preparation and Properties of Steel Slag Fine Aggregate Foamed Concrete

Steel slag was used as fine aggregate, and steel slag foam concrete (SSFC) was prepared by using steel slag with different particle size and replacement amount. According to the unconfined compressive strength of SSFC naturally cured for 7 d, the optimal mix proportion was obtained. Based on the orthogonal test, the influence of steel slag particle size, steel slag substitution and water-cement ratio on the compressive strength of SSFC was analyzed. On this basis, the influence of steel slag substitution on the mechanical properties of SSFC such as thermal conductivity, flexural strength and water absorption was explored, and the microstructure of SSFC under different steel slag substitution was analyzed. The results show that the optimal proportion for preparing SSFC is 1.18 mm steel slag particle size, 20% steel slag replacement (mass fraction, the same below), and 0.45 water cement ratio. The influence degree of three factors on compressive strength is steel slag substitution > steel slag particle size > water binder ratio. With the increase of steel slag substitution, the thermal conductivity and water absorption of SSFC gradually decreases, and the flexural strength first increases and then decreases. When the steel slag replacement amount is 20%, the flexural strength of SSFC is the largest, because the average pore size of SSFC with 20% steel slag substitution is the smallest and the pore space distribution is the most uniform.