Preparation and experimental study of saponified slag fly ash foam lightweight soil.

The accumulation of industrial solid wastes will cause waste of land resources and environmental pollution. In order to improve the utilization rate of industrial solid wastes, this paper uses cement, saponified slag (SS) and fly ash (FA) as raw materials to prepare saponified slag fly ash foam lightweight soil (SS-FA foam lightweight soil). This study mainly focuses on the basic performance indexes of foam lightweight soil, such as dry density, compressive strength, water absorption and fluidity. The optimization interval of water-binder ratio, SS dosage and FA dosage of SS-FA foam lightweight soil is determined through single factor test. Based on the single factor optimization interval, the orthogonal experiment of three factors and three levels is designed, and the optimal mix proportion of SS-FA foam lightweight soil is obtained through the comprehensive balance method. The results showed that the optimization intervals for each factor of SS-FA foam lightweight soil were 0.51–0.59 water-binder ratio, 5 %-15 % SS dosage, and 5 %-15 % FA dosage. When the water-binder ratio is 0.55, SS dosage 5 %, FA dosage 10 %, the comprehensive performance of SS-FA foam lightweight soil reaches the best. Finally, the microstructure and hydration mechanism of SS-FA foam lightweight soil were studied by means of microscopic means XRD and SEM. It is confirmed that the addition of appropriate amount of SS can effectively improve the pore structure of fly ash foam lightweight soil, promote the early depolymerization of FA, and improve the compactness and bonding performance of fly ash foam lightweight soil. • A novel saponified slag (SS) fly ash (FA) foam lightweight soil (SS-FA foam lightweight soil) was prepared. • SS has good synergistic reaction with FA. • The optimum mix ratio for SS-FA foam lightweight soil was determined. • The microstructure of SS-FA foam lightweight soil as well as the hydration mechanism were analyzed. [ABSTRACT FROM AUTHOR]