Study on the applicability of gasification coarse slag as admixture for cement-based materials

Abstract

Abstract To reduce the environmental risks caused by the accumulation of coarse slag and enhance its comprehensive utilization efficiency, this paper takes gasification coarse slag and cement as the main research objects and explores the optimal mix ratio of coarse slag in subgrade materials. By analyzing the fundamental physical and chemical properties of coarse slag and characterizing the hydration products and microstructure of the solidified slurry, the impact of coarse slag content on the strength characteristics of coarse slag-cement-based standard test blocks was investigated. The results showed that the main chemical components of the coarse slag were SiO2, Al2O3, and CaO, and the loss on ignition was 16.18%, which met the suitability requirements of the cement roadbed material. As the mixing ratio of coarse slag continues to increase, the water-cement ratio with fluidity ≥180 mm gradually increases, which would hinder the hydration process of the standard specimen, reduce the generation of hydration products such as C-S-H, destroy the dense structure of the aggregate, and reduce the material strength. When the content of gasified slag was about 15% to 20%, the structure became dense, and the strength of the coarse slag-cement-based material was higher after 28 days of hydration, which was more suitable for engineering applications.