Effect of steel fibre and manufactured sand on mechanical properties of alkali-activated slag green cementitious material after high temperature

This study investigated the mechanical properties of alkali-activated slag cementitious (AASCM) after exposure to 20-800 degrees C considering the effect of steel fibre content and type to promote the use of AASCM in structural engineering. The volume contents of were 0%, 0.5%, 1.0% and 1.5%, and the aggregate types were manufactured sand and river sand. The residual compressive, tensile strength and mass loss were determined. Besides, microstructure and phase composition of AASCM before and after high temperature were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). sults show that the tensile and compressive properties of manufactured sand AASCM were to that of natural river sand after high temperature exposure. Below 600 degrees C, steel improve the mechanical properties of AASCM. Steel fibre oxidation fails and effectively strengthening effect on AASCM with the temperature reaching 800 degrees C, resulting in decrease in strength of AASCM. The models for calculating mass loss, compressive strength, tensile strength of steel fibre reinforced AASCM after high temperature exposure established.