Investigating the impact of foundry by-product sand as an activator on workability improvement and strength development in alkali-activated blast furnace slag mortar

The substitution of alkali-activated furnace slag significantly reduces the necessity of cement manufacture and mitigates the continuous growth of carbon emissions. In addition, it shows superior mechanical properties compared to traditional concrete materials. However, rapid setting issues hinder its widespread applications. This study investigated the innovative use of zero-carbon waste sodium silicate-bonded sand as a substitute for the fine aggregate and sodium silicate in traditional alkali-activated blast furnace slag mortar. The primary objective is to analyze the impact of waste sodium silicate-bonded sand on the workability and mechanical properties of the mortar. The key properties such as flowability, setting time, temperature measurement, compressive strength, and microstructural were analyzed to determine the improvement in workability and the strength development of alkali-activated blast furnace slag mortar resulting from the use of waste sodium silicate-bonded sand. The research showed the integration of waste sodium silicate-bonded sand results in an eco-friendly and cost-effective material, which addresses limitations in traditional activated blast furnace slag mortars. The finding revealed that substituting fine aggregate and sodium silicate with waste sodium silicate-bonded sand significantly improved the mechanical and workability properties of alkali-activated mortars. Notably, the compressive strength of mortars incorporating waste sodium silicate-bonded sand exceeded that of traditional Portland cement and effectively mitigated rapid setting issues. In addition, this approach led to an environmentally friendly mortar with satisfactory workability. The research emphasizes the practical benefits of utilizing waste sodium silicate-bonded sand and offers new insights into its effects on mortar performance. This has provided more details for future exploration and refinement in the field of alkali-activated materials.