Effects of different composite mineral admixtures on the early hydration and long-term properties of cement-based materials: A comparative study

Abstract

The exploration of sustainable and green cement-based materials prepared from industrial solid wastes is an important research direction in the development of new building materials. This paper carried out a quantitative comparative study of the influences of different composite mineral admixtures prepared with fly ash, steel slag, and ground granulated blast furnace slag (GBFS) as supplementary cementitious materials (SCMs) on the early hydration, long-term (360 d and 720 d) mechanical properties and penetrability of cement-based systems. The results show that adding GBFS and steel slag has the greatest influence on the early hydration of cement due to their synergistic reactions. Over time, it becomes increasingly apparent that adding composite admixtures containing GBFS and fly ash can refine the long-term pore structure, reduce the brittleness, improve the long-term strength and chloride ion penetrability resistance of concrete to the greatest extent. However, adding composite admixtures containing steel slag and fly ash has no positive impact on the long-term properties of concrete. From a comprehensive perspective, considering early hydration, long-term properties and economic costs, composite admixtures containing GBFS and steel slag have potential for wide popularization and applications which can promote the sustainable utilization of steel slag and cleaner production of green concrete.