Application on cementitious materials to promote durability of alkali-activated concrete containing co-fired fly ash and water-quenched slag

Abstract

In the present study, we evaluated the effects of using co-fired fly ash (waste product of paper making) and water-quenched slag (waste product of iron smelting) in the manufacture of cementitious materials (CM). Rapid chloride permeability results revealed that less charge passes through CM than through ordinary Portland cement (OPC), indicating the superior durability of CM. However, the results of water permeability testing led to the opposite conclusion. Absorption capacity results revealed that the durability of CM is lower than that of OPC. Previous studies have shown that the strength of CM is only 70% that of OPC. This is a clear indication that CM containing co-fired fly ash and slag should not be used for primary structures, i.e., its use should be limited to secondary structures such as bricks or PC-based materials.