Effect of magnesium slag and fly ash on strength and hydration mechanism of binary and ternary blended cement mortar

Utilizing industrial waste residue in construction is regarded as a crucial technology for advancing renewable resource products and optimizing waste resource use. The objective of this study was to investigate the suitability and feasibility of using modified magnesium slag (MMS) and fly ash (FA) as supplementary cementitious materials in ordinary Portland cement (OPC) mortars. The mechanical strength, microstructure and environmental characteristics of the binary and ternary cement mortars blended with MMS and FA were investigated. The results indicated that the binary mixtures of MMS-OPC and FA-OPC, containing 10 % MMS and 20 % FA, exhibited superior mechanical properties compared to pure cement mortar. In addition, the optimal ratio for the ternary mixtures of MMS-FA-OPC was 10 %: 10 %: 80 %. The hydration products of MMS-OPC, FA-OPC, and MMS-FA-OPC primarily resulted from the interactions between FA and OPC, MMS and OPC, and MMS and FA. Moreover, utilizing MMS and FA as supplementary cementitious materials in cement demonstrates good environmental safety and significant ecological benefits. The results of this study provide a significant reference for the safe disposal and synergistic resource utilization of MMS and FA.