Research on the hydration process of solid waste–based cementitious materials and application in roadbase

In order to improve the high-value utilization of industrial solid waste materials, this study prepared a solid waste–based cementitious material (SWCM) using slag, fly ash, desulfurization gypsum, and gangue. The mechanical strength and hydration process of the SWCM and an ordinary Portland cement (OPC) were studied. The results showed that the compressive strength of the SWCM was lower than that of OPC at 3 d, but the compressive strength exceeded that of OPC after 7 d. The isothermal calorimetry results showed that the induction period of the SWCM was five times that of OPC, and the total 4 d exothermic amount of OPC was 1.7 times that of the SWCM. XRD and SEM showed that the hydration products of the SWCM were mainly ettringite (AFt) and hydrated calcium silicate gel (C-S-H). The unconfined compressive strength and dry shrinkage of stabilized macadam were also studied by using the SWCM to replace OPC. The results indicated that the unconfined compressive strength of the SWCM-stabilized macadam is comparable to that of the OPC-stabilized macadam. The dry shrinkage strain was only 79.7% of the OPC-stabilized macadam.