Preparation and mix proportion optimization of red mud-fly ash-based cementitious material synergistic activated by carbide slag and MSWIFA

The recycling of solid waste materials in the building materials industry is a necessary part of the green and low-carbon development of the building materials industry. In this study, based on the carbide slag (CS)-red mud (RM)-fly ash (FA) ternary binder (CRF) system, another hazardous waste, namely municipal solid waste incineration fly ash (MSWIFA) is introduced through the component optimization design, so that CS and MSWIFA produce a synergistic activation effect, as a result, the CS-RM-FA-MSWIFA quarternary binder (CRFM) is prepare. The feasibility of preparing CRFM binder was explored by synergistic activated of CS and MSWIFA with macroscopic mechanical properties as the index, and the synergistic effect of CS and MSWIFA was characterized by using various microscopic test methods. The results of the macroscopic mechanical properties test show that adding MSWIFA to the CRF ternary cementitious material can effectively improve the strength of the binder. According to the microscopic XRD, FTIR, TG-DTG, SEM-EDS and MIP tests, the hydration products of the CRFM binder are mainly C-A-S-H, calcium chloroaluminate hydrate (HCC), and ettringite (AFt). The hydration products fill up in the pore spaces of the matrix, which then promote the development of the strength of the binder. In addition, the ICP test results show that the CRFM cementitious materials do not pollute the environment. The research results can provide technical guidance for preparing novel cementitious materials using solid waste such as CS and MSWIFA as building materials.