Development of ternary all-solid-waste cementitious materials and utilization in engineering sediment waste stabilization

This study aims to prepare ternary all-solid-waste cementitious materials to completely replace ordinary Portland cement (OPC). Ground granulated blast-furnace slag (GGBS), carbide slag (CS), sulfate solid waste phosphogypsum (PG), electrolytic manganese residue (EMR) and desulfurized gypsum (DG) were used as raw materials to prepare GGBS-PG-CS (GPC), GGBS-EMR-CS (GEC) and GGBS-DG-CS (GDC) ternary all-solid-waste cementitious materials. Macro and microscopic tests were carried out to reveal the mechanical properties and microscopic characteristics, as well as to quantitatively evaluate the environmental and economic benefits. The results show that the optimal ratios of GPC, GEC and GDC are 80:18:2, 60:36:4 and 80:18:2, respectively. The corresponding 28 d-unconfined compressive strength (UCS) are 1.62, 1.22 and 1.01 times that of OPC, respectively. Carbon emissions and costs per unit strength can be reduced by more than 97% and 57%, respectively. Microscopic analysis shows that the incorporation of sulfate solid waste can synergistically activate GGBS with CS to induce the growth of more needle-like ettringite (AFt), which filled the internal pores and improved the strength of the cementitious material. The better mechanical properties of solidified engineering sediment waste (ESW) also confirm the feasibility of replacing OPC. In summary, this study developed all-solid-waste cementitious materials with excellent mechanical performance, low costs and carbon emissions, which provided a sustainable and economic solution for ESW stabilization.