Steel Slag-Based Belite−Ferrite Clinker as a Low-Carbon Component in Portland Cement: Formation, Hydration, and Microstructural Refinement

Abstract

Low-carbon cement requires clinker designs with lower CaO demand and more effective utilization of industrial wastes. In this study, a steel slag-based Belite−Ferrite (BF) clinker dominated by dicalcium silicate (C2S) and tetracalcium aluminoferrite (C4AF) was developed and evaluated. The results indicate that the steel slag-based BF clinker highly promoted the formation of active α-C2S, which formed ∼23.2% active α-C2S in the total C2S phase, as well as reduced about 22−38% CO2 emissions compared with ordinary Portland cement (OPC) clinker. As an alternative material for OPC clinker, the produced BF clinker exhibited low early reactivity but presented a continuing hydration and strength growth in 28 d, which enhanced 5−19% compressive strength at 28 d with 10−40% replacement of OPC clinker in OPC-BF cement system. The estimated CO2 emissions of the OPC-BF cement system were 3−16% lower than those of the pure OPC system, indicating that steel slag-based BF clinker is a promising low-carbon component for OPC.