Exploring the Potential Utilization of Silicon Manganese Slag as a Supplementary Cementitious Material for Cement Replacement in Developing Low-Carbon Composite Binders

Abstract

The continuous increase in demand for cement in the construction industry critically contributes directly to the global carbon dioxide (CO2) emission. Hence, numerous attempts are being made to reduce CO2 emissions in conjunction with cement production, named as low-carbon cement. This has boosted the enthusiasm for searching for alternatives, specifically supplementary cementitious materials (SCM) that are considered the most environmental and economical friendly method for mitigating CO2 emissions associated with the cement-based construction industry. The purpose of this study is to investigate silicon manganese slag (SiMn slag), a by-product of the metal industry as a sustainable alternative for partial replacements with traditional cement. An experimental investigation was conducted utilizing SiMn slag, primarily focusing on evaluating the compressive strength at 3, 7, 14, and 28 days for both binary and ternary sets of binders, the latter being coupled with ground granulated blast furnace slag. The study has investigated the different replacement levels of cement with SiMn slag up to 90% while maintaining water to binder ratio at 0.35. The microstructure and mineralogical analyses of the prepared hardened binders have been conducted using scanning electron microscopy (SEM) and X-ray diffraction (XRD) to identify phases, morphological changes, and various reaction products. The results indicate that the investigated binary mixture at 30% and 50% cement replacement levels, as well as the ternary mixture at a 50% cement replacement level, exhibited better compressive strength performances. The study suggests using SiMn slag as a supplementary cementitious material in binary or ternary mixtures, potentially achieving improved compressive strength even with higher levels of cement replacement.