Sustainable Low Fines Self Compacting Concrete incorporating Magnesite Mine Waste as Partial Replacement for Aggregates and Cement

Abstract

Managing mining waste is a global concern due to its large volume, environmental implications, health risks, and costly disposal. Recent trends emphasize the reuse of newlinesuch waste in construction to promote sustainability. This study investigates the potential of magnesite mine waste (MMW) as a partial replacement for cement and aggregates in the production of self-compacting concrete (SCC). The main objective is to evaluate the performance of MMW-incorporated SCC in terms of fresh, mechanical, durability, microstructural, and bond properties, alongside sustainability metrics such as cost, carbon footprint, and energy consumption. Experimental results reveal that SCC mixtures with MMW as aggregate replacements (FA and CA series) exhibited superior fresh and mechanical performance, including a 10-15% increase in compressive, tensile, and flexural strengths, while mixtures with MMW as cement replacement (BB and TB series) showed a strength reduction of up to 50%. Fresh property tests categorized the SCC under SF1 flow with VF1 and VF2 viscosity classes. Importantly, the incorporation of fly ash and MMW led to significant sustainability benefits, including a 48% reduction in CO2 emissions, a 45% decrease in embodied energy, and a 17% cost saving. Eco-efficiency analysis demonstrated up to 75% higher efficiency in MMW-based SCC compared to conventional mixtures. These findings support the feasibility of using MMW, particularly as an aggregate replacement, in producing sustainable, high-performance SCC, contributing both to waste valorisation and environmental conservation. newline