Carbon-negative manufactured aggregates production from the mixture of calcium and magnesium-based carbonates

Abstract

This study focuses on the development and optimisation of carbon-negative manufactured aggregates derived from calcium and magnesium-based carbonates. Through a series of experiments, such as carbonate synthesis, binder formulation, aggregate production, and mortar performance evaluation, the feasibility and effectiveness of incorporating these aggregates into concrete production are investigated. Various ratios of carbonate synthesis experiments were conducted to determine the optimal ratio of calcium to magnesium carbonate for maximising carbon sequestration potential. Results indicate that a 1:1 ratio exhibits the highest carbon sequestering capability. Binders consisting of CemR3, GGBS, and CS were synthesised and tested for compressive strength, revealing their suitability for structural applications while reducing the overall embodied carbon footprint. Mortar samples incorporating manufactured calcium magnesium aggregates exhibited superior mechanical performance compared to those with natural aggregates, highlighting the effectiveness of carbon-negative aggregates in enhancing both strength and sustainability of concrete. The findings of this study contribute to advancing sustainable concrete construction practices by providing insights into the optimisation of carbon-negative aggregate production. Future research directions may focus on further refining manufacturing processes, evaluating long-term durability, and assessing life cycle environmental impacts to fully realise the potential of carbon-negative concrete technology in mitigating carbon emissions in the built environment.