Tang & Qiu (2024): CO2-sequestering ability of lightweight concrete based on reactive magnesia cement and high-dosage biochar aggregate

Yihong Tang, Jishen Qiu IN: Journal of Cleaner Production, 451, 141922, https://doi.org/10.1016/j.jclepro.2024.141922

In this study, lightweight concretes based on reactive magnesia cement (RMC) and high amount of biochar aggregates (up to 508 kg/m³, 61 vol% of the concrete) are developed. The new material demonstrates the ability to sequestrate massive amounts of CO₂ from ambient air, and thus has the potential to be used for greener non-structural applications. The CO₂ sequestration during curing under high-concentration CO₂ (10 %), which is mainly via the RMC carbonation, is determined by acid digestion. The CO₂ sequestration during service under ambient CO₂ concentration (0.1%, or 1000 ppm), which is via the continued carbonation of RMC and the adsorption of biochar, is determined by monitoring the removal of CO₂ in situ; particularly, the CO₂ sequestrations by the RMC and the biochar are determined separately. The effect of varying biochar content and CO₂ curing time on the overall CO₂ sequestering ability of the concrete are studied, together with the variation of the local CO₂ sequestration with carbonation depth in the concrete.

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