Enhancing CO2-Cured cementitious binder with Mg-doped γ-C2S from high-Mg limestone
Songhui Liu, Pengjie Rong, Saisai Zhang, Hui Guo, Xuemao Guan, Jianping Zhu, Tangwei Mi
Abstract
This study explores the use of Mg-doped γ-C 2 S, an alternative to conventional Portland cement, to address the environmental impact of the cement industry. γ-C 2 S, known for low hydration activity, shows promise as a CO 2 -cured binder. The research investigates Mg substitution in γ-C 2 S synthesis, utilizing high-Mg limestone resources. Varying Mg/Ca ratios in γ-C 2 S synthesis promoted bredigite and merwinite phases during calcination, enhancing specific surface area by over 40%. Optimal Mg doping significantly increased carbonation reactivity, resulting in a 20% strength boost (115 MPa) after 24h of CO 2 curing. This improvement is attributed to enhanced crystallinity in carbonation products, namely hydromagnesite, nesquehonite, aragonite, and magnesite, leading to microstructure densification. The findings highlight Mg-doping as a promising strategy to enhance the carbonation performance of γ-C 2 S from high-Mg limestone, offering prospects for sustainable construction materials with reduced CO 2 emissions. • Increased Mg/Ca ratio enhances the early-stage carbonation of γ-C 2 S. • Mg addition elevates compressive strength by over 20% to 115.33 MPa. • Mg-doped γ-C2S optimizes structure, filling pores for strength.