Effect of CO2 mineralization on phase evolution and microstructure development of blended cement formulated with large proportion of steel slag

作者：Yubin Cao, Mengjie Liu, Shiyinuo Wang, Song Gao, Leqing Lin, Xu Chen, Zhenwei Qin, Qi Yu, Pengjie Song, Ran Li, Yanru Wang · 发表于：Case Studies in Construction Materials · 年份：2025 · DOI：10.1016/j.cscm.2025.e05080 · 被引用次数：1 · 研究领域：Concrete and Cement Materials Research、Magnesium Oxide Properties and Applications、Concrete Properties and Behavior

The presence of larger percentage of inert components, f-CaO and brucite in blended cementitious materials formulated with steel slag results in lower reactivity and poor volume stability, which restricts the utilization of steel slag as supplementary cementitious materials. The aim of this paper is to investigate the effect of CO 2 mineralisation on the strength development, phase evolution and microstructure improvement of blended cementitious materials formulated with different proportions of steel slag at different water to binder ratios (w/b). Densified system with ultra-fine particles (DSPs) was adopted to guide the mixture formulation to enhance the strength. The results showed that, CO 2 mineralisation dominantly increased the compressive strength development compared with the control sample and reduced the flexural strength. Samples with high w/b ratio (i.e., 0.30, 0.35 and 0.40) showed the highest carbonation depth after 3 days carbonation curing. Calcite with good crystal morphology was the mainly carbonated products in the fully carbonation zone, whilst metastable aragonite and vaterite were formed in the carbonation interfacial transition zone, which may be influenced by the CO 2 concentration and curing time. Phase evolution caused by carbonation curing significantly refined the pore size to harmless and reduced the porosity, especially for that with higher w/b ratio.