Abstract: During carbon mineralization process, carbonation reaction and hydration reaction jointly determine the overall process and efficiency. In order to reveal the synergistic mechanism of carbonation and hydration reactions of cement paste, a reactive transport model suitable for the study of carbon mineralization of cement paste was constructed by considering chemical reaction kinetics procedure, CO2 transport and water migration behavior. Based on the comparison and verification with experimental results, the effects of water saturation on CO2 absorption rate and pre-curing time on reactant phase distribution and reaction kinetics were studied accordingly. The research results show that the CO2 absorption rate reaches its maximum value when initial water saturation degree is set to 0.70-0.80. As pre-curing time gradually goes up, the reaction proportion of cement clinker decreases, while the reaction proportion of hydration products increases. The generated CaCO3 content shows a trend of first increasing and then decreasing, and the calcium ions mainly come from C3S and CH. Meanwhile, the process of carbon mineralization has also shifted from being controlled by the diffusion of CO2 in water to being controlled by the amount of available calcium ions in the system.

Key words: highway engineering; construction material engineering; cement-based material; carbon mineralization; carbonation-hydration reaction; reactive transport model

摘要： 在碳矿化反应过程中，碳化反应与水化反应共同决定了整体进程和效率。为了揭示水泥浆体碳化-水化协同作用机制，通过考虑化学反应动力学过程、CO2传输与水分迁移行为，构建了适用于水泥浆体碳矿化研究的反应传输模型，在与实验结果对比验证的基础上，研究了水饱和度对CO2吸收率以及预养护时间对反应物相分布和反应动力学的影响。研究结果表明：当初始水饱和度介于0.70~0.80时，CO2吸收率出现了最大值；随着预养护时间增大，水泥熟料的反应比例减小，而水化产物的反应占比增加，生成的CaCO3含量呈现先上升后下降的变化趋势且钙离子主要来源于C3S和CH，碳矿化进程也由CO2在水中扩散控制转为体系中可用钙离子数量控制。

关键词: 道路工程；建筑材料工程；水泥基材料；碳矿化；碳化-水化反应；反应传输模型