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Mesoscopic mechanisms of dicalcium silicate dissolution
Cement and Concrete Research ( IF 10.9 ) Pub Date : 2024-12-31 , DOI: 10.1016/j.cemconres.2024.107660
Yong Tao, Pablo Martin, Hegoi Manzano, Mohammad Javad Abdolhosseini Qomi

Dicalcium silicate dissolution is crucial in cement hydration and provides long-term durability. However, our understanding of its dissolution process is limited due to its multiscale nature. To resolve this limitation, we combine rare event molecular dynamics and kinetic Monte Carlo (KMC) techniques. At the nanoscale, we reveal the relationship between surface Ca2+ coordination chemistry and dissolution free energy barriers. Leveraging this knowledge, KMC simulations accurately predict the apparent dissolution activation energy and the sigmoidal relationship between dissolution rate and solution activity observed in experiments. Importantly, we find that dislocations have minimal impact on dissolution rates in grains and fast-dissolving cleavages. Instead, these rates are primarily determined by spontaneous pit opening and coalescence on surfaces, and the receding corners and edges within dissolving grains. This multiscale framework paves the path for fundamental studies and quantitative prediction of dissolution–precipitation processes widely encountered in cement chemistry, carbon sequestration, and enhanced geothermal systems.

中文翻译:


硅酸二钙溶解的介观机制



硅酸二钙的溶解在水泥水化中至关重要,并提供长期耐久性。然而,由于其多尺度性质,我们对其溶解过程的理解是有限的。为了解决这一限制,我们将罕见事件分子动力学和动力学蒙特卡洛 (KMC) 技术相结合。在纳米尺度上,我们揭示了表面 Ca2+ 配位化学与溶出自由能垒之间的关系。利用这些知识,KMC 模拟准确预测了实验中观察到的表观溶出活化能以及溶出速率和溶出活性之间的 S 形关系。重要的是,我们发现位错对晶粒中的溶解速率和快速溶解裂解的影响最小。相反,这些速率主要由表面上的自发凹坑打开和聚结以及溶解颗粒内后退的角落和边缘决定。这个多尺度框架为水泥化学、碳封存和增强型地热系统中广泛遇到的溶解-沉淀过程的基础研究和定量预测铺平了道路。
更新日期:2024-12-31
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