Carbonation and self-healing in concrete: Kinetic Monte Carlo simulations of mineralization
Carbonation and self-healing in concrete: Kinetic Monte Carlo simulations of mineralization
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DOI：
10.1016/j.cemconcomp.2023.105281
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发表时间：
2023-09
影响因子：
10.5
通讯作者：
Aleena Alex;B. Freeman;A. Jefferson;Enrico Masoero
中科院分区：
文献类型：
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作者：
Aleena Alex;B. Freeman;A. Jefferson;Enrico Masoero
由于缺乏将分子尺度上的碳化化学与微观结构发展和宏观性质联系起来的可靠预测模型，诸如自愈和碳捕获与储存等碳化的工业应用受到了限制。本研究提出了一种粗粒度动力学蒙特卡罗（KMC）方法来模拟模型水泥浆体在碳化过程中的微观结构演变，以及所涉及的固体物种的孔隙溶液化学和饱和度指数的演变。模拟结果表明，Ca(OH)2溶解和caco3沉淀的有效速率常数分别为kCa(OH)2= 2.20 × 10−5kg/m3/s和kCaCO3= 4.24 × 10−6kg/m3/s。这些数值直接输入宏观尺度反应输运模型来预测碳酸盐渗透深度。分子尺度的速率常数用于边界成核和生长模型来预测裂纹的自愈。并与实验数据进行了比较，结果吻合较好。这种提出的多尺度方法可以帮助理解和管理传统和新型混凝土的碳化，支持在剩余寿命评估、碳捕获和自我修复方面的应用。
Industrial applications of carbonation such as self-healing and carbon capture and storage have been limited, due to a lack of reliable predictive models linking the chemistry of carbonation at the molecular scale to microstructure development and macroscopic properties. This work proposes a coarse-grained Kinetic Monte Carlo (KMC) approach to simulate microstructural evolution of a model cement paste during carbonation, along with evolution of pore solution chemistry and saturation indexes of solid species involved. The simulations predict the effective rate constants for Ca(OH)2dissolution and CaCO3precipitation as kCa(OH)2= 2.20 × 10−5kg/m3/s and kCaCO3= 4.24 × 10−6kg/m3/s. These values are directly fed to a macroscale reactive transport model to predict carbonate penetration depth. The rate constants from the molecular scale are used in a boundary nucleation and growth model to predict self-healing of cracks. Subsequently these results are compared with experimental data, and provide good agreement. This proposed multiscale approach can help understand and manage the carbonation of both traditional and new concretes, supporting applications in residual lifetime assessment, carbon capture, and self-healing.