Carbonation is a common type of concrete deterioration, which can cause various physicochemical changes that adversely affect the performance of reinforced concrete structures. The reinforced concrete structures can be considerably damaged by the reinforcement corrosion caused by the neutralization of concrete under carbonation. This study introduces a numerical analysis approach to examine concrete carbonation with calcium hydroxide (Ca(OH)2), which decreases the alkalinity of concrete. Carbonation analysis is performed by considering the diffusion of carbon dioxide (CO2) and moisture, which play influential roles in the carbonation reaction. A detailed formulation process is established to apply the theoretical equations to the numerical analysis by considering the mentioned influential factors. Further, appropriate modification factors are applied to the numerical analysis under various environmental conditions. The proposed numerical analysis is verified by comparing the carbonation front depths with those obtained from the experimental results via thermogravimetric analysis. Furthermore, a carbonation experiment is conducted using a phenolphthalein solution, and the results are compared with those of the numerical analysis. The experimental carbonation front depth obtained using a phenolphthalein solution is half of that obtained using numerical analysis, which is consistent with the result obtained by other researchers in previous studies. These observations indicate that the proposed numerical analysis considering CO2 and moisture diffusion sufficiently simulates concrete carbonation.

中文翻译：

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考虑水分扩散的混凝土碳化数值方法

碳化是一种常见的混凝土劣化类型，会引起各种物理化学变化，对钢筋混凝土结构的性能产生不利影响。钢筋混凝土结构会因混凝土在碳化作用下中和而引起的钢筋腐蚀而受到相当大的破坏。本研究介绍了一种数值分析方法，用氢氧化钙 (Ca(OH)2) 检测混凝土碳化，这会降低混凝土的碱度。碳酸化分析是通过考虑二氧化碳 (CO2) 和水分的扩散来进行的，它们在碳酸化反应中起着重要作用。通过考虑上述影响因素，建立了详细的公式化过程，将理论方程应用于数值分析。更多，适当的修正系数被应用于各种环境条件下的数值分析。通过将碳化前沿深度与通过热重分析从实验结果中获得的深度进行比较，验证了所提出的数值分析。此外，使用酚酞溶液进行碳酸化实验，并将结果与​​数值分析的结果进行比较。使用酚酞溶液获得的实验碳化前沿深度是使用数值分析获得的一半，这与其他研究人员在之前的研究中获得的结果一致。这些观察结果表明，考虑到 CO2 和水分扩散的拟议数值分析足以模拟混凝土碳化。