Due to the demand for carbon neutrality, concrete carbonation has been reconsidered as an interesting topic because of its potential for capturing CO₂ from the atmosphere. Concrete carbonation can significantly modify the chemical and microstructure properties of concrete and thus will have important effects on chloride diffusion. This paper presents a chloride diffusion model in which the concrete cover is divided into three different zones, each with their own defined porosity and chloride binding isotherm. One is the fully carbonated concrete near the surface, where the porosity and chloride binding isotherm can be obtained from the experimental data of fully carbonated concrete. One is the uncarbonated concrete near the reinforcement, where the porosity and chloride binding isotherm can be obtained from the experimental data of normal concrete. One is the transition zone between the fully carbonated and uncarbonated concretes, where the porosity and chloride binding isotherm can be assumed to vary continuously from the carbonated concrete to uncarbonated concrete. To validate the present model, the comparison of the present model with published experimental results is also provided, which demonstrates the importance of considering different zones in chloride diffusion model when the concrete has a carbonated layer near the surface.

中文翻译：

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模拟具有碳化表面层的混凝土中的氯离子扩散

由于对碳中和的需求，混凝土碳化因其从大气中捕获CO ₂的潜力而被重新视为一个有趣的话题。混凝土碳化可以显着改变混凝土的化学和微观结构性能，从而对氯离子扩散产生重要影响。本文提出了一个氯离子扩散模型，其中混凝土覆盖层被分为三个不同的区域，每个区域都有自己定义的孔隙率和氯离子结合等温线。一种是接近表面的全碳化混凝土，其孔隙率和氯离子结合等温线可以从全碳化混凝土的实验数据中获得。一种是靠近钢筋的非碳化混凝土，其孔隙率和氯离子结合等温线可以从普通混凝土的实验数据中获得。一是完全碳化混凝土和非碳化混凝土之间的过渡区，可以假设孔隙率和氯离子结合等温线从碳化混凝土到非碳化混凝土连续变化。为了验证本模型，还提供了本模型与已发表的实验结果的比较，这表明当混凝土表面附近有碳化层时，在氯离子扩散模型中考虑不同区域的重要性。