| 摘要: |
| 混凝土耐久性研究从环境层面分主要是碳化和氯离子扩散两个方面。碳化过程会改变混凝土的性质,影响氯离子扩散。在相同养护条件下制成混凝土试件,试件在内部环境条件相同的碳化箱中进行不同程度碳化并测量碳化深度。采用标准电流电量法测量不同碳化深度混凝土试件的扩散系数,分析在其他条件相同的情况下碳化深度对氯离子扩散系数的影响及产生这种影响的原因。试验结果表明氯离子扩散系数随碳化深度增加而增大。综合分析碳化影响效应,碳化对于氯离子扩散存在正反两方面的影响。一方面碳化增加混凝土密实度,阻碍氯离子扩散；另一方面碳化增加混凝土内毛细孔数量且增加自由氯离子含量,促进氯离子扩散。实际情况下碳化对于氯离子扩散系数的影响效应取决于哪一方面的作用更具主导性。 |
| 关键词: 混凝土耐久性 碳化 氯离子扩散 电流电量法 |
| DOI： |
| 分类号:TV528 |
| 基金项目: |
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| Experimental studies of concrete carbonization impact on chloride diffusion |
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YANG Wei-wei, ZHENG Yong-lai, ZHENG Sun
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Department of Hydraulic Engineering， Tongji University
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| Abstract: |
| Carbonization and chloride diffusion are the two most important factors which affect durability of concrete in the aspect of environment. The process of carbonization changes the properties of concrete and affects chloride diffusion. The concrete samples were cured under the same conditions. The concrete samples were carbonized to different degrees in the carbonization box with the same conditions inside. Current and electric quantity method has been used to test the chloride diffusion coefficients in the concrete samples with different carbonization depths, and to analyze the effects of carbonization on the chloridion diffusion and the probable reasons for it when other conditions are the same. Experiment results show that the chloride diffusion coefficients will grow when the carbonization depth is increased. Further analysis results show that the carbonization has both positive and negative effects on the chloride diffusion. As the negative effect， carbonization increases the degree of density in concrete which prevents the chloride diffusion. As the positive effect， carbonization increases the amount of capillary porosity and content of free chloridion in concrete which promotes chloride diffusion. The effects given by carbonization on the chloride diffusion depends on the aspect which is more dominant in the practical situation. |
| Key words: durability of concrete carbonization chloridion diffusion current and electric quantity method |
