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由钢筋锈蚀引起的混凝土保护层锈胀开裂是混凝土结构耐久性极限状态的重要标志,是决定结构使用寿命的重要因素。以钢筋均匀锈蚀为前提,考虑锈蚀产物的变形特性以及锈胀裂缝开展过程中锈蚀产物进入裂缝的实际情况,借助弹性力学和Faraday腐蚀定律,建立混凝土保护层锈胀开裂时刻的钢筋锈蚀率以及锈胀开裂时间计算公式。针对影响混凝土保护层锈胀开裂时间各主要因素的分析表明,增大钢筋的混凝土保护层厚度、减小钢筋直径、提高混凝土强度以及控制锈蚀产物的体积膨胀率都有利于混凝土结构耐久性的提高。与已有试验结果的对比分析可知,对于加速锈蚀和长期锈蚀情况,计算公式的预测结果均较为理想,可用于由钢筋均匀锈蚀引起的混凝土保护层锈胀开裂时间的预测分析。
Corrosion cracking of concrete cover caused by steel corrosion is an important symbol of durability limit state of concrete structure and is an important factor that determines the service life of the structure. Based on the uniform corrosion of steel bars, considering the deformation characteristics of the corrosion products and the actual situation of the corrosion products entering the cracks during the development of the corrosion cracks, the corrosion rate of the steel bars and rust Expansion cracking time formula. According to the analysis of the main factors influencing the cracking time of concrete cover, it shows that increasing the concrete cover thickness, reducing the steel bar diameter, increasing the concrete strength and controlling the volume expansion rate of the corrosion products all contribute to the improvement of the durability of the concrete structure . Compared with the existing test results, we can see that the predicted results of the calculation formula are ideal for accelerating corrosion and long-term corrosion, which can be used to predict the corrosion cracking resistance of concrete cover caused by the uniform corrosion of steel bar.