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为揭示常见施工偏差对混凝土结构耐久性能的影响规律,对国内外预测氯离子侵蚀条件下混凝土结构使用寿命的6种模型进行比较,分析氯离子侵蚀环境下影响耐久性的主要参数。选择典型环境下的混凝土桥梁构件,模拟保护层厚度、水胶比等参数的常见施工偏差,在各模型下分析比较保护层厚度对结构耐久性能的影响。结果表明,保护层厚度、水胶比等参数变化(偏差)对预期耐久寿命有显著影响,影响程度与偏差大小、设计参数取值及计算模型的选用有较大关系。保护层厚度不足(-5 mm)的施工偏差会导致预测氯离子侵蚀耐久寿命缩短约20%~40%;水胶比增大(+0.02)会导致预测寿命缩短约15%~25%。可见,施工质量控制偏差对结构抗氯离子侵蚀耐久性能的影响重大,加强关键参数质量控制极为重要。
In order to reveal the rules of common construction deviations on the durability of concrete structures, six models for predicting the service life of concrete structures under chloride ion erosion conditions were compared at home and abroad, and the main parameters affecting the durability under chloride ion erosion were analyzed. The common construction deviations of the concrete bridge members, the simulation protective layer thickness and the water-cement ratio were selected under the typical environment. The influence of the thickness of the protective layer on the durability of the structure was analyzed and compared under each model. The results show that the variation (deviation) of protective layer thickness, water-cement ratio and other parameters have a significant impact on the expected durability life, and the degree of influence is greatly related to the size of deviation, the design parameters and the selection of calculation models. A construction deviation of less than -5 mm in thickness will result in a predicted short-circuit lifetime of chloride ion erosion of about 20-40% and an increase in water-cement ratio of +0.02 will result in a 15% to 25% reduction in life expectancy. It can be seen that the deviation of construction quality control has a significant impact on the durability of the structure against chloride ion erosion. It is very important to strengthen the quality control of key parameters.