氯盐环境下钢筋混凝土构件锈胀开裂风险概率分析

为了研究时间和空间等不确定因素下钢筋混凝土构件的锈胀开裂损伤,针对氯离子腐蚀环境,将钢筋锈蚀划分为2阶段3个特征时刻,分析了锈蚀初始时间、锈胀开裂时间以及锈胀开裂至界限宽度时间的概率特征,建立了钢筋混凝土构件生命周期内锈蚀损伤的风险概率模型,讨论了锈蚀损伤影响参数的敏感性。结果表明:钢筋锈蚀对其影响因素的敏感程度依次为混凝土保护层、临界氯离子浓度、扩散系数和混凝土表面氯离子浓度;钢筋混凝土构件从发生锈胀开裂到裂缝达到界限宽度的时间很短,界限宽度的取值对锈蚀损伤的影响并不显著。

Risk probability analysis of chloride-induced corrosion cracking of reinforced concrete member

A risk probability model of corrosion cracking damage during the service phase of reinforced concrete member lifetime was established to evaluate the effect of uncertainty of space-time in chlorine ion environment.The reinforcement corrosion was divided into two stages with three characteristic times in this model.The probability characteristics of times when corrosion initially occurs,corrosion-induced cracking occurs and the cracks reach limit width were analyzed effectively based on numerical simulation.The sensitivity of influencing parameters of corrosion damage was also discussed.The results show that uncertainty has to be considered for the corrosion damage assessment of existing reinforced concrete members,and the most sensitive parameter for reinforcement corrosion is concrete cover depth,followed by critical chlorine ion concentration,diffusion coefficient and surface chlorine ion concentration.The time from cracks initial appearance till cracks developing to the limit width is very short.The value of limit crack width does not have significant effects on the corrosion cracking damage.