【摘要】 基于改进的碳化深度预测模型,结合IPCC预测大气CO2浓度数据,研究气候变化(CO2浓度)的规律及其对混凝土结构的碳化损伤影响。由于概率预测模型能够考虑CO2排放、环境、结构尺寸、腐蚀电流密度、钢筋布置、保护层厚度和劣化机制的不确定性和变异性,提出时变可靠度模型来计算混凝土结构在多种CO2排放策略作用下将来100年内的开始腐蚀概率和腐蚀开裂比例。研究表明:在最高CO2排放策略下的开始腐蚀概率比其在最好CO2排放策略下高720%;对于耐久性差的混凝土,在将来100年的开裂概率为0.37,这意味着大多数混凝土结构在服役期存在碳化腐蚀损伤现象,将来需要大量的维修和维护工作;当碳化腐蚀裂缝宽度要求设置从1mm降低为0.3mm时,碳化腐蚀开裂比例提高25%～70%;在所有排放策略下高腐蚀电流密度状态的混凝土腐蚀开裂比例比低腐蚀电流密度状态高1.6～2.8倍。这些信息能够为混凝土桥梁全寿命设计和维护提供支持。更多还原

【Abstract】 Based on a modified carbonation depth prediction model,the present study describes how the predicted increases in CO2 levels will affect carbonation-induced corrosion damage to concrete structures,using information on climate change provided by the IPCC.Probabilistic methods are employed as there are significant uncertainty and variability of CO2 emissions,deterioration mechanisms,material properties,dimensions and environments.The time-dependent structural reliability analysis will predict the probability of corrosion initiation and mean proportion of corrosion damage of concrete structures over the next 100 years,considering several IPCC future atmospheric CO2 emission scenarios.For the worst case emission scenario the probability of corrosion initiation is 720% higher than the best mitigation scenario.For a poor durability design specification the mean proportion of corrosion damage is up to 0.37 after 100 years.There is thus a significant likelihood of corrosion damage that will need costly and disruptive repairs during the service life of many concrete structures.If the limit crack width is reduced from 1 mm to 0.3 mm,then the mean proportion of corrosion damage increases by approximately 25%-70%.For the higher deterioration,the mean proportion of corrosion damage is 1.6-2.8 times higher than the lower deterioration.更多还原