CO_2排放和气候变化对混凝土结构开始锈蚀时间的影响

Influence of CO_2 Emission and Climate Change on Initiation Corrosion Time of RC Structures

通过改进碳化深度预测模型,结合IPCC对CO2浓度和气候变暖的预测数据,研究CO2排放对混凝土结构碳化损伤的影响。考虑CO2排放、环境、结构尺寸、保护层厚度和劣化机制的不确定性和变异性,假定某混凝土结构2010年开始服役,用时变可靠度模型计算其在实际气候条件和多种CO2排放策略下未来90 a的开始腐蚀概率。研究结果表明:A1F1和A1B排放策略下,碳化深度平均值分别比不考虑CO2浓度影响增大17%和8%,CO2排放导致混凝土结构腐蚀概率显著增加;地区气候条件对碳化腐蚀有显著的影响;对于保护层厚度为40 mm和水灰比为0.45的混凝土结构,碳化腐蚀损伤可以忽略,对于保护层厚度为20 mm和水灰比为0.55的混凝土结构,钢筋腐蚀风险较高。

The influence of CO2 emission scenarios on carbonation damage of concrete structures was studied using the modified carbonation depth prediction model and prediction information of CO2 concentrations and climate warming presented by IPCC.Considered the uncertainty and variability of CO2 emission,environment,structural dimension,cover depth and deterioration mechanisms,the time-dependent reliability model was employed to predict the probability of corrosion initiation under actual climate conditions and several atmospheric CO2 emission scenarios over the next 90 years,on the assumption that a RC concrete structure was put into service in 2010.The result shows that（1） the carbonation depth in A1F1 scenarios and A1B scenarios was 17% and 8% higher than that under invariant CO2 concentration respectively,and CO2 emission induced significant increase of corrosion probability of RC structures;（2） regional climate conditions have great effects on carbonation damage of concrete;（3） the risk of carbonation corrosion could be neglected for the RC structure with 40 mm cover depth and 0.45 water-cement ratio,while risk of carbonation corrosion is higher for the RC structure with 20 mm cover depth and 0.55 water-cement ratio.