钢筋混凝土结构盐冻破坏分析及寿命预测

为评估北方季冻区除冰盐对钢筋混凝土结构耐久性的影响,开展了混凝土试件的盐冻试验,根据试验测得的混凝土相对动弹性模量与质量损失率,分析了钢筋混凝土结构在冻融环境下的损伤情况,得到了盐冻环境下钢筋混凝土盐冻损伤度随冻融循环周期变化的关系式。同时将钢筋混凝土盐冻损伤度引入到氯离子扩散模型(DuraCete模型)中,修正了公式中氯离子扩散系数,使得该公式更适用于冻融环境,最终得到了钢筋混凝土结构的寿命预测公式。修正后的钢筋混凝土结构的寿命预测公式既考虑了冻融和氯离子侵蚀双重作用,又不需要对氯离子扩散系数进行经验取值,使得本预测模型更方便、实用。

Damage Analysis and Life Prediction of Reinforced Concrete Structure under Salt Frost Condition

In order to evaluate the effect of deicing salt on the durability of reinforced concrete structure in seasonal freezing areas in the north,this paper conducts a test of salt frost on concrete specimens.According to the relative dynamic elastic modulus and mass loss rate of concrete measured in the test,the paper analyzes the damage of concrete under freeze-thaw environment,and obtains the relationship between the damage degree of concrete and the freeze-thaw cycles in the salt frost environment.In addition,the paper introduces the damage degree into the DuraCete model,and modifies the chloride diffusion coefficient in the formula,so that the formula is more suitable for freeze-thaw environment,and finally obtains the formula for predicting the life of reinforced concrete structure.The revised life prediction formula of reinforced concrete structure takes into account the dual factors of freeze-thaw cycles and chloride ion erosion,and does not require empirical value of chloride ion diffusion coefficient,which makes the prediction model more convenient and practical.