多因素作用下钢筋混凝土构件氯离子扩散系数模型

Chloride Ion Diffusion Coefficient Model of R.C.Elements under Multiple Factors

通过对钢筋混凝土氯离子侵蚀机理的分析,在Fick第二扩散定律基础上,建立了综合考虑水灰比、湿度、时间、温度、混凝土材料对氯离子结合作用等多因素作用下的氯离子侵蚀模型,并给出了考虑边界条件的侵蚀模型数学解。通过对长期现场暴露试验数据分析,验证了该侵蚀模型的有效性和可靠性。与传统的Fick第二扩散定律模型对比并分析得:该模型不仅能反映结构实际受氯盐侵蚀的发展趋势和混凝土不同深度处的氯离子浓度,而且能预测不同时期钢筋处的氯离子含量和钢筋开始锈蚀时间。

Based on the analysis of chloride ion-induced erosion mechanism of reinforced concrete and the Fick＇s second law,a multi-factor model of the chloride ion erosion is established.In this model,the influences of water-cement ratio,humidity,time,temperature,and chloride ion binding capacity of concrete are taken into consideration,and the mathematic solution to the new model is provided by considering the boundary conditions.The new model is verified by analyzing the long-term exposed experiment data.Compared with the traditional model of Fick＇s second law,the model can indicate the development trend of the structure eroded by chloride and the chloride ion concentration in different depth,and at the same time,it can predicate the chlorine ion concentration on rebar surface in different corrosion periods and the initiation corrosion time of reinforcement.