海洋环境状态下受氯盐侵蚀钢筋混凝土结构耐久性寿命预测

Prediction on durability and life of reinforced concrete structures eroded by chloride in marine environment

在海洋环境中,Cl^(-)入侵造成的钢筋锈蚀是影响钢筋混凝土结构服役寿命的主要原因。因此,提出合理描述Cl^(-)入侵的耐久性模型对于准确预测港口混凝土结构服役寿命至关重要。文章运用MATLAB软件对Cl^(-)在钢筋混凝土结构中的扩展过程进行仿真模拟,将得到的数据进行Gamma过程建模,提出一种Cl^(-)侵蚀条件下钢筋混凝土耐久性寿命预测的新方法。根据菲克第二定律,得到混凝土的Cl^(-)扩散理论基准模型;同时,运用有限差分法和蒙特卡罗法得出多因素作用下结构钢筋表面Cl^(-)浓度数据和结构耐久性数据,做出直方图,与基于Gamma过程的耐久性寿命概率密度函数理论曲线进行对比分析,证明新方法的可行性。结果表明:理论曲线与直方图高度吻合,表明了基于Gamma过程的氯盐侵蚀环境下钢筋混凝土结构耐久性模型的准确性和可靠性。本文成果可为确保港口混凝土结构在预计服役期内满足适用性和安全性要求提供一定的借鉴与参考。

In the marine environment,the corrosion of steel bars caused by chloride ion intrusion is the main reason affecting the service life of reinforced concrete structures.Therefore,it is very important to propose a durability model to describe chloride ion intrusion to accurately predict the service life of port concrete structures.In this paper,MATLAB software is used to simulate the propagation process of chloride ions in reinforced concrete structures,and the obtained data is modeled by Gamma process,and a new method for predicting the durability life of reinforced concrete under chloride ion erosion is proposed.According to Fick's second law,the theoretical benchmark model of chloride ion diffusion in concrete is obtained.At the same time,the finite difference method and Monte Carlo method are used to obtain the chloride ion concentration data and structural durability data of the structural reinforcement surface under the action of multiple factors,and the histogram is made,which is compared with the theoretical curve of the durability life probability density function based on the Gamma process to prove the feasibility of the new method.The results show that the theoretical curve is in good agreement with the histogram,which indicates the accuracy and reliability of the durability model of reinforced concrete structures in the chloride salt erosion environment based on the Gamma process.The results can provide some reference for ensuring that the port concrete structure meets the applicability and safety requirements during the expected serviceperiod.