氯盐环境下考虑温湿度影响的钢筋混凝土梁桥二维扩散模型及可靠度分析

发布时间：2019-02-27 16:41

【摘要】：结合温湿度效应模型,修正氯离子扩散系数的表达式,利用二维扩散控制方程,建立二维渗透条件下氯盐侵蚀的RC梁桥腐蚀开始发生模型。考虑混凝土表面氯离子浓度、混凝土的扩散系数、保护层厚度以及混凝土抗压强度等参数的时变随机性,建立氯盐环境下腐蚀开始发生概率计算模型,分析在设计寿命期100 a内不同设计参数下结构腐蚀开始概率的变化规律。研究结果表明:海岸线大气区环境下(Zone 2),二维渗透模型对应的腐蚀开始发生概率比一维渗透模型的腐蚀发生概率高9.8%;保护层厚度为20 mm、水灰比为0.55的耐久性设计参数下的氯盐腐蚀发生概率是保护层厚度为40mm、水灰比为0.45时的5.2倍;在浪溅区(Zone 1)的腐蚀开始概率最高,在未来100 a内,达到了96.1%。
[Abstract]:Combined with the model of temperature and humidity effect, the expression of chloride diffusion coefficient was modified, and the two-dimensional diffusion control equation was used to establish the corrosion model of RC beam bridge corroded by chloride under two-dimensional osmotic condition. Considering the time-varying randomicity of chloride ion concentration on concrete surface, diffusion coefficient of concrete, thickness of protective layer and compressive strength of concrete, a calculation model of probability of corrosion starting to occur in chloride salt environment is established. The change rule of structural corrosion initiation probability under different design parameters within the design life of 100 years is analyzed. The results show that the initial corrosion probability of the two-dimensional permeability model is 9.8% higher than that of the one-dimensional permeability model in the coastline atmospheric environment (Zone-2). The probability of chloride corrosion under the durability design parameters with 20 mm, water-cement ratio of 0.55 is 5.2times of that when the thickness of protective layer is 40mm and the ratio of water to cement is 0.45. The initial probability of corrosion in the splash zone (Zone-1) is the highest, reaching 96.1% in the next 100 years.
【作者单位】：湖南城市学院土木工程学院;长沙理工大学土木与建筑学院;
【基金】：湖南省自然科学基金资助项目(12JJ6050) 湖南省教育厅科技计划资助项目(2012GK3066) 交通部应用基础计划资助项目(2014319825160)
【分类号】：U448.34;U441

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