【摘要】 通过对疲劳损伤机理的分析,针对损伤发展的第2阶段,采用不同疲劳循环次数比对应的残余拉应变与疲劳破坏时对应的极限残余拉应变的比值来定义损伤变量,重点研究了疲劳载荷与氯盐协同作用下结构混凝土的耐久性及其寿命预测方法.研究结果表明:随着疲劳损伤所产生的残余拉应变的增大,氯离子在混凝土中的扩散系数逐渐增加;当残余拉应变超过60×10-6时,其增加幅度开始变得显著;当残余拉应变增加到120×10-6时,氯离子扩散系数提高了1个数量级.因此,在海洋大气环境与疲劳载荷的协同作用下,结构混凝土的服役寿命大大缩短.这些方法与结论可为疲劳载荷与环境因素协同作用下混凝土的耐久性设计与评估提供依据.更多还原

【Abstract】 According to the analysis of fatigue damage mechanism,the damage variable is defined by the proportion of relevant residual strain in various fatigue cycle life to ultimate cumulative residual strain in the second fatigue damage stage.Life prediction method of structural concrete that focuses on the fatigue load coupled with chloride environmental factors is presented by considering the effects of different fatigue degrees on the structural concrete durability.It is shown that the diffusion coefficient of chloride ion in the structural concrete increases with the increase of residual tensile strain.As the residual tensile strain exceeds 60×10-6,the ingression of chloride ions into the concrete increases rapidly.While the residual strain is above 120×10-6,the diffusion coefficient raises near 10 times compared with the control concrete.Therefore,service life of structural concrete is obviously reduced by the multi-damage of bending fatigue and chloride environmental loading.The method and conclusion provide a good reference and basis for the research of concrete durability under dynamic load.更多还原