盐冻作用下钢筋混凝土梁的疲劳性能试验研究

Experimental study on fatigue performance of reinforced concrete beams after cyclic freeze-thaw subjoining chloride

为研究寒区钢筋混凝土结构在氯盐和冻融双重作用下的疲劳性能衰变规律,先通过快冻法分别对钢筋混凝土梁进行水冻和盐冻循环,再进行弯曲疲劳试验。试验结果显示试件的残余挠度与相对动弹性模量具有相似的变化规律,符合混凝土损伤破坏机理。研究表明:残余挠度的增长率符合阻滞模型的规律,建立了钢筋混凝土试件的疲劳损伤模型。根据试验数据对所建立的损伤模型进行非线性拟合,拟合相关系数均大于0.98,说明该模型能够较好的反应混凝土的损伤程度。最后结合混凝土损伤模型提出了预测在役混凝土寿命的方法。

To study the fatigue performance decay law of reinforced concrete structures after cyclic freeze - thaw subjoining chloride in cold area, firstly, the concrete beams were subjected to water and salt freezing cycles by fast freezing method, then the bending fatigue tests were carried out. The results show that the residual deflection and the relative dynamic elastic modulus have similar variation, in line with concrete damage mechanism, the growth rate of residual deflection accords with the law of the block model, and the fatigue damage model is established. Nonlinear fitting was done based on the test data for the damage model, fitting correlation coefficients were larger than 0.98, indicating the degree of damage that the model can better response concrete. Finally, the method of predicting service life of concrete is putting forward based on the damage model of concrete.