冻融劣化混凝土动态轴压弹塑性损伤研究

Study on the dynamic elastic-plastic damage of freeze-thaw deteriorated concrete under uniaxial compression

为探明处于不同冻融劣化程度的混凝土材料的动态轴压损伤特性,进行了不同冻融循环次数(0次、10次、20次、30次、40次)下的混凝土动态轴压试验。研究结果表明,改进后的弹塑性损伤本构模型能够很好地描述冻融劣化混凝土动态轴压损伤演化规律。冻融劣化混凝土动态轴压损伤演化过程中,损伤积累与刚度退化和塑性变形发展基本保持同步。应变速率的增大可以减缓混凝土材料损伤的发展,提高混凝土损伤发展的阈值。混凝土冻融劣化程度越低,损伤演化不同发展阶段的特征差异就越显著,并且材料会以更快的速度发生损伤破坏。

In order to find out the dynamic uniaxial compressive damage characteristics of concrete in different freeze-thaw degrees,the concrete dynamic uniaxial compression tests with different freeze-thaw cycles(0 time,10 times,20 times,30 times,40 times)are carried out.The results show that the dynamic uniaxial compression damage evolution of freeze-thaw deteriorated concrete can be described well by the improved elastic-plastic damage constitutive model.The damage accumulation and development of stiffness degradation and plastic deformation are basically in sync during the evolution of dynamic uniaxial compression damage of freeze-thaw deteriorated concrete.The damage development of concrete could be slow down with the increase of strain rate,while the threshold of concrete damage development could be improved.At the same strain rate,the characteristic difference between different stages of concrete damage evolution would be of more significance and the damage rate would be greater with the lower degree of freeze-thaw deterioration.