混凝土硬化变形特征与破坏规律相关性实验研究

Experimental research on the correlations between concrete hardening and its loading failure

通过CCD相机搭建试验的数据采集系统,以数字散斑相关方法对试验中采集的散斑图像数据进行分析,研究混凝土试件硬化过程中试件表面变形场演化特征及其对后期受载破坏规律的影响。试验结果表明:(1)混凝土硬化变形时空演化表现为变形缓慢增加、变形快速增加、变形稳定3个阶段特征;混凝土硬化变形时空演化过程是一个从拉、压区域不断调整到最终稳定的动态过程,调整过程中在受拉区形成损伤集中区;混凝土硬化变形场空间演化特征表现为由不均匀分布演化为拉、压应变区域呈条状相间的分布状态。(2)受载过程中裂纹在硬化变形受拉较大的区域开始发育,随着荷载的增加裂纹沿着硬化过程中形成的条状受拉区域扩展成宏观裂纹且试件表面裂纹具有等距分布特征。

To research the evolution of deformation field of concrete hardening process and its influence on the loading failure.Experi- mental data are collected with CCD camera.Speckle image data acquired in the experiment were analyzed by digital speckle correlation method.The analysis results show that, （ 1 ）In the process of hardening of concrete, the deformation is shown to exhibit the characteristics of three stages, slow increase, rapid increase of deformation and stability of deformation.The deformation evolution of concrete in the hard- ening process is a dynamic process from tension and compression to final stability, and in the process of adjustment, the damage zone is formed in the tension zone.The distribution of deformation field in the hardening process of concrete specimen is changed from nonuni- form distribution to state of ribbon distribution. （2）In the course of loading, the crack always occurs in the area of the concrete hardening deformation, and along with the increase of the load, the crack is always formed in the shape of the strip deformation zone which formed in the process of concrete hardening.The crack of specimen has the characteristic of equal distance distribution.