单轴压缩下透水混凝土的结构损伤演化特征研究

为了研究透水混凝土在单轴压缩过程中的内部孔、裂隙变化规律,对轴向应变为0.4%、1.1%和1.8%的试样开展CT扫描,基于二值化分割方法得到了孔、裂隙的图像,分析了孔、裂隙量化指标与轴向应变的关系。结果表明,透水混凝土的孔、裂隙随破坏程度增加有明显的扩展趋势,孔径频率分布曲线的孔径值不断增大;随着轴向应变的增加,孔隙率呈指数型函数上升趋势,最大孔喉长度L和平均孔喉半径R呈线性增长,连通度指标也不断增加,且增速先慢后快;由微观结构分析,透水混凝土骨料颗粒与凝胶结构发生的位移和形变是孔、裂隙网络形成和扩展的微观机理。

Study on Structure Evolution Characteristics of Pervious Concrete under Uniaxial Compression

In order to study the variation rules of the mesospores and cracks of pervious concrete during the uniaxial compression test,the CT scanning are carried out on samples with axial strain of 0.4%,1.1%and 1.8%respectively.The images of pores and cracks are obtained based on the binarization method,and the relationship between quantitative indexes of pores and cracks and axial strain is analyzed.The results show that,(a)the cracks of permeable concrete have an obvious tendency to expand with the increase of damage degree,and the value in pore diameter frequency distribution curve keeps increasing;(b)with the increase of axial strain,the porosity presents an exponential upward trend,the maximum pore throat length L and the average pore throat radius R show a linear increase,and the connectivity index is also increasing with the growth rate of slow at first and then fast;and(c)according to the microstructure analysis,the displacement and deformation between permeable concrete aggregate particles and gel structures are the microscopic mechanism of the expansion of pore and crack networks.