中文摘要：

以单轴压缩条件下混凝土细观损伤演化的CT图像为研究对象，借助于数字图像处理技术对CT图像进行了阈值分割，提取出了图像中的裂纹形态，分析了单轴压缩条件下混凝土内部微裂纹的萌生、扩展和贯通的全过程，并利用差分盒维数法估算出图像裂纹扩展的分形维数．在此基础上，获得了载荷、扩展裂纹及分形维数三者之间的关系．结果表明：在单轴压缩条件下，定义的分形维数随着裂纹的扩展逐渐增加，可将细观结构分形维数作为研究混凝土细观裂纹扩展的定量参数．

英文摘要：

Based on CT image of concrete meso-damage evolution under unaxial compression. The CT image was analyzed by the method of digital image processing, which included threshold partition,and then the real crack morphologic was got. So the CT image of crack propagation, coalescence and failure the whole process was researched. The fractal dimension of crack propagation of CT image was estimated by Differential Box Counting fractal theory. On the basis of the results, the relationship among the stress load, the crack propagation and the fractal dimension was found. The resuhs showed that the value of fractal dimensions increased with the evolution of crack, so the fracture of the meso-structure was calculated as a quantitative parameter to research the meso-crack propagation.