Abstract：The evolution characteristics of materials play an important role in the research of material damages. Meso-structure images of a cement specimen under various stress levels are investigated by using the scanning electronic microscope (SEM). The fractal dimensions of these meso-structure images are estimated by image analysis and fractal theory. On the basis of the fractal dimension of meso-structure，the characteristics of the evolution of meso-structure are quantitatively analyzed. It is shown that the value of fractal dimensions，derived by the above-mentioned method，increases with the evolution of the damage，and near the end of loading，the fractal dimensions increase prominently，which means that the damage in the cement specimen becomes more chaotic when the strain approaches its limiting value. It has suggested that the fractal dimensions defined in the paper can be used as indicators for damage in cement materials to depict the evolution of damage or micro cracks.
