0引言混凝土是一种由砂石骨料、水泥、水及其他外加材料混合而形成的非均质脆性材料。由于混凝土施工和本身变形、约束等一系列问题,硬化成型的混凝土中存在着众多的微孔隙、气穴和微裂缝,正是由于这些初始缺陷的存在才使混凝土呈现出一些非均质的特性。微裂缝通常是一种无害裂 0 Introduction Concrete is a kind of heterogeneous brittle material formed by the mixture of gravel aggregates, cement, water and other additional materials. Due to a series of problems, such as concrete construction and its own deformation and restraint, there are many micro-pores, air cavities and micro-cracks in the hardened concrete. It is precisely because of these initial defects that concrete exhibits some inhomogeneous properties . Microcracking is usually a harmless crack