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为了研究不同冻融循环次数下混凝土材料内部细观孔隙特征的变化规律,运用CT技术对冻融循环后的混凝土试样细观损伤过程进行了实时扫描,获取了二维断层扫描图像;在此基础上,进行了全数字化的三维孔隙结构重建分析,得到了三维孔隙结构各项特征参数的孔隙率、孔隙分布频率等统计结果。研究结果表明:随着冻融循环次数的增加,混凝土材料的孔隙率呈现出初期增加后期减小的变化规律;体孔隙频率分布曲线也随冻融循环次数的改变而发生显著变化,反映出冻融循环作用下混凝土内部孔隙的发育和扩展特性。通过混凝土内部孔隙结构三维动态量测与分布研究,对实现精细描述混凝土材料冻融损伤内部结构特征及破损机理具有重要意义。
In order to study the variation of mesoporosity characteristics of concrete material under different freeze-thaw cycles, the mesoscopic damage process of concrete specimens after freeze-thaw cycles was scanned by CT technique and the two-dimensional tomography images were obtained. Based on the 3D digital reconstruction of 3D pore structure, the statistical results of porosity, porosity distribution and other characteristic parameters of 3D pore structure were obtained. The results show that with the increase of the number of freeze-thaw cycles, the porosity of concrete material shows a decreasing trend in the later period of initial increase, and the distribution curve of bulk porosity also changes significantly with the number of freeze-thaw cycles, Development and Expansion of Pores in Concrete under Melt Cycle. Through the study of three-dimensional dynamic measurement and distribution of pore structure in concrete, it is of great significance to realize the detailed description of the internal structure and damage mechanism of concrete with freeze-thaw damage.