中文摘要：

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。

英文摘要：

To research the change law of internal meso-porous characteristics of concrete under different freeze-thaw cycles,the CT technology was used to in situ scan the evolution of concrete damage process under freeze-thaw cycles,so the batch of 2D slice images was obtained.On this basis,the 3D porous structure of concrete was reconstructed by means of full digital image processing analysis tools,so the statistics porosity and porous structure distribution of 3D porous structure characteristics parameters were obtained.The results show that the porosity of concrete materials present a ＂down-up＂trend with the growth of cycle numbers. Meanwhile,the frequency distribution curve of volume porous significantly changes with the change of freezethaw cycle numbers.The results show that the characteristics of concrete porous developmentand propagation are indicated under the condition of freeze-thaw cycles.Three-dimensional dynamic measurement and distribution characteristics of interior porous structure is vital for the depiction on interior structure characteristics and damage mechanism of freeze-thaw damage concrete.2tabs,10 figs,24refs.