实际服役混凝土结构不可避免产生微裂纹，而微裂纹的产生会显著影响混凝土的渗透性等物质传输性能。本文从宏、细观两个层次对含裂纹网络混凝土的渗透性进行了系统的理论和试验研究。本文首先推导了含不连通裂纹网络渗透率的相互作用直推（IDD）解；引入连通度定义推导了裂纹部分连通时渗透率的扩展 IDD 解。基于简单二维概念模型，分析了裂纹长度、取向和平均间距对整体渗透性的影响。对裂纹相互平行、随机取向但不连通两种情形的数值分析验证了 IDD 模型的有效性；对裂纹网络部分连通情形的数值的分析验证了扩展 IDD 模型的有效性。将混凝土视作二维三相复合材料，本文对骨料、过渡区影响混凝土材料整体渗透性进行了系统的分析并从统计角度给出了代表体积单元的大小。骨料的稀释作用、曲折度效应会大幅降低有效渗透性，前者的降低幅度近似为骨料的体积比，后者在~20\%~左右。过渡区会显著增大有效渗透率，它会部分抵消甚至超过骨料的有利影响。对再生骨料混凝土来说，要求控制再生骨料的质量及掺量。本文研发的气体渗透率测试系统具有密封效果好、操作简便、精度高、重现性好等优点。采用多个指标表征力学损伤和物质传输性能，试验结果表明轴向残余应变能很好地表征力学损伤；气体渗透指数 GPI 与超声损伤指标 D 之间具有良好的相关性，建议的回归公式可应用于混凝土材料耐久性能的无损检测；毛细吸水率与开放孔隙率之间的相关关系良好且可用双线性规律描述；交流电导率与开放孔隙率密切相关，但对于不同开裂模态的敏感程度有所不同。对损伤试件纵、横断面的微裂纹进行的观测和分析表明，对数正态分布能很好地描述直线微裂纹长度的分布，对数长度均值、方差在纵横方向随损伤演进而发展的规律有较大差别。采用开裂密度~$\rho_2$~描述纵横向微裂纹随损伤演化而发展的过程具有良好规律性；用~$\zeta$~变量分析总体取向性，裂纹在横向呈现明显各向异性而在纵向呈现沿纵向的优势取向，不同高度开裂密度差别较大。横向裂纹累积长度与物质传输性能指标有一定相关性但较离散。沿厚度方向渗透率的稀疏解、扩展 IDD 解、数值解与电导率、气渗指数相关性良好但数值上相差很大，这是由于观测局限于二维平面且忽略更小尺度的微裂纹，开裂密度和连通度被低估。

Micro-cracks unavoidably exist for concrete structure under real services. And transport properties of concrete such as permeability will be degraded significantly by the generation of micro-cracks of concrete. From both macro and mesoscopic levels, this thesis mainly devotes to the theoretical and experimental research on permeability of concrete with cracking damage.Firstly, this thesis theoretically derives the Interaction Direct Derivative (IDD) solution of permeability for matrix with no-interconnecting micro-cracks in the framework of micromechanics. After introducing the definition of cracking connectivity $\phi$, the extended IDD model is developed to determine equivalent permeability of matrix with part-connecting micro-cracks. Based on a simple 2-dimensional conceptual model, the influence of some mesoscopic indexes including crack length, orientation and average spacing on the overall permeability is analyzed. The validity and accuracy of IDD solution for no-connecting situation is examined via two special case analyses, one with parallel micro-cracks and another with random-oriented micro-cracks. The validity and accuracy of extended IDD model is also numerically confirmed by special case analysis with randomly oriented and randomly part-connected micro-cracks.Usually concrete can be thought as three-phase composite with aggregate, mortar matrix and interfacial transition zone (ITZ). Under this assumption, this contribution analyzes the impact of properties of coarse aggregate and ITZ on equivalent permeability and given the size of representative volume element (RVE) statistically. It is indicated that both dilution effect and tortuosity effect when incorporating aggregate have remarkable effect on the overall permeability. The influence degree can be approximated as the volume fraction of aggregate for dilution effect and is about 20\% for tortuosity effect. ITZ will increase the overall permeability of concrete dramatically even overcome the favorable effect of aggregate. For recycled aggregate concrete, it is necessary to control the quality and quantity of incorporated recycled aggregate.Gas permeability test system is developed here and has many advantages, such as excellent sealed effect, easy operation, high accuracy and good repeatability etc. Using several physical indexes to characterize mechanical damage macroscopically, the experimental results show that the residual axial strain and ultrasonic damage can be good indicators for mechanical damage. The gas permeability index (GPI) is well correlated with ultrasonic damage $D$ and the suggested regression formula can be used as a basic relation of non-destructive testing for durability of concrete materials. There is also good co-relationship between capillary absorptivity and effective porosity, which can be described by bilinear laws for both two types of concrete. Ac electrical conductivity is closely related with capillary porosity, but the sensitive degree is obviously different for different cracking pattern.The micro-cracking network on longitudinal and transverse surface of mechanically damaged concrete specimens are also observed and analyzed. Lognormal distribution gives a good description of length distribution of straight micro-cracking on both longitudinal and transverse section. It is quite different for the developing of mean value and variance of log-length of micro-cracks as mechanical damage evolves. When characterizing by defined cracking density $\rho_2$, the evolvement of cracks network has clear regularity as damage increasing. Variable $\zeta$ is developed and defined to characterize overall density and orientation of cracks network. And it is indicated that the cracking network on transverse section is obviously anisotropic while mainly oriented along the longitudinal direction on longitudinal section. There is also much diversion for the cracking density on different location. Cracking density $\rho_2$ on transverse section is well correlated with transport properties including capillary absorptivity, electrical conductivity and gas permeability but with obvious scatter. Based on the observed longitudinal cracking network, the dilute estimate, extended IDD solution and numerical results of gas permeability through thickness of concrete specimen are given and they are well correlated with testing electrical conductivity and gas permeability index but much smaller than the measured values. This is due to the 2-dimensional observation of cracks with relatively low resolution thus underestimation of cracking density and connectivity. Multi-scale and 3-dimensional modeling is needed to quantify the impact of cracking network on transport performance of damaged concrete materials.