中文摘要：

依据试验研究结果和细观断裂力学研究混凝土经流动软水侵蚀后劈拉性能变化的细观机理．试验通过自制的流动软水模拟装置对混凝土试块进行长期侵蚀，测试了侵蚀过程中混凝土孔隙和侵蚀前后混凝土劈拉强度的变化规律．试验结果表明：混凝土试块在历经软水侵蚀后，孔隙率和有害孔径率明显增大，劈拉强度随侵蚀时间的增长逐渐降低．根据断裂力学和侵蚀前后混凝土孔隙的变化规律提出用于理论分析的侵蚀混凝土受拉裂纹构型；以裂纹间距与裂纹初始长度的比值为可变参数，分析混凝土受劈拉时断裂强度与裂纹特征参数之间的关系，对混凝土劈拉强度的变化进行预测．模型分析结果表明，基于弹塑性理论的模型预测结果与试验值较一致．

英文摘要：

The change mesomechanism of split tensile strength of concrete deteriorated by soft water was analyzed based on meso-fracture mechanics and experimental results. A special device was designed to simulate the leaching of concrete caused by soft water. Some experiments were conducted to test the porosity and the split tensile strengths of concretes. The experimental results indicate that the porosity and the harmful aperture ratio of deteriorated concrete increase significantly and the split tensile strength decreases gradually along with the erosion time. A crack model for theoretical analysis was proposed based on the porosity changes of deteriorated and undeteriorated concretes and the fracture mechanics. The relationships between split tensile strength and crack parameters were discussed using the ratio of initial crack length and crack distance as variances. The split tensile strength of concrete was predicted based on the proposed models. Results showed that the elastic-plastic model accorded well with the experimental results.