海洋混凝土结构的表面氯离子浓度反映了海洋氯化物环境的腐蚀作用强度,是海洋混凝土结构耐久性分析和定量设计的重要参数。本文依据国内外不同地区的大量自然暴露试验数据,通过数理统计和回归分析,确定了各种海洋环境条件下表面氯离子浓度的统计特征值,分析了海洋潮汐浪溅区混凝土中氯离子的传输机理和积聚规律,揭示了水胶比对混凝土表面氯离子浓度的影响规律,进而综合考虑水胶比、胶凝材料种类和时变特性等因素的影响,建立了海洋潮汐浪溅区混凝土表面氯离子浓度的改进计算模型。结合国内外各种表面氯离子浓度经验模型的预测结果和海洋自然暴露试验的实测数据,对比验证了所建立表面氯离子浓度计算模型的有效性和适用性,为海洋氯化物环境下混凝土结构的耐久性设计和服役寿命分析提供了重要边界条件。
Surface chloride concentration of the marine concrete structures reflects the intensity of the external chloride attack, which is one of the most important parameters for the quantitative design and durability analysis of the reinforced concrete structures exposed to the marine chloride environment. In this study, statistical characteristics of surface chloride concentration of concrete structures exposed to different marine environment conditions were obtained, based on the statistical and regression analysis of the selected field data from different natural exposure tests. Meanwhile, the transport mechanism and accumulation law of chloride ion within concrete exposed to the marine tidal and splash zones were analyzed and the influences of water-to-binder ratio on surface chloride concentration were also explored. Finally, an improved computing model for the surface chloride concentration of concrete structure exposed to the marine tidal and splash zones was developed by taking into account the influences of water-to-binder ratio, type of binding materials, and time-dependent behavior. Accuracy and applicability of the proposed model were demonstrated by comparing the results of existing empirical prediction models and field investigation data. The paper shows that the proposed model provides an important boundary condition for the quantitative durability design and service life prediction of the reinforced concrete structures exposed to the marine chloride environment.