湿热高盐环境轻骨料内养护混凝土氯离子沉积与传输行为研究

The coastal concrete structures often suffer premature deterioration of durability due to reinforcement corrosion caused by chloride erosion, and hygrothermal and salinity environment is an important reason for accelerating the transport of chloride ions in concrete. The internal curing effect of pre-wetted lightweight aggregate can improve the anti-corrosion ability of concrete to a certain extent. In view of the characteristics of hygrothermal and salinity environment in the coastal area, this project is to develop an internal curing concrete by replacing a portion of the normal weight aggregate with pre-wetted lightweight aggregate, and carry out a systematic research on deposition and transportation of chloride under the simulated hygrothermal and salinity environment. Based on theoretical analysis, laboratory tests and field investigations, the influence of internal curing effect of lightweight aggregate on the interfacial transition zone will be explored, the relationship of chloride ion erosion behavior and concrete meso-structure of the lightweight aggregate concrete will be discussed, the distribution and binding capacity of chloride ion in lightweight aggregate concrete will be studied, the deposition mechanism and transportation behavior of chloride ion in lightweight aggregate concrete will be investigated, and the chloride ion transport model in the lightweight aggregate concrete will be established. The results of this study can provide a theoretical basis and technical support for the construction and maintenance of lightweight aggregate concrete structure in coastal areas.

近沿海既有混凝土结构常因氯盐侵蚀引起的钢筋锈蚀导致其耐久性能过早劣化，湿热高盐环境是加速氯离子在混凝土中传输的重要原因，轻骨料的内养护作用可以在一定程度上提高混凝土的抗介质侵蚀能力。本项目针对近沿海湿热高盐环境的特点，以轻骨料内养护混凝土为研究对象，拟在分析轻骨料内养护机理的基础上，研究湿热高盐环境下轻骨料内养护混凝土的氯离子沉积与传输行为。项目拟采用理论分析、试验研究与工程验证相结合的方法，通过湿热高盐侵蚀环境的模拟试验，探讨轻骨料的内养护作用对混凝土骨料-浆体界面过渡区的影响，分析氯离子侵蚀行为与混凝土细观结构的关系；研究轻骨料内养护混凝土中氯离子浓度的分布规律和结合能力，揭示氯离子在多孔骨料混凝土表层的沉积机理，以及在混凝土内部的传输行为，建立湿热高盐环境下氯离子在轻骨料内养护混凝土中的传输模型。研究成果可为近沿海轻骨料混凝土结构的建设与维护提供理论依据与技术支撑。

近沿海既有混凝土结构常因氯盐侵蚀引起的钢筋锈蚀导致其耐久性能过早劣化，湿热高盐环境是加速氯离子在混凝土中传输的重要原因，轻骨料的内养护作用可以在一定程度上提高混凝土的抗介质侵蚀能力。本项目针对近沿海湿热高盐环境的特点，将珊瑚骨料作为轻骨料拌制珊瑚骨料混凝土，分析了珊瑚骨料的内养护机理，研究了湿热高盐环境下轻骨料内养护混凝土的氯离子沉积与传输行为。通过湿热高盐侵蚀环境的模拟试验，探讨了轻骨料的内养护作用对混凝土骨料-浆体界面过渡区的影响，揭示了湿热高盐环境对轻骨料混凝土内养护作用的影响机理；分析了湿热高盐环境下轻骨料内养护混凝土氯离子沉积机理并分析其沉积规律；研究了轻骨料内养护混凝土在湿热高盐环境中的氯离子传输行为，建立了相应的传输模型，研究成果可为近沿海及岛礁基础设施建设与维护提供理论依据和技术支撑。