耐蚀钢筋混凝土结构及其在海洋环境下的服役性能演变规律

To meet the urgent demands of marine exploitation, many concrete infrastructures will be constructed in the coastal and far-out sea areas. Due to the severe effect of marine environment, these structures will be corroded during their service life. Therefore, some experimental and theoretical studies are carried out in this project to solve this durability issue of concrete structure on basis of the corrosion resistance of steel reinforcement. Firstly, some corrosion tests are conducted to understand the corrosion mechanism and regularity of corrosion-resisting reinforcement. On the foundation of corrosion experiments, the material selection and improvement methods, the mix use technology of corrosion-resisting and ordinary reinforcements, and the structural measures of the new structure will be formed. And then, the feasibility of applying sea water, sea / reef sand and corrosion-resisting reinforcement to construct a durable concrete structure is discussed. When a durable reinforced concrete structure is explored to resist the corrosion in marine environment, the mechanical properties of the structural elements will be experimental studied to establish the prediction models of elements’ performances and the design theory of this new structure. Finally, the durability test of corrosion-resisting steel reinforced concrete structure is conducted, and some corresponding models are developed to predict the servicibility and the durability of the new structure under the erosion of chloride ions. The achievements of this project can provide some technical and theoretical supports for the design and the construction of concrete infrastructures in the sea area. In addition, the use of corrosion-resisting steel reinforcement can guarantee the durability and the service life of concrete structure in the chloride environment by reducing the risk of structural failure, and eliminates or reduces the maintenance investment during the service life.

本项目针对海洋工程建设的迫切需求和海洋混凝土结构、远海岛礁建设急需解决的耐久性技术难题，从钢筋本身的耐蚀性出发开展试验与理论研究，探寻适用于海洋混凝土结构的耐蚀钢材，在明确耐蚀钢筋时随腐蚀规律与腐蚀机理的基础上，形成可靠的耐蚀钢选用和优化方法，耐蚀钢筋-普通钢筋混用技术、结构构造设计措施；探索海水、海/礁砂应用于耐蚀钢筋混凝土结构的可行性；构建海洋环境下高耐蚀长耐久的钢筋混凝土结构，并建立耐蚀钢筋混凝土结构基本构件力学性能分析模型和结构设计理论；根据海洋环境下耐蚀结构的服役性能研究，形成耐蚀结构服役性能评价及服役寿命预测方法。旨在为沿海及远海混凝土基础设施建设提供技术与理论支持，在保障海洋环境下混凝土结构耐久性和服役寿命的同时，免除或者减少后期维护、维修资金的投入，降低结构失效风险。

海洋环境较为恶劣，很容易导致混凝土中的钢筋发生锈蚀，影响工程结构的耐久性、安全性和服役寿命，大大增加结构后期的维护和维修费用。而且，远海岛礁的混凝土基础设施建设若采用传统的钢筋混凝土结构将耗费巨大的人力物力；若就地取材，采用海水、礁沙作为原料，则会大幅度降低工程造价、缩短工期，但是现阶段广为使用的普通钢筋混凝土结构显然不能满足这些材料的选用。因此，建立一种适用的耐蚀钢筋混凝土结构，来提高海洋环境下混凝土工程结构的耐久性、保证其服役寿命，已成为当前海洋工程结构建设急需解决的科学技术问题。.本项目从钢筋本身出发开展试验与理论研究，探寻适用于海洋混凝土结构的耐蚀钢材，利用混凝土孔隙液和电化学方法评价了不同钢材的耐蚀性，获得了耐久性设计所需钢筋的临界氯离子浓度；揭示了氯盐污染混凝土、开裂混凝土中不锈钢钢筋的腐蚀行为；评价了耐蚀钢筋-普通钢筋混用时的腐蚀效应，探讨了耐蚀钢筋与普通钢筋的混用技术，建立了耐蚀钢筋-普通钢筋混用工况下混凝土结构承载能力的计算方法；试验研究了不锈钢筋混凝土梁、柱式构件的受力性能，建立了不锈钢筋混凝土构件承载能力计算模型和构件裂缝与变形的计算公式；利用扫描技术精确衡量了不锈钢筋的锈蚀信息；揭示了锈蚀对不锈钢筋力学性能及钢筋与混凝土之间粘结性能的影响规律；得到了锈蚀不锈钢筋混凝土构件的力学性能退化规律，建立了锈蚀构件承载能力的计算方法；探讨了不锈钢筋混凝土构件的耐久性极限状态，基于概率方法预测了混凝土结构的使用寿命。研究成果可为沿海及远海混凝土基础设施建设提供技术与理论支持，在保障海洋环境下混凝土结构耐久性和服役寿命的同时，免除或者减少后期的维护、维修资金，降低海洋环境中混凝土结构的失效风险。