湿热高盐海洋环境下多元水泥基材料化学-物理稳定性研究

远海气候环境具有“高温、高湿、高盐、高日照”的特点，这些环境因素与海水中的氯、硫酸根、镁离子等侵蚀性介质相结合，使海工混凝土结构发生不同程度的物理和化学失效。因此，设计、制备高稳定性水泥基材料并用之于远海工程十分必要和迫切。本项目拟开展远海环境下多元水泥基材料化学和物理稳定性的研究，重点探讨海水中常见阴离子和阳离子与水泥基硬化体水化产物相互作用的机制，探明氯离子和硫酸根离子等侵蚀介质对水化产物作用的协同效应；对比分析水泥中的铝相和矿物掺合料中的铝相在海水中化学反应的历程；通过对特定环境下钙矾石形成和转化条件的控制，建立维持水化产物化学稳定的组分间平衡关系。在此基础上，综合考虑干湿循环、盐析晶等物理变化，建立多元水泥基材料稳定性多因素影响模型，结合暴露试验数据和数值模拟分析，构建高稳定性多元水泥基材料体系，并在接近远海环境下进行验证，为建造高性能长寿命海工水泥混凝土结构提供科学依据。

The climate environment in mid-ocean has characteristics of hot, humid, high-salinity and strong-sunshine. Combined with other erosive mediums(Cl-, SO42-, Mg2+, etc.) in seawater, these environmental factors will cause physical and chemical damages to marine concrete structures, which makes it quite necessary and urgent to design and prepare high-stability cement-based materials, then applied them to ocean engineering. The project is mainly focus on chemical and physical stability of concretes with different types of mineral admixtures in mid-ocean, in which the interactions between hydration products of hardened cement paste and common ions in seawater are emphasized. The synergistic effect of erosive mediums(Cl-、SO42-, Mg2+, etc.) on hydration products will be explored. Chemical reactions history of aluminum phase in cement and mineral admixtures with seawater will be compared. By controlling the formation and transformation condition of ettringite under certain circumstances, building an equilibrium between components to maintain hydration products’ stability will be achieved. On the base of previous work, comprehensively taking wet-dry cycle, salt crystallization and other physical changes into consideration to establish the multi-factor model about the stability of multivariate cement-based materials. Combined with exposure test data and numerical simulation analysis, a cementitious material system with excellent chemical and physical stability will be constructed. The newly established material system will be verified under practical or similar ocean environment, which will provide scientific evidences for the preparation of high-performance and long-lifespan concrete that serves in ocean engineering.