基于纳米粒子/聚合物复合改性的海工混凝土表面防护材料研究

With the implementation of the national major marine strategy, it is of great significance to explore new materials for marine concrete against harmful ion erosion around the service environment of high salinity, high temperature difference and high humidity. Aiming at the uneconomical phenomenon of using modified concrete, it is scientific and feasible to use the surface protection materials to block the infiltration of harmful ions from the source into the concrete interior. This research is critical to improving the durability of marine concrete.. In view of the advantages and disadvantages of single-doped nanoparticles or polymer-modified surface protection materials, this study aims to achieve the best comprehensive performance of surface protection materials with high crack resistance, high impermeability and high compatibility with matrix by advantages superposition and disadvantages complementation of the two. Then based on the relationship between macroscopic properties, hydration characteristics and microstructures of cement-based materials, the influence mechanisms of nanoparticle/polymer composites on crack resistance, impermeability and compatibility with matrix concrete of surface protection materials are revealed. Moreover, by studying the distribution of chloride ions in the protection layer-structure layer, a chloride ion diffusion theoretical model and a concrete life prediction and evaluation system are established.. The results will not only provide new ideas for the development of marine concrete surface protection materials, but also provide theoretical and technical supports for the construction of green, sustainable and high-performance cement-based materials.

随着国家重大海洋战略的实施，围绕高盐分、高温差、高湿度服役环境探索海工混凝土抵抗有害离子侵蚀的新材料具有重要意义。针对使用改性混凝土的不经济现象，提出采用表面防护材料从源头阻断有害离子向混凝土内部渗入的研究思路显得科学可行。研究对于提升海工混凝土的耐久性至关重要。. 鉴于单掺纳米粒子或聚合物改性表面防护材料的优势和不足，本研究旨在通过二者复合的优势叠加和劣势互补，实现表面防护材料高抗裂、高抗渗及与基体高兼容的最优综合性能；探索纳米粒子/聚合物复合对水泥基材料水化特性及微观结构的影响规律，揭示其对表面防护材料抗裂性、抗渗性及与基体混凝土兼容性的影响机制；研究防护层-结构层中的氯离子分布情况，建立氯离子扩散理论模型及混凝土寿命评估体系。. 研究不仅为适用于海工混凝土表面防护材料的开发提供新思路，同时还为构建绿色环保可持续发展的高性能水泥基材料提供理论和技术支撑。

随着我国海洋强国战略和“一带一路”战略的不断发展，国家加大了对海洋工程的投入，但海工混凝土由于长期处于腐蚀环境，其寿命往往无法达到设计使用年限。表面防护材料可有效阻止有害粒子进入混凝土内部，但其存在易开裂、耐久性不足及界面兼容性差等问题，难以实现对混凝土的有效防护。基于此，本项目研究了纳米粒子/聚合物复合对表面防护材料抗裂性、抗渗性及与基体混凝土兼容性的影响，明晰了表面防护体系高抗裂、高抗渗及高兼容的材料设计方法；通过XRD、SEM、EDS、DSC-TG、MIP等手段研究了纳米粒子/聚合物复合对水泥基材料水化特性及微观结构的影响规律，分析了微观性能与宏观性能之间的联系，揭示了纳米粒子/聚合物复合增强表面防护材料抗裂性能、抗渗性能及与基体混凝土兼容性能的机理；采用RFPA2D模拟了不同龄期、不同界面粘结强度时表面防护材料-基体混凝土试样破坏形态，为不同防护层-基体粘结性能研究提供理了理论基础；建立了复掺纳米粒子/聚合物改性表面防护材料的抗裂、水化、粘结及抗氯离子渗透图示模型，并采用多因素氯离子扩散理论模型对表面防护材料作用下的混凝土寿命进行了预测。研究成果不仅为海工混凝土耐久性提升技术奠定了理论基础，还为混凝土表面防护材料的开发提供了可借鉴的经验和指导。