纤维地聚物复合材料微结构增强增韧机理研究

Because of the excellent durability, acid and salt resistance, the geopolymer materials have huge potential in surface protection of marine and hydraulic concrete . But the large scale applications is limited because of its brittleness. Fiber can effectively improve the toughness of geopolymer materials, but the interface microstructure reinforcing mechanism of fiber reinforced geopolymer composites is not clear, so it is difficult to guide the researches of performance optimization of these composites. By means of AFM, SEM, CT 3D visualization analysis and bending, impact and other methods, the fiber-matrix interfacial microstructure, mechanical properties, fracture behavior characterization and fiber toughening effect will be analyzed, with different forms and different surface characteristic morphology of PVA short fibers. The XPS, AFM will be used to analysis the PVA fiber surface of original and broken composites , and investigate the chemical reactions and physical effects between fiber and matrix surface. Using of the fracture mechanics, the relationship between characteristics and echanical properties of fiber-geopolymer materials will be built, and deducted the toughening mechanism of interfacial microstructure in fiber-geopolymer composites. This research will provide important theoretical guidance and technical support to optimize performance and to promote the use of fiber-geopolymer coating materials.

地聚物胶凝材料具有优异的耐久性和耐酸、盐侵蚀性能，在海工及水工混凝土表面防护中有巨大的应用潜力，但脆性本质限制了其大规模应用。纤维复合能有效提高地聚物材料的韧性，但纤维地聚物增强增韧的微观机理尚不明晰，难以指导复合材料的性能优化研究。本项目拟通过AFM、SEM、CT三维可视化分析和弯曲、冲击试验等手段对不同形态和表面特性的PVA短纤维增韧地聚物复合材料的纤维-基体界面微观形貌、纤维分布、力学性能、断裂行为进行表征并分析纤维增韧效果。利用XPS、AFM等技术对比分析PVA纤维原始表面与复合材料受力破坏后纤维表面的微结构特征，探讨纤维与基体界面发生的化学反应、物理作用及破坏过程。利用断裂力学理论分析，建立纤维-地聚物界面微结构特征与材料力学性能之间的相互关系，揭示纤维地聚物复合材料的界面微结构增强增韧机理。本项目研究成果将为纤维地聚物涂层材料的性能优化及推广应用提供重要的理论指导和技术支持。

项目以研发混凝土高耐久性外防护涂层为目标，开展了纤维-地聚物复合涂层材料的制备和性能研究，并对其微观结构、纤维增强增韧机理进行了探索。研究发现偏高岭土基地聚物涂层在合适的配比和养护条件下可形成致密的陶瓷质地防护涂层，制备的PVA纤维地聚物复合材料具有优异的力学性能，尤其是抗裂和变形性能，通过界面微观形貌、受力模型、断裂耗散能分析了复合材料抗裂的宏观及微观机理：纤维桥接效应及界面摩擦机理。项目研究成果可为制备高性能水工混凝土表面防护涂层材料奠定理论和技术基础，具有重要的理论意义和工程价值。