预应力BFRP筋矿渣-粉煤灰基地聚物混凝土梁的长期性能研究

地聚物具有快硬高强、低碳排放等优点，被视为拥有可持续发展潜力的绿色建材之一，在桥梁及建筑结构建设中应用前景广泛。采用BFRP筋部分代替钢筋能降低地聚物碳化快引起的钢筋锈蚀风险，适于发展预应力地聚物混凝土桥梁。本项目针对混凝土收缩徐变引起的大跨桥梁变形显著这一问题，围绕预应力BFRP筋地聚物混凝土梁的长期性能开展以下研究：1）考察地聚物孔隙结构与收缩行为的相关性，揭示配合比对地聚物收缩的影响，研究骨料的收缩约束作用，构建混凝土收缩模型；2）考察地聚物反应产物与徐变行为的相关性，揭示配合比对地聚物徐变的影响，研究骨料的徐变约束作用，构建混凝土徐变模型；3）通过桥梁长期试验与理论分析，提出预应力BFRP筋地聚物混凝土梁的长期性能分析方法及设计参数建议取值。研究成果将阐述地聚物净浆、混凝土及对应结构的长期性能演变规律，形成从材料到结构的长期设计理论，为地聚物混凝土结构的推广应用提供理论和技术支撑。

Geopolymer has the advantages of rapid hardening, high strength, low carbon emission and so on. It is regarded as one of the green building materials with sustainable development potential and has a wide application prospect in the construction of the bridge and building. Using BFRP bars to replace a part of reinforcing steels in concrete can reduce the risk of steel corrosion caused by the quick carbonization of the geopolymer, which is suitable for the development of the prestressed geopolymer concrete bridge. Aiming at the significant deformation of long-span bridges caused by concrete shrinkage and creep, the following research will be carried out around the long-term performance of the geopolymer concrete beam reinforced with prestressed BFRP bars. First of all, the relationship between the pore structure and shrinkage behavior of geopolymer will be studied, and the influence of the geopolymer mix-ratio on the shrinkage of geopolymer will be revealed. Then, the restriction effect of aggregate on the shrinkage of geopolymer concrete will be studied to establish the prediction model for the concrete shrinkage. What's more, the correlation between the reaction products and creep behavior of geopolymer will be investigated, and the influence of the geopolymer mix-ratio on the creep of geopolymer will be revealed. The restriction effect of aggregate on the creep of geopolymer concrete will be studied to establish the prediction model of the concrete creep. Last but not least, based on the long-term experiment and theoretical analysis of the test beam, the long-term performance analysis method and design parameters of the geopolymer concrete beam reinforced with prestressed BFRP bars will be proposed. The research results will clarify the laws of the long-term performance evolution of the geopolymer paste, the geopolymer concrete, and the corresponding structures, thereby forming a long-term design theory from materials to structures, which provides theoretical and technical support for the popularization and application of geopolymer concrete structures.