氯盐环境下地聚合物/纤维网格加固混凝土梁的力学与耐久性能综合提升机制研究

基于地聚合物和改性多壁碳纳米管的氯离子固化特性，研发具有优越氯离子固化能力和高延性的新型地聚合物，将其作为加固材料的同时兼作防腐材料，并与轻质高强的FRP相结合形成高延性地聚合物/FRP网格加固技术，应用于氯离子环境下锈蚀钢筋混凝土梁的抗弯加固，实现高效修复、受力性能提升和阻止钢筋再次锈蚀的多重效果。项目首先开展改性多壁碳纳米管分散性以及高延性地聚合物制备研究，提出高延性地聚合物制备方法；然后，开展高延性地聚合物的氯离子固化性能研究，揭示其固化机制；研究高延性地聚合物抗拉、抗压性能以及其与既有混凝土界面粘结性能，建立拉、压应力-应变本构关系模型以及界面粘结强度模型；在此基础上，研究高延性地聚合物/FRP网格加固锈蚀钢筋混凝土梁的耐久性能，分析腐蚀时间、氯离子浓度等因素对加固梁受弯力学性能和氯离子固化性能的影响规律，揭示其综合提升机制，建立考虑多因素影响的加固梁受弯承载力计算方法。

According to the superior chloride-curing property of modified Multi-Walled Carbon Nanotube and geopolymers, a new type of geopolymers with superior chloride-curing property and high ductility is fabricated. And then a new strengthening technique of corroded RC beams with FRP grid reinforced the geopolymers as composite strengthened layer is developed to improve mechanical behavior, rapid repair and prevent steel corrosion multiple effects with the advantages of two materials. The research plan focuses on firstly the dispersity of modified Multi-Walled Carbon Nanotubes and PVA modified with Multi-Walled Carbon Nanotubes. Based on the experimental results and theoretical analysis, the chloride curing mechanism of the geopolymer with high ductility is revealed, meanwhile, the corresponding stress-strain model is established by researching on the tensile and compressive properties of geopolymers. The effect of concrete strength and interface treatment methods on the mechanical properties of the bond between the high ductility geopolymers and concrete is investigated and a prediction model is then proposed for calculating the strength of the bonding interface. Based on the experimental results and theoretical analysis, a study on the mechanics and durability of RC beams strengthened with FRP grid reinforced high ductility geopolymers in chloride environment is carried out, the influence of corrosion time and concentration on the properties of the beams and chloride curing is analyzed. Theoretical method is proposed to calculate capacity of corroded RC beams strengthened with FRP grid reinforced high the ductility geopolymers.