新型C/BFRP筋低碱海水海砂混凝土梁的高耐久性机理研究

针对玄武岩纤维复合筋（BFRP筋）在普通海水海砂混凝土（SSC）内强碱环境下的长期性能严重退化问题，本项目拟通过添加矿物掺合料降低SSC内的pH值（降低碱性），和外包碳纤维层提升BFRP筋耐碱腐蚀的方法，发展一种新型高耐久BFRP筋SSC结构，研究其高耐久性机理。研究矿物掺合料对SSC碱性的影响机制，建立SSC强度、pH值及海洋环境下的时变规律模型；研究外包碳纤维BFRP筋（C/BFRP筋）在不同pH值环境下的耐久性，揭示碳纤维层对腐蚀离子扩散与筋材长期性能演化的作用机理，提出针对耐久性提升的C/BFRP筋混杂设计方法，建立C/BFRP筋在特定pH值环境下的长期性能预测模型；结合有限元分析，研究海洋环境下C/BFRP筋-低碱SSC界面粘结本构关系，及C/BFRP筋-低碱SSC梁的抗弯性能演化规律。本研究将推动海水海砂资源利用，丰富纤维增强复合材料的耐久性理论，具有重要的科学研究与工程意义。

In view of the durability problem of basalt fiber reinforced polymer (BFRP) composite bars caused by strong alkaline in common sea-sand seawater concrete (SSC). This project aims to develop of a new type of high durability BFRP reinforced SSC structure and study its high durability mechanism based on reducing pH value of SSC (reduce the alkalinity) by adding mineral admixture and improving the durability of BFRP by coating carbon fibers around BFRP bars. The effects of mineral admixtures on the alkalinity of SSC will be studied, and the relationship of SSC strength, internal alkalinity (pH value) and its time-varying law in marine environment will be established. The long-term performance evolution of carbon fiber coated BFRP (hybrid carbon/basalt-FRP, C/BFRP) in different pH alkaline environments will be studied. The mechanism of carbon fiber coating on the diffusion of corrosion ions and the performance maintenance of BFRP will be revealed. A hybrid design method of C/BFRP bars for durability improvement, and a long-term performance prediction model of C/BFRP bars in specific pH environment will be established. Based on finite element analysis, the constitutive relationship between C/BFRP bars and low alkaline SSC interface and the long-term performance evolution of C/BFRP reinforced low alkaline SSC beams in marine environment will be studied. This study will promote the utilization of sea-sand seawater resources and enrich the durability theory of fiber-reinforced polymer composites, which has important scientific research and engineering significance.