Long-term durability of Carbon CFRP Composites applied to R/C Concrete Bridges

调查的重点是监测和分析犹他州湖城的州街大桥，该大桥已采用碳纤维增强塑料复合材料进行了抗震改造。恶劣的天气变化，冬季盐的应用，以及冻结和解冻模式使这成为一项独特的研究。 测试项目、板和圆柱体将放置在桥梁现场，并在预定的时间间隔内用于破坏性测试。 进一步的实验室检测将研究单变量和双变量。 本研究的目的是：（a）评估碳CFRP复合材料的强度和弹性模量由于温度、碱度、氯化物、紫外线暴露和冻融循环的变化而长期降低的情况：（B）通过机械、热和化学测试评估CFRP复合材料与混凝土之间的粘结耐久性;（c）评估CFRP复合材料加固对钢筋混凝土桥梁强度和结构特性的长期影响;（d）制定一个“耐久性折减系数”，用于碳纤维增强塑料复合材料改造的设计，根据对State Street Bridge的长期监测所收集的信息， 在拟议的耐久性研究中，将使用碳纤维和树脂基质，而不是仅测试商业产品。 总共将研究五种复合材料：三种商业复合材料产品，由三家独立制造商提供，两种非商业产品。

The investigation will focus on the monitoring and analysis of the State Street Bridge in Salt Lake City, Utah, which has been seismically retrofitted with Carbon FRP composites. The severe weather changes, the application of salt in the winter, and the freezing and thawing patterns make this a unique study. Test items, plates, and cylinders will be placed at the bridge site and used for destructive testing at predetermined intervals. Further laboratory testing, will investigate single and dual variables. The objectives of this research are to: (a) evaluate the long-term reduction in strength and modulus of elasticity of the carbon CFRP composite due to changes in temperature, alkalinity, chlorides, UV exposure, and freeze/thaw cycles; (b) evaluate the durability of the bond between the CFRP composite and concrete using mechanical, thermal, and chemical testing; (c) evaluate the long-term effect of the CFRP composite retrofit on the strength and structural characteristics of the reinforced concrete bridge; (d) develop a "durability reduction factor" to be used in the design of a CFRP composite retrofit, based on the information gathered from the long-term monitoring of State Street Bridge. Instead of testing only commercial products in the proposed durability study, a matrix of carbon fibers and resins will be utilized. A total of five composite materials will be investigated: three commercial composite products, to be supplied from three independent manufacturers and two non-commercial products.