High Temperature Residual Properties of Externally-Bonded FRP Systems

Synopsis: The use of externally-bonded FRP plates and sheets to strengthen existing reinforced concrete structures is now widely recognized. However, a primary concern that still discourages the use of FRPs in some cases is their assumed susceptibility to fire. While recent studies have demonstrated that the overall performance of appropriately designed and insulated FRP-strengthened reinforced concrete members is satisfactory, the specific behavior of FRP materials at high temperature and after exposure to high temperature remains largely unknown, particularly for externally-bonded FRP strengthening systems. As a first step in an effort to learn more about the high temperature properties of these systems, an initial series of tests is presented to study the high temperature residual properties of externally-bonded carbon and glass FRP systems for concrete. Axial tension tests, single-lap bond tests, thermogravimetric analysis, and differential scanning calorimetry are all used to elucidate high temperature residual performance. The potential consequences of these initial results for the fire-safe design of FRP-strengthened reinforced concrete members are discussed.