Study On The Fire Resistance Of FRP Bars Reinforced Concrete Beams Covered With Clad Layer

Fiber-Reinforced Polymer (FRP) bars have the advantages of high strength, strong corrosion resistance, good electromagnetic insulation, antifatigue, outstanding designability and so on. In recent years, with the increasing demand of FRP reinforcement in engineering structures, the demonstration is gradually increasing. However, the resin matrix of FRP tendons will soften when exposed to high temperature, which affects FRP tendons'normal use in the high temperature, and that has become one of the bottlenecks for the promotion of the application. To this end, this paper studies the mechanical properties and the fire resistance of FRP reinforced concrete beams strengthened with coated FRP The main content includes the following aspects:1.A systematic summary of the mechanical properties of steel, concrete and FRP during together with after exposure to high temperatures is delivered. Meanwhile, their thermal properties are also summarized. On the basis of previous research, the appropriate values of thermal properties and heat mechanics of various materials are confirmed.2.Through the study on the mechanical properties of CFRP tendon specimens with the clad layer after exposed to elevated temperature of 400 ? for heating periods of lhand 2h, this paper compares the effects of high temperature performance of CFRP tendons when using the ordinary mortar, fiber polymer mortar and fiber polymer mortar with steel wire mesh reinforcement as coated layers, then it can provide references and basis for the design of beams with coated layers in fire.3. Normal temperature static test was carried out using one RC beam, one CFRP bars reinforced concrete beam and one FRP bars reinforced concrete beam-with wire mesh strengthened clad layer. The width and the distribution of cracks, load-deflection relationships and flexural capacities are analyzed.4. Fire test is carried out using one RC beam, one CFRP bars reinforced concrete beam and four FRP bars reinforced concrete beams with clad layer, the temperature field, load displacement curve and fire resistance time are analyzed, and their fire resistance are also evaluated..5. Based on the finite element analysis software ABAQUS, the heat-mechanical coupling performance of CFRP bars reinforced concrete beam in the fire is analyzed. The obtained simulation calculation results of temperature filed and deflection-time relationship show good agreement with the test results.