Experimental research on mechanical performance of reinforced concrete beams strengthened with CFRP sheets bonded with an inorganic adhesive after fire

Abstract:

The organic epoxy adhesive usually used in the concrete structures strengthened with CFRP sheets has low softening temperatures of 60-80℃ and it is difficult to meet the requirement of fire endurance,therefore,an inorganic adhesive is developed and used to bond CFRP sheets to strengthen concrete beams,whose strength at 600℃ is not lower than that at normal room temperature.Experiments on mechanical properties of four strengthened beams that experienced fire test were completed.The flexural failure processes of beams were observed.Flexural carrying capacity of these beams and the load-displace curves at the mid-span were obtained.Flexural carrying capacity was analyzed.The calculation formula of flexural carrying capacity and the calculation method of stiffness were presented.The experimental and analysis results show that the strength of CFRP sheets bonded with the inorganic adhesive can not be played fully when the temperature CFRP sheets experienced is above 300℃ in fire.The calculation values of formula are in good agreement with test results.The formula can be used for computing flexural carrying capacity and stiffness of this kind of beam.