| Retrofit and repair of RC structures has been an important issue in civil engineering nowadays. The utilization of advanced composite materials shows great potential in the area of structural rehabilitation. The implementation of structural strengthening with GFRP sheets is a new trend in the world. Extensive researches have been carried out on using GFRP composites for repair and strengthening; however, information about their durability is still lacking. The long-term durability of GFRP composites is a decisive factor in successful application as repair materials or as reinforcement for concrete. In this study, GFRP is used to investigate the durability on strengthening damaged concrete members.In order to assure the effect of strengthening materials , we adopt the durability sign on the flexural strength , the shears strength , the relative dynamic elastic modulus (RDM) and the permeability of chlorometer etc.After retrofited the damaged concrete members with GFRP on flexura and shears request the concrete beams were freezed 50 times , 100 times and 150 times to research the influence of the freeze-thaw action on the damaged concrete structures strengthened by GFRP .After retrofited the frozen concrete members with GFRP on flexura and shears request , the concrete beams were freezed 25 times , 50 times and 75 times to research the influence of the freeze-thaw action on the frozen concrete structures strengthened by GFRP .To research the influence of the permeability , the primer and GFRP were put on concrete beams .To research the influence of the freeze-thaw action on the permeability , the primer and GFRP were put on concrete beams and freezed 25 times , 50 times and 75 times.From the testing results, all GFRP sheets are effective in retrofit on damaged concrete members. Specimens wrapped GFRP sheets can improve flexural strength and ductility. Both environment tests didn't cause obvious degradation to flexural strength and durability. |
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