Study On Durability Of Bonding Property Between GFRP Reinforcement And Concrete In Short-term

A key technique applying GFRP bars to replace steel reinforcement is the bonding property between bars and concrete. Presently, the property is generally investigated under ordinary circumstance, but the investigation under erosive circumstance is less. Generally, GFRP bars are used in erosive environment to replace steel reinforcement, so what influences will the erosive environment to the bonding property should be investigated in detail.In the paper, bonding property both in ordinary and erosive circumstance has been tested by designing accelerate experiment. The main results of the paper are following:(1) Bonding property for GFRP bars under ordinary environment has been tested, next results were obtained: The failing bonding stress for GFRP bars specimens is close to steel reinforcement specimens. It shows that the failing stress is independent of kinds of reinforcement, but relate to tensile strength of concrete.(2) Durability of the bonding property in short-term between concrete and GFRP bars under different erosive environments has been investigated. The experiment results showed when the exposure time and diameter of reinforcement under erosive environment were same, the failing bonding stress of steel reinforcement was higher than GFRP's. Bonding stress of GFRP specimens and steel specimens were all rising when exposing in water, alkali solution and salt solution.(3) Durability of the bonding property in short-term with different pH value in acid solution for GFRP specimens has been investigated. The results show that the bonding stress falling faster when exposing in lower pH value solution, the pH value and exposure time conform to the Arrhenius relationship. According to modifying some parameters, a modified model for pH value and exposure time has been built.(4) Formulas for critical thickness of cover and minimal anchorage length of GFRP bars under ordinary and erosive environment were developed.The durability study for the bonding property of GFRP concrete will make GFRP bar to serve in some structure come true, and can ease risk, achieve more economical...