Study On Bond Behavior Of The Interface Between GFRP Sheet And High Strength Concrete

GFRP(Glass Fiber Reinforced Plastic/Polymer) is a strengthening material that is widely used in our country. Bonding GFRP to the surface of structure is an efficient method for strengthening concrete structures, however, the relevant codes need to further improve and many problems should be solved especially in the domain of high strength concrete structure strengthened by GFRP on which systemic research has not been carried out in China.Under the background of application problems of GFRP, the fundamental research that is bond behave of the interface between GFRP and High Strength Concrete is studied in this paper combining with the research programs of National Natural Science Foundation of China and the Key Laboratory of Shenyang Jianzhu University and Beijing Polytechnic University.1. Lots of single-face shear type specimens are designed to study kinds of factors that effect the interface between GFRP and High Strength Concrete. The strength grades of concrete prism in specimens are C50,C60,C80 and different bond width,bond length and stiffness of GFRP are adopted. Considering all these factors, tests provide enough preparation for further research and the conclusions in this paper has important reference value because of so many extensive samples.2. Based on experimental phenomena, failure modes of the interfacial are illustrated with detail which are compared with that of the interfacial between FRP and the normal strength concrete and the mechanism of bond failure is analyzed.3. With the test results, bond strength is studied considering aforesaid factors and the bond strength formulas is proposed. The existing models of bond strength are examined with the test data and there are some deficiencies when applying these models to forecast the bond strength of the interfacial between GFRP and High Strength Concrete.4. Using the bond shear stress and slip which are calculated by the test data, bond mechanism is analyzed deeply. The distribution and the development of the shear stress in the process of debonding are studied and effective bond length is also obtained and finally a nonlinear bond-slip model is proposed that fits in with the interfacial between GFRP and High Strength Concrete and that can provide basically condition for further numerical analysis.