Study On The Bond Behavior Of The Reinforced Concrete Specimens With Near-surface Mounted CFRP Rods

Strengthening structural components with near surface mounted FRP improve forced state effectively. This technology is a promising for increasing load-bearing,durability and fire resistance of building. To ensure reinforced effect, material performance and material after bonding working together should be studied on. At present, NSM reinforcement applied widely, while theory of bonding had shortcoming.Therefore, This paper proposed that study on concrete specimens with NSM CFRP bars.The pull-out-test experiment studys on force performance and failure modes of specimens through different parameters such as concrete strength, groove dimension and bond length.The main research and results are as follows:(1) The pull-out-test 14 CFRP bars studies have been done. Different parameters of concrete of deformation, cracking process are described minutely. Meanwhile,bonding mechanism and failure mode are assured. The results show that specimens appear concrete trough cracking, tension-shear damage, shear-split damage. Among failure modes, shear-splitting mode appears mostly.(2) This paper mainly analyzes that strength of concrete, bond length and groove size influence load-bearing and shear stress of specimens. The results show that improving the strength of concrete can increase load-bearing and shear stress. The longer bonding length is, the higher load-bearing and local shear stress are, the lower average shear stress is. Groove width has an impact on cracking load.(3) On the base of test results, the paper gives local shear stress, ultimate load and corresponding bonding slippage. Meanwhile, local bonding shear-slip curve is fitted. The maximum slippage is measured by test.