| Budget Amount *help |
¥3,420,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥420,000)
Fiscal Year 2007: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2006: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
In recent years, the retrofitting method using the CFRP grid and sprayed polymer cement mortar have been adopted for the purpose of recovering or increasing the function of existing reinforced concrete structures. The research for the effect on the shear behavior of existing members has not been executed enough.
The function of CFRP grid may be affected by the uniformity, i.e. shear bond behavior, on the bound between sprayed mortar and existing reinforced concrete structure. Various factors such as the roughness of concrete surface, treatment for concrete surface, kinds of CFRP grid and thickness of sprayed mortar influence the shear bond behavior.
In this study, the specimens were prepared in consideration of the interval of CFRP grid (50 or 100 mm), the types of CFRP reinforcement (CR4, CR8 and CR 13), the roughness of concrete surface (rough or flat), and the treatment of surface (primer or not used). The pull-out behavior of CFRP gird and the shear bond bearing area between concrete and sprayed mortar were investigated using the concrete board (300mm × 300mm × t6Omm) with elongated CFRP reinforcement.
The shear resisting behavior was examined with measuring the strains of CFRP, and the coefficients were proposed considering the degree of influence of each factor for retrofitting method.
Also, the beams with CFRP grid and sprayed mortar were examined in consideration of the types of CFRP reinforcement, the roughness of concrete surface and the treatment of surface.
From these test results, it is clarified that the relationship between the shear bond strength and the roughness of concrete surface, which is modified using the adequate coefficient considering the each factor, can be shown by the linear function. And, it is found that the stiffness of CFRP grid is important factor on the shear bond behavior between sprayed mortar and existing reinforced concrete structure.
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