Crack Behavior of Plain Concrete and Reinforced Concrete Members Strengthened with Carbon Fiber Sheets

In this paper, uniaxial tension tests on CFS (carbon fiber sheet) strengthened concrete specimens with and without steel bar reinforcement and bending tests on CFS strengthened RC beams were conducted to examine the crack behavior in the concrete. The testing showed that the crack spacing of the uniaxial tension members strengthened with CFS was only slightly affected by the diameter of the reinforcing steel bars, the thickness of the concrete covering and the stiffness of the CFS. The crack spacing and the crack width both for tensile and the flexural members was significantly smaller when the CFS was used. And also the cracks were distributed in the plain concrete tension member without steel reinforcement strengthened with CFS. Finally, it was recognized that the tension stiffening effect is realized to be improved by the non-linear behavior of the CFS-concrete interface.