Experimental study to evaluate the flexural behavior of concrete beams reinforced with CFRP grid

Abstract

Fiber reinforced polymer (FRP) is evaluated as an excellent material to replace rebar in reinforced concrete due to its advantages such as high tensile strength-to-weight ratio and high corrosion resistance. Many studies have been conducted to use FRP as substitutes for steel rebar. However, most of these studies were conducted using FRP bars, and research on using FRP grids in the construction field is focused on the field of repair and strengthening. Therefore, this study reports the results of an experimental study to evaluate the flexural behavior of concrete beam with Carbon FRP (CFRP) grid tensile reinforcements as a basic study to evaluate the feasibility of using FRP grid as a as substitutes for steel reinforcement. Thirteen test specimens were prepared for the experiments. The CFRP grids were applied to the specimens as tensile reinforcement. The concrete cover thickness, layers of the CFRP grid and the spacing between the CFRP grids were considered as test variables. The experiment results showed that the specimens without spacing between the CFRP grids were destroyed by side CFRP grid fracture. Also, as the CFRP grid layer increased, the ultimate load increased by 53% to 94%, and when the cover thickness decreased by 10 mm, the ultimate load decreased about 10%. The ratios of the nominal flexural strengths calculated according to the CSA S806–12 and ACI 440.1R-15 standards were 1.004 and 1.09, respectively. Thus, the use of the CSA S806–12 standard enables a relatively accurate prediction of the nominal flexural strength of concrete beams reinforced with CFRP grids.