Study on the bond-slip performance of glass fiber reinforced polymer bars and marine concrete under repeated loading

Abstract

The bond property between glass fiber reinforced polymer (GFRP) bars and concrete under repeated loading is critical in determining the suitability of GFRP bars for marine engineering. This study investigates the bond strength and slip between GFRP bars and marine concrete under repeated loads using a beam-type test. The 16 groups of beam specimens are fabricated, and 50 repeated loads are applied to them. The influences of loading level and loading times on bond strength, slip process, slippage, and residual slippage are analyzed. The loss rate of bond strength exceeds 50%, and irrecoverable cracks in the steel hinge of beam specimens are observed when the repeated load level is 65% of the ultimate load. The slippages rise as the loading level increases. When the number of repeated loadings reaches about 8, the slippage is 50% of the entire slippage, and then the slip difference gradually decreases, and slippages no longer increase. Residual slippages increase with the loading level, but they increase initially and then stabilize with the loading times. The fitting curves agree well with the experimental results, indicating that they could be employed to describe the bond property of GFRP bars in marine concrete under repeated loading.