An anchorage system for enhanced bond behavior between carbon fiber reinforced polymer sheets and cracked concrete

Abstract

The contribution of CFRP wraps, as an anchorage system, to enhancing bond behavior between CFRP sheet and cracked concrete, was investigated. Thirty six concrete blocks (150 x 150 x 200 mm) were cast with 312 mm steel bars embedded laterally at different spacing along the 200-mm-dimension. Half of the moist-cured blocks were subjected to a cyclic treatment in 3% chloride solution until reinforced sides cracked at an average global crack size 0.54 mm; the remaining ones were immersed in a lime solution for a similar period, as controls. Finally, the blocks were attached at their reinforced surface to CFRP sheets at different bond widths and lengths with CFRP wrap anchorages applied over portions where high shearing stresses persist during pull-off testing. The results indicate that the physical status of concrete, the geometry of main CFRP sheets, and the extension of CFRP wrap anchorage are major factors that shape the benefit from the proposed anchorage technique. Empirical models, developed to predict bond strength and slippage at ultimate stress, show very good predictability of literature data.