Effectiveness of a new CFRP anchor in preventing delamination

A new CFRP anchor is developed and tested using full scale RC T-beams externally strengthened with multiple plies of a CFRP sheet. The anchor is made from a carbon fiber tow immersed in an epoxy resin. The anchor head is bonded by epoxy to the surface of the concrete in the vicinity of the FRP sheets and is designed to provide a relatively large surface for resisting interfacial shear stresses. The anchor legs are inserted into pre-drilled holes filled with epoxy adhesive. Four full scale T-beams, each 4880 mm long with span length of 4500 mm, were tested in four point bending. The beams cross-section had a total height of 400 mm and consisted of 500 mm wide by 100 mm thick flange and 250 mm wide web externally strengthened with either 4 or 8 plies of a CFRP sheet. Test results show that the anchor could prevent delamination even in the beams with 8 plies as failure was initiated by the rupture of the FRP. No sign of slippage and/or rupture of the anchors were observed. On the contrary, the companion beams without the anchors prematurely delaminated and they reached only a fraction of their theoretical strength.