Bond Strength Prediction of Externally Bonded CFRP Laminate with Embedded Bar Anchor Through Pull-Out Test of Prism for Shear Strengthening of RC Beam

Strengthening of RC beam for shear with bonded Carbon Fiber Reinforcement Polymer (CFRP) laminate has been widely used in recent years. However, debonding of laminate from concrete substrate is the main drawback of this method. Various anchorage systems had been investigated to prevent the debonding of CFRP laminate. Embedded bar anchor system could be more effective to mitigate debonding of CFRP laminate. This research aimed to predict bond strength of CFRP laminate with embedded bar anchor through pull-out test of strengthened RC prisms. The effects of widths of CFRP laminate on bond strength were investigated. In the experimental program, a total of 15 RC prism specimens were fabricated. The prism specimens were strengthened using various widths of CFRP laminate. Embedded bar of 6-mm-diameter steel was used as anchors of all strengthened prisms. The specimens were tested under pull-out load to investigate bond strength of externally bonded CFRP laminate with embedded bar anchor. Experimental results showed that the prism specimens failed by debonding of CFRP laminate at laminate–adhesive interface and crushing of concrete rather than debonding at concrete–adhesive interface. The maximum bond strength of CFRP laminate with embedded bar anchor was 3.12 MPa. The average bond strength of 20 mm, 25 mm, 30 mm, 35 mm, and 40 mm widths of CFRP laminates were 3.12 MPa, 2.77 MPa, 2.65 MPa, 2.03 MPa, and 2.25 MPa, respectively. Results also showed that lesser width of CFRP laminate had higher bond strength as compared to larger width of laminate.