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The use of fiber reinforced polymer composites as alternative to conventional steel reinforcement have been increased during last decades for their high tensile strength, light weight, and durability. This paper focused on the behavior of CFRP bars embedded in high strength concrete. Thirteen beam spacemen of 100×180×650 mm clear span were cast, each beam consist of two concrete blocks linked together. The parameters studied are: concrete strength, CFRP bar diameter, and two enhancement schemes; coarse sand and steel fibers applied directly to the surface area of the CFRP bars using epoxy adhesive. All beams are tested using four points loading system. The results indicates that the maximum bond stress and the strength ratio of CFRP bars enhanced using coarse sand particles or steel fibers increased by are 9.6 to 24.4% and 9.7 to 24.3% if compared with undeveloped bars due to the improved surface area which provides additional adhesive, friction resistance, and mechanical interlock. However, the bond index decreased up to 24.8%. Also, increasing of concrete compressive strength 55.38 MPa to 78.34 MPa increased the maximum bond stress and the strength ratio by 21.1 to 31.2% and 3.1 to 9% while the decreasing of the relative bond stress and bond index is 6 to 7% and 5.7 to 6.7%. Furthermore, using of CFRP bars of 10 mm diameter instead of 6 mm decreased the bond stress and the strength ratio by 18 to 27% and 42 to 44% due to the larger surface area and higher ultimate tensile strength. |
