Evaluation of tensile strength of unresin continuous carbon fiber cables as tensile reinforcement for concrete structures

As a tensile reinforcement of a concrete structure member, tensile strength of Unresin Continuous Carbon Fiber (UCCF) cables should be stated clearly. It has been reported that, through direct tensile test, tensile capacity of UCCF cables ranged from 30% to 35% for the cables made of 120 strings to 40 strings. By calculate the tensile strength of the cables using the total section area of cables it was found that the tensile strength of cables ranged form 1500 MPa to 1680 MPa. From the other studies, it was reported that it is impossible to use all fibers in a cables to sustain the applied load. The results indicated that the effective section area of the UCCF cables as a tensile reinforcement in concrete beams was 67%. So, the tensile strength reported before should be reevaluated using the consideration of the effective section area. This study present the evaluation of the tensile strength of UCCF cables for concrete structures. The effective section area of 1.5 reported in previous studies is used in evaluation and finally the relationship between tensile strength and the number of string of UCCF cables will be presented. To clarify more about the maximum tensile strength of UCCF cables, the experimental investigation under flexural test of under reinforced beams are carried out. The results indicated that there was a good agreement between the experimental recorded maximum tensile capacity with the predicted results.