earticle

영어

Grid-type FRP reinforcement has been used as reinforcement for cement composites instead of rebars mainly in offshore structures due to its corrosion-resistant properties. Recently, the structural application of grid-type FRP reinforcement has been expanded in order to reduce the weight of members and to improve eco-friendliness of the reinforced concrete (RC) structure. This paper experimentally investigated the effective depth of the section and the spacing of strands in the weft and warp direction on the flexural behavior of textile reinforced concrete (TRC) slabs applied the biaxial warp knitting structure grid-type CFRP reinforcement (hereafter referred to as carbon grid) with the narrow spacing of strands. As a result, it was found that the maximum load increased and the deflection at peak decreased as the effective depth increased. In addition, when the strand spacing was narrow, the load was gradually reduced as the load was transferred to the carbon grid after the peak. On the other hand, compared with the RC specimens, the stiffness of the TRC specimens was sharply lowered due to cracks, resulting in greater deflection at the same load. Although the maximum loads of the TRC specimens were larger than those of the RC specimens, the TRC specimens exhibited brittle behavior due to strand fracture after the peak. In this paper, based on the experimental results, the load-deflection relationship of the TRC structure was modeled as a bilinear curve in which the stiffness changes around the crack initiation point, and to calculate the stiffness after crack initiation, an equation that applied a reduction factor to the cracked transformed moment of inertia was proposed. The stiffness after cracking according to the proposed formula was larger than that to the experimental results, but the overall load-deflection relationship was shown to be able to be simulated.