Experimental investigation into the development length of carbon-fiber-reinforced polymer grids in concrete:

Carbon-fiber-reinforced polymer grids have received much attention lately because of many advantages. The force transfer behavior and development length of carbon-fiber-reinforced polymer grid reinforcement were evaluated using a pull-out test method. A total of 18 pull-out specimens of carbon-fiber-reinforced polymer grid reinforcement were tested under monotonic static loading, and the investigated parameters included the concrete compressive strength, the number of embedded transverse bars, with or without transverse bars, and the number of adjacent longitudinal bars. The slips between the reinforcing carbon-fiber-reinforced polymer grids and the concrete were measured at both the free end and the loaded end during the whole loading process. The test results indicated that first, the concrete compressive strength and the adjacent longitudinal bars had little influence on the force transfer behavior, second, the wedge action of the transverse bars was very important for transferring force; thus, increase in number of embedded transverse bars increased the force transfer stiffness and reduced the slippage. In the case of tested carbon-fiber-reinforced polymer grids, three embedded transverse bars equal to embedment length of 150 mm were sufficient to develop full tensile strength. Based on this experimental investigation, the preliminary design principles were also discussed.