Determination of adherence length of reinforced concrete slabs with polypropylene fiber with the developed experimental design model

Ductile behavior is one of the most important earthquake indicators that have to be possessed by structures. Because of the limited tensile strength of concrete alternative materials such as structural nano synthetic fibers as a three-dimensional reinforcement have already gained increasing popularity since a few decades. However, the contribution of fibers on development length of reinforcement bars has not been investigated. An experimental study was conducted to investigate the effects of fibers on development lengths of reinforcement bars with fibers. Thirty-three concrete slabs at three different volume fractions of fibers as 0.0, 1.0 and %1.5 with different orientations of embedment lengths was studied under the four points of flexural strength tests. Load-displacement curves, energy absorption capacities, ductility ratios and bond-slip relationships were obtained for different embedment lengths of reinforcement bars at three different amounts of fibers used in concrete slabs. Test results revealed that predominant effects of fibers on structural behavior were energy absorption capacities at plastic deformation. It was found that resisted more strains by reinforcement bars with fibers exhibited ductile behavior by reduced development length of reinforced concrete slabs.