Ahmed S. Eisa
This paper presents an experimental study of cracking behavior of reinforced concrete beams made with and without steel fibers. The goal of this paper was to investigate the effect of using steel fibers on the first cracking behavior of concrete. Two groups of reinforced concrete beams with and without steel fiber were used. The first class (group A) consisted of six ordinary RC beams made with three different reinforcement ratios, the second (group B) consisted of additional six RC beams made with steel fiber. The two classes were categorized into three groups according to reinforcement ratios of 0.92%, 1.33% and 2.39%. All beams were designed to crack under pure moment applied to the middle third of the beam span (four-point bending). The main parameters investigated were mainly reinforcement ratios (0.92%, 1.33% and 2.39%) and the type of concrete (with and without steel fibers). The mid-span deflection, reinforcement strains and cracking load of the tested beams were recorded and compared with calculated theoretical values recommended by the Egyptian reinforced concrete and the ACI codes. The test results revealed that steel reinforcement participates in delaying first crack occurrence according to reinforcement ratios, and the effect of steel fibers in additional to reinforcement to improve the cracking behavior. Steel participation ratio was around 15% of cracking capacity of cross section and this participation ratio decreases by using steel fiber.
Concrete Cracking, Steel Reinforcement, Flexural Strength