Effect of steel and polypropylene fiber addition on concrete behavior: Static and dynamic evaluation

In this study, the effect of fiber ratio on the impact behavior of concrete in fiber reinforced concrete was investigated. For these purposes, steel fiber and macro fiber were added to the concrete mixture. By adding three different steel fiber mixtures at the rate of 0.25%, 0.50% and 0.75% (19.5, 39, 58.5 kg / m üç) of the concrete volume to the concrete mixture and three different macro fiber rates (2, 4, 6 kg / m³) into the concrete mixture. mixtures were obtained. Seven different mixed samples were prepared, three of which were steel fiber, three of which were polypropylene fiber, and one of which was plain concrete. CEM II 42.5R Portland cement was used in all concrete mixes and the cement dosage was taken as 350 kg / m3. Plasticizer is added to the concrete mixes as much as ‰4 of the cement dosage. The experiments were carried out on 100x100x100 mm cube and 100x100x500 mm beam specimens. Within the scope of the study, compressive strength test, three point loading test, instrument weight drop test, ultrasound transmission velocity test were carried out on concretes. In addition, the cracks that occurred after the three-point loading test and instrument weight drop tests were measured with the help of a hand microscope. With the addition of fiber, increases in compressive strength were observed compared to lean concretes. In addition, it has been determined that the addition of fiber provides an increase in the bending tensile strength of concrete. In addition, it has been observed that the addition of steel fiber and macro fiber significantly reduces crack width in concretes. In the instrumented weight reduction test, it was observed that the concretes with the addition of steel fiber and macro fiber were more resistant to sudden fracture. As a result of the study, it has been observed that steel fiber has positive effects on the static and dynamic properties of concrete.