عنوان مقاله [English]
Environmental protection is a fundamental issue in today’s world. Using wastes can help protect the environment. Recycled materials can be used to manufacture concrete elements. In concrete structures, the reduction of cracking width and the protection of rust and corrosion of the longitudinal and transverse reinforcements are very important and important. The use of tensile reinforcement patches in case of inadequate patch lengths reduces bearing capacity and increases cracks in RC concrete beams. This also increases the possibility of corrosion of the longitudinal and transverse reinforcements. In this research, the effect of adding 0% and 2% volumetric percent of steel fibers in beams containing three patches of length, 43 cm, 34 cm and 26 cm, and recycled aggregate 0 and 100% on the cracking and expansion path The cracks were examined under static loading. The purpose of this study is to reduce the minimum crack width for adding steel fibers to reinforced concrete beams made of recycled aggregates and tensile reinforcement patches. Hence, twelve specimens of the beam were made at 150, 200, 1500 mm length with a length of different tensile adherence and different percentages of steel and recycled aggregates. The experiments were performed as a quadrilateral bend. In experiments, the load-displacement curve in the middle of the span of the specimens, the trajectory expansion along the beam and at the maximum flexural anchor, the width of cracking, and the effect of adding steel fibers on the compression and elongation of the specimens Indirectly investigated. In addition, the results were compared with those presented in the ACI, CSA, NS, CEB FIP and EuroCode2 regulations. The results of the experiments showed that the addition of steel fibers reduced the slip of the tensile reinforcement in the patched area and reduced the crack-cracking width. Also, by adding steel fibers in beams made of 2% recycled aggregate, the patch length can be reduced by 40%.