Bending of concrete slabs reinforced by recycling waste

This work focuses on the experimental study of mechanical behavior through "3-point bending" tests on concrete slabs reinforced with two types of fibers: metallic fibers (MF) and grids based on polypropylene fibers (PPF). The metallic fibers are sourced from machining waste of steel parts, randomly dispersed within the concrete, while the grids consist of polypropylene fibers. Bending tests are conducted on slabs with dimensions [25x50x7] cm³. Compression tests are also carried out on cylinders with a diameter of Ø160 mm and a height of H320 mm. The fibers are characterized in terms of mechanical strength and pull-out resistance. The concrete composition is determined using the experimental method known as the "Dreux-Gorisse" method. For this study, five contents of metallic fibers (MF) are selected (W = 0.2%, W = 0.4%, W = 0.6%, W = 0.8%, and W = 1%). A control concrete (BT) with a fiber content of 0% (W = 0%) is prepared to serve as a reference. Two variants of polypropylene fibers, small mesh (PPF/SM) and large mesh (PPF/LM), are also included. By comparing and contrasting the results obtained with those of Mohsin Adeel Waris et al [37], it is evident that adding metallic fibers (MF) to concrete at a fiber percentage (W = 0.8%) enhances both strength and stiffness better than adding polypropylene grid fibers, as well as better than the combination of steel and rubber fibers for volumes (V f = 0.1(SF) + 2% (RF)) [37]. The metallic fibers used restrain cracking due to tilting.