Behavior of Concrete Slabs Strengthened with Multi layers of Fabricated Fiber Meshes

Abstract

Abstract: Fiber meshes are used in concrete slabs to strengthen the concrete and slow the spread of cracks, which raises the concrete modulus of elasticity and plasticity. This paper presents the experimental study conducted on six concrete slabs resting on the Winkler support with square dimensions of (800×800) mm and a thickness of (100) mm, with a fabricated steel mesh (∅4mm@150mm) located near the center section of the slab, and strengthened with different types which of fiber meshes are fiberglass, polypropylene, carbon, geogrid and waste rubber fibers, located in the tension and compression zones. The Winkler foundation is used to represent the ground soil in the study of concrete slabs on the ground in terms of toughness, stiffness, and ductility index. Twelve rubber supports with a stiffness of (7500) kN/m are used, and they are supported by a steel plate that is (800×800) mm in size and has a thickness of (10) mm. According to the testing results, all of the specimens strengthened with fiber meshes have shown a considerable improvement in toughness and ductility index, especially the specimen that strengthened two-layer carbon fiber meshes, where the increases were 331.8% and 4.76 respectively, and a large improvement in the stiffness was in the specimen that strengthens two-layer glass fibers by 44.2%. The slab-strengthened polypropylene has the lowest percentage increase in toughness (22.1%), while the slab-strengthened geogrid and waste rubber has the lowest percentage increases in stiffness (37.2%) and lowest improvement in the plasticity index was in slab-strengthened two-layer from polypropylene fiber by (1.90). Early cracking appeared in the slab-strengthened polypropylene, which had less load capacity than the other specimens, and the maximum ultimate load was (45.5) kN/mm, which is near the maximum ultimate load of the control slab.