Experimental Strengthening of the Two-way Reinforced Concrete Slabs with High Performance Fiber Reinforced Cement Composites (HPFRCC) Prefabricated Sheets

Reinforced concrete structures are required to be strengthened and retrofitted for various reasons, including errors during design and/or construction, so in most cases, strengthening of structural elements is much more economical than rebuilding the structure. Employing HPFRCC with tensile stiffening behavior has been developed in order to strengthen the concrete structures over the recent few years. In this paper, applying HPFRCC for strengthening two-way reinforced concrete slabs has been investigated. A total of five two-way slabs were constructed and examined to reach their own collapse stage, one of the specimen was as non-strengthened control slab, and the others were strengthened in various forms. The strengthening was carried out in two ways; by installing precast plate in the tensile area and the other by installing precast plate in both tensile and compression area at two different percentages of the fiber. The bending behavior, cracking, yielding and rupture of the experimental specimens were evaluated. The results revealed that the installation of HPFRCC pre-fabricated laminates significantly ameliorated the bending performance of reinforced slabs, so that the ductility, energy absorption value, cracking strength, and initial hardness of the slabs was increased and the crack width was decreased. Therefore, the proposed precast HPFRCC sheets can be employed in order to strengthen the deficient slabs.