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

Reinforced concrete structures need 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. Using HPFRCC with tensile stiffening behavior has been developed to strengthen the concrete structures over the recent few years. In this paper, the usage of HPFRCC for strengthening two-way reinforced concrete slabs has been studied. A total of five two-way slabs were constructed and tested to reach their own collapse stage, one of 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 indicated that the installation of HPFRCC pre-fabricated laminates significantly improved 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 used to strengthening the deficient slabs.