Shear strength enhancement of prestressed hollow-core slabs using fiber reinforced concrete

Many countries used the precast prestress hollow slabs due to their easy installation and reduced construction time and high-quality control. Shear reinforcements are utilized to improve shear resistance and shift reinforced concrete's failure mode to a more ductile failure mode. Hollow-core slab failure, caused by concrete brittleness, is one of the most hazardous failures in structure construction. Many experimental and analytical research investigations have shown that the addition of fibers in the appropriate amounts improves the shear behavior of Reinforced concrete elements, allowing them to completely or partially replace conventional web reinforcement. The objective of the current research is to study the effect of polypropylene on the shear strength in the prestressed precast hollow slabs. Hollow-core slab (42 cm high, 120 cm wide, and 600 cm long) were investigated under shear loading. Two sample model were investigated on each model varying the shear-span-to-effective depth ratio (𝑎/𝑑 = 2.8 and 𝑎/𝑑 = 3.5 according to EN1168). The test program was carried out to investigate the effect of Polypropylene fiber mix with concrete by varying content such as 0, 0.5, 0.8, 1.15, and 1.5% to find the optimum polypropylene fiber content. All the groups were tested by using the ANSYS program as a tool for finite element investigation. The results showed improvement of up to 35% in the load capacity with 1.15% of fibers, moreover, the deflection decreased by 20% at the same load level