Experimental Investigation on Mechanical Properties of Hybrid Polypropylene-Steel Fiber-Reinforced GGBS Mortar

Research has shown that incorporating various types of fibers into a concrete mix can enhance the strength properties of cementitious matrices. Limiting the crack propagation in slab-like concrete structures, such as pavements, airport runways, and continuous slab-type sleepers for high-speed trains is critical. To achieve this, it is essential to address both crack propagation from loading and shrinkage. Distributed short fiber reinforcing, such as polypropylene fibers, is a smart solution in this scenario. The present study uses hybrid combinations of steel and polypropylene fibers in a mortar mix containing 50% cement and 50% Ground Granulated Blast Furnace Slag (GGBS). Fibers are randomly distributed as 0.5% of the volume of GGBS mortar. Five hybrid combinations of steel and polypropylene fibers are considered (25, 40, 50, 60, and 75%) to determine the mechanical properties. It is found that the addition of fibers enhances the mechanical properties of the mortar. The hybrid combination of 50% steel fiber and 50% polypropylene fiber in the GGBS mortar is optimum in terms of strength and economy. This study also promotes sustainable construction practices by utilizing GGBS as a raw material, which is an industrial byproduct.