Hybrid Fiber Reinforced Concrete Composite for Construction of Rigid Pavements

Reinforcement of cement concrete using a hybrid combination of fibers is one of the recent developments in the concrete composite. This study used a hybrid combination of micro polypropylene graded fiber (up to 6 mm in length) and macro hooked end steel fiber (60 mm in length). The polypropylene fiber was optimized targeting a 20-25% reduction in drying shrinkage and abrasion loss. The steel fiber dosage was optimized for an enhancement of 15-20% in the flexural strength in bending over a conventional pavement concrete. The hardened state properties relevant to pavement concrete such as strengths and durability in terms of abrasion loss and drying shrinkage were investigated. Additionally, flexural behaviour (toughness indices and residual strength factors) and impact resistance were also studied. A minimum improvement of 19% in flexural strength, and 12% in splitting tensile strength, but a reduction in compressive strength (≈ 10%) was noted. A significant reduction in drying shrinkage (53%) and abrasion loss (31%) were noticed for the hybrid fiber reinforced concrete composite (HyFRCC) mix in comparison with the control concrete. Further, a significant improvement up to 14 times in toughness indices, 66-74 units in residual strength factors, and up to 27 times in impact resistance for HyFRCC were encountered. The study finally suggests that a hybrid combination of polypropylene fiber (0.1%) and steel fiber (0.5%) can be used in the construction of a long-lasting, economical, and sustainable concrete pavement including concrete overlays such as bridge deck slabs and white topping pavements.