Laboratory study on the effect of polypropylene fiber on durability, and physical and mechanical characteristic of concrete for application in sleepers

• PPF reduces the compressive strength.
• Both splitting tensile and flexural strengths increase first and then decrease with higher amount of fiber.
• According to SEM, and XRD, fibers could not participate in any chemical reactions.
• Fibers could reduce permeability and capillary porosity by pore blocking effect.
• PPF has enhanced the durability of concrete.

This study investigates the effect of polypropylene fiber (PPF) on both durability, and physical and mechanical characteristics of concrete for application in concrete sleepers. Rapid chloride penetration test (RCPT), water penetration, ultrasonic, and sorptivity tests were performed in order to signify the effects of PPF on durability. Moreover, compressive, splitting tensile, and three-point flexural strength, and Vee-Bee consistometer (VB) tests were performed to indicate physical and mechanical characteristic of PPF reinforced concrete. In addition, in order to study micro structures and interfacial transition zone, and signify the elements, Scanning Electron Microscope (SEM), and X-ray Diffraction analysis (XRD) were used respectively. It was observed that PPF could reduce permeability and capillary porosity by pore blocking effect. It was also concluded that the optimum amount of PPF is 0.7 kg/m3. Results show that the ideal amount of PPF has enhanced the durability of concrete by reducing the velocity of ultrasonic waves, chloride diffusion, water penetration, and sorptivity. PPF has also improved tensile and flexural strength, though it has reduced compressive strength.