Effect of macro synthetic polypropylene fiber utilization on some fresh and hardened properties of concrete mixtures

In this study, the effect of macro synthetic polypropylene fiber utilization on some fresh and hardened state properties of concrete mixtures was investigated. In fibrous mixtures, the macro synthetic polypropylene fiber having a length of 50±2 mm was used in the ratio of %0,1, %0,2, %0,3, %0,4 and %0,5 of the total volume. In all of the concrete mixtures, the w/c ratio, cement dosage and slump-flow value were kept constant as 0.5, 390 kg/m3 and 18±2 cm, respectively. The slump-flow value of the mixtures was obtained as its fresh state properties. As to hardened state properties, compressive strength, split-tensile strength, flexural strength, modulus of elasticity, abrasion resistance, water absorption capacity and drying shrinkage behavior of the mixtures were investigated comparatively. As expected, water-reducing admixture demand for desired slump flow value increased by the utilization of polypropylene fiber. The mentioned effect was more pronounced with the increase in fiber utilization. Addition of macro synthetic polypropylene fiber to the concrete mixtures had no significant effect on their compressive strength and modulus of elasticity. However, split-tensile strength, flexural strength and ductility of the concrete mixtures increased significantly. Besides, durability performance and dimensional stability of the concrete mixtures were positively affected by the addition of the fiber. Particularly the shrinkage-based length change and the weight loss due to abrasion significantly decreased with the presence of fiber in the mixtures.