Influence of micro and macro fibers on the mechanical properties of pavement quality concrete

Abstract: The mechanical properties of concrete play a vital role in designing the thickness of the rigid pavement and its performance during its service life. It is evident that the use of fibers not only improves the mechanical properties of concrete but also improves the service life of pavements. In this study, an attempt has been made to assess the influence of dosages of micro and macro polypropylene fibers on the mechanical properties of pavement quality concrete (PQC). The micro-fiber reinforced PQC specimens with three different dosages, 0.9, 2.1 and 3.1 kg/m3, and the macro-fiber reinforced PQC specimens with three different dosages, 0.25%, 0.5% and 0.75% by weight of the mix were prepared and tested. The mix design was carried out as per IRC 44-2017. All the concrete mixtures were prepared using the 19 mm NMAS aggregates. The slump test was conducted on all concrete mixes in their fresh state. The compressive strength, flexural strength, split tensile strength and modulus of elasticity of the mixes were determined after 28 days of curing in water. It is concluded that the mechanical properties of the PQC mix improved substantially for the macro-fiber reinforced PQC mix. Also, 2.1 kg/m3 and 0.50% are the optimum micro and macro polypropylene dosages for improving the mechanical properties of PQC mixes.