EFFECT OF POLYPROPYLENE FIBERS ON THE MECHANICAL PROPERTIES OF NORMAL CONCRETE

The present work investigates the effect of addition of pure polypropylene fibers to concrete in order to diminish some poor performances particularly in case of ductility and tensile strength. The effect of the addition of polypropylene fibers on the mechanical properties of normal strength concrete is studied. The polypropylene fibers were added at concentration of 0.25, 0.5, 1.0 and 1.5% by volume. Compression, pullout and bending tests were carried out to determine the mechanical properties such as maximum compressive strength, modulus of elasticity, splitting strength, ductility, bond strength, modulus of rupture and the percentage of absorption. On the basis of the experimental results, it can be concluded that, ductility of concrete significantly increased and maximum compressive strength slightly increased with increasing the content of polyproplylene fibers materials. Further increase of polypropylene fibers (higher values than 0.5 vol. %) did not increase the ultimate bond strength, but it provided much more ductile bond behaviour. Besides, the addition of polypropylene fibers caused a significant increase in the percentage of water absorption for the tested concrete specimens.