DURABILITY AND MECHANICAL PROPERTIES OF NANOCOPOSITE FIBER REINFORCED CONCRETE

In this study we investigated the influence of polypropylene/organoclay fibers on durability and mechanical behaviour of concrete. Pure polypropylene fibers and polypropylene nanocomposite fibers of two different lengths (20 and 60 mm) have been mixed in concrete at two volume fractions (0.1% and 0.3%). Nanoclay addition increases fibers elastic modulus (about 27%) reducing ductility. Workability of concrete is greatly influenced by fibers length and volume fraction: increasing these two values workability decreases. Fibers are not influent on compressive and flexural strength while postcracking toughness is increased. Nanocomposite fibers have a better pull-out strength due to a better friction during slipping, but this doesn’t ensure a better adhesion. Water absorption, freeze/thaw cycles and the sulfate attack test demonstrate that concrete durability increases with the volume of the fiber fraction.