Extruded hybrid fiber reinforced cementitious composites: Fid-Bau Portal

Extruded hybrid fiber reinforced cementitious composites

Cyr, M.F. / Peled, A. / Shah, S.P.

Extruded cementitious composites reinforced with two or more different types of fibers, referred to as hybrid fibers, were studied. Fibers were combined to tailor and optimize composite performance. Low-modulus fibers with a weak fiber-matrix bond, such as polypropylene (PP), were combined with high-strength, high-modulus fibers, such as glass or polyvinyl alcohol (PVA) to produce composites that are both strong and tough. The flexural performance of composites containing large amounts of Class F fly ash and various combinations of glass and PP fibers and glass, PVA, and PP fibers was evaluated Several of the hybrid composites were also tested without fly ash to determine the effect of fly ash on composite performance. The effect of moisture content was evaluated by testing composites under both dry and saturated conditions. Composites were subjected to accelerated aging to evaluate durability. It was shown that the flexural performance of these extruded composites can be controlled using hybrid fibers. In glass:PP hybrid composites, the strength increases while the toughness decreases with increasing glass content, however the performance is greatly influenced by the moisture content of the specimen. The performance of this composite is further enhanced by the addition of PVA fibers, which produce a strain-hardening response. The addition of more inert fibers, such as adding polypropylene fibers to a glass fiber composite, improves the durability.