Abstract: The present invention provides a synthetic fiber and methods for its use and formation. The present invention may comprise a fiber component that is a twisted bundle comprised of multiple strands of a nonfibrillating monofilament, the degree of twist being greater than about 0.9 turns/inch (about 0.36 turns/cm). The present invention may further comprise another fiber component, discrete from the twisted fiber component, that is fibrillated.

Abstract: The present invention provides a synthetic fiber blend and methods for its use comprising a first fiber component formed of a homopolymer polypropylene fiber and a second fiber component being a copolymer formed of a polypropylene and a high density polyethylene. The first fiber component is fibrillated and the second fiber component is a twisted bundle comprised of multiple strands of a nonfibrillating monofilament. The synthetic fiber blend imparts improved reinforcement properties to the building materials to which they are added. In particular, the synthetic fiber blend when incorporated into a building material provides reduced permeability, increased fatigue strength, improved toughness, and reduced plastic shrinkage. The unique combination of the twisted second fiber component blended with the first fiber component provides improved mixability and uniform distribution of the synthetic fiber blend in cementitious materials.