ABSTRACT
Almost every imaginable type of fibre has been used at some time or another with cement or concrete. Polypropylene (PP) fibres are the most commonly used polymer fibre for fibre-reinforced cements and concretes (FRC) and are made by extruding high-molecular-weight PP into either monofilaments or films. Acrylic and polyester fibres are not stable in the high pH environment of most cement-based matrices and are thus not suitable for FRC. Historically, the use of steel–FRC has probably outweighed that of any other FRC; it is still very widely used, although polymer–FRC is catching up fast. The motivation for use of a particular natural fibre normally stems from the desire to use a cheap, locally available and sustainable resource. Carbon fibres were commercially developed in the USA in the 1960s. Glass fibres are normally supplied as rovings of up to 64 strands, each with ~200 filaments of ~14 µm diameter.
