Fibres: Technical Benefits

Abstract

The benefits of metallic, organic and inorganic fibres and fillers in both OPC and geopolymers are discussed at length. Cementitious materials are typically characterised by low tensile strength and strain capacity and are sensitive to micro cracking. Fibres, and/or steel and Fibre Reinforced Plastic (FRP) rebar may be incorporated into cementitious matrices to overcome these weaknesses giving materials with increased tensile strength, ductility, toughness and increased durability. The mechanism of fibre reinforcement is common to OPC and geopolymers and as such the literature covering OPC-fibre composites is relevant. The mechanism of fibre reinforcement is discussed together with comments about the effects of fibres on processibility. Fibres also contribute to improvements in durability of cementitious composites such as corrosion and fire resistance. The properties and attributes of each fibre type are outlined with respect to the result achieved in the cementitious matrix. Fibres can reduce plastic cracking in fresh concrete and improve the post crack ductility of hardened concrete. An extensive range of available fibres is covered; natural and synthetic, inorganic and organic as well as a section on carbon based fibres. Hybrid fibre blends, typically steel and polypropylene, can give synergistic effects.