Expansive cement couplers - A means of pre-tensioning fibre-reinforced plastic tendons

Fibre reinforced plastics describes a group of materials composed of inorganic or organic fibres embedded in a resin matrix. FRPs are strong, non-magnetic, light-weight and for the most part, non-corrodable. There is great scope for the use of FRPs as concrete reinforcement and the high strength of the materials is conducive to prestressed applications. However, finding a suitable method of anchoring the tendons without inducing stress concentrations in the fibres has been identified as a problem. The current paper investigates the potential for the use of expansive cement couplers as a means of pretensioning FRP tendons. An experimental study was carried out on couplers to join steel reinforcing bars and then extended to include the coupling of FRP materials to steel prestress wire.