A new technique for retrofitting damaged concrete structures

Abstract

A new retrofitting technique based on a material compatible with concrete is currently under development at Cardiff University. It overcomes some of the problems associated with the current techniques based on externally bonded steel plates and FRP (fibre-reinforced polymer) laminates which are due to the mismatch of their tensile strength and stiffness with that of the concrete structure being retrofitted. This paper will describe the technology necessary for preparing high performance fibre reinforced mixes, designated CARDIFRCs. They are characterised by high tensile/ flexural strength and high energy-absorption capacity (i.e. ductility). The special characteristics of CARDIFRC™s make them particularly suitable for repairing and upgrading (i.e. retrofitting) existing concrete structures, as well as for other remedial activities. The promising results of several studies using CARDIFRC™s for retrofitting damaged concrete structural members will be presented. It will be shown that damaged reinforced concrete beams can be successfully strengthened and rehabilitated in a variety of different retrofit configurations using pre-cast CARDIFRC™ strips adhesively bonded to the prepared surfaces of the damaged beams.