Fibre reinforced polymer and steel rebar comparative performance

Purpose – This paper aims to investigate the necessary requirements that a concrete reinforcement material must satisfy; namely the ability to resist tensile forces and have good bond strength while providing structural qualities of toughness and flexural strength. Design/methodology/approach – The bond and strength properties were mainly tested in a paired comparison test using 6mm diameter steel and fibre reinforced polymer (FRP) rebar specimens in beams and cubes. Bond strength was examined using 12 concrete cube specimens of 150 mm, six cubes had steel rebar and six had FRP rebar inserted through the full depth of the cube and they were subject to pull out tests. To determine flexural strength and toughness, a three point loading test was performed to provide load/extension data on 28 500 £100 £100mm concrete beams. A total of 14 beams were cast with steel rebar and 14 were cast with FRP rebar. Findings – The results showed for equal diameter bars the FRP specimens had outperformed steel in each test. Failure modes of FRP specimens showed higher degrees of toughness when compared to steel. Originality/value – Steel rebar has a long and proven track record of satisfactory use in reinforced concrete. For designers and clients to change from traditionally used materials, there is a need for investigative research to prove the worth of the new material. This paper goes part of the way to fulfil this need.