DURABILITY OF GFRP BARS IN CONCRETE BEAMS

Over the past three decades the use of GFRP bars as more durable alternative materials to traditional steel reinforcement has received a lot of attention in construction. However, given the potential deterioration of glass fibres in alkaline environment, quantifying the durability of GFRP bars in concrete, especially under severe conditions and sustained load, is an issue that requires further investigation. The lack of data on long term performance of GFRP composites in real concrete environments is a major concern and is hindering the wider use of GFRP composites in civil engineering applications. This paper presents the methodology adopted for an ongoing experimental programme to examine the behaviour of GFRP bars embedded in concrete or immersed in alkaline solution and exposed to temperatures varying from 20°C to 60°C, and discusses some preliminary results. After exposure, the specimens are tested in direct tension to assess the environmental effects on their residual tensile strength and elastic modulus. The effect of different degrees of sustained stress on the residual mechanical properties of the tested reinforcement is also investigated. The change in physical properties and possible degradation of the GFRP reinforcement are examined using a set of complementary techniques including gravimetric