Effect of sustained tensile stress and temperature on GFRP composite bars properties: 1. Preliminary experiment in deionised water and alkaline solution

Fibre Reinforced Polymer (FRP) composites represent an alternative construction material to overcome the corrosion problems caused by traditional steel reinforcement. This paper describes a new experimental set-up specially designed to perform accelerated ageing tests on FRP reinforcements. The setup uses a combination of temperature, which can reach up to 80°C, environmental exposure (alkaline, saline, water, and concrete) and sustained loading. Preliminary experimental observations show good performance of GFRP rebars under the combined effects of sustained stress corresponding to 30–40% of the ultimate tensile strength, temperature ranging from 55 to 75°C and in two environmental exposures: deionised water and alkaline solution. Microstructural analyses, using several techniques (Thermogravimetric Analysis, Differential Scanning Calorimetry, Scanning Electronic Microscopy and Fourier Transform Infrared), have been conducted on rebars conditioned in an alkaline solution over 60 days and show that only the internal part of the rebars has not been affected by degradation.