Service life prediction of pultruded glass fibre reinforced polymer composites for building construction

The paper describes an Arrhenius related methodology applied to the prediction of the long-term mechanical behaviour of three commercially available pultruded GFRP plates adopted as cladding in building constructions, having the same E-glass fibres reinforcement. The composites had three different resin systems, namely: isophthalic polyester, orthophthalic polyester and vinylester. Variations of the flexural strength of the materials, after being immersed in water baths at both ambient and warm temperatures (20°C, 40°C and 60°C), were considered to predict the long-term degradation. The flexural strength retention through time was used as measurement of the imparted degradation, and the water uptake was considered to define the diffusion coefficient and the activation energy for the three composites. By defining a performance related threshold, it has been possible to estimate the expected service life. The predictions show that the considered GFRP composites might perform with strength retention higher than 65% for several decades, even though some meaningful differences exist when comparing the three composites.