Long-term bending performance and service life prediction of pultruded glass fibre reinforced polymer composites

This paper presents an experimental investigation on the long-term mechanical performance, focusing on bending, of pultruded composite plates adopted as cladding in building constructions. Three matrices have been used in combination with E-glass fibres: isophthalic polyester, orthophthalic polyester and vinylester. The degradation of the mechanical performance has been monitored through a process of accelerated artificial ageing by using water baths set at different temperatures: 20 C, 40 C and 60 C. Flexural strength retention through time has been used as measurement of the imparted degradation and water absorption has been considered to define the diffusion coefficient and the activation energy for the three compositions. The Arrhenius methodology has been adopted to estimate the long-term degradation of the composites and to predict the expected service life of the materials. The outputs of the research show that isophthalic and vinylester systems have flexural strength retention of 65% for more than 75 and 100 years, respectively, while the orthophthalic composite has the same retention for more than 20 years.