ABSTRACT
For most structural materials, the mechanisms by which they degrade are well understood and protective measures to ensure durability are part of the relevant design codes. As relatively new materials, composites are less well understood with regard to their time-dependent properties. There is some evidence that for loss of primary strength and stiffness in glass-reinforced composites (which is overwhelmingly dominated by the properties of the fibres), the same root causes are at work in both frc and frp but this is still controversial. However, in most cases, the very different chemistry, fibre architecture and applications of frc compared to frp means that the deterioration of these composites is best discussed separately. Ultraviolet (UV) rays from the sun can cause the structure of polymer chains to change, generally through oxidation. All structural components are subject to fluctuating physical and environmental loads and so the fatigue behaviour of frp is important.
