Durability of GFRP composite exposed to outdoors weathering

Abstract Twelve ply glass fibre-reinforced plastic (GFRP) composite samples, hung in the open for out-doors ageing, were characterised in terms of moisture intake, inter laminar shear stress (ILSS) (using 3-point bend test) and glass transition temperature (T g ) (using low temperature differential scanning calorimetry; DSC) as a consequence of the exposure to out-doors. The local relative humidity and the temperature fluctuations were recorded. The responses so obtained were compared with those pertaining to 18 ply GFRP composite samples fabricated with same constituents adopting parallel methods but exposed to higher fixed levels of relative humidity and temperature in a humidity chamber under laboratory conditions (95% of relative humidity at 60 °C). Expectedly, moisture intake was greater for the laboratory-conditioned samples, exposed to higher fixed levels of relative humidity and temperature for longer durations. However, the ILSS decrease and T g depressions for the out-doors conditioned samples were more severe. More importantly, SEM fractographs revealed relatively smoother broken surfaces for the outdoors treated samples indicating a brittle mode of failure that could be catastrophic.