Flexural and web crippling properties of GFRP pultruded profiles subjected to wetting and drying cycles in different sea water conditions

Using glass fiber reinforced polymer (GFRP) composites in marine structures that are subjected to high corrosive conditions has widely increased. This study analyzes the short-term data from accelerated aging tests to investigate the performance of GFRP pultruded profiles exposed to wetting and drying cycles in six sea water conditions differing by salt (NaCl) and chlorine amounts at 40 °C and 60 °C for six months. The profiles were composed of a polyester matrix reinforced with E-glass fibers. Testing for the rate of weight gain, flexural properties, and web crippling were conducted, along with, scanning electron microscopy (SEM) analysis, to obtain the degradation mechanism of the profiles. Finally, empirical equations were developed to determine the contribution of variable parameters in mechanical reduction using a Bayesian regression. It was found that sea water with higher temperature and higher amount of chlorine was the most aggressive condition for the profiles. Furthermore, as a result of the web crushing failure mode in the web crippling test, in which matrix degradation is the most important factor affecting overall specimen degradation, the degradations were higher than those seen in bending tests, in which the fibers and their interface with the matrix are the important factors.