Moisture diffusion and hygrothermal aging of pultruded glass fiber reinforced polymer laminates in bridge application

Gravimetric tests were carried out to investigate the moisture diffusion characteristic and hygrothermal aging properties in pultruded glass fiber reinforced polymer (PGFRP) composite laminates of bridge profiles exposed to the water and artificial seawater at temperatures of 40 °C, 60 °C and 80 °C respectively. The moisture diffusion coefficients are obtained depending on the Levenberg-Marquardt algorithm by assuming the total moisture sorption separated into a diffusion-dominated uptake, a polymer relaxation-dominated uptake and a composite damage-dominated uptake. The effects of temperatures, hygrothermal environment and composite directions on diffusion coefficients were discussed. The variations of Fick-dominated diffusion coefficients were assumed confirming the classical Arrhenius relationship and related coefficients were fitted to provide reference at other temperature.