Moisture diffusion in web‐flange junctions of pultruded glass fiber reinforced polymeric bridge profiles

Abstract Attributed to the rich‐resin zone and potential formation of folded fabrics, the web‐flange junctions (WFJs) usually present premature failure. The moisture diffusion process plays a crucial role in understanding the material degradation of glass fiber reinforced polymeric composite profiles exposed to hydrothermal environments. In this paper, moisture diffusion parameters were calibrated by gravimetric tests of thin plates (100.0 × 6.0 × 2.3 mm) at different temperatures and environmental conditions. Additionally, gravimetric tests of WFJs were conducted to investigate three‐dimensional moisture diffusion at different temperatures and environmental conditions. Experimental results showed that the moisture uptake for specimens exposed to artificial seawater is larger than specimens exposed to freshwater through identical exposure periods. The moisture uptakes ratio of WFJs ranges from 1.66 to 3.07 for and 3.05 to 8.57 for . The non‐Fick water diffusion of WFJs simulated by the finite element method was validated by moisture uptake experimental observations. A good agreement was observed between experimental observations and non‐Fick FE simulations. WFJs specimens exhibited non‐uniform mass concentration at the inner side and lower mass concentration zone gradually formed, and the uneven residual stress occurred during moisture migration.