Moisture Diffusion in FRP Adhesively-Bonded Joints under Hot/Wet Environments

Fibre Reinforced Polymer (FRP) bridge deck systems are finding increasing usage in the constructions of new bridges and renovations of old bridges. Especially hybrid structures are competitive, i.e. steel girders combined with a pultruded FRP bridge deck. Adhesive bonding which provides smoother load transition is often the most attractive joining technique for the connection between steel girders and FRP decks. However, the long-term performance of this connection is not clearly defined. So the durability modelling and life-time prediction of the adhesively bonded joint are still issues which designers and engineers have to face. As a first step of the PhD research, moisture diffusion in FRP adhesively bonded joints is discussed and analyzed numerically. The moisture concentration distribution of FRP adhesively bonded joints after 70 years was obtained, which can subsequently be used as input for the next step stress-strain analysis allowing for the incorporation of moisture-dependent mechanical properties in the FE model.