Durability of Adhesive Joints Made Underwater

Adhesives are increasingly being used in civil engineering applications as a means of bonding together similar or dissimilar materials. The prediction of the strength of bonded components is therefore vitally important and different methods are being used to investigate and predict the durability of adhesive joints when they are exposed to hostile environments. The present work reports the results obtained using adhesive joints made from mild steel and two epoxide based adhesives, a model adhesive and a specially devised adhesive formulation, that bonded to steel underwater. These joints were tested using custom designed, accelerated aging test equipment based on the double-torsion joint design and the application of fracture mechanics. The joints were subjected to various constant loads in the presence of water at room temperature. A graphite-gauge technique was also developed to monitor the incubation time for a crack to form and measure its subsequent velocity as a function of the applied fracture energy. Scanning electron microscopy and X-ray photoelectron spectroscopy were also employed to identify the locus of joint failure and assess the performance of the underwater made adhesive joints.