Cold region durability of a two-part epoxy adhesive in double-lap shear joints: Experiment and model development

This paper presents the behavior of a two-part epoxy adhesive bonded to a steel substrate (typical combination for FRP-repair of deteriorated steel girder bridges) subjected to cold region environment. A total of 43 specimens are tested using double-lap shear joints in wet-dry and freeze-thaw conditions to examine the durability performance of the joint, including load-carrying capacity, interface deterioration, and failure mode. A three-dimensional modeling approach is proposed to predict experimental findings. The model takes into account debonding characteristics of the interface. Empirical bond-deterioration models are suggested. Load-carrying capacity of the specimens tends to be improved with the environmental cycles possibly due to additional curing of the adhesive in a moisture environment, whereas interface deterioration is accelerated with the cycles. Failure mode of the test specimens is altered from cohesion failure to adhesion failure because of the environmental effects. (C) 2012 Elsevier Ltd. All rights reserved.