Effects of low-temperature curing on physical behavior of cold-curing epoxy adhesives in bridge construction

The effect of low-temperature curing on the physical characteristics of a commercial cold-curing epoxy adhesive was experimentally and analytically investigated with a view to a potential application in bridge construction in winter. Curing at low temperatures of 5-10 degrees C took place but the curing process was significantly decelerated due to material vitrification and the associated diffusion-controlled reaction. Existing dynamic and isothermal curing models developed for hot-curing adhesives proved to be applicable to simulate the curing behavior. However, a heating rate-dependent pre-exponential factor and diffusion control had to be taken into account. The relationship between the glass transition temperature and the curing degree could also be described by models developed for hot-curing adhesives. However, at low temperatures, the relationship was curing temperature-dependent, something which had to be taken into account in the modeling in order to provide accurate simulation. (C) 2011 Elsevier Ltd. All rights reserved.