Effects of aging in dry environment on physical and mechanical properties of a cold-curing structural epoxy adhesive for bridge construction

The effect of physical aging and continuation of curing on the physical and mechanical properties of a commercial cold-curing structural epoxy adhesive used in bridge construction has been investigated during the first year. Since adhesive bridge joints are sealed, only dry conditions were taken into account. Predominant physical aging in the earlier age and predominant curing in the later age affected the physical and mechanical properties. The E-modulus exhibited a maximum in the earlier age due to a maxmum mass density caused by physical aging. In the later age, when curing became predominant, mass density and thus the E-modulus decreased while the cross-link density increased. After the first week, the E-modulus development became independent of the curing conditions. Tensile strength and failure strain depended mainly on the cross-link density and their development was thus influenced by the curing conditions but delayed in the earlier age due to physical aging.