The physical and mechanical properties of a cold-curing structural epoxy adhesive, exposed to a representative wet bridge environment, were investigated. A significant decrease of the glass transition temperature, tensile E-modulus and tensile strength was observed which could be attributed to plasticization. The retention of 70% of the E-modulus and strength at an average 10°C reference temperature was predicted using the Arrhenius law after a 100-year bridge service life. The immersion in alkaline water had no detrimental effect in the case of concrete-adhesive joints. In an immersed not yet fully cured material, the continuation of curing and plasticization concurred. The former was dominant in the early age and led to an increase of the glass transition temperature, E-modulus and strength. The latter decelerated the increase of the glass transition temperature and led to a decrease of the E-modulus and strength in the later age. Both approached the values of those of the fully cured material; the E-modulus after one month and strength after 20 months.