When a concrete surface is contaminated by water due to rain, saline water, ground water, and water jetty treatment, water, alkalis, and other contaminants on the concrete surface may interact with an epoxy adhesive used for bonding fiber-reinforced polymer composite sheets to concrete. This can influence both the curing rate and the degree of cure of the curing reaction. This in turn can affect the time required for field application. It can also influence the mechanical properties and durability of epoxy adhesives. In this paper, water effects on the curing and properties of two kinds of commercial adhesives were evaluated. Curing kinetics were studied using isothermal DSC analysis. Results showed that water accelerated the curing reaction. However, excess water offsets part of the accelerating effect. While water is typically considered to be harmful to properties of adhesives, it was seen that a small amount (less than 2%) of water improved degree of cure, mechanical properties, and durability of adhesives. (C) 2004 Wiley Periodicals, Inc.