A study of the migration of corrosion inhibitors in aqueous solution through concrete disks (of approximately 6-mm thickness) has been undertaken. Concrete disk specimens were placed between glass vacuum flanges and aqueous solutions of salts and a vacuum applied on one side of the disk caused inhibitors to penetrate the disk. The contact times of the aqueous solution with the disks were evaluated. The depth of solute migration was measured by surface-sensitive analysis (x-ray photoelectron spectroscopy, XPS) of selected portions of fractured disks. XPS measurements were used to establish whether chemical changes had occurred during solute migration and to determine whether differential migration of solute cation and anion had taken place. The implications of the migration of salts and inhibitors for bridge repair are discussed.