Chloride diffusion through surface-treated mortar specimens

This paper reports on a study of the application of the diffusion cell method in assessing the resistance provided by surface treatments to chloride diffusion into concrete. Coatings, sealers, and penetrants were applied to 10-mm-thick mortar specimens. Chloride diffusion coefficients and chloride diffusion resistance values were calculated and compared. A silane, polymer-modified cementitious coating and polyurethane sealer gave diffusion coefficients ranging from one to over three orders of magnitude lower than the OPC mortar substrate. An acrylic sealer appeared to accelerate chloride transport. Acrylic and polyurethane coatings were too resistant for results to be available within a year of testing, but methods of accelerating the test are discussed. The influences of membrane and osmotic effects on chloride transport into surface treated concrete merit further research. (C) 1998 Elsevier Science Ltd.