Influences of Polymer Modification and Exposure Conditions on Chloride Permeability of Cement Mortars and Composites

On the basis of laboratory investigations, this paper presents the chloride penetration and diffusion over different exposure conditions of three commercial polymer-modified mortars, styrene-butadiene rubber (SBR), polyacrylic ester (PAE), and vinyl acetateethylene (VAE), and unmodified conventional mortar mix and composites. The results indicated that within 15% of polymer addition in cement mortars, there was a substantial decrease in chloride penetration. The diffusion coefficients of chloride ions estimated from the simplified linear error function-based (SLEM), Newton-Raphson, and least-squares fit methods showed increasing value coefficients with the increasing age of specimens or cycles of exposure. The results also revealed that at 15 and 40 cycles of wetting and drying, the cement mortars modified with VAE exhibited a much superior quality in chloride penetration than SBR-or PAE-modified mortars. DOI: 10.1061/(ASCE)MT.1943-5533.0000379. (C) 2012 American Society of Civil Engineers.