Abstract
As the environment in the Caribbean coast is highly aggressive, the housing infrastructure built in this region is continually affected, with heavy losses due to corrosion of the reinforcing steel embedded in concrete. To gather information with respect to the diffusion of chlorides in concrete made with highly-porous crushed limestone under marine environment, two types of cement were employed: ordinary Portland cement and pozzolanic cement. The aggregate used was crushed limestone for both, coarse and fine aggregate (5% absorption). Two water to cementitious materials ratios were employed, 0.5 and 0.7; equivalent to 35 and 20 MPa, respectively. Two curing treatments were employed: 1-day and 14-day wet curing periods. Concrete specimens were prismatic, 15 by 15 by 20 cm. Once concrete specimens were two weeks old, they were exposed to marine environment, at 90 m from the shoreline. Performance of the external concrete layer was determined by chloride ingress. Two extraction methods were employed, acid-soluble (FDOT) and water-soluble (RILEM), followed by potentiometric titration with a silver ion reference electrode. Results indicate that chloride concentrations were significant higher for the 1-day curing specimens than for the 14-day curing ones, as well as for the ordinary Portland cement specimens compared with the pozzolanic cement specimens. Chloride diffusion coefficients were in the same range as those found in other investigations.
