Influence of curing temperature and maturity on chloride permeability of concrete containing fly ash or slag

The resistance to chloride ingress of concrete with water to cement ratio equal to 0.40 was investigated. Concretes containing fly ash or blast furnace slag were compared to pure Portland cement concrete. The concretes were cured immersed in water at different temperatures ranging from 10 to 60 degrees C. Chloride migration and diffusion coefficients were determined at similar maturities, ranging from 28 to 180 maturity days. It was found that the resistance to chloride ingress of blast furnace slag cement concrete was generally very good at all temperatures and maturities. For the ordinary Portland cement concrete, the resistance to chloride ingress decreased as a function of curing temperature for temperatures above 30 degrees C. For the fly ash concrete, the resistance to chloride ingress increased as a function of curing temperature throughout the temperature range investigated. The chloride migration coefficient at 28 maturity days was a factor 10 lower for the fly ash concrete cured at 60 degrees C compared to the fly ash concrete cured at 10 degrees C.