Thermal effects on chloride diffusion in concrete

Corrosion of reinforcing steel in concrete usually initiates from chloride ingress. The temperature of the service environment and cementitious material blends influence chloride ingress. This paper presents data from a multi-year experiment designed to illustrate the effects of temperature and supplementary cementing materials on chloride diffusion in concrete. This experiment consists of six concrete mixtures, five of which contained different supplementary cementing materials. Test specimens were submerged in 6% sodium chloride solution, and stored at a temperature of 10, 23, and 32degreesC for approximately three and one-half years. The chloride ingress data are presented, and the impact of temperature on chloride diffusion coefficients along with its implications for corrosion service life modeling are discussed. Presently, most service life prediction models adjust for the service temperature of a structure by using the Arrhenius Equation. The time-to-corrosion data obtained in this study suggests that the net result of temperature related effects does not match the predictions based on the Arrhenius Equation.