Effect of Cold Temperature on the Chloride-Binding Capacity of Cement

Service life of reinforced concrete structures exposed to chloride ions is closely related to the rate of chloride ion diffusion through the concrete. The determination of the apparent chloride diffusion coefficient of concrete takes into account the chloride-binding capacity but not the effect of temperature on the chloride-binding capacity. This paper examines the effect of temperature ranging from 22°C to –3°C on the chloride-binding capacity for cement paste containing varying percentages of ground granulated blast furnace slag (GGBFS) as cement replacement. This study adopts the Freundlich isotherm form of the chloride-binding isotherm as a function of temperature. Both the experimental and modeled results indicate a nonlinear relationship between the exposure temperature and the chloride-binding capacity for cement paste containing 0–60% GGBFS as cement replacement. The order of chloride-binding capacity as a function of exposure temperature is as follows: 22°C>-3°C>13°C>5°C. The order of chloride-binding capacity as a function of the percentage of GGBFS as cement replacement is as follows: 60%>50%>25%>0%. Service life estimates of reinforced concrete structures in cold climates that are exposed to deicer salts are not conservative if based on chloride-binding capacity evaluated at 22°C.