PFA CONCRETE - EXPOSURE TEMPERATURE EFFECTS ON CHLORIDE DIFFUSION

The results are discussed of a study into the effect of exposure temperature on the coefficient of chloride diffusion (D) of concrete, with PFA contents varying from 0 to 50%, strengths from 20 to 60 N/mm2 and initial curing being in either water 20-degrees-C or in air 20-degrees-C/55% RH. The effect of PFA in reducing D is shown to increase with exposure temperature. This effect is greater than the effect of design strength and is more marked where the initial curing has been poor. The work shows that the diffusion test conditions must be chosen to reflect the exposure environment of the concrete structure, as it is possible to greatly over or underestimate the durability of concrete using the standard temperature of 20-degrees-C.