As part of a study into the controls on the deterioration of concrete due to sulfate attack, mortars (50 mm cubes and 40 × 40 × 160 mm prisms) made with Portland cement CEMI, and 90% CEMI + 10% limestone blend were exposed to BRE DS4 sulfate solution based on magnesium sulfate MgSO4.7H2O under wetting and drying cycles for 12 months at 5°C. The effect of these cycles on thaumasite formation was studied and compared with samples immersed continuously in the same solutions. Visual observations, mass and length changes were used to assess the mortar deterioration, along with X-ray diffraction and infra-red spectroscopy that were used to determine the mineralogy of deterioration products. It was found that at the 5°C, wetting and drying cycles significantly delayed thaumasite formation compared with control specimens.
International Conference on Sustainable Construction Materials and Technologies, SCMT3
Claisse PA, Miyagawa T, Naik TR
Paper no. M3-6 2