Sulfate Attack on Concrete-The Effects of Supplementary Cementitious Materials and Exposure Temperature on External Sulfate Attack (Recorded presentation)

The Effects of Supplementary Cementitious Materials and Exposure Temperature on External Sulfate Attack (Recorded presentation)

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Video Summary

This presentation examines how supplementary cementitious materials (SCMs) and exposure temperatures affect the external sulfate attack on concrete. Conducted during a PhD at the University of New Brunswick, the research involved casting mortar bars to test SCMs like fly ash and silica fume, and their resistance to sulfate solutions at varying temperatures (1°C, 5°C, 10°C, and 23°C). The mortar cubes were also tested for strength gain without sulfate immersion. Results show that SCM blends generally improve sulfate resistance, with fly ash performing best at higher temperatures. The study revealed that current testing standards may be too harsh for limestone-blended cements, as they endure longer sulfate solution exposure, affecting SCM effectiveness due to early immersion. Additionally, metakaolin showed unexpected resilience at lower temperatures. Overall, the study finds that Portland limestone cements with SCMs can be effective against sulfate attacks when appropriately utilized.

Keywords

supplementary cementitious materials

sulfate resistance

fly ash

metakaolin

Portland limestone cements