High temperature resistant fly-ash and metakaolin-based alkali-activated foams

Alkali-activated foams (AAFs) present one of the most promising materials for use in the construction sector. Their main advantages lie in their utilization of waste material and their ability to form at temperatures well below 100 degrees C, while still competing in performance with foamed glass or ceramics. The present body of research has focused on improving the thermal stability of fly-ash foams by i) adding metakaolin, and ii) changing the activator from sodium-based to potassium-based components. It has been confirmed that a certain increase in thermal resistance is achieved through the addition of metakaolin while changing activators played a crucial role. While sodium-based AAFs without metakaolin start to shrink at approximately 600 degrees C, samples that have had metakaolin added start to shrink at approximately 700 degrees C. Samples without metakaolin that have used a potassium activator start to shrink at approximately 800 degrees C, whereas potassium-based samples with the addition of metakaolin start to shrink at approximately 900 degrees C.

Automated summary

Alkali-activated foams (AAFs) are a promising material in the construction sector due to their utilization of waste material, low formation temperatures, and competitive performance with foamed glass or ceramics. Research has shown that improving the thermal stability of fly-ash foams can be achieved by adding metakaolin and changing activators from sodium-based to potassium-based components.