Preparation of facade panels based on alkali-activated waste mineral wool, their characterization, and durability aspects

Mineral wool is a widely used insulation material and one of the largest components of construction and demolition waste, yet it mainly ends up in landfills. In this work, we explored the potential recycling of waste stone wool in the pilot production of alkali-activated facade panels. The current work shows mechanical properties, SEM-EDS, and mercury intrusion porosimetry analyses for three different mix designs used for the preparation of facade panels. They are all composed of waste stone wool and differ in the amount of co-binders (local slag, lime, metakaolin, and/or fly ash) selected by the preliminary studies. In this study, co-binders were added to increase early strength and improve the mechanical properties and freeze-thaw resistance. The mechanical properties of each were measured up to 256 days, different durability tests were executed, and, by evaluating the mechanical properties, microstructure, and workability of the mortar, the most suitable mix was selected to be used for the pilot production. In addition, the leaching test of the selected mixture showed no exceeded toxic trace elements and therefore got classified as non-hazardous waste after its use.