Concrete with bottom ash from municipal solid wastes incinerators.

Mineral solids in the form of fly ash and bottom ash are produced by burning municipal solid wastes in incinerators (MSWI). Fly ash is negligible and it is so chloride-rich that it cannot be used as mineral addition in cement-based mixtures for reinforced concrete structures.
On the other hand, bottom ash is about 25% with respect to MSWI and its chloride content is negligible, so that it could be potentially used as mineral addition for manufacturing concrete mixtures. However, ground bottom ash (GBA) from MSWI does not perform as well as other mineral additions (silica fume or fly ash produced by coal burning) due to the presence of aluminium metal particles which react with the lime formed by the hydration of Portland cement and produce significant volume of hydrogen in form of gas bubbles which strongly increase the porosity of concrete and reduce its strength.

Author: M. Collepardi, S. Collepardi, D. Ongaro, A.Q. Curzio, M. Sammartino

Section: Waste utilization

Keywords: bottom ash, slurry, concrete