Mineral carbonation of industrial wastes for application in cement-based materials

Mineral carbonation is a way to permanently store carbon dioxide (CO2) 2 ) in cement- based materials. Demolished concrete waste and other types of alkaline industrial wastes, like iron and steel slags, fly ash, concrete slurry waste and cement kiln dust are prospective candidates for accelerated carbonation application. This paper presents CO2 sequestration potentials, impacts of the accelerated carbonation on the selected properties of wastes and their possible applications in cement-based materials. Based on the analysis of published research in the area it was concluded that porosity, volume stability and heavy metals leaching of different waste types are improved after accelerated carbonation pre-treatment. This increases the effectiveness and broadness their application as substitutes for aggregates and binders in mortar and concrete. The research is however still very limited in the area of the application of the carbonated wastes with highest CO2 sequestration potential, namely recycled concrete powders and iron/steel slags. Besides, for proper conclusions on the environmental benefits, an LCA (Life Cycle Assessment) which includes all the phases of the life cycle must be performed, which is also lacking in the published research.