Potential for carbon dioxide reduction from cement industry through increased use of industrial pozzolans

Concrete is the most widely used material on earth, eclipsing the combined volumes of all other man made materials by a factor of ten. In terms of its embedded carbon, it is a benign product, being associated with relatively little CO2 per unit mass when compared with metals, glasses and polymers. Conversely, it is made in such vast quantities, that it is responsible for over five percent of anthropogenic CO2. Despite recent advances in kiln design and alternative, low energy clinkers, it seems likely that the greatest carbon savings from the industry are likely to be made by the inclusion of supplementary cementing materials. This article reviews some of the options currently under investigation, especially from the UK perspective, and highlights that some of the research needs to be satisfied before such materials are more widely adopted.