Understanding the chemistry and engineering of low-carbon alkali-activated cements

Grantham Scholar William McMahon’s PhD project is focused on the development and understanding of the chemistry and engineering of low carbon alkali activated cements, with the ultimate goal of his research being to optimise cement formulations for enhanced sustainability, performance and durability. 

The project

William is a PhD researcher based in the Department of Chemical and Biological Engineering at the University of Sheffield. He is supervised by Dr Brant Walkley and is a member of the Sustainable Materials at Sheffield (SMASH) and Cements@Sheffield research groups. His PhD is funded by the Engineering and Sciences Research Council and DB group (Holdings) Ltd. 

The cement industry accounts for 8% of annual global carbon dioxide emissions, and cement production is set to grow by almost 25% until 2050, creating the paradoxical task of severely reducing emissions whilst greatly increasing output in order to create a more sustainable future. The majority of these emissions come from the production and use of ordinary Portland cement (OPC).

Alkali activated cements (AAC) are an alternative to ordinary Portland cement which can offer up to an 80% reduction in carbon dioxide emissions. They are made from industrial waste products, such as blast furnace slag (a by-product from the steelmaking industry), which are mixed with a strong alkali, such as a hydroxide or a silicate, to form a material of comparable strength to OPC. However, these materials have yet to be widely adopted due to a lack of complete understanding, and William’s focus is looking at how the particle-particle, fluid-particle and crystallization processes in these cements affect: the dispersion, fluidisation and rheology of the fresh cement paste, the reaction and setting of the AAC and physical property development of the AAC.


Dr Brant Walkley

Department of Chemical and Biological Engineering