Cement Decarbonization Using Photosynthesis

The production of portland cement is responsible for 7% of global carbon dioxide (CO₂) emissions. Multiple strategies, including portland cement clinker substitution with supplementary cementitious materials (SCMs) and carbon capture, utilization, and storage (CCUS), are being explored to decarbonize the cement production process. This presentation will highlight recent research that leverages the carbon capture and storage mechanisms of microalgae to decarbonize cement production. In one study, the pozzolanic reactivity of biosilica extracted from photosynthetic diatoms was investigated as an alternative SCM. In a second study, raw algal biomass was investigated as a carbon-storing set-retarding admixture for portland cement. Finally, biogenic calcium carbonate from microalgae was investigated as a potential carbon-storing mineral replacement for ground limestone in portland limestone cement. In addition to these studies, other opportunities for cement decarbonization that leverage the carbon capture and storage mechanisms of microalgae will be highlighted and discussed.