Development of a successive stage hierarchy for rational carbon reduction and resource conservation decision-making in the cement industry

Abstract

The cement industry represents nearly 8% of fossil fuel and industrial emissions making it a key area of focus for policymakers around the world. Much of the current effort in cement manufacturing has focused on energy efficiency and material substitution with more recent work focused on carbon dioxide uptake and recycled concrete aggregate use to address greenhouse gas emissions and material conservation, respectively. Currently, no meaningful approach exists for practitioners or policymakers to address greenhouse gas emission reduction for cement manufacturing that incorporates the concepts of material conservation. The Carbon Hierarchy is proposed as a successive stage hierarchy to address this gap. This work is logically and empirically validated using a newly constructed model incorporating the key levers of service life extension, thermal energy decarbonization, limestone substitution, mineral component (MIC), carbon dioxide uptake with consideration for the process flow that incorporated reintroduction of end-of-life (EOL) concrete as raw material or clinker substitution in cement manufacturing and as potential downstream use as aggregate. The Carbon Hierarchy proposed in this research could guide decisions to significantly reduce greenhouse gas emissions for the cement industry while ensuring material conservation.