Decarbonization strategies for the global cement and concrete industry. Highlighting the role of chemical admixtures for successful transition

The objective of this paper is to present the two main possibilities for reducing the CO2 footprint of cement via clinker substitution using supplementary cementitious materials (SCMs) or carbon capture&storage. Engineering properties of mortar prepared from binders holding SCMs indicate that substantial clinker replacement is possible, e.g. using calcined clay or slag. Yet, such comparable properties can only be achieved by applying suitable chemical admixtures (superplasticizers, accelerators, etc.). The second option, carbon capture and storage (CCS), allows us to maintain the current cement production processes, but it is expensive and significantly increases the price for cement. For widespread application of SCMs in cement, novel admixtures are compulsory to facilitate successful transition to low carbon binders. This paper compares both alternatives for CO2 reduction and suggests potential solutions for existing technology gaps.