Self-nanocrystallisation of cement for CO2 emissions reduction

Descrizione del progetto

Una soluzione innovativa per ridurre le emissioni di CO2 del cemento

Sebbene il calcestruzzo sia un materiale fondamentale nell’edilizia e nella società moderna, contribuisce in modo significativo alle emissioni di CO2: l’industria del cemento e del calcestruzzo è infatti responsabile di oltre il 7 % delle emissioni globali, il che evidenzia la necessità di ridurne l’uso per contribuire alla mitigazione dei cambiamenti climatici. Sostenuto dal programma di azioni Marie Skłodowska-Curie, il progetto SNC4CO2RED mira a sviluppare una soluzione di auto-nanocristallizzazione del cemento (SNC, self-nanocrystallisation of cemento) che ridurrà significativamente le emissioni di CO2 e migliorerà l’efficienza del cemento e le prestazioni del calcestruzzo. A tal fine, il progetto svilupperà e convaliderà l’approccio SNC, che prevede la produzione di nano-Ca(OH)2 omogeneo in soluzione di cemento in condizioni di idratazione controllate, seguita da un gorgogliamento controllato di CO2 per convertirlo in CaCO3.

Obiettivo

Concrete, the most widely used man-made material, builds modern society, while also generating massive CO2 emissions. The cement and concrete sector emitted 2.9Gt CO2, over 7% of global emissions. As highlighted in the GCCA Net Zero Roadmap, reducing cement use offers significant mitigation potential. Nanofillers show comprehensive advantages in modifying concrete performance, but some critical shortcomings are related to the complex production process, low production capacity, and high cost of nanofillers. This project proposes a self-nanocrystallisation of cement (SNC) approach. The SNC approach involves producing homogenous nano Ca(OH)2 in cement solution by controlling hydration conditions, followed by its conversion into nano-CaCO₃ through controlled CO2 bubbling. This process enhances cement efficiency and reduce CO2 emissions through improving concrete performance. For this purpose, this project will initially develop, validate, and optimise the SNC approaches, while revealing their underlying mechanisms, thus establishing reproducible and efficient SNC approaches. Then, the modification effect and mechanisms of SNC-derived nanofillers on the mechanical, durability and microstructural properties of concrete will be investigated. Finally, the project will evaluate the load-bearing performance of structures constructed with SNC-modified concrete, and conduct life-cycle assessments, emphasizing the potential benefits of SNC approach in reducing concrete cost and CO2 emissions. The SNC approach is designed based on the hydration characteristics of cement and carbonation process, and it does not require complex preparation processes, large amount of energy, or extra catalysts. Benefiting from the nano-core effect, SNC-derived nano-CaCO₃ can increase concrete compressive strength by 1–3 grades without extra cement, thereby reducing CO2 emissions by 10–40% and costs by 10–26%, while advancing the development of net zero concrete in line with the GCCA 2050 roadmap.