In this talk I will present a few success case studies where calculations using atomistic techniques, typical of the nanoscale, have been employed to study problems in cementitious materials. I will begin by describing challenges associated with powder cement, the clinker, with compounds such as belite, which are currently a key focus in the design of low CO₂ cements [1,2]. Secondly, I will proceed to describe the compounds that are formed following the hydration of the clinker. These include the C-S-H gel, which constitutes the cement glue that holds the aggregates together, as well as other secondary compounds such as portlandite [3]. Furthermore, I will review the characterisation of the C-S-H gel using NMR techniques and how this technique can be used to define the nanoscale structure of the gel phases [4]. Finally, I will examine the potential role of nanoadditions that could be intentionally incorporated into cement pastes [5-7].

[1] Cuesta, A., Ayuela, A., & Aranda, M. A. (2021). Belite cements and their activation. Cement and Concrete Research, 140, 106319.

[2] Rejmak, P., Dolado, J. S., Aranda, M. A., & Ayuela, A. (2019). First-principles calculations on polymorphs of dicalcium silicate—Belite, a main component of Portland cement. The Journal of Physical Chemistry C, 123(11), 6768-6777.

[3] Manzano, H., Dolado, J. S., & Ayuela, A. (2009). Elastic properties of the main species present in Portland cement pastes. Acta materialia, 57(5), 1666-1674.

[4] Rejmak, P., Dolado, J. S., Stott, M. J., & Ayuela, A. (2012). 29Si NMR in cement: a theoretical study on calcium silicate hydrates. The Journal of Physical Chemistry C, 116(17), 9755-9761.

[5] Ayuela, A., Dolado, J. S., Campillo, I., De Miguel, Y. R., Erkizia, E., Sánchez-Portal, D., ... & Echenique, P. M. (2007). Silicate chain formation in the nanostructure of cem.ent-based materials. The Journal of chemical physics, 127(16).

[6] Manzano, H., Enyashin, A. N., Dolado, J. S., Ayuela, A., Frenzel, J., & Seifert, G. (2012). Do cement nanotubes exist?. Advanced Materials, 24(24), 3239-3245.

[7] Izadifar, M., Dolado, J. S., Thissen, P., Ukrainczyk, N., Koenders, E., & Ayuela, A. (2023). Theoretical elastic constants of tobermorite enhanced with reduced graphene oxide through hydroxyl vs epoxy functionalization: a first-principles study. The Journal of Physical Chemistry C, 127(36), 18117-18126.