Doctoral dissertation of Juan Pablo Gallo Molina – A multiscale modelling study of cement paste rheology

PhD reception


Concrete is one of the most produced substances in the world. Its existence therefore comes with gargantuan economic and environmental implications. Cement -the hydraulic binder that makes the transition from a fluid to a hardened state possible- is arguably the most important and most complex component of a concrete mixture. This, in addition to the ascendance of non-traditional aggregates and chemical admixtures, as well as the increasing desire to reduce the overall quantities of cement employed in a given application, have created a number of engineering challenges.
Among those challenges, rheology control during the initial, fluid stage is particularly salient. For this reason, this doctoral research focused on the development of a multiscale modelling framework aimed at predicting the rheological response of fresh cement pastes. Population balances were shown to be ideally suited to reproduce the temporal evolution of the microstructure of a paste, which is the factor that determines rheology in the studied systems. In turn, molecular simulations were used to obtain a high-resolution picture of the colloidal interactions governing the dynamics of said microstructure. As a result, it was possible to reproduce the subtle differences in flow behaviour that arise in cements coming from the same product line, a situation commonly found by industry practitioners.