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.