Machine learning for high-fidelity prediction of cement hydration kinetics in blended systems

The production of ordinary Portland cement (OPC), the most broadly utilized man-made material, has been scrutinized due to its contributions to global anthropogenic CO2 emissions. Thus - to mitigate CO2 emissions - mineral additives have been promulgated as partial replacements for OPC. However, additives - depending on their physiochemical characteristics - can exert varying effects on OPC's hydration kinetics. Therefore - in regards to more complex systems - it is infeasible for semi-empirical kinetic models to reveal the underlying nonlinear composition-property (i.e., reactivity) relationships. In the past decade or so, machine learning (ML) has arisen as a promising, holistic approach to predict the properties of heterogeneous materials, even without an across-the-board comprehension of the underlying composition-properties correlations. This paper describes the use of a Random Forests (RF) model to enable high-fidelity predictions of time-dependent hydration kinetics of OPC-based systems - more specifically [OPC + mineral additive(s)] systems - using the system's physiochemical attributes as inputs. Results show that the RF model can also be used to formulate mixture designs that satisfy user-imposed kinetics-related criteria. Lastly, the presented results can be expanded to formulate mixture designs that satisfy target kinetic criteria, even without knowledge of the underlying kinetic mechanisms. (C) 2021 The Authors. Published by Elsevier Ltd.