The hydration of cement paste: Thermodynamics driven multi-scale modeling of elastic properties and coda wave interferometry based monitoring

Concrete is produced by mixing hydraulic cement and aggregates with water. In contact with water, the cement particles first dissolve and subsequently hydrates form through various chemical reactions determining the overall mechanical material properties. Modeling, simulation, and monitoring of the cement hydration provide insights into the processes involved and allow prediction of overall material properties. Thereby, linking the underlying chemical processes to macroscopic material properties remains a key challenge. In this contribution, thermodynamic simulation and a multi-scale modeling approach were employed for Young’s modulus development prediction for an ordinary Portland cement paste during the first 24°h of hydration. Further, ultrasound based Coda Wave Interferometry (CWI) methods were applied for monitoring of corresponding cement paste specimens. Coinciding trends were found for model and monitoring based results: Initial small alterations are followed by a period of strong material changes with an accelerated stiffness development and a strong increase in wave velocity.