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Description
Cement paste serves as a binder for cementitious materials, playing a crucial role in the development of construction materials. Its composition and constituent ratios can be adjusted to meet specific requirements. The microstructure of cement paste, formed during the hydration process, typically comprises a combination of various hydration products, unreacted clinker particles and pores. Geometric models representing the microstructure of cement paste can be generated based on experimental methods, such as X-ray microtomography, or by using software dedicated to simulating the hydration process. Various numerical models of cement paste microstructure have been proposed in the literature, differing in their level of detail and the properties assigned to individual phases. This work concentrates on investigating the influence of the cement paste’s microstructure model parameters on its effective elastic properties. During this study, the Virtual Cement and Concrete Testing Laboratory (VCCTL) software is used to establish the microstructure model, including detailed information related to different phases. In this case, various clinker phases (alite, belite, tricalcium aluminate), as well as various hydration products (calcium silicate hydrate, portlandite, ettringite, etc.), can be distinguished. On the other hand, models presented in the literature often simplify this description for practical reasons. The simplifications include, for instance, treating clinker phases as a single entity and unifying the properties of hydration products. It is predicted that the results of this study will allow assessing the impact of such simplifications on stiffness predictions. Another factor to be investigated is the influence of the size of the representative volume element. For the determination of the effective elastic constants, computational homogenization based on the fast Fourier transform (FFT) is adopted. The microstructures corresponding to the state after 28 days of hydration are considered; two cases involving different water-to-cement ratios are analysed. It is expected that the obtained results will facilitate the preparation of virtual models of the cement paste microstructure, allowing achieving a balance between model simplicity and accuracy of homogenization. Such models can later be used in the framework of multiscale simulations involving interactions across different scales.
