Third party funded individual grant
Start date : 01.01.2017
End date : 31.03.2020
The lack of understanding of the spatial arrangement (meso-structure) of the calcium-silicate-hydrate (C-S-H) phase in hydrated cement hinders innovation in cementitious materials which is needed to reduce their enormous environmental impact. The primary aim of this proposal is to develop an improved model of the C-S-H meso-structure (Sheet Growth Model``, developed by M. Etzold). This will allow us to use the sheet growth model to predict porosity of hydrated cementitious materials. The approach is to parametrise the Sheet Growth Model with data from Scanning Electron Microscopy (SEM), proton nuclear magnetic resonance (1H-NMR) relaxometry and from some other methods. This will lead to model structures with properties close to experimental observations. A key aspect is the simultaneous pursuit of the modelling and the experimental approach in a single research team. This approach ensures the realism of the model and enables the modelling in turn to provide guidance to the experiments. The initial project is concerned with fundamental developments. On the modelling side, modifications of the computer model required to model domains with sizes of about 1 µm will be implemented. In parallel, an SEM technique developed for clay materials will be transferred to hydrated cement paste, which will enable its imaging with unprecedented resolution. This is an important result on its own right due to the importance of SEM as a standard tool to characterise porosity in hydrated cement paste. Furthermore, some automatic data analysis tools will be implemented for the 1H NMR. In a second step, the improved experimental tools will be used to generate the results (shape and porosity information) needed to parametrise the model, first as a static model and in a second step as a dynamic model trying to mimic time-resolved hydration data. This combined approach provides the tools to image hydrated cement from the nano- to the millimetre scale and develop a 3D model for the pore space at this length scale. The close interaction between modelling and experimentalists is a key aspect of improving the fundamental understanding of cementitious materials. Thus, this project serves as an important starting point for the development of sustainable and innovative new materials.