3D imaging of cement-based materials at submicron resolution by combining laser scanning confocal microscopy with serial sectioning.
A new 3D-microscopy method, focused ion beam-nanotomography (FIB-nt), has been applied to the statistical particle shape analysis and for topological characterization of granular textures in cement samples. Because of its high resolution (15 nm), FIB-nt reveals precise microstructural information at the submicrometer scale, which cannot be obtained with conventional tomography methods. It is demonstrated that even from complex granular textures with dense agglomerates, it is possible to identify the individual sub-grains. This is the basis for reliable statistical shape analysis. For this purpose, moments of inertia were determined for particles from five different grain size fractions of a given cement, which provides important input data for future modeling of rheology and hydration processes. In addition, FIB-nt was used for topological characterization of the particle–particle interfaces in the dense and fine-grained granular textures. The unique 3D-data obtained with FIB-nt thus open new possibilities for quantitative microstructure analysis and the data can be used as structural input for object-oriented modeling.