title: Time resolved X-ray Dark-Field Tomography Revealing Water Transport in a Fresh Cement Sample.
abstract: Grating-based X-ray dark-field tomography is a promising technique for biomedical and materials research. Even if the resolution of conventional X-ray tomography does not suffice to resolve relevant structures, the dark-field signal provides valuable information about the sub-pixel microstructural properties of the sample. Here, we report on the potential of X-ray dark-field imaging to be used for time-resolved three-dimensional studies. By repeating consecutive tomography scans on a fresh cement sample, we were able to study the hardening dynamics of the cement paste in three dimensions over time. The hardening of the cement was accompanied by a strong decrease in the dark-field signal pointing to microstructural changes within the cement paste. Furthermore our results hint at the transport of water from certain limestone grains, which were embedded in the sample, to the cement paste during the process of hardening. This is indicated by an increasing scattering signal which was observed for two of the six tested limestone grains. Electron microscopy images revealed a distinct porous structure only for those two grains which supports the following interpretation of our results. When the water filled pores of the limestone grains empty during the experiment the scattering signal of the grains increases.
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, Garching, 85748, Germany.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Prade
authors.affiliation: Centrum Baustoffe und Materialprufung, Technische Universität München, München, 81245, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Fischer
authors.affiliation: Centrum Baustoffe und Materialprufung, Technische Universität München, München, 81245, Germany.
authors.forename: Detlef
authors.initials: D
authors.lastname: Heinz
authors.affiliation: Institut für Mikrostrukturtechnik, Karlsruher Institut für Technologie, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Pascal
authors.initials: P
authors.lastname: Meyer
authors.affiliation: Institut für Mikrostrukturtechnik, Karlsruher Institut für Technologie, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Mohr
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, Garching, 85748, Germany.|Institut für diagnostische und interventionelle Radiologie, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.
authors.forename: Franz
authors.initials: F
authors.lastname: Pfeiffer