The results show that the fresh cement paste has a higher density than the hardened paste after 14 days, which can be explained by the hydration of the C3S, and the presence of C3S causes higher compressive strength in the early stage . In the case of the unsealed samples, the time-lapse images reveal the presence of a fine, non-uniform interface that can be correlated with changes in the pattern of micro-cracking. The interface is in direct contact with the matrix, which can lead to internal crack densification during hydration, as shown in Fig. 7 and in the time-lapse animations in the Supplementary Information. The strong reduction of the interface thickness observed at 90 min in the unsealed samples can be explained as part of the front propagation of a pre-existing crack. The sealed samples do not show crack propagation in the time-lapse images, as the crack is generated on the sealing surface and propagates in the form of an abrupt front, which is not visible with the X-ray technique (see Fig. 7 and the supplementary information). Such a crack propagation was also reported previously by Li et al.  and is a typical sign of drying shrinkage crack propagation, although other factors may also be involved. The contrast-enhanced X-ray images reveal that the crack is associated with the presence of a gas-filled region , however, the image resolution is not sufficient to resolve such a small region. In summary, the X-ray images indicate that the thin interface layer observed at 90 min in the unsealed samples is the result of pre-existing micro-cracks, which can be related to the observed reduction of the interface width after 90 min since mixing. This method is fully compatible with the common sample preparation and it is not limited to fresh state samples, as we have used it to measure the time-dependent thickness of an unsealed sample after 7 days from mixing.
Other areas of application include the monitoring of other hydration reactions, such as setting and de-setting of the cement paste, which are important characteristics of the fresh state. For example, in a typical cement-based construction, the early reaction of the cement paste makes a crucial contribution to the strength of the cement paste bond to the steel reinforcement. Thus, the time-dependent thickness of the cement paste in the fresh state can be monitored to predict the strength of the paste bond and the durability of the construction.
If you want to spend a relaxing time, do not miss a trip to Kusatsu. Kusatsu is very famous for its beautiful Japanese houses, so if you do not plan to stay in a hotel, you can stay in a Japanese house.
The Custom Module Editor in version 5 of MetaXpress® Software is a flexible, interactive environment where users can create and test a template for image analysis. Galleries of processing options, morphology filters, application modules, and segmentation methods are available for users to construct a sequence of analysis steps. The new Click-to-Find Tool enables easy object identification and auto-populates step card parameters. 827ec27edc