Microgravity Effect on Microstructural Development of Tri-calcium Silicate (C3S) Paste

Abstract

For the first time, tricalcium silicate (C 3 S) and an aqueous solution were mixed and allowed to hydrate in the microgravity environment aboard the International Space Station (ISS). The research hypothesis states that minimizing gravity-driven transport phenomena, such as buoyancy, sedimentation, and thermosolutal convection ensures diffusion-controlled crystal growth and, consequently, lead to unique microstructures. Results from SEM micrographs, image analysis, mercury intrusion porosimetry, thermogravimetry, and x-ray diffraction revealed that the primary differences in µg hydrated C 3 S paste are increased porosity and a lower aspect ratio of portlandite crystals, likely due to a more uniform phase distribution. Relevant observations led by the presence or absence of gravity, including bleeding effect, density, and crystallography are also presented and discussed.

MASON: Betonerhärtung in Schwerelosigkeit – Simulationen mit dem Klinostaten

“…Poren dieser Größe wurden bei vorherigen Untersuchungen unter Mikrogravitation besonders häufig im Vergleich zu Referenzversuchen bei Erdgravitation gefunden [5]. In diesem Zusammenhang wurden in derselben Untersuchung Portlanditkristalle mit deutlich veränderter Größe und Seitenverhältnis im Vergleich zu Referenzproben beobachtet.…”

“…Aufgrund der kurzen Dauer der Schwerelosigkeit (bis zu 22 Sekunden) beschränkten sich die Ergebnisse allerdings auf das unmittelbar einsetzende Kristallwachstum. Im Rahmen des Projekts „MICS“ (Microgravity Investigation of Cement Solidification) [4, 5] wurden 120 Proben mit verschiedenen Zusammensetzungen in Schwerelosigkeit auf der ISS hergestellt. Dabei wurden die trockenen Bestandteile (Zement, Regolith; ca.…”

“…vity Investigation of Cement Solidification)[4,5] wurden 120 Proben mit verschiedenen Zusammensetzungen in Schwerelosigkeit auf der ISS hergestellt. Dabei wurden die trockenen Bestandteile (Zement, Regolith; ca.…”

Rheological Properties of Lunar Mortars

“…The microgravity conditions present on the Moon result in an increase in porosity and pore sizes in hydrated cement pastes [39]. Admittedly, using OPC (and certainly manufacturing it) on the lunar surface is nontrivial; the hurdle is the environment.…”

Simulated microgravity in the ring-sheared drop

“…1–4 Aside from removing complications associated with solid containers, the absence of natural convection afforded by microgravity has been essential for much of the materials research, such as growing 3D crystals under quiescent or very slow and controlled flow conditions. 5–7 On the other hand, in bioreactor applications as well as in many biophysics studies, some agitation, or imposed shear flow is essential. 8 In a new module for the International Space Station (ISS), the Ring-Sheared Drop (RSD, see Fig.…”