Abstract
This paper presents the physical properties and chemical composition of hydrates formed under steam conditions. The test specimens were made with cement as well as individual compounds. A comprehensive study on the characteristics of hardened hydrates in a microscopic scale was carried out. An improved polymerization of silicate anions resulting in an increased CaO/SiO2 ratio at an elevated temperature was verified by the nuclear magnetic resonance (NMR) spectroscopy analysis. Dense microstructures of hydrates and low content of Ca(OH)2 crystals were observed by the scanning electron microscope (SEM), energy dispersive spectrometer, environmental SEM, thermogravimetric analyzer (TGA), and x-ray diffractometer tests. Mercury intrusion porosimetry was used to examine the pore structures of hydrates. It revealed that the hardened paste made with the dry-mixture/steam-injection (DMSI) method developed microstructures with low porosity, small pore radius, and larger surface areas. These observations agree with the NMR/TGA test results. This paper also discusses the effects of sample fineness and compaction on the hydrates microstructures formed under steam environment. The test results verify the validity of the DMSI concept.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
