China
Africa
Explore chapters and articles related to this topic
Hydration and microstructure of alkali-activated slag cements
Published in Caijun Shi, Pavel V. Krivenko, Della Roy, Alkali-Activated Cements and Concretes, 2003
Caijun Shi, Pavel V. Krivenko, Della Roy
Figure 4.16 Tobermorite in Na2CO3-activated phosphorus slag cement cured at 185°C (Tang 1986). was increased to 300°C, well-crystallized tobermorite and xonotlite were detected. At the same time, a more porous microstructure with lower strength was obtained. Thus, it is important to understand how the temperature will affect hydration products and structural characteristics of the cements.
New indirect estimation technique for the determination of the moisture diffusivity from transient moisture content profiles measured by means of X-ray radiography
Published in J. Carmeliet, H. Hens, G. Vermeir, Research in Building Physics, 2020
J. Carmeliet, T. Van Besien, S. Roels
Equation 10 shows that the resolution in moisture content rw depends on the thickness of the specimen, the material (via Idry), the attenuation coefficient of water and the energy of the X-ray source. The optimal thickness can be found by minimising rw with respect to d. In table 1 the optimal thickness and resolution in moisture content is given for calcium silicate. Calcium silicate is a artificial material largely composed of synthetic mineral xonotlite. The material is highly homogeneous, isotropic and shows a high porosity (0.894).
Influence of Cr3+, Co2+ and Cu2+ on the formation of calcium silicates hydrates under hydrothermal conditions at 200 °C
Published in Journal of Asian Ceramic Societies, 2020
Tadas Dambrauskas, Inga Knabikaite, Anatolijus Eisinas, Kestutis Baltakys, Martin T. Palou
It was determined that at the beginning of hydrothermal synthesis (0–8 h) the intensive interaction between raw materials (CaO, SiO2, and Al2O3) proceeded because in all mixtures portlandite was fully reacted and semi-crystalline type compounds C-S-H (I) and/or C-S-H (II) were formed. It was obtained the nature of used metal ions affected the formation of calcium silicate hydrates, because in systems with Cr3+ ions only 1.13 nm tobermorite was formed, while in systems with Cu2+ and Co2+ ions kilchoanite, 1.13 nm tobermorite or xonotlite were formed.
Investigation of high-temperature chemical interaction of calcium silicate insulation and cesium hydroxide
Published in Journal of Nuclear Science and Technology, 2020
Muhammad Rizaal, Kunihisa Nakajima, Takumi Saito, Masahiko Osaka, Koji Okamoto
It should be emphasized that the original calsil sample in our study was a product of hydrothermal reaction (CaO-SiO-H2O) which at last consisted of a combination between xonotlite and tobermorite, while those employed in the reported works [20,22,23] were distinctive/separate experiments on xonotlite and tobermorite. Thus, the second loss of remaining hydroxyls that is observed in our sample around 720°C was not observed in those works. Nevertheless, the onset of transformation into wollastonite (800°C) in our study is in agreement with those reports.