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Sasada, Yuto*; Miyazaki, Yuji*; Nakano, Motohiro*; Matsuo, Yusuke*; Walker, C.*; Sasamoto, Hiroshi; Mihara, Morihiro
no journal, ,
Cementitous materials are to be used in large quantities in the geological disposal of highly radioactive TRU waste. Thermodynamic data on cement hydrate minerals are important to model the long-term dissolution behavior of cement materials during the reaction of these materials with groundwater. Portlandite (Ca(OH)
) is a major component (20 to 25 wt%) of hydrated Portland cement. Low temperature heat capacity measurements of three types of portlandite (low purity, high purity, and large crystal) showed purity dependence. The large crystal sample followed Debye's T
rule at low temperatures, while the high and low purity samples showed upturn of heat capacity, possibly due to difference in absorbed water vapor and/or calcite (CaCO
) contamination. Heat capacities of the cement hydrates (ettringite:Ca
(Al(OH))(SO
)(HO)
and monosulfate:CaAl(OH)
(SO)(HO)) exhibited phase transitions associated with the hydration water.
Ueoku, Aya*; Okamura, Wakana*; Kondo, Toshiki; Kikuchi, Shin; Yamazaki, Atsushi*
no journal, ,
Portland and geopolymer cement mortar moldings were heated from one direction, and the moisture migration and temperature distribution changes on the surface of the moldings were comparatively analyzed mainly using a hyperspectral camera and a thermographic camera. It was revealed that the temperature and the amount of dehydration at which the amount of moisture on the surface of the molded body increases or decreases, moves inside, and dehydrates by clarifying the relationship between reflectance and temperature. Analysis results of hyperspectral camera and thermographic camera indicated that different thermal behavior between Portland and geopolymer cement mortar moldings.