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Changes of pore structure and ionic diffusivity of hardened cement paste exposed to conditions at several levels of temperature and humidity



Title: Changes of pore structure and ionic diffusivity of hardened cement paste exposed to conditions at several levels of temperature and humidity
Author(s): I. Kurashige, T. Yoshida, T. Chida, M. Hironaga
Paper category : conference
Book title: International Conference on Microstructure Related Durability of Cementitious Composites
Editor(s): W. Sun, K. van Breugel, C. Miao, G. Ye and H. Chen
Print-ISBN: 978-2-35158-065-3
e-ISBN: 978-2-35158-084-4
Publisher: RILEM Publications
Publication year: 2008
Pages: 1473 - 1482
Total Pages: 10
Nb references: 11
Language: English


Abstract: Exposure tests of hardened ordinary Portland cement paste specimens to elevated temperature levels such as 60 or 80oC under humidity conditions at 40, 90%RH, or water immersion were conducted to gain a better understanding of the influence of radioactive decay heat generated in wastes on the performance of a cementitious barrier system for lowlevel radioactive waste disposal in Japan. The pore structure of cement paste specimens, which were exposed to high temperature conditions, was determined by mercury intrusion porosimetry in order to compare to the change of their ionic diffusivity.
According to the results, it was confirmed that the exposure to low humidity conditions under 60 and 80oC can rough pore structure and increase total pore volume. On the other, it was observed that the high temperature exposure of specimens of W/C=0.35 to higher humidity conditions such as 90%RH or water immersion changes the pore size smaller due to the hydration of unreacted cement but increased the total pore volume. The higher the temperature, the more total pore volume increased. The ionic diffusivity of specimen of W/C=0.35 increased according to the total pore volume.


Online publication: 2009-06-09
Publication type : full_text
Public price (Euros): 0.00