Change in pore structure and composition of hardened cement paste during the process of dissolution

Journal Article · Sun May 01 04:00:00 EDT 2005 · Cement and Concrete Research

DOI:https://doi.org/10.1016/j.cemconres.2004.06.001· OSTI ID:20702134

Haga, Kazuko; Shibata, Masahito; Hironaga, Michihiko; Tanaka, Satoru; Nagasaki, Shinya

An understanding about the dissolution phenomena of cement hydrates is important to assess changes in the long-term performance of radioactive waste disposal facilities. To investigate the alteration associated with dissolution, dissolution tests of ordinary Portland cement (OPC) hydrates were performed. Through observation of the samples after leaching, it was confirmed that ettringite precipitation increased as the dissolution of the portlandite and the C-S-H gel progressed. EPMA performed on cross-sections of the solid phase showed a clear difference between the altered and unaltered parts. The boundary between the two parts was termed the portlandite (CH) dissolution front. As the leaching period became longer, the CH dissolution front shifted toward the inner part of the sample. A linear relationship was derived by plotting the distance moved by the CH dissolution front against the square root of the leaching time. This indicated Ca ion movement by diffusion.

• OSTI ID: 20702134
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 5 Vol. 35; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALCIUM IONS
DISTRIBUTION
ELECTRON MICROPROBE ANALYSIS
GELS
HYDRATES
LEACHING
PERFORMANCE
PORE STRUCTURE
PORTLAND CEMENT
PRECIPITATION
RADIOACTIVE WASTE DISPOSAL