Applicability of accelerated Leaching Experimental Methods for Long-term Estimation on Performance of Cementitious Engineered Barrier Material
By Takeshi Yamamoto, Michihiko Hironaga, Kazuko Haga and Kazuhito Niwase
Concrete Research and Technology
Vol.16, No.2, Mar 2005 (Issue 38)
- Synopsis:
- It is needed to clarify the alternation phenomena of cementitious materials that will be used for engineered barrier system in radioactive waste repository. We compared three accelerated leaching methods to clarify each characteristic phenomenon by applying same block-shaped OPC paste specimen to each leaching method. The most progression of alteration was observed in the penetrating method with forming the unique sequence of pore size distribution, ranging from 0.9 to 3�~10-6m, which was thought to be derived from advective phenomenon. In the penetrating method, alteration of AFm-phases, AFt and C-S-H that facing to the pore followed after the disappearing of CH. In the process of alteration of C-S-H, Ca2+ leached out with gaining the polymerization (Chain-condition) rate of (SiO4)4- in C-S-H. Even in such progressed alteration stage, much of AFt and Katoite (C-A-S-H) remained as the evidence of its high stability comparing to other cement hydrates.
- Keywords:
- Leaching, Engineered barrier system, Hydrates, Durability, Portland cement
