Modeling of diffusive mass transport in micropores in cement based materials

Yamaguchi, Tetsuji ; Negishi, Kumi*; Hoshino, Seiichi; Tanaka, Tadao 

In order to predict long-term leaching behavior of cement constituents in safety assessments of radioactive waste disposal, we modeled diffusive mass transport in micropores cement based materials. Based on available knowledge on the pore structure, we developed a transport porosity model that enables us to estimate effective porosity available for diffusion (transport porosity) in cement based materials. We microscopically examined the pore structure of hardened cement pastes to partially verify the model. Effective diffusivities of tritiated water in hardened cement pastes were also obtained experimentally, and were shown to be proportional to the estimated transport porosity. We successfully modeled the effective diffusivity in cement based materials consistent with previously acknowledged pore diffusion model.