Diffusion and adsorption studies on hardened cement paste and the effect of carbonation on diffusion rates

✍ Scribed by F.-A. Sarott; M.H. Bradbury; P. Pandolfo; P. Spieler

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 438 KB
• Volume: 22
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(92)90086-b

✦ Synopsis

The diffusion and sorption behaviour in disc shaped samples of hardened cement paste (HCP) has been studied for the radionuclides C1-36, 1-125 and Cs-134 using the through-diffusion technique. The experiments were performed both in controlled atmosphere glove boxes (Pco2 = 10-5.Sbar) and under atmospheric conditions for periods of up to several months. The sampms had a high water to cement ratio (W/C) of 1.3 and a hydraulic conductivity of = 2.10-10m s-1. All tests carried out under atmospheric conditions showed a considerable decrease in diffusion rates with time due to carbonation, whereas no such effect was observed in the experiments performed in the controlled atmosphere glove boxes. Effective diffusion coefficients, De, and sorption values were calculated for each radionuclide. It was possible to model the diffusionsorption results by linear isotherms.