Effect of irradiation and chemically aggressive environment on Brazilian mortar cement

Abstract

Radioactive waste disposal, considered a major technical problem, has as one of the solutions, the construction of repositories that will be exposed to a range of environmental conditions in a timescale which involve thousands of years. Cement-based materials, used in the repositories, have a complex porous structure that changes over time and their durability strongly correlates to the transport of water and ions throughout the pore structure. In this study, the influence of the repository's environment was simulated using two different solution conditions: Water and Na2SO4 at different gamma irradiated condition. Two X-Ray techniques were performed simultaneously: (i) diffraction to characterize the phases contents on cement mortar samples; (ii) tomography to investigate the differences between the pore structure and pores volume. The combination's advantage of the XRay techniques shows their potential application to determine the relation amongst the phases and the pores structures, to demonstrate how the environment and the irradiation modify the structure of mortar.