Signs of in-situ geochemical interactions at the granite ? concrete interface of a radioactive waste disposal

摘要

Eleven unique core samples from the National Radioactive Waste Repository of Hungary, B?ataap?ati were studied in this work. The samples all cross the granite?concrete interface and have been drilled from around 275 m depth from the surface, 1?15 months after concrete injection. Phase analytical techniques, optical microscopy, SEMEDS and Raman-spectroscopy were used for the analysis of interactions between granitic rock and cementitious building material. Newly formed phases, Ca-carbonates and titanite, were observed at the interface. Carbonation may reduce the porosity and permeability in the contact zone. The presence of titanite indicates the changing geochemical and thermodynamical constrains along the reaction front of granite?concrete, furthermore, it may help in the validation of future geochemical models. The cementitious material is seen to penetrate among the sheets of biotite mineral in granite which process is probable to cause the attachment of granite and concrete.