Irradiation resistance of MK-based geopolymers encapuslating oily wastes

Author(s): Daniel A. Geddes, Susan A. Bernal, Martin Hayes and John L. Provis
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials, Systems and Structures (SMSS2019) New Generation of Construction Materials
Editor(s): Marijana Serdar, Nina Štirmer, John Provis
ISBN: 978-2-35158-217-6,
Vol 1. ISBN: 978-2-35158-223-7
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 598-604
Total Pages: 7
Language : English

Abstract: Geopolymerisation is proposed as a potential method for the safe disposal of intermediate- level radioactive nuclear waste, which are considered to be problematic when adopting other cementation methodologies. It is particularly difficult encapsulate oils and/or organic materials in conventional Portland cement based systems, at a sufficient waste loading. In this study a potassium silicate/metakaolin geopolymer grout has been developed, where 20 wt.% of silicone oil can be incorporated without affecting setting characteristics. This grout withstands gamma irradiation to a total dose of 1 MGy without showing significant changes in its microstructure. Irradiation appeared to modify the structure of a secondary phase forming in the geopolymer grout loaded with oil, and increase the susceptibility to carbonation of these materials, as carbonates are the main products identified in irradiated samples. X-ray diffractograms show a slight change in the ordering of the structure of the irradiated sample, which is consistent with thermogravimetry results. The fact that crystalline polymorphs of sodium carbonates are not observed by X-ray diffraction, indicates that the amount of these phases present in irradiated samples is small. In order to better understand the effect of irradiation in these materials, additional studies applying solid-state NMR spectroscopy and scanning electron microscopy will be carried out in the future. The results of this study demonstrate that oils can be incorporated within geopolymers at higher waste loadings than conventional Portland cement, and the loaded grouts appear to withstand gamma irradiation.

Online publication : 2019
Publication type : full_text
Public price (Euros) : 0.00

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