Radioactive waste conditioning using alumina-silicate binary blends

Author(s): Bastien Planel, David Lambertin and Catherine A. Davy
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: 395-401
Total Pages: 7
Language : English

Abstract: For radioactive waste conditioning, geopolymer (GP) cements, and their blends with ground granulated blast furnace slag (GGBFS), are considered as encapsulating media for organic radioactive waste. In practice, fresh GP pastes are mixed with organic waste (oil). They harden and form homogeneous GP-oil composites.
In situ, these composites will be placed in contact with Portland concretes, so that interactions with the highly alkaline pore water of Portland concretes is expected. This may induce chemical reactions, degrade the GP-oil composites and their durability.
In this contribution, leaching experiments are conducted on GP-oil mortars. Each sample is injected with a pressure gradient of highly alkaline water (similar in composition to Portland concrete porewater). Water carbonation is avoided by continuously flowing argon over the water container. Water permeability is deduced in the Darcy’s sense over several weeks. GP mortar made with metakaolin (MK) alone has a water permeability smaller than high performance Portland concretes (1.3x10-18 m2 instead of 3.2-4.0x10-18 m2). By replacing MK with 20%mass GGBFS, water permeability decreases down to 3.9x10-19 m2, hence increasing mortar durability. When adding 20% vol oil, the pure MK GP mortar provides a stable cement matrix (with smaller water permeability than without oil), contrarily to GGBFS-added GP.

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