A Fiber Reinforced Concrete for a Nuclear Waste Container

For the production of caissons, which are cubic containers for nuclear waste conditioning, the use of a fiber reinforced concrete in alternative to a classic reinforced concrete is studied. A numerical analysis approximating the behaviour of a caisson under load is presented in this paper. This numerical analysis allows for identifying the concrete properties that lead to satisfying structural performance of the caisson under load. This information is on his turn used in a second numerical analysis of laboratory bending experiments on notched beams according to the EN 14651 and round panel testing according to the ASTM C1550. The result of this second numerical analysis is a limit curve which identifies the mechanical performance that should be attained in these tests with 95% confidence. It allows thus for easy discriminating between an adequate concrete composition and a non-adequate one. The experimental work focused first on identifying a suitable fiber among three possible commercial candidates. Next a fiber dosage was defined and the concrete composition was submitted to small variations while verifying his performance according to EN 14651. It could be demonstrated however small changes in the concrete in terms of e.g. a variation in the water-to-cement ratio for 0,45 to 0,50 do not influence the performance according to EN 14651 in a significant way. Also it is demonstrated in this paper a concrete with Bekaert’s 3D 80/30 hooked end steel fibers at a dosage of 55 kg/m³ does not perform sufficiently well for the production of these caissons. The development of an adequate concrete would probably demand for higher fiber loads beyond 55 kg/m³ or a significant change in other concrete constituents beyond the current investigated ranges.