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The Effect Of W/C Ratio And Cement Type On The Longevity Of Grouts For Use In A Nuclear Fuel Waste Disposal Vault

Published online by Cambridge University Press:  22 February 2011

Maria Onofrei  and
Malcolm Gray
Maria Onofrei
Affiliation:
Atomic Energy of Canada Limited, Whiteshell Nuclear Research Establishment, Pinawa, Manitoba, Canada ROE 1L0
Malcolm Gray
Affiliation:
Atomic Energy of Canada Limited, Whiteshell Nuclear Research Establishment, Pinawa, Manitoba, Canada ROE 1L0
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Abstract

Cement-based grouts are being considered for use as sealing materials in the Canadian concept for nuclear fuel waste disposal. This paper describes laboratory studies of the longevity of these materials, with special emphasis on the effect of hardened grout porosity and cement type. The longevity properties determined for reference grout (90% Type 50 cement, 10% silica fume and superplasticizer) are compared with those of a slag cement grout.

The fractional factorial statistical method of Box-Behnken was used to design a series of leach tests, which covered a wide range of conditions that could occur in a nuclear waste disposal vault. The leach tests have been carried out to determine the effect of temperature, ionic strength of groundwater, and cation exchange capacity (CEC) of clay (which may be in contact with the grout) on the leach resistance of the cement. The temperature ranged from 25 to 150°C and the ionic strength of the groundwaters from 0.0015 to 1.37 mol. Leach rates of Ca and Si were taken as the major indicators of the long-term chemical stability of the grouts.

Preliminary analysis suggests that the reference grout would be more stable than slag cement in the high-temperature environment of a nuclear fuel waste disposal vault. Within the ranges investigated, decreasing the porosity appears not to significantly decrease leach rates.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 137: Symposium P – Pore Structure and Permeability of Cementitious Materials , 1988 , 359
Copyright
Copyright © Materials Research Society 1989

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