• journal_title：Mineralogical Magazine
• Contributor：E. J. Butcher ; J. Borwick ; N. Collier ; S. J. Williams
• Publisher：Mineralogical Society of Great Britain and Ireland
• Date：2012-12-01
• Format：text/html
• Language：en
• Identifier：10.1180/minmag.2012.076.8.18
• journal_abbrev：Mineralogical Magazine
• issn：0026-461X
• volume：76
• issue：8
• firstpage：3023
• section：Engineering barriers (near field)

Some of the illustrative concepts for the disposal of intermediate-level waste in a geological disposal facility in the UK employ a cementitious backfill around the waste packages. The concept for higher strength rocks would use a highly alkaline backfill composed of Portland cement (now known as CEM I), hydrated lime and limestone flour, referred to as Nirex reference vault backfill (NRVB).

This paper reports a study of the extensive leaching of cured NRVB in a range of generic leachant compositions (deionized water, 0.1 m and 1 m NaCl solutions) under flow-through conditions using a flexible wall permeameter. The experiments were designed to run for up to two years and to pass at least 1000 volumes of leachant (defined as the cumulative leachate volume produced/NRVB solid specimen volume) through the NRVB samples. Results for the pH evolution profiles of the leachates and the microstructural analysis of the unleached and leached samples are presented.