09 Feb, 2023

Celtest can carry out slag expansion testing on samples following one of two methods:

  • Steel Slag Expansion BS EN 1744-1:2009 + A1 2012 Cl 19.3

  • BR 481 (Part B) Appendix B Measurement of the expansion of steel slag at 80 ͦC by BRE In-house method

Our facility can process high volumes of samples for slag expansion testing.


BS EN 1744-1 Cl 19.3: Steel Slag Expansion Test (Steam bath method)

This testing procedure is employed to assess the possibility of expansion in crushed steel slag, which stems from the delayed hydration of dead burned free lime and/or free magnesium oxide. The test is performed at a heightened temperature to expedite the process and produce quantifiable expansion measurements for the classification of suitable slag materials.

The specimen, of predetermined particle sizes, is subjected to a 100°C steam flow in a steam unit at atmospheric pressure, which continuously provides the moisture necessary for a reaction with the free lime and free magnesium oxide. The resulting change in volume is determined by observing a displacement indicator at the top of the specimen. The expansion is calculated as a percentage increase in relation to the original volume of the compressed slag specimen.


BRE Appendix B Steel Slag Expansion Test Method

The procedure involves creating a compacted layer of steel slag in a cell and immersing it in a water bath at 80°C. The expansion is then measured using either a dial gauge or linear transducer. A minimum sample size of 5 kilograms should be obtained, typically in a sealed container or plastic bag. The test usually lasts one month but can be extended if necessary to determine long term expansion. The expansion cells consist of a 150mm diameter steel cylinder with a fixed porous base, a top porous plate which is placed on the sample and a dial gauge / linear transducer attached to the top plate to measures any expansion. The results of the test are typically used as part of an evaluation of the suitability of slag materials.

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