The European Standard Test Method for the Expansion of Steel Slag

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The European Standard Test Method for the
Expansion of Steel Slag

• Nick Jones
• Slag Business Development Manager
• MultiServ

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Content

• Background
• Development of the test
• Test method
• Proposed amendments to the standard
• Development of a test for single sized aggregate

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Background

• Need to evaluate expansion within steel slag
• Many countries developed own tests (e.g.
  Belgium, France, Canada, UK)
• Types
• Soak in water at elevated temperature
• Autoclave
• Breakdown of particles
• Variation in grading
• Measure increase in volume

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Background

• Development of European Standards Late 80s Early
  90s
• Various national test methods reviewed
• German test method had backing of full scale road
  trial
• Adopted in 1998 in EN 1744-1 Tests for Chemical
  properties of aggregates part1 Chemical
  analysis

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Background

• EN1744-1 comprises many chemical tests including
  these slag related ones
• Free Lime
• Iron disintegration BFS
• Di-calcium silicate unsoundness BFS
• Format of the standards segments the test
• Reagents
• Apparatus
• Method
• Calculations

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Development of the test

• Developed by Fehs German research establishment
• Based on the unbound sub-base material used in
  Germany
• 22mm maximum size aggregate graded to the fuller
  parabola
• Laboratory tests correlated with performance of
  sub-base in the field in-situ tests.

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Summary of test method

• Sample of slag graded to the Fuller Parabola
  (0/22mm)
• Compact into a steel cylindrical pot (with holes
  in the base-plate) to target voids content
• Heat sample to 1100C to stop condensation
• Force steam through the sample for
• 24 hours if MgO lt5
• 168hours if MgO gt5
• Measure increase in volume
• Test in duplicate average the two results

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Test pot
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Steam hole pattern
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Compacting the slag
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Compacting the slag
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Adding glass beads
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Placing the surcharge support
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Final surcharge
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Placing sample on test machine
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Sample ready for test
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Completed Sample
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Multi-cell expansion machine
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Level indicator sensors
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Control interface
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Control interface
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Typical BOF Result
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Typical EAF Result
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Smorgon EAF slag
0.19
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Acceptance Limits

• EN 130432002 Aggregates for bituminous mixtures
  and surface treatments for roads, airfields and
  other trafficked areas

Type of steel slag Expansion Percent by volume Category V
BOF slag/EAF slag lt 3.5 lt6.5 lt10 gt10 V3.5 V6.5 V10 VDeclared
No Requirement VNR
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What does this test do?

• This tests places slag in a very hostile
  environment accelerating expansion through the
  hydration of free lime and magnesia
• It accentuates/exaggerates the potential
  expansion of the slag
• Generates sufficiently large numbers to enable
  ranking of acceptable/unacceptable slags
• Does not reflect levels expected in the field

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Summary of proposed amendments

• Review procedure every 5 years
• Points of clarity
• Description of equipment improve and add
  diagrams
• Description of procedure surcharge weight was
  ambiguous
• Improve controls Rate of generation of steam
• Changes target voids content hard to hit
  through experience
• Add note on predictive software to reduce test
  time
• Add note these values are not representative of
  expansion levels in the field

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Steam test for single size fractions

• MultiServ Holland
• Corus RDT Holland

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Background

• Rationale for developing a single size fraction
  test
• 1) market for single size fractions requires
  stability information
• 2) aged single size fractions cannot be tested
  with conventional "bulk slag 0-22 mm" steam test.
• Test requirements
• - chosen test method should closely correspond to
  steam test EN1744-1 to allow comparison to
  conventional Vol. exp. data

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Methodology

• 50 SLAG 50 FILLER
• Single size fraction of interest - 2,25 kg
  (e.g., 5.6-8 mm, or 8-11.2 mm, or other )
• rest of material is inert 0-3 mm corundum with
  Fuller distribution - 2.25 kg (layer by layer
  assembly of slag and inert filler)
• standard steam test performance according to
  EN1744-1

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Sample characteristics

• Slag batch from single converter heat
• Slag conditioning with dolomite and lime
• Cooled by pooring onto steel slabs
• No water involved

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Summary of Samples

• Normal steam test on slag sample yields 17 Vol.
  exp.
• 8-11 mm size fraction from same bulk sample
• 11-16 mm size fraction from same bulk sample
• 16-22 mm size fraction from same bulk sample

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Single size fraction bulk sample
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Single size fraction 11-16 8 -11
Sample name Single11/16 Single8/11
Material Single size ms 17 Single size ms 17
Produced by 0 0
Date Start test 17/06/05 1222 17/06/05 1222
Duration of test hours 168.94 168.94
Unit no UNIT 1 UNIT 2
Cylinder no 1 2
Sample Weight g 4494 4500
Sample Volume cm3 0.00 0.00
Bulk Density (comp.) g/cm3 2.70 2.78
Rel. Density of slag g/cm3 3.62 3.65
Voids 25.4 24.0
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Single size fraction 11-16mm 8 -11mm
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Single size fraction 11-16 16-22
Sample name Single1116 Single1622
Material Single size ms 17 Single size ms 17
Produced by 0 0
Date Start test 01/07/05 1249 01/07/05 1249
Duration of test hours 171.02 171.02
Unit no UNIT 1 UNIT 2
Cylinder no 3 4
Sample Weight g 4500 4500
Sample Volume cm3 0.00 0.00
Bulk Density (comp.) g/cm3 2.78 2.91
Rel. Density of slag g/cm3 3.62 3.62
Voids 23.1 19.6
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Single size fraction 11-16 16-22
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Combined Results
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Summary of trial

• Test results of single size fractions diluted
  with 50 filler give Volume expansions
  approximately half of those of conventional bulk
  test.
• Coarser fractions show somewhat lower expansion
  than half
• Finer fractions show a somewhat higher value
• Test is very easy to perform and requires little
  slag sample preparation
• Further testing is required

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Thank You for Your Attention