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The European Standard Test Method for the Expansion of Steel Slag

The European Standard Test Method for the Expansion of Steel Slag . Nick Jones Slag Business Development Manager MultiServ. Content. Background Development of the test Test method Proposed amendments to the standard Development of a test for single sized aggregate. Background.

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The European Standard Test Method for the Expansion of Steel Slag

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  1. The European Standard Test Method for the Expansion of Steel Slag Nick Jones Slag Business Development Manager MultiServ

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

  3. 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

  4. Background • Development of European Standards Late 80’s Early 90’s • 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”

  5. 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

  6. 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.

  7. 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 <5% • 168hours if MgO >5% • Measure increase in volume • Test in duplicate – average the two results

  8. Test pot

  9. Steam hole pattern

  10. Compacting the slag

  11. Compacting the slag

  12. Adding glass beads

  13. Placing the surcharge support

  14. Final surcharge

  15. Placing sample on test machine

  16. Sample ready for test

  17. Completed Sample

  18. Multi-cell expansion machine

  19. Level indicator sensors

  20. Control interface

  21. Control interface

  22. Typical BOF Result

  23. Typical EAF Result

  24. Smorgon EAF slag 0.19%

  25. Acceptance Limits • EN 13043:2002 Aggregates for bituminous mixtures and surface treatments for roads, airfields and other trafficked areas

  26. 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

  27. 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

  28. Steam test for single size fractions MultiServ Holland Corus RD&T – Holland

  29. 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

  30. 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

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

  32. 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

  33. Single size fraction: bulk sample

  34. Single size fraction: 11-16 & 8 -11

  35. Single size fraction: 11-16mm & 8 -11mm

  36. Single size fraction: 11-16 & 16-22

  37. Single size fraction: 11-16 & 16-22

  38. Combined Results

  39. 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

  40. Thank You for Your Attention

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