Definition of Steel Slag

Transcription

1 Definition of Steel Slag Edw. C Levy Co / National Slag Association John J. Yzenas Jr. jyzenas@edwclevy.net The American Society for Testing Materials (ASTM) defines Steel Slag as: n the nonmetallic product consisting essentially of calcium silicates and ferrites combined with fused oxides of iron, aluminum, manganese, calcium and magnesium, that is developed simultaneously with steel in basic oxygen, electric, or open hearth furnaces. Ohio Sustainable Roadway Materials - Dec 3rd, ODOT Central Auditorium 1 2 Steel Making Flow Integrated Steel Mills 3 4 John T. Yzenas Jr - Steel Furnace Slag Use in Soil/Roadway Stabilization 1

2 EAF (Mini) Mills 5 6 SFS Slag Steel Furnace Slag(s) BOS / BOF: Basic Oxygen Steelmaking Basic Oxygen Furnace EAF: Electric Arc Furnace LMF / Caster: Ladle Metallurgy Furnace AOD: Argon-Oxygen Decarburization (Stainless Steel) 7 8 John T. Yzenas Jr - Steel Furnace Slag Use in Soil/Roadway Stabilization 2

3 Characterization (Source / Type) Physical Gradation Durability Chemical Volumetric Stability Chemistry Available Lime Environmental TAL metals TCLP - Leaching Physical Properties Angularity Density Gradation Durability Freeze Thaw / Soundness Strength LA Abrasion Micro Deval Friction 9 10 Chemical Properties XRF / ICP TCLP Leaching TAL Metals Volumetric Stability CaO (Lime) / MgO (Periclase) Free Lime Water Bath: ASTM / PTM Autoclave Expansion Expansive Items CaO (Lime): Early MgO (Periclase): Delayed Free Lime Doesn t Correlate to Expansion Doesn t Indicate MgO Variable procedures Free MgO No currently viable test 11 John T. Yzenas Jr - Steel Furnace Slag Use in Soil/Roadway Stabilization 3

4 Expansion Testing Water Bath ASTM D-4792 PTM % Max for confined applications Only Indicates Short Term Doesn t Always Indicate MgO 7 to 14 Days Embedded Lime NSA Comparison (1971) Compares Water Bath, Free Lime and Autoclave Canadians (90 s) Disruption European Indiana Autoclave Correlation Correlation Equation: Water bath Expansion Limit (X) = 0.5% Autoclave (Confined) Limit = ~ 4.633% Conservative < 5.0% y = x R² = Applications Hot Mix Asphalt (HMA) Surface SMA / OGFC / Dense Graded Intermediate Base Aggregate Shoulders Soil Stabilization Secondary Road Stabilization 16 John T. Yzenas Jr - Steel Furnace Slag Use in Soil/Roadway Stabilization 4

5 Secondary Road Stabilization Aggregate Specifications Liquid Limit: Max 35 Plasticity Index: 4 to 9 LA Abrasion: Max 50 Soundness: Sodium Sulfate 12% 5 Cycles Crush Count: 75% One Face Best Available Aggregate Steel Slag Available Lime 17 Gradation for Aggregate Surface Course Percent Passing Sieve No. 1 No. 2 1" /8" # # # # Triaxial Data Existing Roadway Unconfined Compression No Aging 28 Day 23.0 psi 46.5 psi W/ 30% Blend 26.4 psi 80.9 psi W/ 40% Blend 39.5 psi 85.3 psi W/ 50% Blend 57.5 psi 90.3 psi W/ 60% Blend 61.8 psi 96.0 psi John T. Yzenas Jr - Steel Furnace Slag Use in Soil/Roadway Stabilization 5

6 Project Scope US-12 Washtenaw County 50/50 blend 10 deep Aggregate placed with grader Surface treated with double chip & seal Tuesday, February 7th, 2005 Road Commission for Macomb County Base Presentation 31 John T. Yzenas Jr - Steel Furnace Slag Use in Soil/Roadway Stabilization 6

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9 Unconfined Compressive Strength of Soil +7% Steel Slag + 3% Fly Ash Mixture Steel Slag Requirements Material Type High Lime Ladle Slag Gradation Minus 2mm Free Lime Australia: +4% John T. Yzenas Jr - Steel Furnace Slag Use in Soil/Roadway Stabilization 9

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11 Environmental Considerations Slag is not Slag / Characterization Iron and Steel Slag Copper Lead Etc. RCRA Iron and Steel Slag are Excluded as a Hazardous Waste Environmental Regulations RCRA Health Considerations Risk Assessments Human Health Risk Assessment (2) Processing Wastes Covered by the Mining Waste Exclusion Iron blast furnace slag Basic oxygen furnace and open hearth furnace slag from carbon steel production HHRA 2002 (Human Health Risk Assessment) Over the past several years, the Steel Slag Coalition ("SSC"), a group of 63 companies that produce steel, process slag, or both, has undertaken a comprehensive study of the chemical composition of three slag types generated during the steelmaking process and the potential human health and ecological risks associated with possible exposure to such slag. HHRA 2011 Exposure: Contact / Ingestion / Inhalation Characterization by particle size. Based on new slag characterization data and the most current risk assessment guidance, including the new exposure models and toxicity information. As described herein, the current HHRA confirmed the previous assessment finding that commercial and construction uses of steel industry slagsdo not pose a health risk John T. Yzenas Jr - Steel Furnace Slag Use in Soil/Roadway Stabilization 11

12 References Yildirim, I. Z., and Prezzi, M. (2009). "Use of Steel Slag in Subgrade Applications." FHWA/IN/JTRP /SPR-3129, Joint Transportation Research Program, Purdue University. FHWA: Gravel Roads Maintenance & Design Manual USDA Forest Service: Stabilization Selection Guide for Aggregate & Native-Surfaced Roads USACE: UFGS Section Aggregate Surface Course MnDOT: Design Guide for Low-Volume Aggregate Surfaced Roads ASTM: D1241 Specification for Materials for Soil-Aggregate Subbase, Base and Surface. Poh, Ghataora and Ghazireh. ): Soil Stabilization Using Basic Oxygen Steel Slag Fines : Journal of Materials in Civil Engineering (March/April 2006) Magieux, Aubert and Escadeillas. Utilization of Weathered Basic Oxygen Slag in the Production of Hydraulic Road Binders, Construction and Building Materials (Feb 2009) Androjic and Dimter. Compressive Strength of Steel Slag Stabilized Mixes, Gradevinar (Jan 2012) Thank you Questions? jyzenas@edwclevy.net 46 John T. Yzenas Jr - Steel Furnace Slag Use in Soil/Roadway Stabilization 12