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The Basics Of The Bailey Method

The Basics Of The Bailey Method. William J. Pine Emulsicoat, Inc. / Heritage Research Group Urbana, IL / Indianapolis, IN. Chris Holman, PE Holman Consulting Engineers & PJ Shea, MDT. Aggregate Blending The Bailey Method. Originally developed by Robert D. Bailey

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The Basics Of The Bailey Method

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  1. The Basics Of The Bailey Method William J. Pine Emulsicoat, Inc. / Heritage Research Group Urbana, IL / Indianapolis, IN Chris Holman, PE Holman Consulting Engineers & PJ Shea, MDT

  2. Aggregate BlendingThe Bailey Method • Originally developed by Robert D. Bailey • Evaluate aggregate packing characteristics • Determine what is “Coarse” and “Fine” • Evaluate individual aggregates and the combined blend by VOLUME as well as by weight

  3. Aggregate PackingWhat Influences the Results? • Gradation- continuously-graded, gap-graded, etc. • Type & Amount of Compactive Effort- static pressure, impact or shearing • Shape- flat & elongated, cubical, round • Surface Texture (micro-texture)- smooth, rough • Strength • Weak vs. Strong, Influence of particle shape?

  4. Defining “Coarse” and “Fine” • “Coarse” fraction • Larger particles that createvoids • “Fine” fraction • Smaller particles that fillvoids • Estimate void size • Using Nominal Maximum Aggregate Size (NMAS) • Break between “Coarse” and “Fine” • Primary Control Sieve (PCS)

  5. Diameter = NMAS Average Void Size = 0.22 x NMAS Primary Control Sieve ≈ 0.22 x NMAS

  6. Primary Control Sieve PCSdetermines the break betweenCoarseandFinein thecombinedblend andif a given aggregate is a CA or FA

  7. Evaluating Aggregates by Volume • Why? • Better understand aggregatepacking • Control VOLUME of Coarse and Fine for Mix “Type” • How? • Test the individualCoarse and Fine aggregates Fine-graded Coarse-graded SMA

  8. Loose Unit Weight - CA • NOcompactive effort applied • Start of particle-to-particle contact • Use shoveling procedure • Strike off ~ level • Careful not to compact • Determine LUW • Kg/m3 or lbs./ft3 • Determine volume of voids AASHTO T19

  9. Rodded Unit Weight - CA • Withcompactive effort applied • Increased particle-to-particle contact • Three equal lifts using shoveling procedure • Rod 25 times per lift • Strike off ~ level • Careful not to compact • Determine RUW • Kg/m3 or lbs./ft3 • Determine volume of voids AASHTO T19

  10. ChosenUnit Weight - CA(s) < LUW LUW RUW Fine-Graded Coarse-Graded SMA 60-85% 95-105% 110-125% INCREASING CACUW

  11. Combined Blend Evaluation • Evaluation method depends on which fraction (Coarse or Fine) is in control: • Coarse-graded, SMA • Fine-graded

  12. Combined Blend Gradation Sieve % Passing A 100  B 97 C 76 D 63 E 39 F 25 G 17 H 11 I 7 J 5 K 4.2 100 2 90 Coarse-graded 80 70 1 60 % Passing 50 40 30 20 4 3 10 Fine Coarse 0 K J I H G F E D C B A Sieve Size (mm) Raised to 0.45 Power

  13. Combined Blend EvaluationCoarse-Graded Mixes CA Ratio = % Half Sieve - % PCS 100 - % Half Sieve 2 Coarse Fraction Half Sieve = 0.5 x NMAS 1 CA CUW (% PCS) PCS = 0.22 x NMAS FAc Ratio = % SCS % PCS Fine Fraction 3 SCS = 0.22 x PCS TCS = 0.22 x SCS FAf Ratio = % TCS % SCS 4

  14. Combined Blend EvaluationCoarse-Graded Mixes • CACUWincrease = VMAincrease • 4% change in PCS1% change in VMA or Voids • Range 3 - 5% • CARatioincrease = VMAincrease • 0.20 change 1% change in VMA or Voids • Range 0.10 – 0.30 • FAcRatioincrease = VMAdecrease • 0.05 change 1% change in VMA or Voids • Range 0.025 – 0.075 • FAfRatioincrease = VMAdecrease • 0.05 change 1% change in VMA or Voids • Range 0.025 – 0.075 Has the most influence on VMA or Voids

  15. Combined Blend Gradation Sieve % Passing A 100  B 98 C 85 D 72 E 58 F 40 G 32 H 21 I 12 J 7 K 4.4 100 Fine-graded 90 1 80 70 60 2 % Passing 50 40 3 30 4 20 10 Fine Coarse 0 K J I H G F E D C B A Sieve Size (mm) Raised to 0.45 Power

  16. Combined Blend EvaluationFine-Graded Mixes Original Coarse Fraction Original Half Sieve 1 Original PCS % CA LUW New Coarse Fraction New Half Sieve 2 New CA Ratio NewPCS New Fine Fraction 3 New FAc Ratio NewSCS NewTCS 4 New FAf Ratio

  17. Combined Blend EvaluationFine-Graded Mixes • CACUWdecrease = VMAincrease • 6% change ORIGINALPCS1% change in VMA or Voids • Range 5 - 7% • NewCARatioincrease = VMAincrease • 0.35 change 1% change in VMA or Voids • Range 0.25 – 0.45 • NewFAcRatioincrease = VMAdecrease • 0.05 change 1% change in VMA or Voids • Range 0.025 – 0.075 • NewFAfRatioincrease = VMAdecrease • 0.05 change 1% change in VMA or Voids • Range 0.025 – 0.075 • Old CARatiostillrelates to segregation susceptibility Has the most influence on VMA or Voids

  18. Trial #1 (% Passing) 25.0mm 100.0 19.0mm 97.4 12.5mm 76.2 9.5mm 63.5 4.75mm 38.2 2.36mm 23.6 1.18mm 18.8 0.60mm 13.1 0.30mm 7.4 0.15mm 5.7 0.075mm 4.0 Trial #2 (% Passing) 25.0mm 100.0 19.0mm 98.0 12.5mm 76.5 9.5mm 63.6 4.75mm 37.2 2.36mm 22.1 1.18mm 16.5 0.60mm 11.8 0.30mm 6.8 0.15mm 5.2 0.075mm 3.5 Estimating VMA or VoidsCoarse-Graded Mix Example NMAS HALF PCS SCS TCS

  19. PCS 37.2 – 38.2 = - 1.0 CA ratio 0.725 – 0.693 = + 0.032 FAc ratio 0.444 – 0.492 = - 0.048 FAfratio 0.412 – 0.394 = + 0.018 IncreasesVMA or Voids 1.0/4.0 = + 0.25% Increases VMA or Voids 0.032/0.2 = + 0.16% Increases VMA or Voids 0.048/0.05 = + 0.96% Decreases VMA or Voids 0.018/0.05 = - 0.36% Total Estimated Change: Plus~ 1.0% VMA Estimating VMA or VoidsTrial #2 vs. Trial #1

  20. The Four Main Principles • % PCS(Volume of CA) • Increase/decrease in VMA depends on mix type • CA ratio (Control with CAVolume blend) • Low values can be susceptible to segregation • High values can be difficult to compact • As it increases, VMA increases • FAc ratio (Control with FAVolume blend) • As it increases, VMA decreases • FAf ratio (Control with % minus 0.075mm) • As it increases, VMA decreases

  21. So How Does the Method Help? • In Developing New Blends: • Field Compactability • Segregation Susceptibility It's a TOOL! • In Evaluating Existing Blends: • What’s worked and what hasn’t? • More clearly define principle ranges Not a SPEC! • In Estimating VMA/Void changes: • Between Design trials • Between QC and/or QA samples • For PROPOSED blend changes • Saves Time and Reduces Risk!

  22. No Questions or Comments? Good Thank You! Bill Pine Emulsicoat, Inc. / Heritage Research Group Cell: (217) 840-4173 E-mail: bill.pine@heritage-enviro.com

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