Recycled Asphalt Pavement

Transcription

1 Recycled Asphalt Pavement What s Going On In There? Gerry Huber Heritage Research Group

2 RAP Use

3 AASHTO STANDARD M323 Superpave Volumetric Mix Design Changes Dec 2014

4 M323 Terminology Percent RAP Reclaimed Asphalt Pavement Binder Ratio (RAPBR) RAPBR = Pb RAP x PRAP Pb total

5 Indiana DOT Virgin Binder Graded Based on Asphalt Binder Replacement (RAP or Shingles) 0 to 25% 25 to 40% Based on properties of RAP binder New binder

6 Properties of RAP Sample RAP Stockpiles Recover Asphalt Binder Measure Grade Sample New Asphalt Binder Measure Grade PG PG58-28

7 Location of RAP Stockpiles Sampled

8 Frequency RAP High Temperature Properties RAP High Temp

9 Frequency RAP Low Temperature Properties RAP Low Temp

10 PG64-22 Low Temperature Properties Low Temp Frequency

11 Frequency PG58-28 Low Temperature Properties Low Temp

12 Maximum RAP (PG64-22) %RAP = Tblend Tvirgin Trap Tvirgin (-25.1) = = 23% (-25.1)

13 Maximum RAP (PG58-28) %RAP = Tblend Tvirgin Trap Tvirgin (-28.7) = = 38% (-28.7)

14 INDOT Binder Grade Selection Virgin Binder Grade No Change in Grade < 25% One Grade Softer >= 25%

15 Pa.s Diffusion shear Virgin asphalt acts as a lubricant Pavel Kriz Esso Canada

16 η*, Pa.s Diffusion Happens with Time 100 RAP 10 50/50 Blend Diffusion Virgin y L Diffusion Time, s Pavel Kriz Esso Canada

17 Stiffness Effect of Temperature on Diffusion 170 F Homogenous Blend Blending by Diffusion 210 F 260 F Pavel Kriz Esso Canada Time to equilibrium 2 hours 25 hours 6 hours

18 Looking at Blending Zone TU Delft Research

19 Mixing Occurs by Diffusion

20 Blending * / * homogenous blend, 107 Pa.s Diffusion In Practice service 100 days transport mix silo paving HMA WMA Time, days Pavel Kriz Esso Canada

21 Investigation of Low and High Temperature Properties of Plant-Produced RAP Mixtures North Central Superpave Center

22 Design and Produce Mix RAP Binder Grade PG PG % 15% 25% 40% X X X X Mix A Mix B Mix C Mix D X X Mix E Mix F

23 Hot Mix Plant

24 E*, MPa Mix Stiffness (PG 64-22) PG Mix4-A (0%0 RAP) Mix4-B (15% RAP) Mix4-C (25% RAP) Mix4-D (40% RAP) E-03 1.E-01 1.E+01 1.E+03 1.E+05 1.E+07 Reduced Frequency, Hz

25 E*, MPa Mix Stiffness (PG 64-22) PG Mix4-A (0%0 RAP) Mix4-B (15% RAP) Mix4-C (25% RAP) Mix4-D (40% RAP) E-03 1.E-01 1.E+01 1.E+03 1.E+05 1.E+07 Reduced Frequency, Hz

26 Log E*, MPa Same Mix (PG58-28) Control versus PG MixA (0% RAP) MixE (25% RAP) MixF (40% RAP) E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 Log Reduced Frequency, Hz

27 Log E*, MPa Same Mix (PG58-28) Control versus PG MixA (0% RAP) MixE (25% RAP) MixF (40% RAP) E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 Log Reduced Frequency, Hz

28 Cracking Temperature, C Cracking Temperature Example PB-A PB-B PB-C PB-D PB-E PB-F -10 Strength Temperature PB-A PB-B PB-C PB-D PB-E PB-F Axis Title -28

29 Cracking Temperature, C Cracking Temperature Example Strength Temperature 2000 JH-A JH-B JH-C JH-D JH-E JH-F Mixes -28

30 Where is the Limit? Hot recycling How much can be put through a plant? Issues Virgin Aggregate temperature Drum temperature Baghouse temperature

31 Asphalt Binder Replacement %Asphaltbinderreplacement recycled binder totalbinder RAP Coarse RAP Fine RAP Shingles

32 Typical Asphalt Binder Content RAP 4 5% Fine RAP 5 7% Coarse RAP 2 3% Manufacturer Scrap 18 22% Post Consumer 22 25%

33 Mix Experiment Counterflow drum mix plant With mixing drum 19 mm NMPS 25 mm crushed gravel 12.5 mm crushed limestone 12.5 mm pea gravel Natural sand

34 Counter Flow Drum RAP Feeder Mixer Drum

35 Recycled Materials Fine RAP Coarse RAP Post Consumer Shingles

36 Post Consumer Shingles

37 Coarse RAP (1/2 to 1 inch)

38 Fine RAP (minus 1/2 inch)

39 Recycled Percentage Recycled Components Coarse Fine Shingles 5 0 Mix Mix Mix Mix Mix

40 Asphalt Binder Replacement, % Asphalt Binder Replacement Mix Mix Mix Mix Mix

41 Percentage Volumetric Properties Asphalt Content Air Voids Mix Mix Mix Mix Mix

42 Percentage Asphalt Binder Grade Mix Mix Mix Mix Mix

43 Aggregate Temperature, F New Aggregate Temperature % 50% 50% 50% Temp F

44 720 F 737 F 176 F

45 Drum Shell Temperature, C Drum Temperature % 60% 50% 50% 50%

46 Drum Mix Plant Limits Maximum 50% RAP Drum Shell Temperature max 800 F Aggregate Temperature max 700 F Exhaust Temperature min 220 F max 400 F

47 Dutch Experience

48 Contractor Visits Trials at 90%

49 RAP entry point into weigh hopper U.S. Direct Addition

50 RAP Elevator RAP Bins

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58 RAP Use in Indiana Percent limits based on Laboratory research Properties of Plant mix Properties of new asphalt binder Properties of reclaimed asphalt binder Percent reclaimed asphalt binder

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