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U"liza"on of Post-‐Consumer Recycled Asphalt Shingles (RAS) and Frac"onated RAP in HMA
Andrew Cascione R. Christopher Williams
Debra Haugen
Acknowledgements
• Illinois Tollway Authority-‐ Steve Gillen • Quigg Engineering, Inc.-‐ Ross Bentsen • EPA Region 5-‐ Julie Gevrenov • Rock Road Companies-‐ BreR Williams • STATE Tes"ng-‐ Jay Benhke • University of Illinois U-‐C-‐ Bill BuRlar • Iowa DOT-‐ ScoR Schram
Introduc"on
§ Illinois Tollway Authority undertaking unprecedented rehabilita"on/expansion program
§ Looking to new technologies to solve financial challenges
§ Tollway sponsored 2007 study on increasing the percentage of RAP in HMA shoulders (FRAP)
§ New 2009 research to study use of post-‐consumer RAS in HMA shoulders
Illinois Tollway Authority, Interstate 90
§ Field demonstra"on conducted in July 2009
§ Mixes containing RAS and FRAP were placed in the shoulder
§ Iowa State obtained field samples for laboratory tes"ng
Objec"ves
1. Characterize performance of HMA with RAS and varying percentages of FRAP
2. Can 5% RAS replace 5% FRAP in Tollway mixtures and maintain quality?
3. Performance difference between laboratory and field samples
Mix Design Experimental Plan
§ Base mix designed at lower air voids to reduce permeability
§ Binder mix designed as a “rich boRom layer” mix
§ One grade bump in the high temperature Performance Grade
Mix Type
NMAS (mm)
Design Air Voids Ndes
Performance Grade
Base 19.0 2 50 58-‐22
Binder 19.0 3 50 58-‐22
Surface 9.5 4 70 58-‐22
Mix Design Experimental Plan
ID Mix Type FRAP RAS
Experiment ID
Field Sample
Lab Sample
1 Base 25 5 Experimental X X
2 Base 35 5 Experimental X X
3 Base 45 5 Experimental X X
4 Base 50 0 Control X
7 Surface 20 5 Experimental X X
8 Surface 25 0 Control X
5 Binder 35 5 Experimental X
6 Binder 40 0 Control X X
Shoulder Pavement Cross-‐Sec"on
Standard Shoulder Surface
25% FRAP
RAS Shoulder Surface 5% RAS / 20% FRAP
Standard Shoulder Surface
25% FRAP
RAS Subbase
5% RAS / 25% FRAP
RAS Subbase
5% RAS / 35% FRAP
RAS Subbase
5% RAS / 45% FRAP
RAS Shoulder Binder 5% RAS / 35% FRAP
2”
4”
Laboratory Tes"ng Plan § Binder Characteriza"on
§ Dynamic Shear Rheometer -‐ Rukng § Bending Beam Rheometer -‐ Thermal Cracking
§ Mixture Characteriza"on § Dynamic Modulus -‐ Rukng § Flow Number -‐ Rukng § Tensile Strength Ra"o -‐ Freeze Thaw Damage § Flexural Beam Test -‐ Fa"gue Life § Fracture Energy* -‐ Thermal Cracking
*By University of Illinois Urbana-‐Champaign
§ Master Curves -‐ Viscoelas"c Behavior
Field Samples
Laboratory Samples § Samples Prepared by STATE
Tes"ng § Aggregate heated to 325⁰F § RAP heated separately un"l
300⁰F § RAS carefully heated but no
standard protocol § Agg, RAP, and RAS added to
mixing bucket individually § No curing "me § Reheated in oven for 4-‐6
hours
RAS & FRAP Binder Contribu"on
R² = 0.9883
R² = 0.98776
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 10 20 30 40 50 60
Percen
t Binde
r Rep
lacemen
t
Percentage of Recycled Materials
Contains 5% RAS
Contains 0% RAS
Field Binders -‐ High Temperature Grades
58 64 70 76 82 88 94
50% FRAP / 0% RAS
45% FRAP / 5% RAS
35% FRAP / 5% RAS
35% FRAP / 5% RAS
25% FRAP / 5% RAS
20% FRAP / 5% RAS
25% FRAP / 0% RAS
Performance Grade
Surface
Surface
Base
Base
Base
Binder
Binder
Lab Binders – High Temperature Grades
58 64 70 76 82 88 94 100 106 112
45% FRAP / 5% RAS
40% FRAP / 0% RAS
35% FRAP / 5% RAS
35% FRAP / 5% RAS
25% FRAP / 5% RAS
20% FRAP / 5% RAS
Performance Grade
Surface
Base
Binder
Binder
Base
Base
Field Binders – Low Temperature Grades
-‐28 -‐22 -‐16 -‐10 -‐4 2
50% FRAP / 0% RAS
45% FRAP / 5% RAS
35% FRAP / 5% RAS
35% FRAP / 5% RAS
25% FRAP / 5% RAS
20% FRAP / 5% RAS
25% FRAP / 0% RAS
Performance Grade
Surface
Surface
Base
Base
Base
Binder
Binder
Lab Binders – Low Temperature Grades
-‐28 -‐22 -‐16 -‐10 -‐4 2
45% FRAP / 5% RAS
40% FRAP / 0% RAS
35% FRAP / 5% RAS
35% FRAP / 5% RAS
25% FRAP / 5% RAS
20% FRAP / 5% RAS
Performance Grade
Surface
Base
Binder
Binder
Base
Base
Binder Master Curves
§ Describes Shear Modulus G* as a func"on of temperature and rate of loading
§ Frequency Sweeps in linear viscoelas"c range in the DSR and BBR
§ Converted Creep S"ffness to Shear Modulus values § Frequency curves shired horizontally with respect to 28°C
§ CAM Model used to construc"on master curves
|#↑∗ (')|= #↓* [1+('↓, /' )↑. ]↑− 0/.
Master Curve Construc"on
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E-‐06
1E-‐05
1E-‐04
1E-‐03
1E-‐02
1E-‐01
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
Complex M
odulus, G
* (P
a)
Frequency, radians/second
-‐18° C -‐12° C -‐6° C 0° C 16° C 28° C 40° C 46° C 58° C 64° C 70° C 76° C 82° C
Base Course Master Curves
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E-‐06
1E-‐05
1E-‐04
1E-‐03
1E-‐02
1E-‐01
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
Complex M
odulus, G
* (P
a)
Frequency, radians/second
25% RAP, 5% RAS
35% RAP, 5% RAS
45% RAS, 5% RAS
50% RAS, 0% RAP
25% FRAP, 5% RAS
35% FRAP, 5% RAS
45% FRAP, 5% RAS
50% FRAP, 0% RAS
Surface Course
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E-‐06
1E-‐05
1E-‐04
1E-‐03
1E-‐02
1E-‐01
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
Complex M
odulus, G
* (P
a)
Frequency, radians/second
20% RAP, 5% RAS
25% RAP, 0% RAS
20% FRAP, 5% RAS
25% FRAP, 0% RAS
Dynamic Modulus, E*
§ Five Replicate Samples § 4” dia. by 6” height § Axial Cyclical Load § Constant Strain Mode § Strain measured with three LVDTs
§ Nine Frequencies § 4, 21, and 37°C
HMA Mixture Master Curves
§ Describes Dynamic Modulus E* as a func"on of temperature and rate of loading
§ Used for Mechanis"c-‐Empirical Pavement Designs § Frequency curves shired horizontally with respect to 21°C
§ Sigmoidal func"on used to construc"on master curves
Log|1↑∗ |=2+ 3/1+ 4↑5+6(78*9↓: )
Dynamic Modulus Master Curve
1.0.E+04
1.0.E+05
1.0.E+06
1.0.E+07
1.0.E+08
1.E-‐05 1.E-‐03 1.E-‐01 1.E+01 1.E+03 1.E+05 1.E+07
|E*|, kPa
Frequency, Hz
37°C at Low Freq ( Rukng)
21°C at Med Freq (fa"gue)
4°C at High Freq (thermal cracking)
What effect does FRAP have on the Base Mix?
§ High Temp/Low Freq E* § 25 to 35% is Significant
§ Low Temp/High Freq E*
§ No Significant Diff.
E*
E*
%FRAP
%FRAP
What effect does RAS have on the Dynamic Modulus?
§ High Temp/Low Freq E* § RAS increases E* § No Significant Diff.
§ Med Temp/Med Freq E* § Significant but no trend
§ Low Temp/High Freq E* § RAS decreases E* § Significant in the Base
Course
Flow Number • Uses Dynamic Modulus
Samples • Test Temperature 37⁰C • Constant Stress • Cyclic Repeated load • 0.1s pulse and 0.9s rest • Measured Accumulated
Strain arer 10,000 load cycles
• Indica"on of Rukng Resistance
Accumulated Strain in Flow Number Test
0.00
0.50
1.00
1.50
2.00
5 5 5 0 5 5 0 5 5 5 5 0 5
25 35 45 50 35 20 25 25 35 45 35 40 20
Base Base Base Base Binder Surface Surface Base Base Base Binder Binder Surface
Field Field Field Field Field Field Field Lab Lab Lab Lab Lab Lab
% strain
p-‐value = 0.6462
p-‐value = 0.0162*
p-‐value = 0.0048*
Tensile Strength Ra"o (TSR)
0.76
0.77
0.78
0.79
0.80
0.81
0.82
0.83
0.84
0.85
25% FRAP, 5% RAS,
base course
35% FRAP, 5% RAS,
base course
45% FRAP, 5% RAS,
base course
50% FRAP, 0% RAS,
base course
35% FRAP, 5% RAS,
binder course
20% FRAP, 5% RAS,
surface course
25% FRAP, 0% RAS,
surface course
Beam Fa"gue • Repeated traffic loading • Haversine loading at 10Hz • Linear Kneading Compactor • Six beams for each sample
tested at a different constant strain level
• Test Temperature 20⁰C • Test is complete arer a 50%
reduc"on in flexural s"ffness
• K2 indicates damage accumula"on rate
• Above 3.5 is acceptable
;↓< ==1(1/>↓8 )↑=2
Base Course Mixes
R² = 0.80296
R² = 0.97158
100
1000
1E+02 1E+03 1E+04 1E+05 1E+06 1E+07 1E+08
% m
icro strain
Load Cycles (N)
45% FRAP / 5% RAS
50% FRAP / 0% RAS
Binder Course Mixes
R² = 0.97618 R² = 0.91342
100
1000
1E+02 1E+03 1E+04 1E+05 1E+06 1E+07 1E+08
% m
icro strain
Load Cycles (N)
35% FRAP / 5% RAS
40% FRAP / 0% RAS
Surface Course Mixes
R² = 0.98871 R² = 0.95121
100
1000
1E+02 1E+03 1E+04 1E+05 1E+06 1E+07 1E+08
% m
icro strain
Load Cycles (N)
20% FRAP / 5% RAS
25% FRAP / 0% RAS
K2 Coefficients
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
25% FRAP, 0% RAS, surface
20% FRAP, 5% RAS, surface
25% FRAP, 5% RAS, base
35% FRAP, 5% RAS, base
35% FRAP, 5% RAS, binder
40% FRAP, 5% RAS, binder
45% FRAP, 5% RAS, base
50% FRAP, 0% RAS, base
K2
Field Mixes
Lab Mixes
Compact Disk Tension
• Conducted by Univ. of Illinois Urbana-‐Champ.
• Test Temperature -‐12⁰C • 4 Specimens 120mm in height by 150mm in dia.
• Measures Fracture Energy
• Minimum recommended value is 350J/m2
Average Fracture Energy by % recycled materials
388 363.1 357.7 299.9
25% 30% 40% 50%
Fracture Energy Comparison
391.0
386.5
319.0
388.3
338.3 278.0
No
RAS
RA S
RA S
No RAS
No RAS
RA S
50% Recycled Base
40% Recycled Binder
25% Recycled Surface
Conclusions
§ Tollway mixes exhibit good resistance to rukng
§ 5% RAS is not detrimental to the fa"gue performance of the Tollway mixes
§ Mixtures may see some cracking due to lower fracture energies and higher low performance grade temperatures
Illinois Tollway Conclusions § Mixes with greater than 40% recycled will likely see the greatest amount of cracking
§ Their performance may be improved by grade bumping the virgin binder from 58-‐22 to 58-‐28
§ Fibers could be contribu"ng to the performance of the mixtures
§ Tollway mixes exhibit sa"sfactory freeze-‐thaw durability
§ Laboratory RAS mix design procedures may need to be reevaluated
1.00E+04
1.00E+05
1.00E+06
1.00E+07
1.00E+08
1.00E-‐05 1.00E-‐02 1.00E+01 1.00E+04 1.00E+07
|E*|, KPa
Frequency, Hz
Mix #1 5% Mfr RAS Mix #2 5% Tear-‐offs RAS Mix #3 30% RAP
MNDOT MIXES
1.00E+04
1.00E+05
1.00E+06
1.00E+07
1.00E+08
1.00E-‐05 1.00E-‐02 1.00E+01 1.00E+04 1.00E+07
|E*|, KPa
Frequency, Hz
Mix #11 HMA -‐ 15% RAP Mix #12 HMA -‐ 3% RAS Mix #13 WMA -‐ 3% RAS
INDOT MIXES
Iowa DOT: WMA+RAP+RAS • Musca"ne County (Hwy 61 Shoulders) • Evotherm 3G (Plant Temp = 250F) • 3 Test Sec"ons – 20% RAP/0% RAS
• 20% Binder Replacement • 4.6% Design AC
– 15% RAP/5% RAS • 30% Binder Replacement • 5.0% Design AC
– 8% RAP/7% RAS • 30% Binder Replacement • 5.5% Design AC
WMA + 5% RAS + 15% RAP
WMA + 7% RAS + 8% RAP
WMA Control + 20% RAP
WMA with RAS
• RAS contains much s"ffer binder • Not all RAS is ac"vated • 15-‐40% Acts like black rock = Requires more AC to coat
• May need to add oil • May need to raise temperature • HIGH RAS STOCKPILE MOISTURE – Reduce produc"on rate – Increase plant temperature
Addi"onal Demonstra"on Projects
• Iowa-‐ 4%, 5%, 6% RAS • Missouri-‐ Coarse vs. Fine Grind • Colorado-‐ to be determined. • Wisconsin-‐ to be determined. • California-‐ to be determined.
Missouri DOT
Items Considered Best Prac"ces
• Minimize water usage during grinding • Store ground shingles under a covered roof • Use mul"ple recycled cold feed bins-‐ one that is dedicated to shingles
• Use a 2nd recycle bin on drum plants closer to the hot zone for adding shingles
Purpose for Developing Asphalt Mix Design
• Meet client needs – Economics – Performance
• Meet producer/contractor needs – Mix can be produced – Mix can be placed and compacted – U"liza"on of other “technologies”
Type of Facility • High volume-‐ greater than 10million ESALs – Interstates
• Medium volume-‐ 1 to 3million ESALs – Four-‐lane divided – Two lane – Urban collectors
• Low volume-‐ less than 1million ESALs – Most local agency roads – Residen"al developments
• Specialty Facili"es
Mix Cons"tuents
• Aggregate • Baghouse fines • Asphalt • Air
• So what is different when shingles are added?
Shingle Composi"on
Shingles vs. Asphalt Mixtures
• S"ffer asphalt in shingles • Granules are ceramic like material-‐ as good or beRer aggregate than asphalt mix aggregates
• Dust in shingles is lime dust-‐ lime dust is used as an"-‐strip agent in asphalt mixes
• Fibers in shingles are as good or beRer than when fibers are used in asphalt mixes
Integra"ng Shingles into Mix
• Account for s"ffer binder • Binder content determina"on & contribu"on • Mix volumetrics • Other considera"ons – RAP – Warm mix asphalt
Development of Mixture Design
• Process is no different than current methods of asphalt mix design development.
• Need to pay aRen"on to integra"on of RAS into batching materials – Propor"oned materials should be pre-‐blended prior to placement into oven.
– Ensures even distribu"on of RAS throughout aggregate structure.
Outcomes of Mix Design
• Virgin binder content will be lower when RAS is u"lized.
• 60-‐80% of RAS binder will be integrated into HMA mix.
• Voids in the Mineral Aggregate will increase with RAS u"liza"on.
• Contribu"on of RAS binder to overall binder grade will not be known………but!
Challenges
• AASHTO M323 binder recommenda"ons assume complete mixing of new and recycled binder
• AASHTO M323 does not address RAS binders • RAS rheology is different than paving binders
1. Binder proper"es alone will not determine asphalt mix performance.
2. Mix tes"ng will capture the
benefits of the fibers.
Thank You! &
Ques"ons?
