Advanced Asphalt Technologies, LLC “Engineering Services for the Asphalt Industry” WHRP Project 0092-10-06 Effect of Recovered Binders from Recycled Shingles

Advanced Asphalt Technologies, LLC

“Engineering Services for the Asphalt Industry”

WHRP Project 0092-10-06

Effect of Recovered Binders from Recycled Shingles and Increased

RAP Percentages on Resultant Binder PG

Ramon Bonaquist, Ph.D., P.E.




Outline

• Objectives

• Approach

• Major Findings

• Conclusions and Recommendations



Objectives

• Improve the AASHTO performance graded binder blending chart analysis.

• Use the improved blending chart analysis to evaluate current WisDOT criteria for binder replacement.

• Identify potential effects of using RAP and RAS on pavement service life, both positive and negative.



Approach

• Review of current practice– WisDOT specs relative to other agencies– AASHTO M323 blending chart analysis

• Blending chart improvements– RAS– Multiple recycled binders

• Characterization of WI recycled materials– 6 RAP, 6 FRAP, and 6 RAS– Northern and Southern sources



Approach Continued

• Reliability based blending chart analysis– Considered variation in temperature and

continuous grade temperature– Effect of WisDOT binder replacement criteria on

low temperature properties– Recommendations for adjustments



Review of Current Practice

• WisDOT binder replacement relative to:– Alabama – Georgia– Minnesota– Missouri– South Carolina– Texas– Virginia



Surface Mixtures

0 5 10 15 20 25 30 35 40 45 50

RAS

RAP/FRAP

RAS/RAP/FRAP

Binder Replacement, %



Lower Layer Mixtures

0 5 10 15 20 25 30 35 40 45 50

RAS

RAP/FRAP

RAS/RAP/FRAP

Binder Replacement, %



Blending Chart Improvements

• Issues– AASHTO M323 and AASHTO PP53 use linear

blending charts for RAP and RAS– Linear blending charts were developed for blends

of recovered RAP binders in virgin binder. Do they apply to RAS and blends with RAP and RAS?

– Can’t grade recovered RAS binders due to different rheology primarily at low temperatures.

• Fails stiffness at very low temperature• Fails m-value at very high temperature



Blending Charts for RAS

-20

-10

0

10

20

30

40

50

0 10 20 30 40 50 60 70 80 90 100

% RAS Binder

Cri

tical T

em

pera

ture

fo

r m

-valu

e

Known Virgin Binder

50/50 Virgin/RAS Blend

Estimated RAS



High Temperature

58

64

70

76

82

88

94

100

0 10 20 30 40 50 60

Conti

nuou

s H

igh

Tem

pera

ture

Gra

de, Σ

C

% RAS Binder

Unaged RTFOT Aged



Intermediate Temperature

16

19

22

25

28

0 10 20 30 40 50 60

Conti

nuou

s In

term

edia

te Te

mpe

ratu

re G

rade

, ΣC

% RAS Binder



Low Temperature

-34

-28

-22

-16

-10

0 10 20 30 40 50 60

Conti

nuou

s Lo

wTe

mpe

ratu

re G

rade

, ΣC

% RAS Binder

m-valie Stiffness



Linearity Limit

-34

-28

-22

-16

-10

0 10 20 30 40 50 60

Conti

nuou

s Lo

wTe

mpe

ratu

re G

rade

Bas

ed o

n m

-Val

ue, Σ

C

% RAS Binder



Grading RAS Binders

• Extract and recover RAS binder

• Prepare a 30/70 blend of recovered RAS in virgin binder of known performance grade

• Grade blend per AASHTO R29

• Knowing virgin and 30/70 blend continuous grade extrapolate RAS continuous grade



Notes on RAS Binder Recovery

• AASHTO T164 Method A, centrifuge extraction

• Rotovapor primary distillation

• Abson recovery

• Modifications– Heat flask in oven after primary distillation and

prior to start of Abson recovery– Use higher temperatures in Abson recovery



Blending Chart for Multiple Recycled Binders

Tblend=Tvirgin+ቀ%RB1100 ቁ×൫TRB1-Tvirgin൯+ቀ

%RB2100 ቁ×൫TRB2-Tvirgin൯+…ቀ%RBn100 ቁ×൫TRBn-Tvirgin൯

Where:

Tblend = continuous grade for the blended binder °C,

Tvirgin = continuous grade for the virgin binder, °C TRB1= continuous grade for recycled binder 1, °C

%RB1 = percentage of total binder made up of recycled binder 1, % TRB2= continuous grade for recycled binder 2, °C

RB2 = percentage of total binder made up of recycled binder 1, % TRBn= continuous grade for recycled binder n, °C

RBn = percentage of total binder made up of recycled binder 1, %

n = number of recycled binders



Blending Chart vs R29 High

64.0

66.0

68.0

70.0

72.0

74.0

76.0

78.0

80.0

82.0

84.0

86.0

88.0

64.0 66.0 68.0 70.0 72.0 74.0 76.0 78.0 80.0 82.0 84.0 86.0 88.0

Blen

ding

Cha

rt C

onti

nuou

s G

rade

, �C

AASHTO R29 Continuous Grade, � C

Tank RTFOT Equality



Blending Chart vs R29 Intermediate

16.0

17.0

18.0

19.0

20.0

21.0

22.0

23.0

24.0

25.0

16.0 17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0 25.0

Blen

ding

Cha

rt C

onti

nuou

s G

rade

, �C


Equality



Blending Chart vs R29 Low

-34.0

-32.0

-30.0

-28.0

-26.0

-24.0

-22.0

-34.0 -32.0 -30.0 -28.0 -26.0 -24.0 -22.0

Blen

ding

Cha

rt C

onti

nuou

s G

rade

, �C


S M Equality



Recycled Material Characterization

Recycled Material

North Wisconsin Sources South Wisconsin Sources 1 2 3 1 2 3

RAP Cisler Wimmie Glenmore Christian Tri-

County I94 Badger Interchange

FRAP Menasha Eau Claire Rhinelander Rock Road Madison Vienna

Waukesha

RAS Northeast Asphalt

Bruce Co. A Amon Allied Black

Top Co. Tri-

County LaCrosse

City



RAP/FRAP High

70.0

76.0

82.0

88.0

RAP South FRAP South RAP North FRAP North Grand Average

Hig

h Te

mpe

ratu

re G

rade

, o C

Source



RAP/FRAP Intermediate

22.0

25.0

28.0

31.0

RAP South FRAP South RAP North FRAP North Grand Average

Inte

rmed

iate

Tem

pera

ture

Gra

de, o C

Source



RAP/FRAP Low

-28.0

-22.0

-16.0RAP South FRAP South RAP North FRAP North Grand AverageLo

w T

empe

ratu

re G

rade

, o CSource



Average Grade of WI RAP

• PG 82.8 (26.9) -21.8

• Standard Deviation

Property WI RAP Virgin PG 64-22

High 2.2 0.5

Intermediate 1.4 1.1

Low 1.4 0.8



Extrapolated RAS High

106.0

112.0

118.0

124.0

130.0

136.0

North South Grand Average

Hig

h Te

mpe

ratu

re G

rade

, o C

Source



Extrapolated RAS Intermediate

28.0

31.0

34.0

37.0

40.0

North South Grand Average

Inte

rmed

iate

Tem

pera

ture

Gra

de, o C

Source



Extrapolated RAS Low

-16.0

-10.0

-4.0

North South Grand AverageLo

w T

empe

ratu

re G

rade

, o CSource



Average Grade of WI RAS

• North– PG 122.1 (34.4) -4.7

• South– PG 111.3 (31.0) -8.4

Property WI RAS Virgin PG 64-22

High 5.4 0.5

Intermediate 1.8 1.1

Low 1.8 0.8



WI RAP vs WI RAS

Property WI RAP North RAS South RAS

High 82.2 122.1 111.3

Intermediate 26.9 34.4 31.0

Low -21.8 -4.7 -8.4



Reliability Analysis

• Two sources of variability– Pavement temperature at the project location– Continuous grade of blended binder

• Overall reliability

GradeeTemperatur rxrR

Average and Standard Deviation of Pavement Temperature at Project Location

Average and Standard Deviation of Continuous Grade Temperature



Standard Deviation of Blend

2Virgin

2RAS

22RAP

2c 1

where:

c = standard deviation of the blended binder

RAP = standard deviation of the RAP binder

RAS = standard deviation of the RAS binder

Virgin = standard deviation of the virgin binder

= proportion of the total binder made up by the RAP binder

= proportion of the total binder made up by the RAS binder




0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 10 20 30 40 50 60 70 80 90 100

Stan

dard

Dev

iatio

n of

Ble

nd o

f Tw

o Bi

nder

s

% Binder 2

s2 =s1

s2 = 1.5 s1

s2 = 2.0 s1




0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 10 20 30 40 50 60 70 80 90 100

Stan

dard

Dev

iatio

n of

Ble

nd o

f Tw

o Bi

nder

s

% Binder 2

s2 =s1

s2 = 1.5 s1

s2 = 2.0 s1

Property Virgin RAP RAS

High 0.5 2.2 5.4

Intermediate 1.1 1.4 1.8

Low 0.8 1.4 1.8



Reliability AnalysisPG 58-3461 Weather Stations

PG 58-2879 Weather Stations

Mid Grade BinderExceptional Binder



Mid Grade Surface Current Limits

0

10

20

30

40

50

60

70

80

90

100O

vera

ll Lo

w T

empe

ratu

re G

rade

Rel

iabi

lity,

%

Mixture



Exceptional Surface Current Limits

0

10

20

30

40

50

60

70

80

90

100O

vera

ll Lo

w T

empe

ratu

re G

rade

Rel

iabi

lity,

%

Mixture



Mid Grade Surface Revised Limits

0

10

20

30

40

50

60

70

80

90

100

Ove

rall

Low

Tem

pera

ture

Gra

de R

elia

bilit

y, %

Mixture



Mid Grade Lower Revised Limits

0

10

20

30

40

50

60

70

80

90

100O

vera

ll Lo

w T

empe

ratu

re G

rade

Rel

iabi

lity,

%

Mixture



Revised Limits

Recycled Binder Type Maximum Binder Replacement1, % Surface Layers Lower Layers2

RAP3 20 45 RAS 5 20

Combination of RAP and RAS Reduce RAP binder replacement 4 % for each 1 % RAS binder replacement.

Reduce RAP binder replacement 2.25 % for each 1 % RAS binder replacement.

Notes: 1 Defined as ratio of recycled binder content to total binder content 2 Layers 50 mm (2 in) or more below surface of the pavement 3 Includes RAP, FRAP, and combinations of RAP and FRAP



Conclusions

• Linear blending is applicable to blends of RAS up to about 30 percent

• Linear blending provides a reasonable estimate of the continuous grade of blends of multiple recycled binders

• WI RAP/FRAP is very consistent having a recovered grade of PG 82.8 (26.9) -21.8



Conclusions

• Appears to be a geographic difference in WI RAS– North 122.1 (34.4) -4.7– South 111.3 (31.0) -8.4

• RAS changes binder grade much more than RAP

• Current WisDOT binder replacement does not treat RAP and RAS mixtures equally



Recommendations

• Consider modifying binder replacement criteria to provide similar reliability for RAP and RAS mixtures

• Use reliability analysis to approve mixtures with recycled contents greater than the binder replacement limits

• Monitor continuous grade of recycled sources using the procedures developed in this project



Recommendations

• Monitor continuous grade of virgin binder sources

• Monitor cracking performance of pavements with recycled binders



Questions/Discussion

Ramon BonaquistAdvanced Asphalt Technologies, LLC108 Powers Court, Suite 100Sterling, VA [email protected]

Documents

Advanced Asphalt Technologies, LLC “Engineering Services for the Asphalt Industry” WHRP Project 0092-10-06 Effect of Recovered Binders from Recycled Shingles