The Latest Rap on RAP

RECYCLED ASPHALT PAVEMENT

Gerry HuberHeritage Research GroupChairman RAP and Shingle ETG

CANADIAN USER

PRODUCER GROUP

FOR ASPHALT 2010

RAP Expert Task Group

Formed 2007

Members

DoTs

Industry

Academia

Purpose of ETG

National Guidance

Coordinate

Develop

Improve

Recommendations

Correct use of technology

State of practice

Main Issues Identified

Performance Test

Best Practices Manual

Binder Grade Changes

Field Performance

Variability

5

Performance Studies of Asphalt Pavements with Greater than 25% RAP

Randy C. West, NCAT

October 7, 2009

Barriers to Increasing RAP

6

7

A Performance Comparison of RAP vs. Virgin Mixes

LTPP SPS-5 pavement sections

18 U.S. states and Canadian provinces

At least 30% RAP used in recycled mixes

Projects range in age from 6 to 17 yrs

General Performance

8

Distress Parameter

Threshold RAP Sections Virgin Sections

IRI 2.0 m/km 86% 89%

Rutting 10 mm 71% 78%

Fatigue Cracking 25% of WP area 60% 72%

Longitudinal Cracking

25% of section length

79% 86%

Transverse Cracking

20 cracks per section

47% 64%

Block Cracking 10% of section area

89% 94%

Raveling 10% of section area

75% 69%

Percentage of Sections Below General Pavement Performance Thresholds

9

10

11

12

13

14

High RAP Performance in Florida

Jim Musselman

Florida Department of Transportation

Statewide Pavement

Performance

Deficient Pavements (%)

Criteria 2004 2005 2006 2007 2008 2009

Ride 6.3 5.6 3.8 3.5 3.2 2.6

Crack 16.5 17.0 15.8 14.6 14.9 13.0

Rut 1.2 1.2 0.9 0.9 1.0 0.6

Section 334.046 of Florida Statutes: “Ensuring that 80% of the

pavement on the SHS meets Department Standards”

D.R.I.P

Data Rich….

Information Poor

Pavement Management Data

0

2

4

6

8

10

12

14

16

18

Age

(yr

s)

Percent RAP (%)

0 % 30 %

35 %

40 %

45 %

50 %

Only Projects >5,000 tons(No consideration for traffic)

20

RAP Management Best Practices

RAP Needs Analysis

Milling for Success

Multiple-source RAP piles

Crushing Considerations

Screening Options

Best Practices for Stockpiling

Sampling and Testing of RAP Stockpiles

Production of Recycled Asphalt Mixes

Barriers to Increasing RAP

21

Keep millings from different projects in separate stockpiles.

Milled RAP can typically be used “as is” in HMA without further crushing.

Milled RAP

Multiple Source RAP Stockpiles

• It is vital to prevent dumping of any deleterious materials in the pile from the beginning.

• Clearly instruct all truck drivers hauling materials to the yard where to dump different types of materials

RAP Crushing Process

Small dozer to break up

RAP and push it to a loader

Mix up the material while

feeding it into the

Processing Unit

25

Fractionating RAP

The practice should not be mandated; it should be the contractor’s business decision if and when to fractionate RAP.

26

Variability: RAP vs. Aggregate

27

Based on 74 RAP stockpiles in 14 states, and 60 Aggregate stockpiles in 6 states

Fractionated vs. Unfractionated

28

Becky McDanielRAP ETG

December 17, 2009

Investigation of Low and

High Temperature Properties

of Plant-Produced RAP

Mixtures

Experimental Design

Reclaimed Asphalt Pavement

Asphalt Binder Grade

0% 15% 25% 40%

PG 64-22X

Mix AX

Mix BX

Mix CX

Mix D

PG 58-28X

Mix EX

Mix F

Example Binder Data

ID GradeHT

Grade(DSR)

LT Grade(BBR)

True Grade

Tcrit

(TSAR)

Virgin Binders

PG64-22 67.4 -24.2 67-24PG58-28 60.7 -28.3 60-28

4A

PG64-22

73.7 -20.5 73-20 -22.64B 72.8 -20.8 72-20 -22.54C 74.4 -20.5 74-20 -20.14D 75.0 -19.6 75-19 -20.24E

PG58-2867.8 -24.2 67-24 -26.2

4F 70.0 -23.3 70-23 -23.4

One Example - Mix |E*|

100

1000

10000

100000

1.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

Lo

g |E

*|, M

Pa

Log Reduced Frequency, Hz

PG64-22

MixA (0%0 RAP)

MixB (15% RAP)

MixC (25% RAP)

MixD (40% RAP)

One Example - Mix |E*|

100

1000

10000

100000

1.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

Lo

g |E

*|, M

Pa

Log Reduced Frequency, Hz

Control versus PG58-28

MixA (0% RAP)

MixE (25% RAP)

MixF (40% RAP)

One Example - Mix |E*|

100

1000

10000

100000

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

Lo

g |E

*|, M

Pa

Log Reduced Frequency, Hz

PG64-22 versus PG58-28

MixC (25% RAP)

MixE (25% RAP)

MixD (40% RAP)

MixF (40% RAP)

Second Example - Mix |E*|

100

1000

10000

100000

1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 1.E+06

|E*|

, M

Pa

Reduced Frequency, Hz

Control versus PG58-28

Mix 5A (0% RAP)

Mix 5E (25% RAP)

Mix 5F (40% RAP)

IDT Strength Example 1

-28

-22

-16

-10

2500

3000

3500

4000

PB-A PB-B PB-C PB-D PB-E PB-F

Pv

mt. C

rack

ing T

em

per

atu

re,

C

Str

eng

th,

kP

a

Mixes

Strength

Temperature

IDT Stiffness Example 1

-28

-22

-16

-10

10

15

20

25

PB-A PB-B PB-C PB-D PB-E PB-F

Pv

mt. C

rack

ing

Tem

per

atu

re,

C

Sti

ffn

ess,

GP

a

Mixes

Stiffness

Temperature

IDT Strength Example 2

-28

-22

-16

-10

2000

2500

3000

3500

JH-A JH-B JH-C JH-D JH-E JH-F

Pv

mt. C

rack

ing

Tem

per

atu

re,

C

Str

eng

th,

kP

a

Mixes

Strength

Temperature

IDT Strength Example 3

-22

-16

-10

3000

3500

4000

EB-A EB-B EB-C EB-D EB-E EB-F

Pv

mt. C

rack

ing

Tem

peratu

re, C

Str

eng

th,

kP

a

Mixes

Strength

Temperature

IDT Stiffness Example 3

-22

-16

-10

20

30

40

EB-A EB-B EB-C EB-D EB-E EB-F

Pv

mt. C

rack

ing T

em

per

atu

re,

CS

tiff

nes

s, G

Pa

Mixes

Stiffness

Temperature

General Conclusions

Low Temperature Cracking (IDT)

Slight effects on critical cracking temp at up to 25% RAP with PG64-22

Critical cracking temp of 40% RAP with PG64-22 was slightly warmer but still around -22°C

Current ETG Activities

Best Practices document by TRB 2011

Research Needs statements

Performance Prediction tests

Shingles

Recommend changes to R35

Superpave Volumetric Design

Change to % Binder Replacement