paving with high rap | ctep

PAVING WITH HIGH RAP

Western CanadaPavement WorkshopFebruary 1, 2012

Gerry HuberHeritage Research GroupIndianapolis, IN

Outline

Issues

Specifications

Limits

Barriers to Increasing RAP

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

• 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

Mix up the material while feeding it into the Processing Unit

7

RAP 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

Variability: RAP vs. Aggregate

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

Fractionated vs. Unfractionated


10

High RAP Performance in Florida

Jim MusselmanFlorida Department of Transportation

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)


Percent

34%

18%13%

11%

24%

Stockpile Management

Long-term Performance

Binder Issues

Availability of RAP

Other

Becky McDaniel

North Central Superpave CenterRAP ETG

December 17, 2009

Investigation of Low and High

Temperature Properties

of Plant-Produced RAP Mixtures

Experimental Design

RAP

Binder Grade

0% 15% 25% 40%

PG 64-22X

Mix AX

Mix BX

Mix CX

Mix D

PG 58-28X

Mix EX

Mix F

Hot Mix Plant

One Example - Mix |E*|

100

1000

10000

100000

1.E-03 1.E-01 1.E+01 1.E+03 1.E+05 1.E+07

|E*|

, M

Pa

Reduced Frequency, Hz

PG64-22

Mix4-A (0%0 RAP)

Mix4-B (15% RAP)

Mix4-C (25% RAP)

Mix4-D (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)

IDT Strength Example 1

-28

-22

-16

-10

2500

3000

3500

4000

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

Pvm

t. Crack

ing T

emp

erature, °C

Str

engt

h,

kP

a

Mixes

Strength

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

Pvm

t. Crack

ing T

emp

erature, °C

Str

engt

h,

kP

a

Mixes

Strength

Temperature

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

AASHTO M323 SPECIFICATIONS

Virgin Binder Grade Based on RAP

0 to 15%

15 to 25%

>25%

Asphalt Binder Replacement

RAP

Coarse RAP

Fine RAP

Shingles

bindertotal

binderrecycledtreplacemenbinderAsphalt %

Typical Asphalt Binder Content

RAP 4 – 5%

Fine RAP 5 – 7%

Coarse RAP 2 – 3%

Manufacturer Scrap 18 – 22%

Post Consumer 22 – 25%

Where is the Limit?

Hot recycling

How much can be put through a plant?

Issues

Virgin Aggregate temperature

Drum temperature

Baghouse temperature

Phase One

RAP

50%

60%

70%

Post Consumer Shingles

0%

3%

Counter flow drum mix plant

Embedded burner

RAP inlet capacity

Mixing chamber volume

Water injection

Mixing aid

Phase One Mixes

Mix Size RAP RAS AC BR

1 25.0 70 0 6.0 33

2 25.0 60 0 4.1 41

3 12.5 60 0 (47)

4 12.5 50 3 5.6 29

5 12.5 50 3 7.1 31

6 12.5 50 3 6.6 33

Discharge Temperature

0

50

100

150

200

Dis

ch

arg

e T

em

pera

ture

, C

70% 60% 60% 50% 50% 50%

Aggregate Temperature

0

100

200

300

400

500

Ag

gre

gate

Tem

pera

ture

, C

70% 60% 60% 50% 50% 50%

80 C

391 C

382 C

Drum Temperature

0

100

200

300

400

500

600

Dru

m S

hell

Tem

pera

ture

, C

70% 60% 60% 50% 50% 50%

60% RAP

70% RAP

Decisions from Phase One

Maximum 50% RAP

Drum Shell Temperature

max 425 C

Aggregate Temperature

max 370 C

Exhaust Temperature

min 105 C

max 200 C

Phase Two 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

RAP Feeder

Mixer Drum

Counter Flow Drum

Phase Two Recycled Materials

Fine RAP

Coarse RAP



Coarse RAP (1/2 to 1 inch)

Fine RAP (minus 1/2 inch)

Recycled Components

0

5

10

15

20

25

30

35

Recycle

d P

erc

en

tag

e

Mix 9

64-22

Mix 10

52-28

Mix 11

52-28

Mix 12

52-28

Mix 13

64-22

Coarse

Fine

Shingles

Asphalt Binder Replacement

0

10

20

30

40

50

60

70

Asp

halt

Bin

der

Rep

lacem

en

t, %

Mix 9

64-22

Mix 10

52-28

Mix 11

52-28

Mix 12

52-28

Mix 13

64-22

Volumetric Properties

0.0

1.0

2.0

3.0

4.0

5.0

6.0

Perc

en

tag

e

Mix 9

64-22

Mix 10

52-28

Mix 11

52-28

Mix 12

52-28

Mix 13

64-22

Asphalt Content

Air Voids

Asphalt Binder Grade

-30.0-20.0-10.0

0.010.020.030.040.050.060.070.080.0

Perc

en

tag

e

Mix 9

64-22

Mix 10

52-28

Mix 11

52-28

Mix 12

52-28

Mix 13

64-22

Cantabro Loss Test (Durability)

LA Abrasion Test Machine

Test withoutSteel Balls

Cantabro Test (Durability)

10

12

14

16

18

20

22

24

40 50 60 70

Asphalt Binder Replacement, %

Can

tab

ro L

oss,

%

Placement

County Road resurfacing

50 mm base

19.0-mm mix

38 mm surface

Placed

May 31, 2011

June 1, 2011

Construction Conditions

Haul time

30 minutes approx

Weather

30C sunny

Paver

Roadtec RP150 15 to 18 m/min

Compactor

Bomag BW266 3 vibratory passes, 1

static

Existing Condition

Laydown Operation

Uncompacted Mat

Compaction

Compacted Mat

Paving Crew Observations

Flows through paver

Mat lays well

(little handwork in this application)

Compacts well

No tenderness

RAP in HMA

Black Rock?

Limestone 20 – 80 GPa

Aged Asphalt Binder 1 GPa glassy stiffness

0.01 GPa (10C)

Homogenous Blending?

No

Partial Blending??

Partial Blending

Composite Material

Virgin Binder

ReclaimedBinder

paving with high rap | ctep

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