Matthew Corrigan, P.E.

Asphalt Pavement Engineer

Mobile Asphalt Testing Trailer Technical Manager 

U.S. DOT – Federal Highway Administration

November 19, 2014

Pavements / Materials 

Conference

Warm Mix Asphalt in the United States:

From Evolution to Revolution
Where have we been?

2004-05

Number of named WMA 

technologies in the U.S.?

2013-14

Number of named WMA 

technologies in the U.S.?
Where have we been?

2004-05

No. of WMA Technical 

Working Groups?

2013-14

No. of WMA Technical 

Working Groups?
Stakeholder Engagement:

WMA Technical Working Group

FHWA

NAPA

Industry

State DOT

NCAT State APA

AASHTO

Labor

NIOSH

Co-Chairs:

Matthew Corrigan

Ron White

Established in 2005

Adjourned in 2012
Where have we been?

2004-05

No. of WMA International 

Conferences?

2013-14

No. of WMA International 

Conferences?
International WMA 

Conferences

1st Conference on November 11-13, 2008 in 

Nashville, TN

Processes, Mix Production & Placement, Energy 

consumption, Mix Design, Material Properties

2nd Conference October 11-13, 2011 in St. 

Louis, MO

Lab & Field Properties, Design & Performance, 

Health & Environment, RAP w/ WMA, Binder & 

Mix Properties, Moisture Susceptibility, 

Construction, etc.

6
Where have we been?

2004-05

Number of WMA NCHRP 

Research Projects?

2013-14

Number of WMA NCHRP 

Research Projects?
9-43 $522,501 completed

9-47 $79,000 completed

9-47A $1,121,000 completed

9-49 $450,000 completed

9-49A $900,000 Jul 2016

9-52 $800,000 Nov 2014

9-53 $700,000 Dec 2014

9-54 $800,000 May 2016

9-55 $600,000 Sept 2016

9-58 $1,500,000 July 2017est.

20-07 (311) $50,000 completed

NCHRP Projects funded as a result of WMA TWG efforts:

-Mix Design Practices for WMA

-Engineering Properties, Emissions, and 

Field Performance of WMA Technologies

-Properties and Performance of WMA 

Technologies

-Performance of WMA Technologies: 

Stage I--Moisture Susceptibility

-Performance of WMA Technologies: 

Stage II--Long-Term Field Performance

-Short-Term Laboratory Conditioning of 

Asphalt Mixtures

-Properties of Foamed Asphalt for Warm 

Mix Asphalt Applications

-Long-Term Aging of Asphalt Mixtures for 

Performance Testing and Prediction

-Recycled Asphalt Shingles in Asphalt 

Mixtures with WMA Technologies 

-Effects of Recycling Agents on Asphalt 

Mixtures w/High RAS & RAP Binder Ratios

-Development of a WMA 

Tech. Evaluation Program
9-43 $522,501 completed

9-47 $79,000 completed

9-47A $1,121,000 completed

9-49 $450,000 completed

9-49A $900,000 Jul 2016

9-52 $800,000 Nov 2014

9-53 $700,000 Dec 2014

9-54 $800,000 May 2016

9-55 $600,000 Sept 2016

9-58 $1,500,000 July 2017est.

20-07 (311) $50,000 completed

NCHRP Projects funded as a result of WMA TWG efforts:

-Mix Design Practices for WMA

-Engineering Properties, Emissions, and 

Field Performance of WMA Technologies

-Properties and Performance of WMA 

Technologies

-Performance of WMA Technologies: 

Stage I--Moisture Susceptibility

-Performance of WMA Technologies: 

Stage II--Long-Term Field Performance

-Short-Term Laboratory Conditioning of 

Asphalt Mixtures

-Properties of Foamed Asphalt for Warm 

Mix Asphalt Applications

-Long-Term Aging of Asphalt Mixtures for 

Performance Testing and Prediction

-Recycled Asphalt Shingles in Asphalt 

Mixtures with WMA Technologies 

-Effects of Recycling Agents on Asphalt 

Mixtures w/High RAS & RAP Binder Ratios

-Development of a WMA 

Tech. Evaluation Program
• Products:

– Appendix to AASHTO R35 with commentary 

“Special Mixture Design Considerations and 

Methods for Warm Mix Asphalt (WMA)”

– WMA Mix Design Workshop/Training Module

– Chapter on WMA Mix Design for the NCHRP 

Project 09-33 Mix Design Manual

– “Standard Practice For Measuring Properties of 

Warm Mix Asphalt (WMA) for Performance 

Analysis Using the AASHTO MEPDG” (AASHTO 

DARWin-METM Software)

NCHRP Project 09-43

http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=977
Course Number:

FHWA-NHI-131137

11
• Original Project 9-43

– Binder Absorption limited to 0.5 - 1.0 %

• ETG Work Item: Expansion to Higher 

Absorption Mixtures ≥ 2.0%

– Includes High Absorption Lab Foamed Mix

• Completed by Dr. Ray Bonaquist, AAT

• Confirmed impact of WMA on mixture 

volumetrics and performance during 

design and AASHTO R 35 WMA Appendix

Expansion of NCHRP 9-43 Mix Design 

Study to Higher Absorption Mixtures
• NCHRP 20-07/ Task 311, Development 

of a Warm Mix Asphalt Technology 

Evaluation Program

– Myers McCarthy Consulting Engineers, LLC

– http://apps.trb.org/cmsfeed/TRBNetProjec

tDisplay.asp?ProjectID=3075

• AASHTO NTPEP Program for evaluating 

WMA technologies is in development 

www.ntpep.org
Where have we been?

2004-05

Number of WMA Best 

Practices Publications?

2013-14

Number of WMA Best 

Practices Publications?
Quality Improvement Series 125

3rd Edition

– Stockpile Moisture 

Management

– Burner Adjustments and 

Efficiency

– Aggregate Drying and 

Baghouse Temperatures

– Drum Slope and Flighting

– Combustion Air

– RAP usage

– Placement Changes
Where have we been?

2004-05

Number of AASHTO 

Standards on WMA?

2013-14

Number of AASHTO 

Standards on WMA?
Approved by AASHTO 

Subcommittee on 

Materials and published: 

Standard Specifications 

for Transportation 

Materials and Methods 

of Sampling and Testing 

(32nd Edition, 2012)

Appendix to AASHTO R35 with commentary “Special Mixture 

Design Considerations and Methods for WMA” 
Published 

as Appendix 

within 

AASHTO 

TP 79-13

AMPT Flow Number standardization
Where have we been?

2004-05

Number of WMA tons 

produced annually?

2013

Number of WMA tons 

produced annually?
Information Series 138

www.asphaltpavement.org/recycling

4th Annual Asphalt 

Pavement Industry 

Survey on Recycled 

Materials and 

Warm-Mix Asphalt 

Usage: 2009–2013 

(released Oct 2014)

Product of FHWA & NAPA Cooperative 

Agreement Contract
WMA Usage in HMA/WMA

Percentage of Total Mix Production in USA

0%

5%

10%

15%

20%

25%

30%

35%

2009 2010 2011 2012 2013

5% 11%

30%

16.8 

million 

tons

41.1 

million 

tons

19%

68.7 

million 

tons

86.7 

million 

tons

2006

WMA trials 

begin

Total asphalt mix:

(million tons)

24%

358.4 359.8 366.0 360.3 350.7

106.4

million 

tons
StateDOT WMA Usage in HMA/WMA

0%

5%

10%

15%

20%

25%

30%

35%

40%

2009 2010 2011 2012 2013

5% 12%

20%

Percentage of State Mix Production in USA

26%

Total asphalt mix:

(million tons) 169.2 172.5 175.3 179.1 160.1

8.6 

million 

tons

20.0 

million 

tons

34.6 

million 

tons

46.4 

million 

tons

2006

WMA trials 

begin

55.7

million 

tons

35%
WMA Usage by Technology

Percent of market for WMA production in USA

Organic Additive

Additive Foaming

Chemical Additive

Plant Foaming

0

20

40

60

80

100

2009 2010 2011 2012 2013
Where have we been?

2004-05

Number of WMA projects 

evaluated by FHWA?

2013-14

Number of WMA projects 

evaluated by FHWA?
• Mobile Asphalt Pavement Materials Lab

– Site Visit

– Field Data/Testing 

– Use/Demo Emerging Test Devices

– POC: Matthew Corrigan, P.E.

FHWA Field Support 

Mobile Asphalt Testing Trailer (MATT)
WMA Project Locations

VI

VT

RI

MA

NH

CT

NJ

DE

MD

DC

495

CA

AZ

CO

NM

TX

OK AR

LA

MO KY

AL GA

FL

VA

OH

MI

AK

MT

NV

Guam

ME

WA

OR

UT

KS

ID

WY

ND

SD

MN

NE

WI

IA

IL

IN

MS

TN

SC

NC

WV

PA

NY

PR

HI

Mobile Asphalt Testing Trailer Program 
CT

NJ

DE

MD

DC

78

495

CA

AZ

CO

NM

TX

OK AR

LA

MO KY

AL GA

FL

VA

OH

MI

VT AK

VI

MT

NV

ME

WA

OR

UT

KS

ID

WY

ND

SD

MN

NE

WI

IA

IL IN

MS

TN

SC

NC

WV

PA

NY MA

NH

PR

RI

90

70

35

10

37

30

40

820

75

5

75

55

94

MnROAD

495

70

65

465

15

90

87

81

86

95

10 295

VT

VI

MA

NH

RI

295

Interstate Highway WMA Usage

HI

Guam

This image cannot currently be displayed.

I-WMA

... circa 2011
Every Day Counts 28
Every Day Counts 29
Every Day Counts 30
“The collective efforts from highway agencies and industry 

partners to advance warm mix asphalt technologies as a 

standard practice has been tremendous.”

- U.S. DOT Federal Highway Administration

“[We] support the development and implementation of warmmix asphalt ... this will inevitably become the standard practice 

for asphalt mixture production.”

- Global Asphalt Pavement Alliance

“WMA technology provides an important tool to the pavement engineer ... 

designers and contractors alike now have a great opportunity to learn more about 

this promising practice which is revolutionizing the paving industry in North 

America.” 

-Pete Grass, President, Asphalt Institute 

“WMA is the future of flexible pavements in the U.S. ... lowering our 

production and paving temperatures promises improved energy 

consumption, operations, and quality.”

-Mike Acott, President, NAPA 
Th

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ank Discussion / Comments / Questions

FHWA’s Mobile Asphalt Testing Trailer

Office of Asset Management, Pavement, and Construction