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Warm Mix Asphalt

---

Flexible Pavements

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WMA - What is it? Plant mix asphalt produced at

lower temperatures whilemaintaining the workability

requ re o e success u yplaced

Warm Mix may be amisnomer - its still quite hot!

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How does it work? Although there are several different

WMA technologies and products, thebasic function is to change the binder

allow for sufficient coating of theaggregates, while maintaining good

workability and durability

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(. 23, 2011).

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50 ,

( , , % , ).

50 , ( , % )

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Northeast Asphalt User/ Producer Group

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()

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( 50 , 25 80 ( , ,% , ).

( 50 , ( , % ) .

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Classification by Temperature

5

6

7

8

9

/

0

1

2

3

0 100 200 300 400

,

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Brief History1997 German Bitumen Forum2000 Second Euroasphalt & Eurobitume Congress

(Barcelona)NAPA 2002 European Scan Tour Germany and Norway

connecting people

NAPA 2003-2008 Annual MeetingsWorld of Asphalt 20042005-2007 Many U.S. Field Trials

2007 FHWA/AASHTO Scan Tour2008 Permissive Specifications2010 FHWA Promotes as Focus Technology

77

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Potential Advantages ofLower TemperaturesLower fumes and emissions (~30-90%)

Lower energy consumption (~30%)

Lower plant wear

Early site opening

Cool weather paving

Compaction aid for stiff mixes

Cooler working conditions

Less Asphalt Absorption88

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National Warm Mix AsphaltTechnical Working Group

Members: FHWA, NAPA, SAPA,AASHTO, State DOTs, NCAT,Contractors, Labor, NIOSH

Mission: Evaluate and validate WMA andshare information

Purpose: Guidance for research andimplementation of WMA

99

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Jan 2007Jan 2007

10

IncludesIncludes

local, city,local, city,

and countyand county

projectsprojects

Mobile Asphalt Mixture Testing Laboratory (MAMTL)

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Jan 2008Jan 2008

11 Mobile Asphalt Mixture Testing Laboratory (MAMTL)

IncludesIncludes


and countyand county

projectsprojects

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Jan 2009Jan 2009


IncludesIncludes


and countyand countyprojectsprojects

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Jan 2010Jan 2010


IncludesIncludes


and countyand countyprojectsprojects

Over 140 documented

WMA projects

constructed to date.

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How Many WMA Technologies are

Available in the U.S.?

Currently Twenty One (21)Technologies Marketed and

Available in the U.S.

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There are three categories (types)

of WMA Technologies:

Chemical Organic

Foaming

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1616

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Typical Mixing Temperature Ranges

HMA

Plant Foaming

Water CarriersChemical

Water Carriers

(Non-Chemical)

Chemical Additives

RheologicalModifiers

200 220 240 260 280 300 320 340

Mixing Temperature (F)

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Plant Foaming Techniques

Small amount of moisture introduced tobinder ahead of mixing

Expansion allows for coating at lowertemperatures

1818

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Material Foaming Processes

Use water-bearing zeolite which releasesmoisture at high temperatures.

Use a carefully controlled amount ofmoisture in sand added to hot coarseaggregate and asphalt.

1919

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Plant modifications for foaming

Astec Double Barrel Green

Gencor Green Machine

Maxam AQUABlack Terex Warm Mix AsphaltStanSteel Accu-Shear

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Plant Foaming Process

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Foaming

systems addtoo much

mix

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300 ton of mix x 6.0% ac

18 liquid ton x ~1.25 (to

2.5)% Equals 450 (900) lbs. water

Or54 (108) gallons

Allowable moisture incompleted mix = 88 - 90 -

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2011

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SR 3019 sec03M Tioga Co

Placed 2,588 tons

9.5mm scratch and12,243 tons of 19mmLeveling as a finalcourse

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30

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Astec

Gencor Terex

Sasobit Evotherm

Meeker Stansteel

Eastern Ind

Rediset WMX LEA

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Timeline of Warm-Mix in PA

11/30/07Letter toDistricts

soliciting WMApilot projects

12/17/08SOL 421-08-09

PennDOT expands

WMA use to non-federal aid projects

6/17/09SOL 423-09-01

WMA expanded to

federal aid projectswith work plan

6/29/10SOL 423-10-01

Internal Target of

20% Warm mixasphalt for 2010

www.dot.state.pa.us

April 2008First WMA

pilotprojects let

3 Pilotprojects

constructed

20092008 2010

15 WMA projectsconstructed

2011

23 WMA projectsconstructed + additionalDept. force paving and

gas well pavingSlide provided by Garth Bridenbaugh, P. E.

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/ .

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3012

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414

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Issues / Concerns

Long-term durability

High RAP usage

Construction season extension

Issues / Concerns

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Issues / Concerns(Continued)

No formalized mix designprocedure

standard guidelines

No formalized process to handle

evaluation and approval of newtechnologies

Answers to Concerns

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Answers to Concerns

Evaluation of performance(Europe, Test Tracks, APT)

NCHRP 9-43 Ramon Bonaquist

W.O. #32 Penn State University

Acceptance protocols for new

technologies

NEAUPG WMA Task Force QCP

PAPA Warm Mix Subcommittee

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Goal:Develop and promote protocols of


es ava a e ec no ogy anpractices for specifying and

advancing the use of Warm Mix

Asphalt to promote the success ofWMA for all stakeholders.

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Action Items:

Distribute benefits brochure

,

contractors and owners

Synthesize long-term performance data

Develop acceptance protocols Develop mix design/production QC/QA

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Why we need Warm Mix

Better air quality Better energy efficiency

Better performance

Better compaction

Better working conditions

6363

States that have or will havePermissive WMA Specifications

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p

OH

MI

VTAK

MT

NV

ME

WA

OR

IDWY

ND

SD

MN

NE

WI

IA

IL IN

PA

NY

CT

NJ

MA

NH

RI

CA

AZ

CO

NM

TX

OKAR

LA

MOKY

ALGA

FL

VA

VI

Guam

KS

MS

TN

SC

NC

MD

DC

PR

HI

6464

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warm mix

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