S7 Going Beyond Foaming LTC2013

7/29/2019 S7 Going Beyond Foaming LTC2013

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Advanced Asphalt Technologies, LLC

Engineering Services for the Asphalt Industry

Warm Mix Asphalt:Going Beyond Foaming

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



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Outline

WMA Technologies

WMA Usage

Why Use a WMA Additive?

Summary


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WMA Technology Categories

1. Foaming Processesa. Foaming additives

b. Water injection systems

2. Organic additives3. Chemical additives

4. Hybrid Technologies

3

20 + WMA products marketed in theUnited States fit into one of thesecategories
http://www.warmmixasphalt.com/Default.aspxhttp://www.warmmixasphalt.com/Default.aspx


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Another WMA Resource

NAPA QualityImprovementPublication 125

3rd Edition


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For Each WMA TechnologyCategory

How does it work?

Temperature reduction

Potential concerns Example products and dosage

How do you use it?


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How Do Foaming ProcessesWork?

Water expands 1600times whenconverted to steam atatmospheric pressure

Water turns to steam Steam is encapsulated by

viscous asphalt binderproducing foam

The foamed asphaltoccupies greater volume

Improves coating andcompaction at lowertemperatures


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Ways to Produce Foamed AsphaltWater Injection

Nozzles on plant

1.25 to 2.0 % water by weightof AC

30 to 50 F reduction in mixingand compaction temperature

Additive

Synthetic zeolites

20 % water

Dose at 0.1 to 0.3 % by weightof mix

50 to 70F reduction in mixingand compaction temperature

7


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Concerns With FoamingProcesses

Will all binders foam?

Is all foam equal?

How long is the foam effective?

Can foamed asphalt be replicated in thelaboratory for mix design?

These issues are being investigated

in NCHRP Project 9-53, Propertiesof Foamed Asphalt for Warm MixAsphalt Applications


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Example Foaming Processes

Water Injection AESCO/Madsen

Astec

Gencor Herman Grant

Maxam

Meeker

Stansteel Tarmac

Terex

Additive Advera

Aspha-min


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How are Foaming ProcessesUsed

Water Injection Nozzle

Accurate control of AC

and water Plant controls

Additives Weighing system

Conveyor system

Pneumatic

Auger

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How Do Organic AdditivesWork?

Waxes or other

hydrocarbonmodifiers Improve lubrication

Reduce viscosity

Temperatures

50 to 70 F reduction inmixing and compactiontemperature


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Concerns With OrganicAdditives

Grade Changes? Some waxes increase

high PG and decrease

low PG Other organic additives

may decrease bothhigh and low PG

Grade binder afteraddition


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Example Organic Additives &Typical Dosage

Example Products Sasobit

SonneWarmix

ECOBIT

LEADCAP

BituTech WA1

WMA Dosage 0.5 to 1.5 % by weight

of binder

Modifer Dosage 2.0 to 4.0 % by weight

of binder


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How are Organic AdditivesAdded?

Mixing chamber at plant Additive directed into binder

Pneumatic

Auger

Binder supply at plant Tanks with agitation

In-line (molten)

At binder terminal Low shear

Preferred


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How Do Chemical AdditivesWork?

Surfactants (surface active agents) Reduce surface tension between polar aggregate and

non-polar asphalt

Improves wetting and reduces internal friction

Polar Aggregate

Non-Polar AsphaltSurfactant

Molecule

Polar Head

Non-Polar Tail

Temperatures

50 to 90 F reduction in

mixing and compactiontemperature


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Concerns With ChemicalAdditives

Effect on BinderGrade Grade binder with

additive

Aggregatemineralogy andeffectiveness Perform mix design with

additive


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Example Chemical Additives &Typical Dosage

Example Products Evotherm

CECABASE RT

QualiTherm Rediset LQ

LEA Lite

WMA Dosage 0.20 to 0.75 percent by

weight of binder


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How are Chemical AdditivesAdded?

Binder supply at plant

Tanks with agitation

In-line

At binder terminal Preferred


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Hybrid WMA Technologies

Combination of two ormore WMA technologies

Marketed Product

LEA

Created by producer toaddress weaknesses in

a technology Using a chemical additive with

a water injection system toimprove coating at lower

temperatures 19


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WMA Usage

NAPA AsphaltPavement MixProduction Survey

Survey of Producers Categories

DOT

Other Agency Commercial

Technologies

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Estimated Producer WMAUsage

5.4

13.2

0.0

10.0

20.0

2009 2010

Percent of Total Tonnage

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Estimated Producer WMA Usage(by Technology)

15.5% 19.6%1.5% 0.7%

82.7% 78.8%

0.29% 0.88%

2009 2010

Organic

Additive %

Plant Foaming

%

Additive

Foaming %

Chemical

Additive %

22


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Why Use an Additive?

Ease of Use

Lower EffectiveTemperature Range

Alter Binder Grade

Anti-Strip Properties


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Ease of Use

Greater Use ofWMA

WMA Additives at

Terminal Chemical

Organic

Reduces AdditiveCost

No Modifications


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Lower Temperature Range

-100

-90

-80-70

-60

-50

-40

-30

-20

-100

TemperatureRedu

ction,

F

HMA

Plant Foaming

Foaming & Organic Additives

Chemical Additives


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Alter Binder Grade

Some Organic Additives

Increase High Temperature Grade One to two grade levels

Reduce polymer loading

Decrease Low Temperature Grade High RAP mixtures


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Anti-Strip Properties

Some Chemical Additives

-50.0

-40.0

-30.0

-20.0

-10.0

0.0

10.0

Process A Process B Process C

AverageDiffe

renceinTSR,%

NCHRP 9-43 MixDesign Study


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Key Points

WMA Use is Increasing

Variety of Ways to Produce WMA

Plant Foaming is Most Popular But

Additives are Gaining Market Share Terminal Addition Decreases Cost and

Requires no Plant Modifications

Allow Production at Lower Temperatures Alter Binder Grade

Anti Strip Properties


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Questions/Discussion

Ramon Bonaquist

Advanced Asphalt Technologies, LLC108 Powers Court, Suite 100Sterling, VA 20166703-444-4200

[email protected]

Documents

S7 Going Beyond Foaming LTC2013