TRB 2004 Tack - IBEF - International Bitumen Emulsion ... · TRB 2004 tack.ppt rev 1/11/04 7 New Processes Ultrathin bonded wearing course – Tack: Polymer emulsion membrane –

©2004 Koch Materials Company. TRB 2004 tack.ppt rev 1/11/04

1

Look Ma, No MessLook Ma, Look Ma, No MessNo Mess

New Approaches to Tack Application

TRB, January 14, 2004

TopicsTopicsTopics

• The need for a tack coat– Strains, strength &

pavement life

• Improved tack technologies– Performance-related testing

• Measuring bond strength

– Materials & construction techniques

Tension

Stress Distribution

Soil Subgrade

Aggregate Base

Shear Transfer ?Pavement BehaviorPavement Pavement BehaviorBehavior

Compression

4 5/16 in.

DemonstrationDemonstrationDemonstrationTwo pieces of plywood - Unloaded

Top of “Pavement”

3 12/16 in.


9/16 in. deflection

DemonstrationDemonstrationDemonstrationTwo pieces of plywood - Loaded

DemonstrationDemonstrationDemonstration

Two bonded pieces of plywood - Loaded

With Nails

3 15/16 in.


6/16 in. deflection33% Less


2

What’s the Impact of Bonding Strength?What’s the Impact of What’s the Impact of Bonding Strength?Bonding Strength?

6 in. Aggregate Base (207 MPa)

4 in. Asphalt Concrete (3447 MPa)

4 in. Asphalt Concrete (2758 MPa)

Subgrade Soil (5 & 10 ksi)(34 & 68 MPa)

9,000 & 12,000 lbs(40 & 53 kN)

VaryingDegrees of Slip(0 to 1000) Between Layers

BISAR

More Slip -More Deflection at SubgradeMore Slip More Slip --More Deflection at SubgradeMore Deflection at Subgrade

0

5

10

15

20

25

30

35

40

45

0 200 400 600 800 1000

Relative Interface Slip

Deflection at top of

Subgrade (mils) 5 ksi SG; 12000 lbs

5 ksi SG; 9000 lbs10 ksi SG; 12000 lbs10 ksi SG; 9000 lbsBond

No Bond

Increasing Deflection

More Slip -More Vertical StressMore Slip More Slip --More Vertical StressMore Vertical Stress

0

1

2

3

4

5

6

7

8

9

10

0 200 400 600 800 1000Relative Interface Slip

Vertical Stress at

Top of Subgrade

(psi)5 ksi SG; 12000 lbs5 ksi SG; 9000 lbs10 ksi SG; 12000 lbs10 ksi SG; 9000 lbsBond

No Bond

Increasing Subgrade Stress

More Slip -More StrainMore Slip More Slip --More StrainMore Strain

0

200

400

600

800

1000

1200


Vertical Microstrain

at Top of Subgrade 5 ksi SG; 12000 lbs

5 ksi SG; 9000 lbs10 ksi SG; 12000 lbs10 ksi SG; 9000 lbsBond

No Bond

Increasing Strain at Subgrade

More Slip -Lower Deformation LifeMore Slip More Slip --Lower Deformation LifeLower Deformation Life

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

0 200 400 600 800 1000


Repetitions to

Deform-ation

Failure, NF

5 ksi SG; 12000 lbs5 ksi SG; 9000 lbs10 ksi SG; 12000 lbs10 ksi SG; 9000 lbs

BondNo

Bond

Decreasing Deformation Life

Failure Criteria:0.5” Rut

More Slip -More AC Tensile Strain at BottomMore Slip More Slip --More AC Tensile Strain at BottomMore AC Tensile Strain at Bottom

0

50

100

150

200

250

300

0 200 400 600 800 1000


Horizontal Microstrain at bottom of HMA


BondNo

Bond

Increasing AC Tensile Strain


3

More Slip -More Stress mid ACMore Slip More Slip --More Stress mid ACMore Stress mid AC

-40-20

020406080

100120140160

0 200 400 600 800 1000


Horizontal Stress -

Mid AC (PSI)


BondNo

Bond

Middle of AC - Not in Compression!

More Slip -More Tensile Strain mid ACMore Slip More Slip --More Tensile Strain mid ACMore Tensile Strain mid AC

0

50

100

150

200

250

300

350

0 200 400 600 800 1000


Horizontal Microstrain

Mid AC 5 ksi SG; 12000 lbs5 ksi SG; 9000 lbs10 ksi SG; 12000 lbs10 ksi SG; 9000 lbs

BondNo

Bond

Increasing Mid AC TENSILE Strain

More Slip -Lower Fatigue LifeMore Slip More Slip --Lower Fatigue LifeLower Fatigue Life

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

0 200 400 600 800 1000


Cycles to Fatigue

Failure, Nf


Bottom of AC

BondNo

Bond

Decreasing Fatigue Life

Failure Criteria:> 20% Cracking


0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

0 200 400 600 800 1000


Cycles to Fatigue

Failure, Nf


Middle of AC

BondNo

Bond


Failure Criteria> 20% Cracking



0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000


Cycles to Fatigue Failure,

Nf


All of AC

Top Lift Controls

BondNo

Bond



0500,000

1,000,0001,500,0002,000,0002,500,0003,000,0003,500,000


Cycles to

Fatigue Failure,

Nf


Bottom of AC

0500,000

1,000,000

1,500,0002,000,000

2,500,0003,000,000

3,500,000


Cycles to

Fatigue Failure,

Nf


Middle of AC

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

0 200 400 600 800 1000


Cycles to

Fatigue Failure,

Nf


All of AC

Top Lift Controls




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Horizontal Loads & Slip?Horizontal Loads & Slip?Horizontal Loads & Slip?

8.5” Base (1000 and 350 MPa)

2” Asphalt Concrete (3100 MPa)

1.5” Asphalt Concrete (3100 MPa)

Subgrade Soil (83 MPa)

Subgrade Soil (24.3 MPa)

- Romanoschi & Metcalf (TRB 2001)ABAQUS

17,600,00014,200AggregateLost Bond (Vert & Horiz)

31,600,000135,000AggregateFull Bond (Vert & Horiz)

33,100,000227,000AggregateFull Bond (Vertical only)

49,600,00028,000Soil Cement

Lost Bond (Vert & Horiz)

90,300,000355,000,000Soil Cement

Full Bond (Vert & Horiz)

95,300,000766,000,000Soil Cement

Full Bond(Vertical only)

Subgrade Deformation Life (reps)

Fatigue Life (Reps)Type of

BaseInterface Condition

What Affects Interface Bonding ?What Affects Interface What Affects Interface Bonding ?Bonding ?

• Temperature• Normal Stress• Application Rate• Type of Tack Material• Moisture• Aggregate interlock / milling

Improved tack technologies

Improved tack Improved tack technologiestechnologies

Performance-related testingMeasuring bond strength

Photo courtesy Florida DOT

Uzan, et. al.Direct Shear TestingUzan, et. al.Uzan, et. al.Direct Shear TestingDirect Shear Testing• 2.5 mm/min until failure• Pen 60-70• Tack Coats increase interface strength• Optimum App Rate : At 25oC, 0.22 gal/SY• Optimum App Rate : At 55oC, 0.11 gal/SY

Uzan, Livneh, and Eshed, AAPT 1978

Shear

International Bitumen Emulsion Federation

Worldwide Survey ResultsInternational Bitumen Emulsion Federation International Bitumen Emulsion Federation

Worldwide Survey ResultsWorldwide Survey Results• Design models: bond affects long-term

structural behavior• Most countries have liquid test specs• Only a few bond-strength performance

tests:– Austria: shear resistance test– Switzerland: SN 671 961 - tensile strength test– United Kingdom draft: torsion test

Chaignon, International Symposium on Asphalt Emulsion Technology, 1999

Swiss Standard SN 671 961:Shear modeSwiss Standard SN 671 961:Swiss Standard SN 671 961:Shear modeShear mode

• 150-mm core• Thin surfacing pushed off

substrate in shear mode• Minimum shear force

requirement :– 15 kN between thin

surfacing & binder course– 12 kN between binder

course & road base

Chaignon & Roffe, CTAA, 2001

Shear


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Austrian Method:Tensile modeAustrian Method:Austrian Method:Tensile modeTensile mode• Metal plates bonded to each end of field core • Core pulled apart in tensile mode• Specifications :

– < 1.5 n/mm² for polymer modified bond coat– < 1.0 n/mm² for non-polymer modified bond coat

• For each 0.1 N mm² below specifications severe fine imposed

Tensile


United Kingdom Draft Method:Torque modeUnited Kingdom Draft Method:United Kingdom Draft Method:Torque modeTorque mode• Lab or field test method using 100-mm

diameter core• Metal plate bonded to thin surfacing• Bond measured in torque mode• No specification set - record value only

Torque


LTRC Method Simple Shear TestingLTRC Method LTRC Method Simple Shear TestingSimple Shear Testing

Mohammad, TRB 2002

• 50 lb/min until failure• Residual: 0, 0.02, 0.05, 0.1, & 0.2 gal/SY• CRS-2P, SS-1, CSS-1, SS-1h• PG 64-22 & PG 76-22M• 25 & 55oC• Best : CRS-2P @ 0.02 gal/SY• Not as strong as single lift!

LTRC MethodSample PrepLTRC MethodLTRC MethodSample PrepSample Prep

Shear

Mohammad, TRB 2002

LTRC MethodTest ProcedureLTRC MethodLTRC MethodTest ProcedureTest Procedure

Shear Stress vs Displacement

Test Temperature 550C

0

10

20

30

40

50

60

0 2 4 6 8 10 12

Displacement (mm)

Sh

ear

Str

ess

(kp

a)

Mohammad, TRB 2002 Zhang; Courtesy of NCAT, 2003

NCAT MethodBond Strength Testing DeviceNCAT MethodNCAT MethodBond Strength Testing DeviceBond Strength Testing Device

Shear

Equipment includes:Environmental Chamber & MTS


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NCAT MethodLoading EquipmentNCAT MethodNCAT MethodLoading EquipmentLoading Equipment

Shear Loading Rate: 2”/minParameters: Shear strength

Shear deformationDissipated energy

Zhang; Courtesy of NCAT

Florida DOT MethodFlorida DOT Florida DOT MethodMethod

Sholar, Page, Musselman, Upshaw & Moseley, TRB 2004

Shear

Max LoadMax LoadMax LoadMax Load

Innovative Tack Technologies

Innovative Tack Innovative Tack TechnologiesTechnologies

New MaterialsNew Construction Methods

New MaterialsNew MaterialsNew Materials

• Polymer modified emulsions– CRS-2P, CSS-1P, SS-1P, etc.

• Rapid setting emulsions• Materials developed for special

processes

Colnet® Process 1. Interface additive

• To adjust surface tension & improve adhesion

2. Emulsion3. Breaking agent (Emulcol® process)

• For instantaneous cure• Vehicles will not disturb / track cured

emulsionColas

1.2.

3.

New ProcessesNew New ProcessesProcesses

Colnet DistributorColnet Colnet DistributorDistributor


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New ProcessesNew ProcessesNew ProcessesUltrathin bonded wearing course

– Tack: Polymer emulsion membrane

– Special machine applies both tack & PMAC

– Heavier membrane application; hot AC cures emulsion

– HMA applied without

damaging membrane

– No emulsion tracking

– Traffic in <15 minutes

Emulsion applicationHMA application

One-Pass PaverOneOne--Pass PaverPass Paver

One-pass PaverOneOne--pass Paverpass Paver

Existing Pavement

The emulsion membrane “wicks up” around the HMA aggregates

9-12 µmcoating on aggregates

5/8” minimum

Depth of Mix

The UTBWC ProcessThe UTBWC ProcessThe UTBWC Process

3/16”Emulsionmembrane

depth

The emulsion cures, bonding the mix & pavement

3/8” Nominal Ag Size

UTBWC One-Pass Machine -New applications

UTBWC OneUTBWC One--Pass Machine Pass Machine --New applicationsNew applications

• Florida DOT– 2003: 5 test sections on US 27

– UTBWC (FDOT bonded asphalt concrete friction course, BACFC), FDOT FC-5 (open graded GTR crumb rubber mix), with & without special machine

– Preliminary results: one-pass machine placed materials look best

Engineering News Record, 3/3/03

UTBWC One-Pass Machine -New applications

UTBWC OneUTBWC One--Pass Machine Pass Machine --New applicationsNew applications

• Arizona– 2003: UTBWC with asphalt-rubber

binder in HMA

• Texas DOT– 2004: Thin Bonded Permeable

Friction Course (TBPFC) over PCC


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Lessons learned:Lessons learned:Lessons learned:• Bonding between lifts essential for pavement

design life

• Performance tests & specifications needed for bond strength

• Stronger binders (PMA) & faster breaking emulsions can help

• Improved construction equipment – reduces tracking – allows heavier application of modified emulsions

Thank You.Thank You.Thank You.

. . . Longer Lasting Roads

Questions?Questions?Questions?

Documents

TRB 2004 Tack - IBEF - International Bitumen Emulsion ... · TRB 2004 tack.ppt rev 1/11/04 7 New Processes Ultrathin bonded wearing course – Tack: Polymer emulsion membrane –