NCHRP 9-50 ETF Chip Seal Final 5-6-16 · 5.Laboratory testing and dataanalysis ... Dynamic Shear,T315 G*/SinδMinimum: 0.65 kPa Test Temperature @10 rad/s,°C ... BMT 70 22,73 22

5/27/2016

1

Implementation of the Surface Performance-Grade (SPG)

Specification in Texas

TxDOT Implementation Project 5-6616

D. Hazlett, J. Peterson

A. Epps Martin, E. Arambula, T. Freeman,

N. Chang, S. Theeda, J. Epps

Emulsion Task Force

May 5-6, 2016

OUTLINE

• Motivation & Objective• Development of SPG• Validation of SPG• Current SPG Specification• SPG Binder Selection• Industry Interaction• Effects of SPG• Challenges of SPG• Next Steps

MOTIVATION & OBJECTIVE• Increase performance and reduce cost

• Improve chip seal/seal coat binder spec & selection– performance-related tests– @ temperatures that cover entire in service range for

specific climate– consider aging during critical 1st year– reduce variability in grades– possibly adjust due to traffic

• Implement SPG in TX in 4 year, staged effort– Replace Seal Coat Binder Tier Selection Table & Item 300 Seal Coat Binder Properties in service

DEVELOPMENT OF SPG

• TxDOT Research Project 0-1710 (45 field sections)• TxDOT Research Project 0-6616 (30 field sections)• NCHRP Research Project 14-17 (3 field sections)• SPG specification for chip seal/seal coat binders in service

– Method B for emulsion residue recovery– + shear strain sweep with new threshold– X m-value– MSCR not added

• SPG specification part of system to be used with–design guidelines–quality control procedures–construction techniques

VALIDATION OF SPG• TxDOT Implementation Project 5‐6616

• 29 Binders, 19 Sections built in 2013

– 89% Lab:Field Correlation @ THIGH– 68% Lab:Field Correlation @ TLOW @ 2yrs

– Freq. Sweep – BBR: Poor correlation

• 16 Binders, 24 Sections built in 2014

– 71% Lab:Field Correlation @ THIGH– 75% Lab:Field Correlation @ TLOW

• + @ THIGH threshold for Useful T Interval (UTI)>890C

• X shear strain sweep @ TINT

Chip Seal Validation Process

1. SPG requirement grade determination

2. Chip seal binder collection

3. Highway section selection

4. Field performance monitoring

5. Laboratory testing and data analysis

with PP 72 Method B RecoveryFP > 230 by T 48 RV < 0.15 Pa*s @ 205°C by T 316

Performance GradeSPG 67 SPG 70 SPG 73

‐13 ‐16 ‐19 ‐22 ‐25 ‐16 ‐19 ‐22 ‐25 ‐16 ‐19 ‐22 ‐25

Average 7‐day Maximum Surface Pavement Design Temperature, °C

<67 <70 <73

Minimum Surface Pavement Design Temperature, °C >‐13 >‐16 >‐19 >‐22 >‐25 >‐16 >‐19 >‐22 >‐25 >‐16 >‐19 >‐22 >‐25

Original BinderDynamic Shear, T315 G*/SinδMinimum: 0.65 kPaTest Temperature @10 rad/s, °C

67 70 73

Phase angle (δ), Max, @ temp. where G*/sin δ = 0.65 kPa – – – 80 80 – 80 80 80 80 80 80 80

Pressure Aging Vessel (PAV) Residue (AASHTO PP1)PAV Aging Temperature, °C 100 100 100

Creep Stiffness, T 313S, Maximum: 500 MPaTest Temperature @ 8s, °C

‐13 ‐16 ‐19 ‐22 ‐25 ‐16 ‐19 ‐22 ‐25 ‐16 ‐19 ‐22 ‐25

CURRENT SPG SPECIFICATION

5/27/2016

2

with AASHTO PP 72 Method B RecoveryFP > 230 by T 48 RV < 0.15 Pa*s @ 205°C by T 316

Performance GradeSPG 70

‐16 ‐19 ‐22 ‐25

Avg 7‐day Max Surface Pavement T, °C <70

Min Surface Pavement T, °C >‐16 >‐19 >‐22 >‐25


• Method B for Emulsion Residue Recovery

– Thin Film on Silicone Mat

– 60 °C for 6 hrs


‐16 ‐19 ‐22 ‐25

<70

>‐16 >‐19 >‐22 >‐25

Original Binder

G*/Sinδ > 0.65 kPa by T 315Test Temperature @ 10rad/s, °C

70

Phase angle (δ), Max, @ temp. where

G*/sin δ = 0.65 kPa‐ 80 80 80




‐16 ‐19 ‐22 ‐25

<70

>‐16 >‐19 >‐22 >‐25

PAV Residue

S < 500 MPa by T 313Test Temperature @ 8s, °C

‐16 ‐19 ‐22 ‐25

PG vs. SPG THIGH = average 7‐day max high Tpvmnt @ 20mm

1

±6⁰C @ THIGH& TLOW;

‐10 ⁰C for TLOW grade2

DSR, T315, @THIGH (RTFO) and @TINT (PAV)

3

Creep Stiffness, T 313,

S and m‐value @ 60s4

No specification on

δ at THIGH5

1THIGH = average 7‐day max high Tpvmnt @ surface

2±3⁰C@ THIGH& TLOW;

No ‐10 ⁰C for TLOW grade

3No specification on RTFO aged binder & No TINT

4Creep Stiffness, T 313, S @ 8s; no m‐value

5 < 80 @ continuous THIGHfor UTI > 89

SPG BINDER SELECTION1. Determine

Climate‐Based SPG Grade by Map or Spreadsheet

2. Adjust SPG Grade for Traffic, Flexibility, & Modification

3. Compare with SPG Grades of Traditional Materials

4. Select Final SPG Grade

SPG Climate‐Based Requirement Map

SPG BINDER SELECTION

1. Determine Climate‐Based SPG Grade by Map or Spreadsheet

5/27/2016

3


1. Determine Climate‐Based SPG Grade by Map or Spreadsheet


Increase THIGH for High Traffic

• AADT < 1000 SPG 64‐25

• 1000 < AADT < 5000 SPG 67‐25

• AADT > 5000 SPG 70‐25

Decrease TLOW for Weak Pavement Structure

Increase UTI > 890C to ensure polymer modification if desired

Climate‐Based Requirement

Moderate Traffic

High Traffic

2. Adjust SPG Grade for Traffic, Flexibility, & Modification

SPG GRADES FOR TRADITIONAL BINDERS

Traditional Binder (2013/ 2014)

District SPG Grades

AC10 AMA 61‐19

SJT 61‐13

SAT 64‐25

AC10 – 2TR AMR, BWD, WAC, WFS

67‐22

LBB 64‐16, 67‐16

ODA 67‐16

SJT 67‐19

AC 15P CRP 73‐19

LUF 67‐25

PHR 70‐31

SAT 70‐28, 73‐31

WAC 67‐22

Traditional Binder (2013/ 2014)

District SPG Grades

AC20 – 5TR AMA 73‐19

ATL 70‐22, 70‐25

LBB 73‐22, 76‐19, 70‐19

LUF, TYL 70‐22

SJT 76‐19

SAT 73‐25, 76‐28

WAC 73‐22

BRY, BMT, PAR

67‐22

CRS 2 CRP 67‐19

CRS 2P LFK 73‐19

HOU 73‐22

BMT 70‐22, 73‐22

SPG GRADES FOR TRADITIONAL BINDERS

0

1

2

3

4

5

6

7

8

9

10

61‐13 61‐19 64‐16 64‐25 67‐16 67‐19 67‐22 67‐25 70‐19 70‐22 70‐25 70‐28 70‐31 73‐19 73‐22 73‐25 73‐31 76‐19 76‐28 79‐25

District Environmental Requirement

Traditional Binder (2013/2014)

Selected SPG Grade

ABL 67‐19 ‐‐‐‐ 73‐19

AMA 64‐25, 67‐22 AC20‐5TR: 73‐19AC10‐2TR: 67‐22AC10: 61‐19

64‐2570‐25

AUS 67‐16, 67‐13 ‐‐‐‐ 70‐1973‐16

BWD 67‐19, 67‐16 AC10‐2TR: 67‐22 67‐22CRS‐2(67‐22)

CRP 67‐13 AC15P: 70‐28, 73‐28CRS‐2: 67‐19

70‐19

PAR 67‐19 AC20‐5TR: 67‐22 73‐19

PHR 67‐13 AC15P: 70‐31 73‐1670‐19 (Tier II)

2016 SPG BINDER SELECTION

3. Compare with SPG Grades of Traditional Materials

4. Select Final SPG Grade

INDUSTRY INTERACTION• Technical Briefings w/TxDOT & Industry

– AGC of TX, TxAPA

– WASHTO

– ETF

– Suppliers, AEMA/ARRA/ISSA

• SPG Round Robin Testing Program– AC‐15P & CRS‐2P

– Guidelines with & without Reheating for THIGH– 5 suppliers + TxDOT + TTI

5/27/2016

4

SPG ROUND ROBIN

67

68

67

75

70

69

72

‐27

‐27

‐26

‐26

‐26

‐27

‐26

‐40 ‐20 0 20 40 60 80 100

Supplier A(67‐25)

Supplier B(67‐25)

Supplier C(67‐25)

Supplier D(73‐25)

Supplier E(70‐25)

Supplier F(67‐25)

Supplier G(70‐25)

AC 15P ‐ Round Robin Results

Cont. Low Temp.

Cont. High Temp.

SPG ROUND ROBIN

77

74

80

72

76

78

75

77

74

80

71

74

78

75

0 10 20 30 40 50 60 70 80 90

Supplier A(67‐25)

Supplier B(67‐25)

Supplier C(67‐25)

Supplier D(73‐25)

Supplier E(67‐25)

Supplier F(67‐25)

Supplier G(70‐25)

Phase Angles for AC 15P

Cont. δ @ G*/sin δ = 0.65 kPa

δ @ Grading Temp.

(70‐25)

SPG ROUND ROBIN

69

65

66

67

68

66

68

66

67

66

68

67

‐27

‐26

‐25

‐25

‐26

‐25

‐40 ‐20 0 20 40 60 80

Supplier A(Hot: 67‐25)(Cold: 67‐25)

Supplier B(Hot: 64‐25)(Cold: 64‐25)

Supplier D(Hot: 67‐25)(Cold: 64‐25)

Supplier E(Hot: 64‐25)(Cold: 67‐25)

Supplier F(Hot: 67‐25)(Cold: 67‐25)

Supplier G(Hot: 67‐25)(Cold: 64‐25)

CRS ‐ 2P Results: With & without reheating

Cont. Low Temp.

Cont. High Temp. (with reheating)

Cont. High Temp (without reheating)

SPG ROUND ROBIN

80

81

82

83

83

82

80

80

82

83

83

81

0 20 40 60 80

Supplier A(67‐25)

Supplier B(64‐25)

Supplier D(64‐25)

Supplier E(64‐25)

Supplier F(67‐25)

Supplier G(64‐25)

Phase Angles for CRS 2P (Hot)Cont. δ @ G*/sin δ = 0.65 kPa with reheating

δ @ Grading Temp

81

83

82

82

83

82

81

83

83

82

82

82

0 20 40 60 80

Supplier A(67‐25)

Supplier B(64‐25)

Supplier D(64‐25)

Supplier E(64‐25)

Supplier F(67‐25)

Supplier G(64‐25)

Phase Angles for CRS 2P (Cold)Cont. δ @ G*/sin δ = 0.65 kPa without reheatingδ @ Grading Temp

(70‐25)

(70‐25)

ROUND ROBIN RESULTS• All results were rounded to the nearest 10C due to the DSR &

BBR precision & bias.

• For both materials, there was Very Good agreement @ TLOW.

• For both materials, there was Good agreement @ THIGH with the CRS‐2P @ the threshold.

• There was no difference (within 10C) in the two procedures (with and without reheating) considering DSR & BBR precision & bias.

• No changes to the phase angle requirement for UTI >= 89 are proposed with the majority showing no difference (within 10) between the value @ the threshold & that @ the grading T.

ROUND ROBIN RESULTS

• Considering DSR precision & bias, the 30C SPG increment is too tight @ THIGH.

• Considering BBR precision & bias, the 30C SPG increment is ok @ TLOW.

• Thus 60C increments are proposed @ THIGH, and 30C or

60C increments are proposed @ TLOW.

• Offset SPG temperatures (from those for PG) are proposed to capture the statewide 670C climate in TX and make the SPG grades unique and fewer in number and possibly decrease the adjustments that are needed from the climate‐based requirement.

5/27/2016

5

60C SPG GRADES FOR TRADITIONAL BINDERS

0

2

4

6

8

10

12

14

16

18

61‐13 61‐19 61‐25 67‐13 67‐19 67‐25 67‐31 73‐19 73‐25 73‐31 79‐25

Freq

uen

cy

SPG Grades

Frequency of SPG Grades for Traditional Binders

Revised SPG Climate‐Based Requirement

Map

SPG BINDER SELECTION w/60C increments @ THIGH

Revised SPG Climate‐Based Requirement

Map

SPG BINDER SELECTION w/60C increments @ THIGH & TLOW EFFECTS of SPG

• Each material meets a grade• Tighter spec that ensures less variability• More open competition• Higher performing binders by current spec still higher performing binders

• Current Tier Selection Table replaced by SPG Binder Selection guidelines– Retain selection of material type (hot applied or emulsion)– Retain allowance for wider SPG grade with payment at narrower grade

– Retain season restrictions by district

CHALLENGES of SPG

• CHANGE

• New recovery procedure

• Requires BBR

• No property @ TINT

• Some differences between PG & SPG

NEXT STEPS• Continue Validating Thresholds

– 1 Binder, 10 Sections in 1 District built in 2015

– 11 Binders, 20 Sections in 7 Districts to be built in 2016

• Continue Gathering Industry Input

• Modify SPG Specification

• Submit to AASHTO & ASTM & Respond

• Document & Market with TxDOT, TTI Communications

• Adjust to CHANGE in Formulations

5/27/2016

6

ContactAmy Epps Martin, Ph.D., P.E.Professor and A.P. & Florence Wiley Faculty FellowZachry Department of Civil EngineeringResearch Engineer (TTI)310D CE/TTI3136 TAMUCollege Station, TX 77843‐3136(979)862‐1750a‐[email protected]

6/8/2016

1

Emulsion PG (EPG) Specification for Chip SealsNCHRP Project 09-50

Presented at the Emulsion Task Force Meeting

Denver, CO

May 6, 2016

Y. Richard Kim, Cassie Castorena, Javon Adams

NC State University

EPG Framework

� Materials are considered in two phases:

• Fresh emulsion - Constructability

• Residue - Performance

� Define critical failure mechanisms for different

temperatures and propose test methods to address

those specific mechanisms

� Retain designation for emulsifier type and set rate

� Replace 1 vs. 2 viscosity designation with Emulsion

Performance Grade (EPG)

6/8/2016

2

EPG Framework – Cont’d

� Introduce climatic considerations

• Test temperatures selected based on climate

• Spec. limits independent of test temperature

� Introduce traffic considerations

• Different spec limits for different traffic levels

• Low –> 0-500 AADT

• Medium –> 501-2500 AADT

• High –> 2500 - 20000 AADT

� Example grade: CRS-EPG64-22M

EPG Specification Tests

MSCR

Fresh EmulsionResidue

Min. Jnr (TH)Fracture Toughness, KIC

(TL)

SENB

RVSprayability,

mixability,

drain-out,

storage stability

(Supplier Spec)

Low Temp. Aggregate

Loss

Bleeding & Rutting

Workability & Stability

6/8/2016

3

Tested Chip Seal Emulsions

Chip

Sea

l

C-CRS-2 (A)

C-CRS-2P (A)

C-HFRS-2P (A)

C-CRS-1-(B)

C-CRS-1H-(B)

C-RS-1-(B)

C-CRS-2P/L (C)

C-HFRS-2 (C)

C-CRS-2 (E)

C-CRS-2P (E)

C-CRS-2P-HP(E)

C-CRS-2 (F)

C-CRS-2L (F)

C-CRS-2 (NC)

C-CRS-2L (NC)

PP-C-CRS-2 (A)

PP-C-HFRS-2 (C)

PP- C-CRS-2P (E)

18 Emulsions Tested

MMLS3 vs. VialitAggregate Evaluation

0

5

10

15

20

25

0 5 10 15 20 25

Ag

gre

gate

Lo

ss b

y M

ML

S3

Aggregate Loss by Vialit Test

GraniteGranite

LightweightLightweight

6/8/2016

4

MMLS3 vs. VialitBinder Evaluation

0

5

10

15

20

25

0 5 10 15 20 25

Ag

gre

gate

Lo

ss b

y M

ML

S3


Polymer-Modified

Emulsions

Polymer-Modified

Emulsions

Unmodified

Emulsions

Unmodified

Emulsions

Sensitivity of Vialit Test

0

5

10

15

20

25

0 5 10 15 20 25 30 35 40

Via

lit

% A

gg

reg

ate

Lo

ss

Temperature (°C)

PP-CRS-2-A

CRS-2-A

CRS-2-NC

CRS-2-F

CRS-2-E

CRS-2L-NC

CRS-2L-F

CRS-2P-E

CRS-2P-HP-E

CRS-2P/L-C

CRS-2P-A

6/8/2016

5

Fresh Emulsion

Storage StabilityModified ASTM D6930

� Rotational Viscometer to measure:

• Separation Ratio (Rs): ηTop/ηBottom

� Stability under sedimentation, creaming

• Stability Ratio (Rd): ηMixed/ηReference

� Potential for flocculation, coagulation

Top

Bottom

Mixed

Samples stored at high

temperature

6/8/2016

6

Sprayability and Drain-outModified AASHTO TP48

� Rotational Viscometer

• 3-step-shear test: Vary the shear rate to simulate

spraying and drain-out potential

Sprayability

Drain-out

Tank to SprayerTank to Sprayer SprayingSpraying In-

Service

In-

Service

Fresh Emulsion EPG Spec.

EPG TestTemperature

(°C)

Performance

ParameterEPG Limit

Rotational

Viscometer60

Separation

Ratio0.5 to 1.5

Stability Ratio Max 2

Sprayability Max 400 cP

Drainout Min 50 cP

6/8/2016

7

Emulsion Residue

Residue Recovery

� ASTM D7497 Method B

• Best represents field aging conditions

• Repeatable

• Provides sufficient residue for testing

Oven @ 60 C

Cure for 6 hours

Thin film of emulsion

spread on silicone mat

6/8/2016

8

Two-Step Approach

� Use of laboratory results to develop the

specification limits

� Calibration/validation using field results

• Short term validation – Done

• Long term validation – Future study

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4

% B

leed

ing

Jnr (in kPa-1)

Unmodified 46C

Modified 46C

Unmodified 52C

Modified 52C

Unmodified 58C

Modified 58C

Underlying Concept for EPG System

Mix

ture

Pe

rfo

rma

nce

Mix

ture

Pe

rfo

rma

nce

Binder PropertyBinder Property

HypothesisThere exists a relationship between binder

properties and performance of chip seals that

applies to all emulsions regardless of

modification.

Mixture Performance

Upper Limit

Binder Property

Upper Limit

6/8/2016

9

Field Material Rate Variability

0.0

0.1

0.2

0.3

0.4

0.5

1 2 3 11 12 7 8 9 13 14 15

EA

R

Section Number

Measured Target

0

5

10

15

20

25

1 2 3 11 12 7 8 9 13 14 15

AA

R

Section Number

Measured Target

0%

5%

10%

15%

20%

25%

30%

35%

1 2 3 11 12 7 8 9 13 14 15

Ab

solu

te V

alu

e o

f %

Diffe

rence

fro

m T

arg

et A

AR

Section Number

0%

10%

20%

30%

40%

50%

60%

70%

1 2 3 11 12 7 8 9 13 14 15

Asb

olu

te V

alu

e o

f %

Diffe

rence

fro

m T

arg

et E

AR

Section Number

Granite Lightweight

Gradation AGradation A Gradation BGradation B

Gradation CGradation CGranite

78M

Granite

78M

0

20

40

60

80

100

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

Ble

ed

ing

(%

)

EAR (gal/sq yd)

0

20

40

60

80

100

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

Ble

ed

ing

(%

)

EAR (gal/sq yd)

0

20

40

60

80

100

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

Ble

ed

ing

(%

)

EAR (gal/sq yd)

6/8/2016

10

EPG Summary Table for Residue

Temperature Test MethodMeasured

Parameter

High PG MSCR Jnr

Intermediate PGVialit Compatibility Check in Mix

Design Phase

Low PG SENBFracture

Toughness, KIC

High Temperature

� Spec Limit: MSCR Jnr at 3.2 kPa

• Current HMA PG spec uses MSCR at high temperature

• HMA PG spec uses G*/sin δ as a consistency check on

unaged asphalt

• G*/sin δ is a linear viscoelastic property whereas

bleeding occurs in nonlinear range.

6/8/2016

11

MSCR Jnr as a Bleeding Indicator

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4

% B

leed

ing

Jnr (in kPa-1)

Unmodified 46C

Modified 46C

Unmodified 52C

Modified 52C

Unmodified 58C

Modified 58C

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9 10 11 12

% B

leed

ing

Jnr (in kPa-1)

High Traffic

Medium Traffic

Low Traffic

MSCR Jnr Limit Determination

Max. Jnr

for High

Traffic

Max. Jnr

for Med.

Traffic

Max. Jnr

for Low

Traffic

6/8/2016

12

High Temperature EPG Spec.

EPG TestPerformance

Parameter

Traffic

LevelEPG Limit (kPa)

MSCR

Non-

Recoverable

Creep

Compliance (Jnr)

Low Jnr < 3.25

Medium 3.25 < Jnr < 5.25

High 5.25 < Jnr < 8

Intermediate Temperature

� Raveling largely driven by the compatibility

between the emulsion and aggregate, which

cannot be assessed in an emulsion purchase

specification using binder alone.

� The EPG spec. recommends that the aggregate-

binder compatibility check be conducted during

the mix design phase using the Vialit test.

� This compatibility check during mix design

measures early raveling, late raveling, and wet

raveling potential of the chip seal.

6/8/2016

13

Intermediate Temperature

� Testing residue binder directly would not yield

adequate information on raveling performance

of chip seals in the field.

• Emulsifier-aggregate interaction during curing

significantly affects the raveling performance of chip

seals.

• Emulsifier adsorption on the aggregate surface

neutralizes the charge and influences bond strength.

Bond Strength

� Measured using the Bitumen Bond Strength

(BBS) Test

Pressure Regulator

Pressure Ring Load Direction

6/8/2016

14

ROR vs. COR Compatibility

� Residue on the rock (ROR)

• Recover residue

• Apply residue to aggregate using

heated stub

• Condition for 24 hours prior to

testing

� Cure on the rock (COR)

• Emulsion poured onto substrate

using template and allowed to cure

• Heated stub affixed to residue and

conditioned for 1 hour prior to

testing

Effects of BBS Sample Fabrication

y = -0.0111x + 24.641

R² = 0.7493

0

5

10

15

20

25

0 500 1000 1500

% A

gg

reg

ate

Lo

ss

BBS (kPa)

non-PME at 15C

PME at 15C

non-PME at 25C

PME at 25C

CORCOR

0

5

10

15

20

25

0 500 1000 1500 2000

% A

gg

reg

ate

Lo

ss

BBS (kPa)

Unmodified Emulsions

Modified Emulsions

RORROR

• No universal relationship between unmodified and modified emulsions

using ROR method whereas COR method shows the existence of such a

relationship.

• COR yields much lower bond strengths than ROR.

• No universal relationship between unmodified and modified emulsions

using ROR method whereas COR method shows the existence of such a

relationship.

• COR yields much lower bond strengths than ROR.

6/8/2016

15

Evaluation of Strain Sweep Results

� Lack of clear delineation between modified and

unmodified residue results

0

2

4

6

8

10

12

16°C 22°C 28°C

Str

ain

at

0.8

x|G

*|i

CRS-2 A

CRS-2 E

CRS-2L A

CRS-2P HP E

CRS-2P E

Relationship between Residue Strain Sweep and Vialit Results

0

5

10

15

20

0 4 8 12

Ag

gre

ga

te L

os

s (

%)

Strain at 0.8x|G*|i

CRS-2 A

CRS-2 E

CRS-2L A

CRS-2P HP E

CRS-2P E

Unmodified Unmodified

Modified Modified

6/8/2016

16

Low Temperature

� Raveling is the critical distress at low temperatures.

� Raveling at low temperature is due to cohesive fracture

within the binder.

� EPG specification recommends measuring fracture

toughness (KIC) using the Single Edge Notched Beam

(SENB) test.

Stiffness (S) and Relaxation Modulus (m) vs. % Aggregate Loss

0

5

10

15

20

25

30

35

40

45

0 50 100 150 200 250 300

Ag

gre

gate

Lo

ss

(%

) at

Via

lit

Te

st

Tem

pe

ratu

re:

-16°C

, -2

2°C

, a

nd

-2

8°C

S(60) (MPa) at BBR Test Temperature: -6°C, -12°C, and -18°C

C-CRS-2-AE C-CRS-2-FC-CRS-2L-C C-CRS-2P-AC-CRS-2L-AE C-CRS-2L-F

0

5

10

15

20

25

30

35

40

45

0.20 0.25 0.30 0.35 0.40 0.45 0.50

Ag

gre

ga

te L

os

s (

%)

at

Via

lit

Te

st

Te

mp

era

ture

: -1

6°C

, -2

2°C

, a

nd

-2

8°C

m (60) (MPa) atBBR Test Temperature: -6°C, -12°C, and -18°C


6/8/2016

17

y = 27.187x-0.463

R² = 0.5235

0

5

10

15

20

25

30

35

40

45

0 1 2 3 4 5

Ag

gre

ga

te L

os

s (

%)

Fracture Toughness,KIC (MPa√mm)


(b)

SENB Fracture Toughness vs. Agg. Loss

Minimum

EPG Limit

Low Temperature EPG Spec.

EPG TestPerformance

Parameter

Traffic

Level

Temp.

RangeEPG Limit

Single

Edge

Notched

Beam

Fracture

Toughness

(KIC)

All

Traffic

Levels

LowKIC > 1

MPa√mm

6/8/2016

18

Aging

� EPG testing occurs on unaged binders for the

following reasons:

• Low temperature raveling occurs during the first

winter prior to significant aging.

• Aging does not negatively contribute to bleeding

potential in a chip seal.

Fresh Emulsion Specification

6/8/2016

19

Binder SpecificationResistance to Bleeding & Rutting

Binder SpecificationResistance to Low Temperature Raveling

6/8/2016

20

Questions?

Binder Parameter vs. Field Performance Correlation

Source: Data shown was extracted from Vijaykumar et al. (2013) and graphed.

� A poor correlation exists between the binder test parameters shown and the SCI

score.

� Without accounting for critical factors such as emulsion application rate, using

the SCI of field sections alone does not provide conclusive results.

0

20

40

60

80

100

120

0 0.5 1 1.5 2 2.5 3

SC

I (b

lee

din

g)

G*/sin delta

0

20

40

60

80

100

120

0 1 2 3 4

SC

I (b

lee

din

g)

Jnr @ 3.2 kPa

6/8/2016

21


0

5

10

15

20

25

0 5 10 15 20 25

Ag

gre

gate

Lo

ss b

y M

ML

S3


GraniteGranite



0

5

10

15

20

25

0 5 10 15 20 25

Ag

gre

gate

Lo

ss b

y M

ML

S3


Polymer-Modified

Emulsions

Polymer-Modified

Emulsions

Unmodified

Emulsions

Unmodified

Emulsions

6/8/2016

1

Footer Text Date

STATUS OF THE

SPG BINDER

SPECIFICATION

IMPLEMENTATION

Status Report and Future Planning

June 2015

Footer Text Date

DEVELOPMENT OF A PERFORMANCE-BASED SEAL

COAT BINDER SPECIFICATION: A Long-term Goal

2

�TxDOT Research Project 1367, CTR (1993-1996)

�TxDOT Research Project 0-1710, TTI (1999-2003)

�TxDOT Research Project 0-6616, TTI (2010-2012)

�TxDOT Implementation Project 5-6616, TTI (2014-2017?)

23 Years and Counting

6/8/2016

2

Footer Text Date

State of Current Chip Seal Binder Specifications

� AC specifications:

– Viscosity, Penetration, Short-term aging to simulate HMA plant (not seen in

these binders)

– A few binders have some PG-type tests added

– Elastic Recovery/Ductility for polymer

A very few polymer modified AC binders have a hybrid AC/PG type spec to

include DSR and/or BBR at one specific temperature – not based on

climate. (AC-15P, AC20XP and AC-10-2TR, AC-20-5TR).

� Emulsion specifications:

– Residue Penetration test

– Some materials have viscosity, and ductility (for polymer).

No emulsion materials have PG-type requirements.

3

Footer Text Date

Current SPG Projects to be Built This Summer

�11 Contracts Let and will be built this

summer

�7 TxDOT Districts

�Projects total $58.6M

�Binder Pay Items Total $20.8M

�8 Grades

4

6/8/2016

3

Footer Text Date 5

Questions?

6/8/2016

Asphalt Binder Alternatives

September, 2008

GHK, Inc.Page 1

AASHTO Emulsion Purchase Specification

Merging SPG + EPG

ETF – Lakewood, CO

May 4-5, 2016

Gayle King, GHK

Pen-Graded PME Residue Specs Tied to High Pavement Temps

Six Penetration Grades (6°C range)

Three Penetration Grades (12°C range)

6/8/2016


September, 2008

GHK, Inc.Page 2

AASHTO Chip Seal Documents

Recent ETF Updates

1.Materials Specifications� Materials (Aggregates & Emulsion Properties)

� Anionic

� Cationic

� Polymer Modified

2.Design Specifications� NCHRP 14-17:Shuler, Epps-Martin

� NCHRP Report #680

3.Construction Guidelines


ETF: Materials & Design

� M-XXX-15: Materials for Emulsified Asphalt Chip Seals (emulsion & aggregate)

� M-140-15: Emulsified Asphalt

� M-208-15: Cationic Emulsified Asphalt

� M-316-15: Polymer Modified Emulsified Asphalt

� PP-XX-15: Emulsified Asphalt Chip Seal Design

� R-XX-15: Standard Practice for Sampling Asphalt Materials: Update status?

6/8/2016


September, 2008

GHK, Inc.Page 3


Construction Guidelines

Division 400: Flexible Pavements

� Section 40x: Emulsified

Asphalt Chip Seal

� R-XXX-XX: Emulsified Asphalt Chip Seal Best Practices

Pre-Qualification

� AASHTO R-26: Asphalt Emulsion Certified Supplier Program

� Pre-Qualified Aggregate Sources

� Gradation

� Consensus aggregate properties

� Lightweight

� Moisture Damage

� May depend upon emulsifier chemistry

6/8/2016


September, 2008

GHK, Inc.Page 4

Chip Seal Emulsion

Purchase Specifications:

� Emulsion Properties� Application & Stability

� Residue Recovery Method

� Residue Specifications:

� Performance Tests & Properties

� Bleeding, Low Temp Aggregate Loss

� Climate/Traffic-based (LTPPBind)� Summer vs Early/Late Season

� Emulsion Break/Cure?� Demulsibility: vs Sweep Test, Water Loss

Chip Seal Design and Performance Specification

� Emulsion:

� Type; Grade; Shot Rate

� Aggregate:

� Gradation; Application Rate; Fracture

� Cover: Fog Seal or Flush Coat

� Performance Tests Required for Individual Job Materials

� Cure time to traffic – Sweep, water loss

� Vialit – Compatibility (Emulsion vs agg.)

� Moisture Damage?

6/8/2016


September, 2008

GHK, Inc.Page 5

Lab and Field

Validation� Lab validation: NC State

� Vialit (Temperature, Wet and Dry)

� MMLS-3 with Imaging & Prep. Equipment

� Field Validation Sites:

� NCDOT

� TXDOT/TTI:

�>100 field sections using SPG

SPG vs EPG

Emulsion Specifications� Emulsion Viscosity

� Brookfield vs Saybolt-Furol

� Field Viscosity Test & Acceptance � Morganstern (WDOT); Shuler (NCHRP 14-17)

� Sieve Test, %

� Storage Stability

� Demulsibility

� Particle Charge

� Residue %

6/8/2016


September, 2008

GHK, Inc.Page 6

Emulsion Viscosity

Field Test for Acceptance

Wyoming Field Emulsion Viscosity Test

� WYDOT Materials Testing Manual (MTM), Section 842.0

� http://www.dot.state.wy.us/home/engineering_technical_programs/materials--testing/materials_testing_manual/mtm-8420---field-emulsion-viscosity-test.html

Shuler Modifications to WFEVT

� NCHRP report #680: From NCHRP 14-17

Should Sieve be determined in the field?

Sprayability and Drain-outModified AASHTO TP48

� Rotational Viscometer

� 3-step-shear test: Vary the shear rate to simulate spraying and drain-out potential

Sprayability

Drain-out

Tank to SprayerTank to Sprayer SprayingSpraying PSTPST

NC State University

6/8/2016


September, 2008

GHK, Inc.Page 7

Storage StabilityModified ASTM D6930

� Rotational Viscometer to measure:� Separation Ratio (Rs):

ηTop/ηBottom� Stability under sedimentation, creaming

� Stability Ratio (Rd): ηMixed/ηReference� Potential for flocculation, coagulation

Top

Bottom

Mixed

Samples stored at high temperature

NC State University

Fresh Emulsion Specification

NC State University

6/8/2016


September, 2008

GHK, Inc.Page 8

SPG vs EPG

Residue Recovery Method

Forced Draft Oven: Method B

� 6 hr; 60°C: Thin Film - Silicone Mat

SPS: AASHTO PP 72: Method B

EPS: ASTM 7497: Method B

ETF is creating AASHTO standards

SPG vs EPG

Residue Specifications

� Climate/Traffic Adapted to LTPPBind

� Bleeding

� Low Temperature Aggregate Loss

� PAV Aging

6/8/2016


September, 2008

GHK, Inc.Page 9

SPG vs EPG

Tie Climate to LTPPBind

� Avg. 7-day max/min pavement surface design temperature (°C)

� Th ≈ 3-4°C higher than Th for HMA

� ½ grade bump harder than PG

� Grade Increments

� EPG: 6°C per LTPPBind

� SPG: changing from 3°C to 6°C?

� Alters strategy for traffic grade bumping

with PP 72 Method B Recovery

FP > 230 by T 48

RV < 0.15 Pa*s @ 205°C by T 316

Performance Grade

SPG 67 SPG 70 SPG 73

-13 -16 -19 -22 -25 -16 -19 -22 -25 -16 -19 -22 -25

Average 7-day Maximum Surface Pavement Design

Temperature, °C <67 <70 <73

Minimum Surface Pavement Design Temperature, °C >-13 >-16 >-19 >-22 >-25 >-16 >-19 >-22 >-25 >-16 >-19 >-22 >-25

Original Binder Dynamic Shear, T315

G*/Sinδ Minimum: 0.65 kPa

Test Temperature @10 rad/s, °C

67 70 73

Phase angle (δ), Max, @ temp. where G*/sin δ = 0.65 kPa – – – 80 80 – 80 80 80 80 80 80 80

Pressure Aging Vessel (PAV) Residue (AASHTO PP1) PAV Aging Temperature, °C 100 100 100

Creep S ffness, T 313

S, Maximum: 500 MPa

Test Temperature @ 8s, °C

-13 -16 -19 -22 -25 -16 -19 -22 -25 -16 -19 -22 -25


6/8/2016


September, 2008

GHK, Inc.Page 10

SPGEmulsion Residue Specifications

Original Performance Properties

Dynamic Shear, T 315: G*/sin, Min 0.65 kPa, Test temp @ 10 rad/s, °C

64 67

Phase angle3 (), Max, @ temp. where G*/sin

80 - - - 80 80

Pressure Aging Vessel (PAV) Residue

PAV aging temperature, °C 100 100

Creep stiffness, T 313: S, Max 500 MPa, Test temp. @ 8 sec., °C

-25 -13 -16 -19 -22 -25

Grade-Bump 3°C & 6°C for Traffic; Increase UTI for PME

EPG

Residue Specification

6/8/2016


September, 2008

GHK, Inc.Page 11

NC State University

One Third Scale Model Mobile Loading Simulator (MMLS3)

NC State University

Laboratory Chip Seal Specimen Fabrication Using ChipSS

6/8/2016


September, 2008

GHK, Inc.Page 12

MMLS3 Test Preparation

NC State University

NC State University

Bleeding Measurement

� ABleeding = area of specimen (total number of pixels)

� ATotal = area of bleeding on specimen (sum of pixels obtained from bleeding image (c).

� ABleeding measured using Matlab code.

(%) 100

Bleeding

Total

ABleeding

A= ×

c) Image input into Matlab

b) Bleeding extracted

a) Original Image

6/8/2016


September, 2008

GHK, Inc.Page 13

NC State University

Jnr Limits for EPG Spec.

y = 13.126ln(x) + 53.06610

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9 10 11 12

% B

leed

ing

Jnr @ 3.2 kPa

Measured BleedingExtrapol. Bleed (Prediction) - 64C Unmodified JnrExtrapol. Bleed (Prediction) - 64C Modified JnrExtrapol. Bleed (Prediction) - 70C Modified JnrExtrapol. Bleed (Prediction) - 70C Poor Modified Jnr

Mix

ture

Pe

rfo

rma

nce

Mix

ture

Pe

rfo

rma

nce

Binder PropertyBinder Property

Mixture Performance Upper Limit

Binder Property

Upper Limit

SPG vs EPG

Resistance to Bleeding

SPG

� G*/sin δ ≥ 0.6 kPa (10 rad/s @ Th)

� Phase Angle ≤ 80° @ Th

EPG

� Jnr (3.2 kPa @ Th):

� ≤ 8 kPa-1: Low Traffic

� ≤ 5.5 kPa-1: Medium Traffic ≈+4°C

� ≤ 3.25 kPa-1: Heavy Traffic ≈+8°C

6/8/2016


September, 2008

GHK, Inc.Page 14

Conventional AC - Linear Range

Jnr vs G*/sin δ

SPG vs EPG

Bleeding at Th (surface)

SPG – Standard Traffic

EPG – Light Traffic

EPG – Medium Traffic

SPG & EPG – Heavy Traffic

SPG – Moderate Traffic

6/8/2016


September, 2008

GHK, Inc.Page 15

EPG vs SPG

Traffic Adjustment @ Th

EPG:

� @ Th: 3 traffic levels (reduce Jnr)

SPG:

� @Th: 3 traffic levels (2 x 3°C bumps)

� high UTI requires δ≤80°

Consider:

� Traf1: G*/sin δ ≥ 0.5 kPa; Jnr ≤ 8 kPa-1

� Traf2: PME @ Double G*: ≈ 6°C offset

SPG vs EPG

Bleeding at Th

Observation:

� SPG & EPG consistencies are close for light to medium traffic.

Questions:

� Are extra grades needed for traffic?

� If yes, add one or two grades?

� Are polymers needed? δ or % recovery?

� Are PME residues pushed far enough into the non-linear range to require MSCR?

6/8/2016


September, 2008

GHK, Inc.Page 16

Shelling/Raveling

Low Temperature Aggregate Loss

SPG

Low Temp Aggregate Loss

6/8/2016


September, 2008

GHK, Inc.Page 17

NC State University

Vialit Test Method for Raveling

� Curing samples in the oven at intermediate temperature until fully cured.

� Flip over samples to remove excess aggregate.

� Place samples upside down on a device.

� Drop the ball three times within 10 sec.

� Measure the weight of samples.

� Fast and simple!


0

5

10

15

20

25

0 5 10 15 20 25

Ag

gre

gate

Lo

ss b

y M

ML

S3


GraniteGranite


6/8/2016


September, 2008

GHK, Inc.Page 18


0

5

10

15

20

25

0 5 10 15 20 25

Ag

gre

gate

Lo

ss b

y M

ML

S3


Polymer-Modified

Emulsions

Polymer-Modified

Emulsions

Unmodified

Emulsions

Unmodified

Emulsions

EPGLow Temperature Agg. Loss

� Single Edge Notched Beam (SENB) Test

� Binder beam specimen dimensions are 6.25 mm by 12.5 mm by 102 mm with a 3 mm notch depth.

� Fracture toughness (KIC) measured at 0.1 mm/s loading rate at the low temperature grade

NC State University

6/8/2016


September, 2008

GHK, Inc.Page 19

EPGLow Temperature Spec

SENB Fracture Toughness

� K1c @ 0.1 mm/sec ≥ 1 MPa/mm

ReviewPG vs. SPG

THIGH = average 7-day max high Tpvmnt @ 20mm1

±6⁰C @ THIGH & TLOW;

-10 ⁰C for TLOW grading2

DSR, T315, @THIGH

(RTFO) and @TINT (PAV)3

Creep Stiffness, T 313,

S and m-value @ 60s4

No specification on

δ at THIGH

5

1THIGH = average 7-day max high Tpvmnt @ surface

2±3⁰⁰⁰⁰C @ THIGH & TLOW;

No -10 ⁰C for TLOW grade

3No specification on RTFO aged binder & No TINT

4Creep Stiffness, T 313, S @ 8s; no m-value

5δδδδ < 80 @ continuous

THIGH for UTI > 89

TTI

6/8/2016


September, 2008

GHK, Inc.Page 20

EPG and SPG Summary Table

Temperature

EPG SPG

Test

Method

Measured

Parameter

Test

Method

Measured

Parameter

High PG Grade MSCR Jnr DSR G*/sin δ

Intermediate

PG

Vialit Compatibility Check

in Mix Design Phase

Low PG Grade

@ Tlow

SENB

Fracture

Toughness,

KIC

BBR/PAVCreep

Stiffness (S)

Qualification Tests?

Moisture Damage:

� Determining Asphalt Binder Bond Strength by Means of the Bitumen Bond Strength (BBS) Test

� AASHTO Designation: TP-XX-11

� Vialit after Moisture Conditioning

Aggregate Loss:

� Vialit

� MMLS-3

6/8/2016


September, 2008

GHK, Inc.Page 21

BBS Specimen Curing Method

y = -0.0111x + 24.641

R² = 0.7493

0

5

10

15

20

25

0 500 1000 1500%

Ag

gre

ga

te L

os

s

BBS (kPa)

non-PME at 15C

PME at 15C

non-PME at 25C

PME at 25C

CORCOR

0

5

10

15

20

25

0 500 1000 1500 2000

% A

gg

reg

ate

Lo

ss

BBS (kPa)

Unmodified Emulsions

Modified Emulsions

RORROR

Questions & Challenges1. Should “High Float” be specified? How?

2. Should low temperature properties vary with Traffic or with Use of Snow Plows?

� e.g.: Higher fracture toughness from polymers in EPG specs

3. Is PAV aging necessary?

4. What is implementable?

� Emulsion vs AC testing time/cost

� Purchase vs qualification tests

5. What about construction?

6/8/2016


September, 2008

GHK, Inc.Page 22

Construction Guidelines

Field Variability: Application Rates

0.0

0.1

0.2

0.3

0.4

0.5

1 2 3 11 12 7 8 9 13 14 15

EA

R

Section Number

Measured Target

0

5

10

15

20

25

1 2 3 11 12 7 8 9 13 14 15

AA

R

Section Number

Measured Target

0%

5%

10%

15%

20%

25%

30%

35%

1 2 3 11 12 7 8 9 13 14 15

Ab

solu

te V

alu

e o

f %

Diffe

rence

fro

m T

arg

et A

AR

Section Number

0%

10%

20%

30%

40%

50%

60%

70%

1 2 3 11 12 7 8 9 13 14 15

Asb

olu

te V

alu

e o

f %

Diffe

rence

fro

m T

arg

et E

AR

Section Number

Granite Lightweight

NC State

University

6/8/2016


September, 2008

GHK, Inc.Page 23

Thoughts & Questions?