High Modulus Asphalt (HiMA) Technology Transfer (T2) May ... - CSIR

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High Modulus Asphalt (HiMA) Technology Transfer (T2) May ... - CSIR

High Modulus Asphalt (HiMA)

Technology Transfer (T 2 )

May 2010 Progress report

Prepared for presentation at the 19 th meeting of

the Roads Pavements Forum (RPF), Salt Rock, 5

May 2010

Erik Denneman


Presentation structure

• Background on HiMA,

• The sabita HiMA T 2 project,

• Progress,

• Preliminary results,

• Way forward.

Slide 2

© CSIR 2006 www.csir.co.za


High Modulus Asphalt (HiMA)

• Origin: France early 90s “Enrobés à Module Elevé”

(EME)

• Typical characteristics:

High binder content ≈ 6% by mass of aggregate,

• Hard binder: Pen 10-25,

• Low air voids content,

High Modulus > 14 GPa at 10°C, 25 Hz,

High resistance against permanent deformation,

• Good fatigue resistance,

• Impermeable,

High mixing temperature.

Slide 3

© CSIR 2006 www.csir.co.za


Slide 4

Application examples

Case #1: HMA vs HiMA

70mm HiMA, 9000 MPa 70mm HMA, 3500 MPa

150mm G1, 300 MPa

© CSIR 2006 www.csir.co.za

300mm C3, 1500 MPa

Subgrade, 100 MPa


Slide 5

Case #1: HMA vs HiMA

Vertical plane parallel to Y-Z at X = 0

Normal Stress ZZ

3

-37

-77

-116

-156

-195

-235

-275

-314

-354

-394

-433

-473

-512

-552

-592

-631

-671

-710

-750

Vertical plane parallel to Y-Z at X = 0

HiMA HMA

© CSIR 2006 www.csir.co.za

Normal Stress ZZ

3

-37

-77

-116

-156

-196

-235

-275

-315

-354

-394

-434

-473

-513

-553

-592

-632

-671

-711

-751


Case #2: BTB+HMA vs HiMA

Slide 6

50mm HMA, 3500 MPa

180mm BTB, 5000 MPa

450mm C3, 1500 MPa

Subgrade, 100 MPa

Reduction of 130mm in thickness

© CSIR 2006 www.csir.co.za

100mm HiMA, 9000 MPa

450mm C3, 1500 MPa

Subgrade, 100 MPa


Case #3: G1+HMA vs HiMA

Slide 7

50mm HMA, 3500 MPa

150mm G1, 300 MPa

300mm C3, 1500 MPa

Subgrade, 100 MPa

Reduction of 130mm in thickness

© CSIR 2006 www.csir.co.za

70mm HiMA, 9000 MPa

300mm C3, 1500 MPa

Subgrade, 100 MPa


Slide 8

sabita HiMA T 2 project

© CSIR 2006 www.csir.co.za


Slide 9

sabita HiMA T 2 progress

• Phase I: Feasibility, completed July 2008

• Phase II: Prelim guidelines mix design and structural

design

• Task 1: Finalisation mix designs and benchmarking,

partially completed. Task had to be revised after

French mix design failed to make specs.

• Task 2: Structural design and cost comparisons,

ongoing

• Task 3: Experimental design for phase 3, ongoing

• Tests feed into SANRAL revision of SAPDM project

© CSIR 2006 www.csir.co.za


Dynamic modulus (MPa)

Master curve development

100000

10000

1000

Slide 10

100

10

1E-06 0.001 1 1000 1000000

© CSIR 2006 www.csir.co.za

Reduced frequency (Hz)

Model (Master curve)

-5-deg C

5-deg C

20-deg C (Tref)

40-deg C

55-deg C


100000

Dynamic Modulus (MPa)

10000

Comparison of mix moduli

1000

100

10

1

0.00001 0.001 0.1 10 1000 100000

Slide 11 © CSIR 2006 www.csir.co.za

Reduced frequency (Hz)

BTB Mix

Coarse/SBS

Medium/SBS

HiMA


Permanent strain [%]

Permanent deformation (RSST-CH)

5.0%

4.5%

4.0%

3.5%

3.0%

2.5%

2.0%

1.5%

1.0%

0.5%

0.0%

Mix 1 25°C Mix 1 40°C Mix 1 55°C

Mix 2 25°C Mix 2 40°C Mix 2 55°C

Mix 3 25°C Mix 3 40°C Mix 3 55°C

HiMA 25°C HiMA 40°C HiMA 55°C

0 5000 10000 15000 20000 25000 30000

Load repetitions

Slide 12 © CSIR 2006 www.csir.co.za


10000

STRAIN (Microstrain)

1000

100

10

Fatigue results (10 °C 25 Hz)

1000 10000 100000 1000000 10000000 100000000

Slide 13

Strain-fatigue relationship at test temperatures at 70% initial stiffness reduction

All at 10 Degrees C

Number of load cycles

© CSIR 2006 www.csir.co.za

Mix 1 (BTB)

Mix 3

Mix 4 (HiMA)


French mix design effort

Parameter Requirement Result SA equivalent

test

Workability

(Gyratory

compactor)

Durability

(Duriez test)

Rutting

(Wheel tracker)

Beam dynamic

modulus

Fatigue

(Prism)

Slide 14

Max 6% voids

after 100

gyrations

Retained

strength: >0.7

Rut depth after

30 000 cycles

14 GPa

µε for 106 fatigue life:

>130

© CSIR 2006 www.csir.co.za

5.7 % Gyratory

0.9 Modified Lottmann

5.2 mm RSST-CH, Wheel

tracking

17 GPa Beam or cylinder

dynamic modulus

90 µε Beam fatigue


Binder specifications

Property Result Test method Specification

Before RTFOT

Penetration @ 25 , 10 -1 mm 25 ± 1 ASTM D5 (20-30)

(15-25)

Softening point, R&B, °C 62.8 ASTM D36 (55-63)

Dynamic Viscosity @

60°C, Pas 2713.0

Slide 15 © CSIR 2006 www.csir.co.za

ASTM D4402

(55-71)

(≥550)

After RTFOT

Mass change, % (m/m) ±0.061 ASTM D2872 (±0.5)

Softening point, R&B, °C

Increase

69.2

6.4

Penetration @ 25 , 10-1mm % Original 76

(≤0.5)

ASTM D36 (≥57)

(≥ Orig. Min

+2)

ASTM D5 (≥55)

(≥55)


Binder

Mixing temperature

Slide 16

Mixing

Temperature

Lower Mixing

HiMA Temperature

binder Upper Mixing

Temperature

TMH1 C2

Recommen

ded

viscosity

Temperat

ure at the

viscosity

190cSt 172°C

150cSt 177°C

© CSIR 2006 www.csir.co.za

Mixing

Temperatu

re Used

175°C


Mix improvement

• Develop mix that fulfils the requirements for:

• Workability,

• Durability,

• Resistance against permanent deformation,

• Rutting,

• Dynamic modulus,

• Fatigue.

• Use French mix design as benchmark

• Current challenge: Increase VMA to allow more binder

and increased fatigue life

Slide 17

© CSIR 2006 www.csir.co.za


100

90

g

80

in

s 70

s

a

p 60

e

g 50

ta

n

e 40

r

c

e 30

P

20

10

Mix improvement

0

0

Slide 18

Control points

Target

Reference

Trial C

.075 .300 1.18 2.36 4.75 6.7 9.5 13.2 19.2

.015 .600

Sieve © size CSIR 2006 (raised www.csir.co.za to power 0.45)


Structural design

• Short term: Use French philosophy i.e. design such

that strains in pavement remain below threshold.

• Medium term: Develop shift functions from APT trials.

Slide 19

© CSIR 2006 www.csir.co.za


Way forward:

• Improve mix design

• Complete preliminary mix design and structural design

guideline,

• Perform APT and LTPP,

• Finalize mix design and structural design guidelines

Slide 20

© CSIR 2006 www.csir.co.za


Thank you

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