Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Senior/Graduate
HMA Course

Modified Asphalt Binders

Asphalt Binder

Modified Binders

1
Why are Modifiers Used?
• Mitigate both traffic- and environmentally
induced HMA pavement distresses
– Rutting resistance
...
Types of Modifiers
• Polymers
– Plastomers
– Elastomers
• Fillers
– Gilsonite
– Mineral fillers
– Misc.
Asphalt Binder

Mo...
Polymers
• Plastomers
– Quick early strength but with little ability to
strain without brittle failure
– Any strain tends ...
Plastomer Product Examples
Trade
Name
Novophalt

Manufacturer

Type

Chemistry

Novophalt

Copolymer

LDPE

Elvax

DuPont
...
Polymers
• Elastomer
– Resist permanent deformation by an ability
to stretch and recover shape once load is
removed
– Only...
Elastomer Examples
• Natural Rubber
• Synthetic Rubber
– Styrene-Butadiene Rubber (SBR)
• Random block
• Thermoplastic Rub...
Elastomer Product Examples
Trade
Name
Downright

Type

Chemistry

DOW

Random
Copolymer

SBR

Kraton

Shell

Block
Copolym...
Common Polymer Terms
Straight Chain or Linear

Polymer with Branches

Radial
Asphalt Binder

Modified Binders

Crosslinked...
Step 2

SBS Polymers
in Asphalt Binders
Step 1
Polymer
Step 3

Styrene
Butadiene
Asphalt Binder

Polymer
in hot AC

Polyme...
Traditional Testing for Modified
Asphalt Binders
• Vacuum viscosity
– Asphalt Institute tubes
• Ductility
– Elastic recove...
TEM Microphotographs

White area = Asphalt Binder and Black area = polymer

500 nm

2% Linear SBS

Asphalt Binder

500 nm
...
TEM Microphotographs
White area = Asphalt and Black area = polymer

500 nm

6% Linear SBS
Asphalt Binder

1 υm

10% Linear...
TEM Microphotographs
White area = Asphalt Binder and Black area = polymer

4% Radial SBS
Asphalt Binder

Modified Binders
...
NCHRP Report 459
Characterization of Modified Asphalt
Binders in Superpave Mix Design

Asphalt Binder

Modified Binders

1...
Topics Covered
• Storage stability of modified asphalt
binders
• Shear-rate dependency of viscosity
• Strain dependency of...
Modified Asphalt Binders
• Simple asphalt binders
– Do not violate assumptions of Superpave
rheological tests
• Complex as...
Simple Asphalt Binders
• <2% by vol of additives retained on No. 200
sieve
– PAT with toluene
• Stable for 2 or more days ...
Particulate Additive Test (PAT)

Asphalt Binder

Modified Binders

19
Laboratory Asphalt Stability Test
(LAST)

Asphalt Binder

Modified Binders

20
Other Topics
• Researchers addressed
– Effect of traffic volume
– New procedures for low temperature
cracking prediction m...
QUESTIONS?

Asphalt Binder

Modified Binders

22
Upcoming SlideShare
Loading in …5
×

Block 6 SP 14

1,249 views

Published on

  • Be the first to comment

Block 6 SP 14

  1. 1. Senior/Graduate HMA Course Modified Asphalt Binders Asphalt Binder Modified Binders 1
  2. 2. Why are Modifiers Used? • Mitigate both traffic- and environmentally induced HMA pavement distresses – Rutting resistance • Stiffer asphalt binders at warm temps – Thermal cracking • Inhibit crack propagation – Internal elastic network (polymers) – Crack pinning (solid particles) Asphalt Binder Modified Binders 2
  3. 3. Types of Modifiers • Polymers – Plastomers – Elastomers • Fillers – Gilsonite – Mineral fillers – Misc. Asphalt Binder Modified Binders 3
  4. 4. Polymers • Plastomers – Quick early strength but with little ability to strain without brittle failure – Any strain tends to be permanent • Little elastic behavior Asphalt Binder Modified Binders 4
  5. 5. Plastomer Product Examples Trade Name Novophalt Manufacturer Type Chemistry Novophalt Copolymer LDPE Elvax DuPont Copolymer EVA Polybuilt Exxon Copolymer EMA or EVA Starflex Carraux Copolymer EVA Asphalt Binder Modified Binders 5
  6. 6. Polymers • Elastomer – Resist permanent deformation by an ability to stretch and recover shape once load is removed – Only contribute to tensile strength when stretched Asphalt Binder Modified Binders 6
  7. 7. Elastomer Examples • Natural Rubber • Synthetic Rubber – Styrene-Butadiene Rubber (SBR) • Random block • Thermoplastic Rubbers – Styrene-Butadiene-Styrene (SBS) • Triblock copolymer that form network Asphalt Binder Modified Binders 7
  8. 8. Elastomer Product Examples Trade Name Downright Type Chemistry DOW Random Copolymer SBR Kraton Shell Block Copolymer SBS Styrelf Koch Block Copolymer Blended Vector Exxon Block Copolymer SBS Asphalt Binder Manufacturer Modified Binders 8
  9. 9. Common Polymer Terms Straight Chain or Linear Polymer with Branches Radial Asphalt Binder Modified Binders Crosslinked 9
  10. 10. Step 2 SBS Polymers in Asphalt Binders Step 1 Polymer Step 3 Styrene Butadiene Asphalt Binder Polymer in hot AC Polymer in cool AC Modified Binders 10
  11. 11. Traditional Testing for Modified Asphalt Binders • Vacuum viscosity – Asphalt Institute tubes • Ductility – Elastic recovery • Softening Point – Increases with polymer concentration • Toughness and Tenacity • Separation Asphalt Binder Modified Binders 11
  12. 12. TEM Microphotographs White area = Asphalt Binder and Black area = polymer 500 nm 2% Linear SBS Asphalt Binder 500 nm 4% Linear SBS Modified Binders 12
  13. 13. TEM Microphotographs White area = Asphalt and Black area = polymer 500 nm 6% Linear SBS Asphalt Binder 1 υm 10% Linear SBS Modified Binders 13
  14. 14. TEM Microphotographs White area = Asphalt Binder and Black area = polymer 4% Radial SBS Asphalt Binder Modified Binders 14
  15. 15. NCHRP Report 459 Characterization of Modified Asphalt Binders in Superpave Mix Design Asphalt Binder Modified Binders 15
  16. 16. Topics Covered • Storage stability of modified asphalt binders • Shear-rate dependency of viscosity • Strain dependency of rheological response • Effect of mechanical working • Loading-rate dependency and time-temp equivalency Asphalt Binder Modified Binders 16
  17. 17. Modified Asphalt Binders • Simple asphalt binders – Do not violate assumptions of Superpave rheological tests • Complex asphalt binders – Behavior (characteristics) violate one or more assumptions Asphalt Binder Modified Binders 17
  18. 18. Simple Asphalt Binders • <2% by vol of additives retained on No. 200 sieve – PAT with toluene • Stable for 2 or more days at mix/compact temps – LAST • Reasonably linear over range of stress and strain • Insensitive to cyclic damage during testing Asphalt Binder Modified Binders 18
  19. 19. Particulate Additive Test (PAT) Asphalt Binder Modified Binders 19
  20. 20. Laboratory Asphalt Stability Test (LAST) Asphalt Binder Modified Binders 20
  21. 21. Other Topics • Researchers addressed – Effect of traffic volume – New procedures for low temperature cracking prediction models Asphalt Binder Modified Binders 21
  22. 22. QUESTIONS? Asphalt Binder Modified Binders 22

×