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

General Rheology

Asphalt Binder

General Rheology

1
Rheology
• Rheology:
– the study of flow and deformation
• Constitutive relations
– fundamental relationships between forc...
Rheometers
• Equipment used to measure rheology
• Shear rheometers
– Drag flow
– Pressure driven flows
• Rheometers for me...
Shear Rheometers

Asphalt Binder

General Rheology

4
Drag Flow Rheometers
• Sliding plate

Asphalt Binders

General Rheology

5
Schematic of Sliding Plate
Viscometer

Chart Recorder
(not to scale)
Asphalt Binders

General Rheology

6
Assumptions
• Steady, laminar flow, isothermal flow
• No radial or vertical flow
• Negligible gravity and end effects

Asp...
Drag Flow Rheometers
Concentric Cylinder
τ

Mi

Rθ

=
2 π Ri2 L

γ =

θ R
Ro - Ri

Narrow gaps: Ri / Ro > 0.99

Asphalt Bi...
Drag Flow Rheometers
• Cone and Plate

Similar triangles for
shear flow
Homogeneous flow

Asphalt Binders

General Rheolog...
Drag Flow Rheometers
• Parallel Plate
Shear flow varies with
gap height and radius
Non-homogeneous flow

Asphalt Binders

...
Assumptions
• Steady, laminar, isothermal flow
• Negligible body forces
• Cylindrical edge

Asphalt Binders

General Rheol...
Oscillating Plate
B

C
A

Fixed Plate

B

Time

A

Test operates at 10 rad/sec
or 1.59 Hz

A
360o = 2 p radians per circle...
Elastic

Viscous

B

Strain
A

Time

A

C

Strain out-of-phase
δ = 90o

Strain in-phase
δ = 0o
Asphalt Binders

General Rh...
Complex Modulus, G*
Viscous Modulus, G”

δ
Storage Modulus, G’
Complex Modulus is the vector sum of the
storage and viscou...
Master Curves
• DSR testing can be used to develop master curves
– Need range of temps and frequencies at each
temperature...
Equipment Example

Asphalt Binders

General Rheology

16
Equipment Examples

Asphalt Binders

General Rheology

17
Equipment Example
25 mm Plate with Sample

Asphalt Binders

General Rheology

18
Pressure Driven Rheometers
• Vacuum Viscometer

Velocity Profile
Asphalt Binders

Shear Stress Profile
General Rheology

1...
Viscometer Tube
• Asphalt Institute Tube

Asphalt Binders

General Rheology

20
Stiffness and Strength
Rheometers

Asphalt Binder

General Rheology

21
Bending Beam Rheometer

Deflection Transducer

Computer
Air Bearing
Load Cell

Asphalt Binders

General Rheology

Fluid Ba...
Bending Beam Rheometer
• S(t) =

P L3
4 b h3 δ (t)

Where:
S(t) = creep stiffness (M Pa) at time, t
P = applied constant l...
Bending Beam Rheometer
• Evaluates low temperature stiffness properties
– Creep stiffness
– Slope of response (called m-va...
Direct
Tension
Test

Load
Stress = σ = P / A

σf

∆L

∆ Le

Strain
Asphalt Binders

General Rheology

εf
25
Equipment Example
Fluid Bath

Loading
Ram

Cooling
System
Asphalt Binders

General Rheology

26
Direct Tension Test

Asphalt Binders

General Rheology

27
QUESTIONS?

Asphalt Binder

General Rheology

28
Upcoming SlideShare
Loading in …5
×

Block 3 SP 14

1,830 views

Published on

Published in: Technology, Business
  • Be the first to comment

Block 3 SP 14

  1. 1. Senior/Graduate HMA Course General Rheology Asphalt Binder General Rheology 1
  2. 2. Rheology • Rheology: – the study of flow and deformation • Constitutive relations – fundamental relationships between force and deformation Asphalt Binders General Rheology 2
  3. 3. Rheometers • Equipment used to measure rheology • Shear rheometers – Drag flow – Pressure driven flows • Rheometers for measuring stiffness and strength – Bending beam – Direct tension Asphalt Binders General Rheology 3
  4. 4. Shear Rheometers Asphalt Binder General Rheology 4
  5. 5. Drag Flow Rheometers • Sliding plate Asphalt Binders General Rheology 5
  6. 6. Schematic of Sliding Plate Viscometer Chart Recorder (not to scale) Asphalt Binders General Rheology 6
  7. 7. Assumptions • Steady, laminar flow, isothermal flow • No radial or vertical flow • Negligible gravity and end effects Asphalt Binders General Rheology 7
  8. 8. Drag Flow Rheometers Concentric Cylinder τ Mi Rθ = 2 π Ri2 L γ = θ R Ro - Ri Narrow gaps: Ri / Ro > 0.99 Asphalt Binders General Rheology 8
  9. 9. Drag Flow Rheometers • Cone and Plate Similar triangles for shear flow Homogeneous flow Asphalt Binders General Rheology 9
  10. 10. Drag Flow Rheometers • Parallel Plate Shear flow varies with gap height and radius Non-homogeneous flow Asphalt Binders General Rheology 10
  11. 11. Assumptions • Steady, laminar, isothermal flow • Negligible body forces • Cylindrical edge Asphalt Binders General Rheology 11
  12. 12. Oscillating Plate B C A Fixed Plate B Time A Test operates at 10 rad/sec or 1.59 Hz A 360o = 2 p radians per circle 1 rad = 57.3o C 1 cycle Asphalt Binders General Rheology 12
  13. 13. Elastic Viscous B Strain A Time A C Strain out-of-phase δ = 90o Strain in-phase δ = 0o Asphalt Binders General Rheology 13
  14. 14. Complex Modulus, G* Viscous Modulus, G” δ Storage Modulus, G’ Complex Modulus is the vector sum of the storage and viscous modulus Asphalt Binders General Rheology 14
  15. 15. Master Curves • DSR testing can be used to develop master curves – Need range of temps and frequencies at each temperature • Information – Affect of loading time on asphalt binder stiffness – Estimate of thermal coefficient of expansion Asphalt Binders General Rheology 15
  16. 16. Equipment Example Asphalt Binders General Rheology 16
  17. 17. Equipment Examples Asphalt Binders General Rheology 17
  18. 18. Equipment Example 25 mm Plate with Sample Asphalt Binders General Rheology 18
  19. 19. Pressure Driven Rheometers • Vacuum Viscometer Velocity Profile Asphalt Binders Shear Stress Profile General Rheology 19
  20. 20. Viscometer Tube • Asphalt Institute Tube Asphalt Binders General Rheology 20
  21. 21. Stiffness and Strength Rheometers Asphalt Binder General Rheology 21
  22. 22. Bending Beam Rheometer Deflection Transducer Computer Air Bearing Load Cell Asphalt Binders General Rheology Fluid Bath 22
  23. 23. Bending Beam Rheometer • S(t) = P L3 4 b h3 δ (t) Where: S(t) = creep stiffness (M Pa) at time, t P = applied constant load, N L = distance between beam supports (102 mm) b = beam width, 12.5 mm h = beam thickness, 6.25 mm d(t) = deflection (mm) at time, t Asphalt Binders General Rheology 23
  24. 24. Bending Beam Rheometer • Evaluates low temperature stiffness properties – Creep stiffness – Slope of response (called m-value) Log Creep Stiffness, S(t) 8 15 30 60 120 240 Log Loading Time, t (sec) Asphalt Binders General Rheology 24
  25. 25. Direct Tension Test Load Stress = σ = P / A σf ∆L ∆ Le Strain Asphalt Binders General Rheology εf 25
  26. 26. Equipment Example Fluid Bath Loading Ram Cooling System Asphalt Binders General Rheology 26
  27. 27. Direct Tension Test Asphalt Binders General Rheology 27
  28. 28. QUESTIONS? Asphalt Binder General Rheology 28

×