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Binder Testing

 

Asphalt binder behaves both viscously and elastically making it a viscoelastic material. Complicating matters, this viscoelastic behavior is dependent upon temperature. Finally, this behavior is also dependent upon age. Therefore, in order to adequately characterize asphalt binder for use in HMA, Superpave uses the following test:


DSR---Dynamic Shear Rheometer



The DSR is used for fatigue and rutting potential. The standard test includes measurement of complex shear modulus (G*) and phase angle. Other modes of testing include Oscillation, Creep/Recovery and Viscometry. Testing can be carried out at 4oC to a maximum of 90oC at several modes of loading. The two models include:

 

� DSR II (Manual with Mechanical Bearing)

� CVO/ADS (Automatic with Air Bearing)

 

 

Typical results

 
 

 

BBR---Bending Beam Rheometer

BBR is used to evaluate thermal cracking properties of the binder up to a minimum temperature of -40oC. According to the new SUPERPAVETM specification, test temperature relates to a pavement�s lowest service temperature. The test method uses beam theory to calculate the flexural creep stiffness or compliance of an asphalt binder under a creep load. Applicable test:

1. AASHTO T313

2. ASTM 6648

3. AASHTO TP1

Typical results

RV-----Rotational Viscometer


Rotational Viscometer determine the viscosity i.e. flow characteristics of asphalt binders at higher temperatures. The system has the capability to test the binder as a function of temperature and shear rate. This help to study the viscous and visco-elastic properties. High temperature testing is also used to establish mixing and compaction temperatures for the asphalt mix. Applicable Test: 1. AASHTO T 316 ASTM D 4402

Typical results

 
 

RTFO ----Rolling Thin Film Oven



This test simulates the short term asphalt aging that occurred during blending and production of asphalt mix.  The procedure exposes the thin binder films to heat and air in designated test environment.  A total of eight bottles loaded with asphalt binder is used.  In addition, mass loss can also be computed by weighing the sample before and after the test.
Applicable Test

  1. AASHTO T 240
  2. ASTM D 2872

PAV ----Pressure Aging Vessel


The Pressure Aging Vessel (PAV) simulates long term aging of asphalt binder.  PAV aging is carried out after the sample is exposed to RTFO aging.  The standard SUPERPAVETM  test protocol simulated 7 to 10 year period in field.  The simulation is carried by exposing the sample at high temperature and pressure.
Applicable test:

    • AASHTO R 28
    • AASHTO PP1