Experimental Study on Creep-Recovery Behavior of Polyphosphoric Acid (PPA) Modified Asphalt Binders under Multiple...

Area of Science:

• Materials Science
• Civil Engineering
• Geotechnical Engineering

Background:

• Polyphosphoric acid (PPA) modified asphalt binder offers excellent high-temperature performance and cost-effectiveness for pavement materials.
• Understanding the deformation behavior of modified asphalt binders under varying temperatures and loads is crucial for pavement service life prediction.

Purpose of the Study:

• To investigate the impact of temperature and load on the deformation behavior of PPA-modified asphalt binders.
• To evaluate the effectiveness of PPA modification on asphalt binder properties using rheological and energy-based approaches.

Main Methods:

• Multiple Stress Creep and Recovery (MSCR) tests were conducted on six asphalt binders with varying PPA dosages across five temperature levels.
• Deformation behavior was analyzed using basic parameters, rheological simulations (three-element model), and energy parameter changes (stored and dissipated energy).

Main Results:

• Increased temperature led to a sharp decrease in percent recovery (R) and a slight increase in non-recoverable creep compliance (Jnr).
• A three-element model effectively described creep behavior, while a logarithmic model better simulated recovery behavior than the power-law model.
• Stored and dissipated energy parameters correlated significantly with deformation parameters, reflecting changes under different conditions.

Conclusions:

• PPA modification enhances the elastic component of asphalt binders, improving their deformation resistance and recovery capacity.
• The study recommends a PPA dosage of 1.5% for optimal performance.
• Findings provide valuable insights into the deformation mechanisms of PPA-modified asphalt binders for engineering applications.