Performance of Cold Recycled Micro-Surfacing with WER Asphalt and Ultrasonic-Mechanical Pre-Regenerated RAP

Area of Science:

• Materials Science
• Civil Engineering
• Sustainable Pavement Technology

Background:

• Recycled micro-surfacing offers sustainability in pavement maintenance.
• Fine reclaimed asphalt pavement (RAP) presents challenges due to aged asphalt and particle agglomeration.
• Existing methods struggle to effectively utilize fine RAP in recycled micro-surfacing.

Purpose of the Study:

• To develop cold recycled micro-surfacing using waste edible oil (WEO) and waterborne epoxy resin (WER)-modified emulsified asphalt.
• To propose a novel pre-regeneration method for fine RAP using ultrasonic-mechanical mixing with WEO.
• To optimize WEO content, mixing time, and WER dosage for enhanced mixture performance.

Main Methods:

• Molecular dynamics (MD) simulation to assess rejuvenator diffusion and asphalt binder interaction.
• Dynamic Shear Rheometer (DSR) tests to evaluate rheological recovery of aged asphalt.
• Performance testing of recycled mixtures including wear, rutting, low-temperature splitting, and water resistance.

Main Results:

• WEO demonstrated effective diffusion and interaction with aged asphalt, with 4% WEO restoring rheological properties.
• Ultrasonic-mechanical mixing (4 min) significantly reduced wear (WTAT by 9.6%).
• 20% WER improved water resistance (WTAT by 72.6%), rutting resistance (PVD by 68.9%), and tensile strength (by 88.7%), while maintaining acceptable low-temperature performance.

Conclusions:

• Pre-regeneration of fine RAP with 0.4% WEO and 4 min ultrasonic-mechanical mixing effectively activates aged materials.
• Incorporating 20% WER in cold recycled micro-surfacing significantly enhances durability and mechanical properties.
• The developed technique provides a sustainable and high-performance solution for pavement maintenance using recycled materials.