Hybrid Devulcanized/Vulcanized Crumb Rubber Strategy for High-Performance Asphalt with over 40% Recycled Tire Rubber...

Area of Science:

• Materials Science
• Civil Engineering
• Sustainable Materials

Background:

• Waste tire crumb rubber (CR) enhances asphalt pavement performance and aids waste disposal.
• High CR content in conventional modified asphalt compromises pavement properties.
• Developing methods for higher CR incorporation is vital for sustainability.

Purpose of the Study:

• To develop a high-performance modified asphalt using a hybrid of CR and devulcanized CR (DCR).
• To achieve a total rubber content exceeding conventional limits without performance degradation.
• To investigate the microstructural mechanisms behind the enhanced properties.

Main Methods:

• Hybridization of CR and DCR to create modified asphalt.
• Characterization of physical properties (softening point, ductility).
• Rheological analysis (rutting resistance, fatigue tolerance), sol fraction, GPC, and AFM testing.

Main Results:

• A hybrid asphalt with 30 wt% CR and 13 wt% DCR (30CR-13DCRMA) showed excellent properties (softening point 78.4 °C, ductility 15.33 cm).
• Superior rutting resistance and fatigue tolerance compared to neat CR or DCR modified asphalt.
• Synergistic effects of CR and DCR promote particle absorption and swelling, creating a biphasic microstructure.

Conclusions:

• The hybrid rubber system allows high CR incorporation with balanced performance.
• This approach offers a sustainable pathway for pavement engineering.
• The enhanced asphalt properties stem from improved rubber particle interaction and asphalt matrix microstructure.