SMA-13 Recycled Asphalt Mixtures with Flocculent Basalt Fiber: Experiment and Random Forest Analysis

Area of Science:

• Materials Science
• Civil Engineering
• Sustainable Construction

Background:

• Recycled asphalt mixtures benefit from additives like flocculent basalt fiber (FBF).
• Previous studies focused on FBF content, overlooking synergistic effects of fiber size (diameter, length) and content.
• This limits precise optimization and application of FBF in recycled asphalt.

Purpose of the Study:

• To investigate the combined effects of FBF diameter, length, and content on recycled asphalt mixtures.
• To optimize the asphalt-aggregate ratio, mechanical properties, and road performance (rutting, cracking, water stability).
• To determine the relative importance of FBF parameters on mixture performance.

Main Methods:

• Investigated SMA-13 recycled asphalt mixtures with varying FBF diameter, length, and content.
• Utilized a random forest approach to quantify parameter importance.
• Evaluated optimal asphalt-aggregate ratio, mechanical properties, high-temperature rutting resistance, low-temperature cracking resistance, and water stability.

Main Results:

• Optimal asphalt-aggregate ratio and road performance increased with FBF content and length, but decreased with diameter.
• Performance deteriorated when FBF content exceeded 0.4%.
• Fiber content was the most significant factor, followed by diameter, then length.

Conclusions:

• Identified optimal FBF content: 0.4% for 6 µm diameter fibers and 0.3% for 3 µm diameter, 4 mm length fibers.
• Provided precise parameter guidance for FBF application in SMA-13 recycled asphalt.
• Promoted sustainable utilization of recycled materials through optimized FBF reinforcement.