Investigating Nonlinear Fatigue Damage Evolution of SBS-Modified Asphalt Mixtures with Physical Gel Structure

Area of Science:

• Materials Science
• Civil Engineering
• Polymer Chemistry

Background:

• Styrene-butadiene-styrene (SBS) modifiers improve asphalt resistance to deformation and fatigue cracking via physical gel networks.
• A detailed mechanical characterization of this mechanism in SBS-modified asphalt is currently lacking.
• Understanding nonlinear fatigue damage evolution is crucial for asphalt pavement performance.

Purpose of the Study:

• To elucidate the nonlinear fatigue damage evolution in SBS-modified asphalt mixtures.
• To establish a robust mechanical characterization based on residual strain response analysis.
• To correlate residual strain behavior with fatigue cracking and deformation resistance.

Main Methods:

• Conducted indirect tensile fatigue tests to measure residual strain response in SBS-modified asphalt.
• Developed a damage-informed residual strain model to describe material behavior.
• Defined a relative residual strain change rate to assess fatigue cracking resistance.

Main Results:

• A strong correlation was found between fatigue cracking and viscoplastic strain in SBS-modified asphalt.
• The proposed residual strain model accurately captures nonlinear fatigue damage evolution and residual strain.
• The relative residual strain change rate effectively indicates resistance to fatigue cracking and strain accumulation.

Conclusions:

• The SBS modifier enhances asphalt resistance to fatigue cracking and residual strain through a 3D physical gel network.
• The developed residual strain model provides a quantitative method for characterizing fatigue damage.
• The relative residual strain change rate is a reliable indicator of material durability under cyclic loading.