Infrared heating of asphalt pavement can lead to aging or performance decline if improperly controlled, but these risks can be effectively mitigated with proper operation. Below are the key influencing factors and control measures:

1. Causes of Potential Aging

(1) Excessive or Localized Overheating

• When asphalt exceeds 180°C, light oil fractions evaporate, accelerating oxidation of resins and asphaltenes, leading to hardening and brittleness.

• High-power infrared heating or prolonged exposure may carbonize (burn) the surface layer.

(2) Prolonged Heating Duration

• Extended radiation increases oxidation, reducing flexibility and crack resistance.

(3) Incorrect Wavelength Selection

• Short-wave IR (0.76–1.5 μm): Shallow penetration, prone to surface overheating.

• Medium-/long-wave IR (1.5–4 μm): Deeper, more uniform heating, better suited for asphalt repair.

2. Actual Impact on Asphalt Performance

(1) Short-Term Performance Changes

• Positive Effects: Moderate heating (120–160°C) softens asphalt, enhancing bonding between old and new materials.

• Negative Risks: Uncontrolled temperatures reduce penetration, increase softening point, and decrease ductility.

(2) Long-Term Durability

• Proper Heating: Studies show infrared-repaired asphalt matches traditional methods in rutting and fatigue resistance.

• Overheating: Aged asphalt becomes prone to cracking and raveling, shortening pavement life.

3. Key Measures to Prevent Aging

(1) Precise Temperature Control

• Use infrared thermometers for real-time monitoring (140–160°C for conventional asphalt; slightly higher for modified asphalt).

• Opt for auto-temperature-control IR systems to avoid human error.

(2) Optimized Heating Parameters

• Power Adjustment: 15–20 kW/m² for 3 cm thick asphalt.

• Movement Speed: Maintain 0.5–2 m/min to prevent localized overheating.

(3) Rejuvenator Application (Optional)

• For severely aged asphalt, apply rejuvenators before heating to restore light oils.

(4) Layered Heating (For Thick Layers)

• For >5 cm layers, use intermittent heating (heat → penetrate → reheat) to avoid surface aging before deep softening.

4. Comparison with Traditional Heating Methods

Conclusion

Infrared heating does not inherently cause asphalt aging—the risk depends on temperature, duration, and operational practices. With scientific temperature control, optimized equipment settings, and standardized procedures, infrared heating can preserve or even enhance asphalt performance compared to traditional methods.

Recommendations for field applications:

• Conduct lab tests (e.g., TFOT aging tests) to validate heating parameters.

• Implement real-time monitoring during construction to ensure repair quality.

(Note: Technical terms like "penetration" , "softening point , and "ductility"  are translated with standardized asphalt industry terminology.