Infrared Thermography for Defect Detectability in Structural Health Monitoring of Concrete Structures: Heat Transfer...

Area of Science:

• Civil Engineering
• Materials Science
• Non-Destructive Testing

Background:

• Infrared thermography (IRT) is crucial for structural health monitoring (SHM) of reinforced concrete.
• Quantitative links between heat transfer physics and defect detectability using IRT are underdeveloped.

Purpose of the Study:

• To establish a physics-oriented framework for IRT-based diagnostics in SHM.
• To clarify mechanisms, parameters, and constraints governing IRT for defect detection.
• To provide a foundation for automated, intelligent infrastructure diagnostics.

Main Methods:

• Analysis of heat transfer physics, including thermal diffusivity, emissivity, and transient conduction.
• Quantitative synthesis of defect-induced thermal contrasts.
• Evaluation of operational parameters and technological constraints for IRT.

Main Results:

• A minimum thermal contrast of 0.5 °C is required for reliable defect detection.
• Active thermography effectively detects defects at depths of 5-10 cm.
• Moisture variations exceeding 10% in emissivity introduce significant uncertainties.

Conclusions:

• Detectability in IRT for SHM is governed by diffusion physics, not just temperature readings.
• Integrating heat transfer theory with AI is essential to overcome current resolution limits.
• This framework supports the development of intelligent, automated infrastructure diagnostics.