Detection and Identification for Void of Concrete Structure by Air-Coupled Impact-Echo Method

Area of Science:

• Civil Engineering
• Materials Science
• Acoustics

Background:

• Traditional air-coupled impact-echo technology for concrete non-destructive testing (NDT) faces challenges with operational complexity and efficiency.
• Effective detection of internal defects like voids is crucial for the integrity of concrete structures.

Purpose of the Study:

• To develop an improved method for concrete void detection using air-coupled impact-echo.
• To investigate the relationship between void dimensions and peak frequency variations.
• To establish a reliable method for identifying concrete voids based on peak frequency analysis.

Main Methods:

• A finite element model (FEM) of concrete structures with varying void sizes was created using Comsol software.
• The variation in peak frequency was analyzed in relation to void dimensions (width and depth).
• Theoretical explanations and experimental validation were employed to support the findings.

Main Results:

• Void width has a more significant impact on peak frequency than void depth.
• A decrease in peak frequency was observed with increasing void width beyond 0.3 m.
• The air-coupled method is applicable for concrete void depths less than 0.4 m.

Conclusions:

• Peak frequency can effectively identify void widths greater than 0.3 m in concrete structures with depths less than 0.4 m.
• The proposed method enhances the efficiency and accuracy of void detection in concrete.
• Findings are beneficial for the inspection of tunnel linings, pavements, and other concrete infrastructure.