![Impact Echo Scanning Technology for Internal Grout Condition Evaluation in Post-Tensioned Bridge Ducts Impact Echo Scanning Technology for Internal Grout Condition Evaluation in Post-Tensioned Bridge Ducts](https://www.ndt.net/article/ndtce03/papers/v041/fig1.gif)
Impact Echo Scanning Technology for Internal Grout Condition Evaluation in Post-Tensioned Bridge Ducts
![Sensors | Free Full-Text | Concrete Condition Assessment Using Impact-Echo Method and Extreme Learning Machines Sensors | Free Full-Text | Concrete Condition Assessment Using Impact-Echo Method and Extreme Learning Machines](https://pub.mdpi-res.com/sensors/sensors-16-00447/article_deploy/html/images/sensors-16-00447-g001.png?1461896406)
Sensors | Free Full-Text | Concrete Condition Assessment Using Impact-Echo Method and Extreme Learning Machines
![Sensors | Free Full-Text | A Study on the Applicability of the Impact-Echo Test Using Semi-Supervised Learning Based on Dynamic Preconditions Sensors | Free Full-Text | A Study on the Applicability of the Impact-Echo Test Using Semi-Supervised Learning Based on Dynamic Preconditions](https://www.mdpi.com/sensors/sensors-22-05484/article_deploy/html/images/sensors-22-05484-g001.png)
Sensors | Free Full-Text | A Study on the Applicability of the Impact-Echo Test Using Semi-Supervised Learning Based on Dynamic Preconditions
![An impact echo method to detect cavities between railway track slabs and soil foundation | Journal of Engineering and Applied Science | Full Text An impact echo method to detect cavities between railway track slabs and soil foundation | Journal of Engineering and Applied Science | Full Text](https://media.springernature.com/lw685/springer-static/image/art%3A10.1186%2Fs44147-021-00008-w/MediaObjects/44147_2021_8_Fig7_HTML.png)
An impact echo method to detect cavities between railway track slabs and soil foundation | Journal of Engineering and Applied Science | Full Text
![Applied Sciences | Free Full-Text | Guidelines for Impact Echo Test Signal Interpretation Based on Wavelet Packet Transform for the Detection of Pile Defects Applied Sciences | Free Full-Text | Guidelines for Impact Echo Test Signal Interpretation Based on Wavelet Packet Transform for the Detection of Pile Defects](https://www.mdpi.com/applsci/applsci-10-02633/article_deploy/html/images/applsci-10-02633-g001.png)