Subsurface anomaly assessment in asphalt layers using Rayleigh waves dispersion characteristics: a test-pit study

ABSTRACT

Any subsurface anomaly present in asphalt pavement layers may lead to their localised progressive structural failure. The detrimental effects of such anomalies are not visible on the top surface in the early stages. It may cause a major cost escalation if gone unnoticed during construction or maintenance works. Hence, there is a need for their quick and reliable detection and assessment. Present study explores the non-destructive assessment of subsurface anomalies (such as void/buried utility, etc.) in asphalt layers. This work developed a simple experimental approach using the two-receiver Spectral Analysis of Surface Waves (SASW) method to generate the experimental dispersion curves (EDC) whose shape characteristics are utilised for the detection, location, and identification of subsurface anomalies. An in-situ asphalt pavement test-pit facility was developed consisting of a number of different sub-sections with various anomaly conditions. A test system utilising high-frequency accelerometers was custom-integrated for such assessments. Based on the EDC shape characteristics, a direct information extraction technique was developed which does not require backcalculation procedures. The study found the proposed technique to be reasonably applicable for a quick, non-destructive detection and assessment of the subsurface anomalies. Further extensive testing with different profiles, anomalies, and test conditions will help in further acceptance of this simple approach.

KEYWORDS:

• Asphalt pavements
• NDT&E
• buried utility
• subsurface assessment
• spectral analysis of surface waves

Acknowledgements

I would like to thank Prof. Partha Chakroborty and Prof. Animesh Das of IIT Kanpur for their support for this work. I would also like to thank the administration of IIT Kanpur for their support, and a special thanks to the National Highway Authority of India for their help in the construction of the flexible test pavement section.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Logistics support was provided by IIT Kanpur.