Impulse radar for the investigation of pavements: Fid-Bau Portal

Impulse radar for the investigation of pavements

Milligan, R.W.

Impulse radar can be used as a high speed investigation technique. Road closure is no longer a requirement for carrying out a pavement investigation using impulse radar unless high resolution lateral sections are a requirement. The data results are not degraded by the increase in speed. Using arrays of antenna of differing frequencies it is possible to collect data in one pass containing information on layer thickness' and defects within the pavement. The data set can be interpreted for a simple specific purpose e.g. layer thickness', but may be interrogated at a later stage for other reasons e.g. possible causes of pavement failure. The resolution required in pavement engineering can be achieved by impulse radar and with careful handling new build pavements could be quality controlled to be within the specified tolerances. In order to achieve the accuracies required the data should be collected digitally and the material velocities for calibration extracted directly from the data. Cores supply valuable information on strength and composition of a pavement which radar cannot produce and therefore engineers will still require cores but not specifically for use with impulse radar. Cores are needed for material confinement. With increasing computer power digital processing of impulse radar waveforms data has become a reality giving the advantages of improving accuracy and make extraction of calibration velocities direct from the data a possibility. To simplify reporting and make the data available to road engineers reporting in digital from on a floppy diskette is advantageous thereby eliminating vast volumes of paper and allowing impulse radar to be integrated easily with other road investigation techniques.