TRL Dynamic cone penetrometer

This apparatus, originally developed by the TRL-UK Transport Research Laboratory, has been designed  under licence from TRL for the rapid in-situ measurement of the structural properties of existing road pavements constructed with unbound materials. Continuous measurements can be made down to a depth of approximately 850 mm or, when extension shafts are used, to a recommended maximum depth of 2 m. Where pavements layers have different strengths the boundaries can be identified and the thickness of the layers determined. Correlation’s have been established in earlier work (Van Vuuren, Klein and Van Herden, Smith and Pratt) between  the TRL penetrometer and CBR (California Bearing Ratio) so that results can be interpreted and compared with CBR specifications.