Bearing capacity of airfield pavements

In situ survey, measurements and calculations using GPR and FWD

Abstract

Runways, taxiways and aprons must have documented their bearing capacity with PCN value (Pavement Classification Number), preferably by a technical evaluation. On new structures this is normally relatively simple to accomplish. On older parts with unknown layer structure and material properties this can be a challenging task. SINTEF/NTNU has been using data from FWD (Falling Weight Deflectometer) in combination with GPR (Ground Penetration Radar) to estimate the PCN value both of asphalt and concrete pavements. GPR is used to estimate layer structures, layer thickness and to a certain extent the type and characteristics of material in each layer. Backcalculation of FWD data is used to estimate the modulus of elasticity of each material layer. By using GPR data, FWD data and aircraft traffic data as input in a suitable calculation program system the PCN value can be estimated. Despite several challenges and many uncertain factors this could be a cost-effective way to estimate PCN values compared to other extensive destructive investigations and material testing.