The Use of Non Destructive Testing and Backcalculation of Moduli in the Rehabilitation Project of the Runway of the Otopeni Airport at Bucarest (Romania)

Results of a rehabilitation project for the runway nr.1 of the Otopeni Airport at Bucarest by using the Falling Weight Deflectometer (FWD). The paper describes how the deflection basin produced by the FWD can be used to characterize the pavement behaviour and to backcalculate the Young modulus (E) of the concrete and the subgrade reaction (K) according to the caissical Westergaard rigid pavcmcnt theory. The applied testing scheme, including location of tests, magnitude of loading and sensor spacings are described, and a description of the modulus backcalculation process is also provided. Information on the layer thickness, pavement and air temperature, Portland cement concrete flexural strength is provided for a more accurate evaluation. Non destructive measurements have been successfully utilised to analyse the deterioration of slabs subjected to the action of water, frost and traffic; and for the development of a pavement rehabilitation procedure. In order to increase the bearing capacity of the slabs as needed, this final evaluation has been based on a forecast of the total number of passes of the most critical aircraft that the pavement will be expected to support during its design life. This paper presents the most recent experiences acquired in the field of non-destructive testing and the evaluation procedure for rigid pavements, whose growing acceptance confirms that it the quickest and and efficient method to determine the structural capacity of pavements with a minimum disturbance to traffic operations and the achievement of the maximum possible accuracy.