Use of NDT and Pocket Computers in Pavement Evaluation

Abstract

The profile and clearance heights at seven bridges of the New Jersey approach roads to the George Washington Bridge needed upgrading. To do this, nondestructive test (NDT) techniques were carried out on the pavement surfaces to determine the subgrade properties under the existing pavement. The NDT dynamic load and the measured deflection basin were analyzed to calculate the subgrade parameters, the elastic modulus (E) the CBR, and the modulus of reaction (K). The testing and calculation of 100 points, under heavy traffic volume, were completed in four hours. The subgrade parameters were used to design the reconstructed new pavement structure for local environmental conditions and for 20‐yr projected traffic loading.