Evaluation of a highway pavement using non-destructive tests: Falling Weight Deflectometer and Ground Penetrating Radar

Abstract

This paper presents the results of the application of two non-destructive tests (NDT): Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR) to assess the bearing capacity of a flexible pavement. The main motivation of this research was the evaluation of the use of this two methodologies, over time-consuming, unsafe and costly traditional destructive methods, as a support for the decisions regarding pavement maintenance with concerns to its structural condition. The structural models were established based on the deflections from the FWD and using the design thickness and GPR measured thickness. The layers elastic moduli were estimated through back-calculation.The influence of having continuous accurate data on layer thickness was evaluated for a case study of a rehabilitated flexible highway pavement, in which surface cracking occurred only one year after reinforcement. The results show that the variability of the layers thicknesses was high and therefore the main focus was on the sensitivity of the estimated elastic moduli to the layers thicknesses. It was concluded that the thickness of the bound layers had a high influence on the estimated bituminous layers moduli and consequently on the pavement response models. Even though the results obtained are specific to this case study this research reinforced the importance of using GPR for continuous assessment of layer thickness together with load tests performed by FWD for an accurate structural evaluation of existing pavements.This paper is of interest for COST Action TU1208 Civil Engineering Applications of Ground Penetrating Radar.