Pavement evaluation with a non-destructive method, the falling weight deflectometer

Abstract

Accurate determination of the modulus of asphalt layers for rehabilitation purposes and design of asphalt coating is of particular importance in the structural condition of flexible pavements. Structural evaluation of in-service pavement involves the in-place determination of the elastic modulus of pavement layers by destructive or nondestructive testing. Nondestructive testing has many advantages, such as high speed and low cost compared to destructive testing. The falling weight deflectometer (FWD) test is the most widely accepted and used technique for nondestructive evaluation of pavements and has been conducted extensively in the last decades to evaluate structural conditions and to determine the modulus of pavement layers. One of the most important applications of FWD test results is the analysis and backcalculation of layers modulus. The modulus of elasticity of the materials used in the pavements is used for the analysis of the remaining life and the design of new pavements and overlays. This critical value is computed through the backcalculation method, which uses FWD raw data. Various methods have been developed and applied to perform backcalculation. In most programs, the FWD data are used as if they are the results of static loads, while the real loads have the dynamic behaviour. Therefore, the results can vary for flexible pavements. The objective of this study is to present the results and analysis of some FWD data, which have been obtained by some FWD tests carried out in the USA; in particular, to document the results, which were backcalculated by the DBSID program. These results can be compared to the results of the MODULUS program, which has been developed by the Texas Transportation Institute (TTI). Then, the effects of different parameters such as pavement temperature and the surface layer thicknesses on the FWD layer modulus are performed. A comparison between the FWD layer modulus obtained from both programs and the International Roughness Index (IRI) values of the same test sections is also done. This study will enable us to have more precise and reliable results with the FWD.

Date	22 Jun 2022
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Alan Carter (Supervisor) & Michel Vaillancourt (Co-supervisor)