Comparative Study of the Deflection of a Flexible Pavement Under the Effect of a Low Traffic

Abstract

The flexible pavement deformations, during their services, can reach levels such that they represent a danger for the users. Among the permanent deformations, authors are interested in rutting, which is a very evolutionary phenomenon, because, it has been tried to indentify the process of evolution of rutting due to the accumulation of permanent deformations in the layers of materials composing the pavement. This work aims to propose more efficient methods of analysis of deflection basins done in the TCPW (technical control of public works) of Algiers by the Lacroix Deflectograph and Falling Weight Deflectometer (FWD), also taking into account the dispersion of the measurements along itinerary of the Medea’s national road No 18, associating a modeling work of the mechanical response of pavement and statistical processing of the measurements taken. The presented approach consists in a modeling based on the back-calculation of deflections obtained from the FWD with the ELMOD6 program, completed by an approximate analytical method, which adopts a mathematical adaptation technique. The last one uses the Boussinesq formulas with Odemark's consecutive three-layer system in order to estimate modules of pavement layer. The results of the comparative analysis show which modules of bituminous layers estimated from two techniques are in an average change of minimum deflection of 8.80%. Knowing that the average change of maximum deflection and of characteristic deflection at all test sites is respectively to 4.23% and 3.57%. So the results show that they are consistent with the measured deflection. This means too, that this comparative study validates the applicability of the analytical method because of its simplicity and speed for the structural evaluation of the flexible pavement.