Thesis defense of Marina AL BACHA
Marina AL BACHA, PhD student at Lames, Université Gustave Eiffel, has defended her thesis entitled
"Experimental study and modelling of the impact of road loads on the mechanical behavior of pavement surface layers"
on
tuesday november 26th 2024
at 9.00 AM at the amphitheatre of Université Gustave Eiffel, campus of Nantes (France)
The thesis has been presented before the following jury:
| Reporters : Cédric SAUZEAT Christiane RAAB | Professeur – ENTPE, Vaulx-en-Velin Professeure – EMPA, Science and Technology, Dübendorf, Switzerland |
| Examinators : Cyrille CHAZALLON Frédéric GRONDIN Cyrile SOME | Professeur des Universités – INSA de Strasbourg Professeur des Universités – Ecole Centrale de Nantes Chercheur, HDR – CEREMA, Sourdun |
| Thesis director : Pierre HORNYCH | Ingénieur Divisionnaire des TPE, HDR – Université Gustave Eiffel, Nantes |
| Supervisors : Mai-Lan NGUYEN Olivier CHUPIN | Chargé de recherche – Université Gustave Eiffel, Nantes Chargé de recherche – Université Gustave Eiffel, Nantes |
Abstract:
This PhD thesis focuses on the analysis and modelling of the behavior of pavement surface layers under traffic loads, with a particular emphasis on the effects of interface bonding conditions between layers. The study is part of the French National (ANR) project BINARY, and is based on the analysis of two full-scale pavement experiments carried out on the fatigue carrousel of Université Gustave Eiffel. These experiments consisted in testing new and rehabilitated pavement structures, under different axle loads and temperature conditions. The pavements were instrumented with strain gauges and optical fibers, a novel instrumentation technique allowing distributed strain measurements under moving loads. The results highlight the significant effect of interface bonding conditions on the performance of surface layers, and their evolution with traffic and temperature conditions.
Two modelling approaches were developed to predict the behavior of the experimental pavements, and in particular interface bonding condition. The first approach is based on the Viscoroute©2.0 software, simulating the interface as a thin elastic layer with an elastic modulus depending on temperature. The second approach is based on finite element analysis using FreeFem++, simulating the interface as a frictional surface governed by Coulomb’s friction law, with a temperature-independent friction angle. This second approach was introduced to improve modelling of damaged interfaces, presenting partial sliding. The manuscript also discusses the effect of tridem axles with wide-base tires on pavement damage. This research enhances the understanding of traffic-induced strain distribution in pavement surface layers and opens up perspectives for developing a more rational approach to pavement design in the future.
Keywords: surface layers, interface bonding, pavement modelling, tridem axle, fatigue testing.