Under the objectives of the European Energy Agency to reduce the CO2 emissions for 2050, electrified Roads (eRoad) are proposed. Among all the proposed idea, one of them is to inductively charge the moving Electric Vehicle (EV). In that aim some Charging Units (CU) are introduced in one of the top layers of the existing multi-layered structures. Then an additional thin layer is placed to covert the all and to assure perfect wheel/pavement contact. Among all the behaviour material problems to solve, some structural solutions need to be proposed to avoid possible delamination between such CU inclusion and the standard pavement materials. Indeed, due to severe different loadings (number of truck axles, speed of the moving load, lateral wandering effect of the loads, etc) environmental conditions (temperature, water, freezing, etc), failures between the different materials involved may occur quickly. In such condition, depending on the ratio of modulus between the different materials, cracking and debonding phenomenon between the CU and the structure is one of the major distress parameter to take into account for the durability of such new road concepts.

To analyse such composite structure, the Multi-Particle Model of Multilayer Materials (M4) with 5n of equilibrium equations (n: total number of layers) (Chabot, 1997) is used. The M4-5n is specially designed to analyse the delamination of composite materials for multilayer bending problems. It allows convenient parametric calculations without singularity problems. In the so-called M4-5nW tool developed for 2D plane strain problems (Nasser and Chabot, 2018), the pavement is chosen equivalent to 3 material layers resting on a soil. The soil is assumed equivalent to a combination of a fictitious layer (shear soil layer) ensuring the transfer of shear stresses between the pavement multilayer and Winkler's springs. In that case, a series of M4-5nW equation manipulations lead to the writing of a second-order differential system of twelve analytical equations depending only on one variable. Following several previous works, the 2D tool solves semi-analytically the equations using the Newmark discretization.

This paper presents the new development done in the modelling in order to introduce the change of material in one (or several) layer (s). For eRoads, it leads to modify the second-order differential system of M4-5nW analytical equations. Depending on the case of bonding chosen, the M4-5nW lateral boundary conditions use (or not) a system of continuity equations written in terms of the generalized stresses and generalized displacements of the layer(s) with the CU. A Finite Difference Method numerical scheme is then used with approximations around the CU edges in this(ese) layer(s). To test if the M4-5nW would be a convenient tool for the parametrical study of material inclusions in eRoads with possible macro cracks between materials, it is then proposed to analyse the elastic stress distribution around the charging box for the 2D plane strain example of Chen's PhD works (Chen et al., 2017). Due to the symmetry of the problem, only the half cross geometry is studied. Illustrations show that closest the load is near to the box, the higher the intensity of the interface stresses are between layers. Different combinations of materials are made in the aim to reduce the interface stress intensities between layers around the CU edge. That first development aims to propose to engineers alternative pavement structures that could be an interesting option to be studied with more detail and tested further by means of full-scale accelerated experiments.