SolDuGri

Road infrastructures construction and renovation in the framework of sustainable development should nowadays include future scarcity issues, such as oil byproducts. Considering the existing road heritage, at least in France, renovation constitutes a major challenge. The ageing of infrastructures requires the development of Ecological reengineering affordable solutions, which allow for total, partial, even gradual, renovation. In the area of new construction, the question is to develop and implement solutions minimizing environmental and energy impacts, under managed costs, during the construction phase but also throughout the pavement lifespan. Grids, notably glass fiber grids, are an efficient and economical solution for asphalt pavement stiffening, to increase their lifespan and slow down the coming up to the surface of cracks, as well on new pavements as well as for reinforcement. Grids are used for reinforcement, to improve the traction performances and cracking resistance. As for every composite product, this is of paramount importance that the support and the matrix constitute a “unique” product in situ. Moreover, this cover should not lose performance during the application and when it is subject to constraints related to stress under traffic loadings. Nowadays, the grids are more and more used to improve the pavement lifespan, but this use mainly lays upon empirical rules, which are based on learnings from past experience. This project aims at gathering laboratories studies, observations from full size tests and modelings, in order to: • Improve the grids design: arrangement of threads and resins, opening of the stitch. • Improve the tests used for the laboratory characterisation of the grids mechanical performances: traction, indentation and fatigue tests on grids, resistance tests during implementation, fatigue tests on reinforced asphalt concrete • Better understand, through laboratory and full size tests, the impact of implementation conditions on the grids behavior, the sticking of asphalt concrete layers, and their modus operandi in pavement, with various asphalt materials (hot, warm) • Develop models suitable for describing the mechanical behavior and evaluating the reinforced materials lifespan. • Verify the possibility of integral recycling of these materials • Engineer evaluation methods of economical impacts and apply a method for analysing the life cycle assessment to evaluate environmental impacts of the reinforcement process. As expected results, one can list the optimisation of the grid mechanical properties in the context of existing pavements reinforcement and new pavements, relating experimental studies in laboratory with in situ studies on in situ and fatigue test tracks. The scientific and theoretical originality lies in the engineering of a model coupling fatigue and damage to predict the influence of the reinforcement grids on fatigue behavior of a reinforced pavement structure. Special attention will be devoted to the issue of quantification of grid spoiling during its implementation and sticking. This last idea will be the object of a laboratory test. Finally, the environmental impact of road strengthening by fiberglass grids will be considered from the manufacture of the grid to its full recycling and its use with warm mix asphalts, these latter being set to grow.