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The development and maintenance of infrastructures are important societal issues in northern context, where the extension of human and economic bonds is vital. The establishment of infrastructures is a constant geotechnical challenge due to thaw-sensitive permafrost, the presence of compressible soils and damages induced by freeze-thaw cycles (differential frost heave and seasonal loss of bearing capacity).
In this context, the use of lightweight and insulating materials is an alternative increasingly used as a sub-surface layer in road foundations and as embankment material. Such materials allow to reduce the weight of structures limiting the charge applied to the natural ground, preserve permafrost by reducing heat exchange and limit frost penetration in a context of seasonal frost.
Currently in Québec and Canada, it is common practice to use extruded polystyrene panels and blocks to meet those needs. New alternative materials exist elsewhere in the world, in particular foam glass aggregates produced by recycling glass residues from various origins. This material present interesting properties: lightweight, insulating, draining and easy to be installed. It improves the durability and therefore reduce maintenance costs in many applications, such as protection of building foundations, embankments, pipe insulation and road engineering.
Despite an increasing use over the last 20 years in Europe, Japan and Russia, foam glass technology applied to road engineering, has not yet been optimized. The objectives of this postdoctoral project are to develop and optimize the technology of foam glass in the cold region context in order to implement this technology in Canada. This research program will be conducted at Laval University in Guy Doré’s team, and in close collaboration with the producers and the potential users of the material.
The project is based on laboratory evaluation of material properties, coupled with in-situ characterization of structural properties for real scale building sites, and numerical simulations of the performance of different grades of foam glass in order to maximize their use for each specific applications (insulation, permafrost, embankment). This materials properties evaluation is intended to be as exhaustive as possible in terms of mechanical (compressive strength, granular arrangement, elastic modulus), thermal (study of heat transfers by conduction and convection) and environmental properties (studies of potential pollution by leaching, resistance to various environments) to ensure the sustainability of structures that incorporateing this material and the benefits to their environment.
Various laboratory setups (reduced scale pavement structure, specific boxes for heat exchange study) will be used to evaluate the drainage capacity, the thermal regimes likely to be developed as well as the mechanical performances of the structures including foam glass. The database of the properties will be completed with data from a controlled environment at Laval University Civil Engineering laboratory, where a pavement structure pit will be constructed and coupled with a traffic simulator capable of reproducing extreme mechanical stresses and winter thermal regimes (freeze/thaw cycle).
Simultaneously with laboratory characterization tests, instrumented experimental sites based on European expertise have been set up at the end of 2015 in Kingsey Falls, Victoriaville and Drummondville. All three structures, i.e. a pavement structure, an insulation culvert and a pipe insulation are in real conditions of use. These sites incorporating foam glass, will consider the structural performances compared to the use of polystyrene panels. At the pavement insulation site, an additional reference section composed of traditional granular materials is also studied.
Data collected, both in the laboratory and in-situ, will feed numerical simulation models to validate the performance of foam glass in various situations and to develop the principles of design structures and limitations. The results obtained for this new material will be used to be integrated in the pavement and embankments design methods in northern context.