MECHANICAL BEHAVIOR OF INSULATED PAVEMENTS

Resumen

Pavement insulation is a widely accepted technique for the mitigation of frost effects on pavements. Many of studies were carried out on the mechanical implications of using insulation materials; however most of them deal with lightweight fill and rarely with insulated pavement. As a consequence, little information is available on insulated pavement mechanical behavior. A test track, including three 150 meter sections, was built in southern Québec, Canada. One section is insulated with extruded polystyrene, another with saw dust and the last one is a non-insulated reference section. All sections are instrumented in order to monitor frost depth and frost heave and to measure the mechanical response under standard load with a deflectometer. This paper presents an assessment of the pavement mechanical behavior in relationship with its long-term condition. The long-term performance of the test sections is analyzed with considerations for frost protection advantages versus possible disadvantages due to insulation material low strength. The main conclusion of this experimental study is that if thermal and mechanical efficiency of extruded polystyrene used as an insulation material in pavement is clearly demonstrated for almost all kinds of traffic loads, it is much different for saw dust. In fact, saw dust used as an insulation material in pavement causes a significant loss of bearing capacity which leads to a limitation of traffic loads even though it shows a good thermal performance.