Development of High Modulus Asphalt Mixes for Cold Climate

摘要

Fatigue is one of the principal failure modes observed in pavement structures. One way to improve bituminous pavement fatigue performance is by reducing the magnitude of the pavement deflection, which can be done by increasing the stiffness of the asphalt base layer(s). In collaboration with Quebec road industries, a research program has been started in 2013 at the Laboratoire sur les Chaussees et Materiaux Bitumineux (LCMB), at the ecole de Technologie Superieure (ETS), to develop a high modulus asphalt mix for cold region applications. To reach that goal, new Performance Graded (PG) bitumen was investigated in two asphalt mixture types with different aggregate gradation. In this paper, the relationship between the stiffness of asphalt material layers and the fatigue performance of the bituminous pavement are introduced. Laboratory results of two high modulus asphalt mixtures are presented and discussed. The laboratory trial clearly shows the feasibility to design a high modulus asphalt mixture with an optimized granular skeleton and with special PG bitumen to reach low temperature performance. Moreover, the test results show that the designed asphalt mixtures performed well at low temperatures in the Thermal Stress Restrained Specimen Test (TSRST) with failure temperature less than -28°C for both mixes.