In cold winters we experience frost heave problems on both newly constructed and existing roads and railways. This accelerates deterioration and reduces the bearing capacity of the structures during spring time, and consequently increases maintenance costs.
Since the large research program "Frost i Jord" ended about 40 years ago, very little research has been done in Norway on this problem. Since then, used materials have changed from the well graded natural gravel to coarser and openly graded crushed/blasted rock. There is no good understanding of the equivalent thermal conductivity of these materials including internal convection and radiation. Existing frost susceptibility criteria for soils and coarse material are mainly based on grain size distribution and allowable fines content. However, the mineralogy of the fines is also an important factor to consider.
In this project we plan to investigate materials in the laboratory and field conditions, and build a numerical model to simulate different climate conditions, thickness of structures and material combinations.
We will educate two PhD-students in this project. One student will focus on frost susceptibility of subgrade soils and pavement materials. The second one will make an assessment of the frost protection layer. We plan to have good interaction between the two students and the rest of the team. The PhD-students will be co-supervised from University of Laval and NTNU and will spend some time at both universities to maximize the learning and use of experimental resources.