Light-weight aggregates as frost protection in roads

The design char developed for the Norwegian guidlines, Handbook 018 Road Construction

Abstract

Large deformations and reduced bearing capacity caused by frost heave and thawing every cause significant problems and result in major maintenance costs of the roads in the Nordic contries. Extruded polystyrene has been the most preferred material for frost protection for some years. However, light weight clay aggregate (LWA) has now become a regular material used for frost insulation in roads in Norway based on a rresearch project by SINTEF. To optimize the design, SINTEF has performed a number of numerical analyses and develop a design chart that gives the required layer thickness for frost insulation. The design chart in the lastest Norwegian guidlines for road construction, Handbook 018 Road Construction, is based on this design chart. The calculations showed that the frost protection layer using LWA should be 3-5 times thicker than a frost protection of extruded polystyrene (XPS).