Contact Pressure Measurement of a Small-Scale Wheel Tracking Device for Different Surface Types

In pavement engineering design, the pressure under a tyre is assumed to be a circular vertical contact pressure for analytical design methods. The true contact pressure and area is very difficult to predict due to the complexity of the system. A normal test that is undertaken to understand an asphalt’s performance for near surface rutting is the small-scale wheel tracker. The contact pressure and area of the tyre for different loads and surface types is not known. This is an area that needs to be addressed to better understand the contact pressures in this crucial test for asphalt rutting. Different pavement surface material slabs were made all with different surface textures for testing in the small-scale wheel tracker. A device was chosen to measure contact pressure between the tyre and these different surfaces. The device deforms around the surface aggregates and gives a very good understanding of the forces between the tyre and the pavement surface. It was shown that there is a great deal of variability between the different surface types. It is recommended that pavement loading for design should have a factor based on the contact pressure characteristics of a pavement surface.