EFFECTS OF TIRE PRESSURES ON FLEXIBLE PAVEMENT STRUCTURES; A LITERATURE SURVEY

The Norwegian Public Roads Administation is currently studying effects of tire inflation pressures on flexible pavement structures. The project is part of a major 4 years research program which primarily will focus on various rehabilitation and construction methods and techniques to ensure 10 tons allowable axle load on roads with no load restrictions during spring-thaw periods. The first phase of the tire pressure investigation consists of a literature study and review. The purpose of the study is to review the international knowledge of the effects of tire pressure on flexible pavement structures. The need for such knowledge is generally promoted by the increase in tire inflation pressure experienced in the last 10 years. For Norway, the knowledge of tire pressure effects is specially important as our network mostly consists of low volume roads (ADT is approx. 2000 vehicles) with thin asphalt surfacings over granular bases. The spring-thaw period is considered critical in this respect. The combination of the use of base course materials with fines, and partly frozen pavement structures with high water content during spring-thaw periods are expected to make the base materials particularly sensitive to tire inflation pressure damage. This project presents a state-of- the-art report of international knowledge of the effects of tire pressure on deterioration, serviceability and maintenance of flexible pavement structures. The project also reflects current and anticipated future regulations of tire pressure as well as trends in tire manufacturing and use. (A)