Effect of road surfacing condition on tyre life

Abstract

Road engineers usually maintain roads with the objective of supplying a road surface with a certain serviceability standard. This serviceability standard typically include aspects such as the allowable rutting, skid resistance and riding quality of the road. While the road is performing within the set requirements for functional and structural performance, the road is deemed to be in a serviceable condition. Once these parameters are exceeded the road will be maintained using an option ranging from simple patching of potholes and sealing of cracks to a reseal of the road or even recycling and rehabilitation of the failed sections of the road. These maintenance actions affect the surfacing of the road and therefore the experience of the tyre in contact with the road surface. Tyres are typically designed to operate under specific conditions that include the applied vehicular load, tyre inflation pressure, temperature, allowable tyre deflection etc. It is generally assumed that as long as the road surface is relatively even and the vehicle not overloaded, the tyres will not be overstressed using the road. Tyre engineers conduct route studies on routes to determine the stresses and strains that a tyre will experience when traveling along the specific route. The route studies include an evaluation of concepts such as the rutting on the road, but also focus on factors causing undue stresses and strains on a tyre using the road. These include the excess heat build-up as a tyre has to traverse uneven surfaces and potholes, the stresses caused by varying surface textures due to differences in road surface type and patches in specific wheel lanes, and the subsequent reduction in tyre life due to use on a specific route. In this paper some of the aspects typically investigated in such a route study are highlighted, and the typical factors affecting the tyre life discussed. The paper is partly based on experiences with various routes in the country, and it aims to highlight to road engineers and roads authorities the major role that they can play in potentially extending the lives of tyres using their roads, and ultimately in the national economy through lower transport costs and improved safety conditions.