Influence of unbound material properties on rutting potential of low volume roads

Abstract

More than 80% of roadway mileage in the world carries less than 400 vehicles per day and these roads are classified as low volume roads. India has essentially a rural oriented economy with 72% of its population living in villages. The low volume roads are part of tertiary road system, which consists of other district roads and village roads. The traffic conditions on these roads are distinctly different from the major roads. A variety of vehicles are used for transportation of goods on rural roads, ranging from bullock-carts to the fast moving commercial vehicles. Permanent deformation of the unbound base and sub-base layer is one of the distress types on these roads that require extensive maintenance. The gradation is the most important property that an aggregate can contribute to the performance of pavement. In the present study, an attempt has been made to investigate the rutting potential of low volume roads, taking into account base course gradation, sub-base course gradation, sub-base field density, subgrade field density, subgrade moisture content, subgrade California Bearing Ratio, and traffic volume. The influence of these factors on the rutting potential of in-service pavements has been investigated and a response type model has been developed.