INFLUENCE OF UNBOUNDED MATERIALS PROPERTIES ON ROUTING POTENTIAL OF LOW VOLUME ROADS.

Rural roads are the tertiary road system in total road network which provides accessibility for the rural habitations to market and other facility centres. In India it consistutes about 85% of the total road network. However, merely creating the road assets is not enough and it has to be maintained periodically and preserved carefully. Majority of these roads are provided with flexible pavement. But the rate of deterioration of flexible pavement is much higher than the rate of deterioration of a rigid pavement and hence maintenance cost involved is higher. The Government of India lunched the Pradhanamantri Gram Sadak Yojana (PMGSY) in December – 2000 with an aim to provide all weather roads to rural areas. It was proposed to take up 173,000 unconnected habitations of population above 500 (250 in case of hilly, desert and tribal areas) under PMGSY programme. With this background in the present study, fifteen low volume roads were identified in Warangal, Guntur and Kurnool districts in Andhra Pradesh to carry out the pavement performance study. The main objective of this study is to evaluate the influence of unbound material properties such as Water Bound Macadam (WBM) base course gradation (grading II and grading III) granular sub-base gradation, sub-base and subgrade field densities and subgrade moisture content on the rutting potential of low volume roads. The detailed analysis was carried out using the SPSS stastical tool and permanent deformation (rutting) model has been developed.