INVESTIGATIONS ON COST EFFECTIVE DESIGN OF ROADS UNDER PMGSY

Abstract

The important aspect of developing low volume roads in rural areas is to aim at providing basic access at minimum cost covering as many as villages as possible, within the allocated funds. To keep the developmental costs to minimum, yet at appropriate levels of serviceability, choice of materials is an important consideration. If the same quality of materials is insisted up on, as specified for higher road facilities, the cost of materials and consequently the high initial cost of construction will defeat the very objective of adopting low cost techniques for low volume roads. Experience all over the world has shown that it is possible to incorporate locally available materials at low cost and yet provide a road facility at an appropriate, acceptable level of serviceability. The local materials may be incorporated as such, as they occur in nature, or may be suitably processed at low cost to render them suitable for use in road works. The present study engineering properties of low grade materials are studied. The mix proportions are obtained from codal provisions. CBR tests and flexural strength tests are carried out on these mixes. Pavement sections are designed in accordance to rural road manual IRC SP 20: 2002. Costs of these pavement sections are analyzed. It is observed that lime fly ash bound macadam can replace conventional WBM construction and up to 27 % decrease in cost can be achieved. Pavement sections designed with steel industry wastes have shown 30 to 40 % reduction in cost as compared to other alternatives that are studied in the present study. Lime fly ash stabilized base courses showed 25 % decrease in cost as compared to conventional type of construction.