STUDY ON USE OF SHINGLE AS ROAD CONSTRUCTION MATERIAL FOR BASE COURSE

Abstract

Shingle is the aggregate occuring in river bed. Aggregates form the major portion of the pavement structure and it is the prime material used in pavement construction. Aggregates primarilly bear the stresses and have to resist wear due to abrasive action of traffic. Due care should be given in the proper selection of the aggregates. Although hard aggregates are found almost all over India, but these are scarce at certain places like Indo-Gangetic planes. Similarly soft aggregates occur at all, places in India, while these aggregates have low crushing and abrasion value than the hard aggregates. In the present study, attempts have been made to review the various types of aggregates and their properties including soft aggregates. Shingle has been used in base course for road construction instead of conventional crushed stones. Various tests for judging the suitability of the ,aggregates using shingle density tests and shear tests (using large shear box) have been conducted. Plate load test on different pavement models using different types of base course material have also been conducted and various curves have been drawn. The thickness <DJE''pavements have also been calculated using Burmister's two layer theory and compared. It has been found that shingle can be used successfully in base course construction instead of crushed iv stones. Economic analysis shows that cost of pavement material, is much less when shingle : Screening : sand in proportion 4.5:2.5:1 by weight are used, in comparision to that when crushed stones are used in base course construction. Further, the use of shingle will be much more economical if it is found locally. It has been recommended that vast potentials offered by shingle should be fully exploited for the construction of base course in the flexible pavements.