Use of Locally Available Materials in Pavement Sub-Base

Abstract

Now-a-days the depletion of natural resources has been a major issue in the construction sector from which the road segment cannot be excluded. Because of the extensive road construction processes the aggregate demand is so huge that lots of blastings, quarrying, crushing and transportation activities are consuming a lot of energies, but also the aggregate materials are depleting fast and are in short supply. On the other hand, industrial wastes, by-products and locally available unused materials which are considered as non-conventional materials are causing environmental and dumping problems, but can have a potential for their application in road constructions. In the present study, an attempt has been made to utilise two types of materials such as the slag, a waste material from the steel industries and locally and abundantly available gravel (moorum) in the road sub-bases. The chemical composition, phase composition, toxic and heavy metals present in both the slag and its leachate water are studied. Its gradation and other physical properties are studied by using suitable tests and techniques. Conventional crushed aggregates are also used in conjunction with the slag or moorum to satisfy the desired grading for use in a particular layer as per the specifications of the Ministry of Road Transport and Highways. The optimum percentage of the slag and moorum that can be used in sub-base layer is found to be 80% and 50% respectively. In case of moorum, cement has also been used in required quantity to get the desired strength. The physical properties have been studied. It is observed that both the slag and hard moorum have excellent properties as road aggregates and can be used in the road base and sub-base applications