Journal of Civil Engineering and Environmental Technology Print ISSN: 2349-8404; Online ISSN: 2349-879X; Volume 1, Number 4; August, 2014 pp. 49 – 52 © Krishi Sanskriti Publications http://www.krishisanskriti.org/jceet.html A Comparative Study of River Borne Coarse Aggregates Of The Rivers - Pagladiya, Kopili And Kulsi (Assam) In Their Natural Form For Their Utility As A Road Construction Material Nabanita Sharma Civil Engineering Department Royal Group of Institutions, Guwahati, Assam, India Abstract: Aggregates play an important role in civil engineering construction. They are used to build and maintain urban,suburban, and rural infrastructures including commercial and residential buildings; highways,bridges, sidewalks, and parking lots; factories and power generation facilities; water storage, filtration, and delivery systems; and wastewater collection and treatment systems. In the past, the river borne aggregates and aggregates collected from quarry were both used in construction purposes depending upon their availability. Collection of aggregates by blasting can create huge amount of pollution and excessive destruction of hilly structures and forest materials. Thus, it has become necessary to locate the alternative sources of locally available natural aggregates.The Northeastern part of India is a hub to several rivers and their tributaries, which carry considerable amount of coarse aggregates. The engineering properties of such river borne aggregates need to be studied in details for better evaluation of their utility as road construction material. The present study involves a detailed analysis of river borne coarse aggregates in their natural state collected from three rivers, viz. Pagladiya, Kopili and Kulsi. The aggregates have been collected from the banks of these rivers flowing through various places of Assam. Also, a comparative study has been made between the engineering properties of the aggregates collected from the three rivers showing the nature of variation in these properties and thus, inferring that the aggregates collected from which river is more suitable for road construction purpose. Keywords – River borne aggregates, road construction, engineering properties 1. INTRODUCTION Aggregates are essential constituents of concrete. They are crystalline or granular rocks that are extracted for use in the various construction works. With the increasing demand of construction, use of aggregates has become equally necessary. Aggregates can be collected from the river sites or by blasting of rocks in the quarries for their use in construction purposes, depending upon their availability. But due to quarrying by blasting various harmful and noxious gases are released into the environment which eventually pollutes the environment [2]. Thus it has become necessary to locate the alternative sources of locally available natural, river borne aggregates. The present study involves a detailed analysis of river borne aggregates in their natural state. The aggregates have been collected from the banks of the river Pagladiya, river Kopili and river Kulsi, which flow through the various places of Assam and a comparative study has been made between the engineering properties of the aggregates collected from the three rivers. From this study, we can interpret the suitability of the river borne aggregates as construction material. The main purposes of the study are as follows: 1. To carry out the geotechnical tests on natural form of river borne aggregates. 2. To see the property variation, if any, of the aggregates collected from river Pagladiya, river Kopili and river Kulsi. 3. Finally, interpretation of results to find their suitability as road construction material. 2. STUDY AREA The Pagladiyariver originates from southern slopes of Bhutan hills latitude of 26°59’ north and longitude of 91°27’ east. It is outfalls of Brahmaputra near Laopara. The river flows for a length of 19 K.M. in the hilly track of Bhutan and rest 177.80 K.M. flows through the Nalbari and Baksa districts of Assam. The aggregates were collected from the banks of the river Pagladiya in a place