A THESIS SUBMITTED TO THE FACULTY OF CIVIL ENGINEERING ARBA MINCH INSTITUTE OF TECHNOLOGY, SCHOOL OF GRADUATE STUDIES

Abstract

Road construction is frequently fraught with hazard due to a shortage of good quality materials, and the rising of paving materials cost during the restoration and expands of highway building. As a result of the construction of new roads as well as the maintenance of the existing road network, this problem worsens over time. These have encouraged to Recycling wasted pavement material for economic benefit and reduce the exploitation of natural resources. The main purpose of this study was to investigate the use of Reclaimed asphalt pavement (RAP) as an alternative pavement material in an asphalt mix, and its impact on the engineering material properties. A total of four asphalt mix containing RAP were investigated, each comprising different percentage amounts of RAP blended with 10/90, 15/85, 25/75, and 35/65 proportions by total weights of aggregate. Laboratory studies have been conducted on a flexible pavement mix with these materials. The physical properties test results for natural blended with RAP aggregate gives ACV, AIV, LAA, Water absorption, Moisture content and Soundness test, of 16%, 9.72%, 14.11%, 1.99% ,1.58% and 7.41% respectively. Marshall tests were carried out in the laboratory to determine the optimum asphalt content according to standard specifications. The effects of RAP on marshal physical properties i.e., Stability, Flow value, Void in the Mix (VIM), Void in Mineral Aggregate (VMA) and Void Filled with Asphalt (VFA) were investigated. The indirect tensile strength test was used to study the influence of the proportion of RAP in the mixtures on moisture damage. From results in laboratory mixtures containing 25% RAP was found to be the best fitted percentage amount to replace virgin aggregate in binder course mix. The optimum bitumen content for this mix was determined as 5.2%.