Use of recycled aggregates in bituminous mixes

Abstract

Increased construction activities especially in the developing countries like India are consuming huge quantity of construction materials. Construction industries are at the booming level and among the construction activities, pavement construction consumes abundant quantity of natural aggregates as it runs over longer stretches. In addition to this, construction of residential buildings, bridges, public utilities, government offices also consume large quantity of aggregates. Inspite of India having the has second largest road network in the world after United States (US) many of the roads are under upgradation and some of the new roads are being constructed in the upcoming years. This leads to scarcity of natural aggregates and it is high time to seek for sustainable design approaches. Reclaimed asphalt pavement (RAP) is the removed material obtained from the demolition of existing bituminous surfaced pavements. RAP is usually dumped as a stockpile on either side of the roads which causes environment related issues. RAP in its original form constitutes aggregates coated with bitumen. If properly processed, RAP possesses reusable aggregates. To address the scarcity of natural aggregates demand and issues related to waste disposal, present study focusses on investing the effect of recycled aggregates on the performance of bituminous concrete (BC). Initially the stability, flow and volumetric properties of conventional bituminous concrete are determined through Marshall mix design and testing. With the obtained optimum bitumen content, bituminous mixes containing recycled aggregates (RA) with varied proportions (0 to 30%) were tested. From the Marshall test results, it is observed that mix containing 25% RA and 75% conventional aggregates satisfy the requirements of the bituminous concrete.