Mechanical characterization of dry asphalt rubber concrete for base layers by means of the four bending points tests

Abstract

The mechanical characterisation of the asphalt concrete in terms of both the fatigue resistance and the stiffness modulus is necessary to use any design method of the flexible road pavements. Even more the determination of these mechanical properties is necessary if the asphalt concrete investigated is an innovative material as a dry asphalt rubber concrete DARC (i.e. a bituminous mixture with rubber via dry process). Such material is less known and investigated than the asphalt rubber concrete via wet process, even if its application implies peculiar economical and environmental advantages such as no specialized equipment or significant plant modifications and large quantity of recycled waste tires compared to the wet process. This paper focused on the mechanical behaviour of some DARCs with different rubber content that varies within 0, 3.0% by weight of the aggregates; these materials are designed to the base layer of the flexible pavements. In particular an experimental survey was carried out in order to determine the stiffness modulus of the DARCs by means of the four point bending test on prismatic specimens (UNI EN 12697-26:2004).