Recycling of reclaimed asphalt & the influence of its varying quantitative utilisation on the technological properties of hot asphalt base-course mixes

Abstract

Recycled asphalt can be an economic alternative to new asphalt. Government authorities, such as the ADT (Malta Transport Authority) and private project managers should start ensuring that contractors are aware of the opportunities to recycle this material and to use recycled material in the new asphalt pavement construction. In this study an attempt was thus made to instil awareness in both local authorities as well as local contractors of the great economical, environmental and technical opportunities offered by the use of reclaimed asphalt in new hot asphalt mixes. The study focused on the comparison of four asphalt base-course mixes having 50%, 30%, 15% and 0% of reclaimed asphalt (RA) respectively, the latter mix (0%) being a standard hot asphalt base-course mix complying with current MTA Roads Directorate specifications. An analysis of the varying technological properties, such as stability, flow, voids content, density and compactability of the Marshall specimens was thus performed as to better determine the influence of the increasing utilisation of reclaimed asphalt as a constituent material. Mixture properties, aggregate requirements, RAP handling and homogeneity were also discussed since, together with project economics, these factors need to be considered in actually determining the amount of RAP to be used in asphalt mixes.