Prospect of Using Reclaimed Asphalt Pavement in Highway Wearing Asphaltic Layer

Abstract

Reclaimed Asphalt Pavements (RAP) usually acquired from abandoned or damaged pavement, using it in HMA mixtures has grown into a regular practice all over the world. Incorporating RAP in fresh materials has been favored over fresh materials in the light of the increasing cost of asphalt, lacking of quality aggregate, lacking of asphalt and pressuring the need to preserve the environment. The use of reclaimed asphalt pavement is effective in improving the performance which is equal or better than the fresh mixtures. Unfortunately, asphalt pavement recycling is yet to take off in Iraq. The purpose of this study was to examine the performance between virgin mixtures and various RAP mixtures, whereas (10, 20, 30 and 40%) of RAP were obtained from two different sources. Best results can be achieved without any modifications by using 15% of RAP in both surface (IIIA & IIIB) A.M.S mixtures so that the volumetric properties were within the limits of Superpave volumetric design criteria (NCHRP-673, 2011) and by using 35% of RAP in both surface (IIIA & IIIB) A.M.S mixtures so that the volumetric properties were within the limits of Iraqi standards (SCRB, R/9 2003). Using waste engine oil (WEO) as a recycling agent to rejuvenate the aged RAP has proven to be very effective in the recycled mixtures, in which the best percentages of waste engine oil were found to be (2%, 4% and 6%) for (20, 30 and 40%) RAP in wearing mixtures, whereas all the volumetric properties and performance tests (Indirect Tensile Strength (ITS) and Tensile Strength Ratio (TSR)) were almost within Superpave and Iraqi standards.

Keywords: Reclaimed Asphalt Pavements, waste engine oil, Indirect Tensile Strength, Tensile Strength Ratio