Empirical Study of Warm Mix Asphalt Incorporating Recycled Asphalt Pavement

The depletion of natural resources along with the progressive change of climate due to high heat and harmful gas emission into the atmosphere are the concerns engineers, scientists and politicians have been addressing and cooperating toward finding efficient solutions to palliate to this global issue. Thus, the use of Warm Mix Asphalt (WMA) incorporating Recycled Asphalt Pavement (RAP) as part of a long-term solution has gained prominence in part of Europe, Asia and America and most recently in South Africa. Though the WMA–RAP possesses environmental benefits, yet it presents inconsistent mechanical performances related to many factors. Hence, this paper aims to evaluate the tensile strength, the rutting and the fatigue performance of WMA incorporating RAP, at 15% and 30%, and also to compare them against the performances of the traditional Hot Mix Asphalt (HMA). Consequently, laboratory experiments such as Indirect Tensile Strength (ITS), the Four-Point Beam Bending test and the Hamburg Wheel Tracking (were) carried out to evaluate the mechanical properties of the WMA–RAP. Results of the study show that, the control hot mix asphalt (HMA-CM) exhibits lower tensile strength and rutting performance than the WMA–RAP. As far as the fatigue cracking performance is concerned, the WMA (15% RAP) performs better than the HMA-CM and the WMA (30% RAP). Overall, the incorporation of RAP in the WMA at up to 30% may possess satisfactory mechanical performance and can be applied to the construction and the rehabilitation of medium traffic volume roads.