Rejuvenator effectiveness in reducing moisture and freeze/thaw damage on long-term performance of 20 % RAP asphalt mixes: An Australian case study

Due to hoisted ecological and economic awareness, the use of Reclaimed Asphalt Pavement (RAP) in road pavements is universally recognized as a practical choice to limit the use of raw material, such as aggregates and bitumen, and reduce construction costs. Despite the environmental and economic benefits, in any given year of their service life pavements undergo a range of conditions that may affect their long-term performance. These may include moisture damage and freezing and thawing, for instance. This study presents a laboratory investigation that has been conducted on asphalt mixes containing 20 % RAP material, commonly used by the Australian road industry, to analyse the effect of moisture and freeze/thaw cycles on asphalt long-term performance. The use of a rejuvenator was tested to evaluate any potential increase in durability due to the improved degree of blending and activation of the RAP binder in the asphalt mix. In addition to the standard tensile strength ratio (TSR), asphalt samples were tested - before/after moisture and freeze/thaw damage - under cyclic loading for the assessment of the residual stiffness value, moisture-affected residual fatigue life and rutting. Results highlighted how the use of the rejuvenator can contribute to slow down the deterioration of RAP mixes and reduce moisture and freeze/thaw damage effects on pavement durability.