Optimizing rejuvenator content in asphalt concrete to enhance its durability

The use of rejuvenators in asphalt concrete (AC) have been receiving greater attention recently due to their effect on improving the performance of AC mixes to control the impact of the increasing use of recycled asphalt. This study evaluates the effectiveness of a rejuvenator to reduce AC's cracking susceptibility utilizing the Illinois Flexibility Index Test (I-FIT). The AC's rutting potential was assessed using the Hamburg Wheel Track Test. Samples were prepared on unaged and short-term aged conditions to identify the effect of service time on AC mixes. This study found that increasing rejuvenator content on AC mixes may reduce cracking susceptibility, but possibly increase rutting. Both 2-D and 3-D balanced mix design interaction plots show that designing a durable AC mix with recycled material can be achieved by controlling rejuvenator content with and without aging. Contractors and agencies alike may use interaction plots to develop AC mixes with optimal balanced performance.