Polyphosphoric acid and styrene-butadiene-styrene block copolymer modified asphalt: evalutation of paved section at the NCAT test track built in 2000 and 2003

Since the first pavement construction at Auburn University, USA in 2000, multiple pavement made of mixes produced from binders modified with Polyphosphoric Acid (PPA) in conjunction with Styrene-Butadiene-Styrene (SBS) block co-polymer, with different design and with diverse aggregate sources have been laid down and monitored. The NCAT test track monitoring constitutes a unique opportunity to assess, under known conditions, the impact of PPA on ultimate pavement performance. Although PPA has been used for decades in the process of producing improved binders, very little pavement performance data, over significant period of time and under heavy traffic conditions, were available to address the remaining questions of some transportation agencies. The results of the monitoring of several sections involving binders, modified with SBS in combination with polyphosphoric acid, over the past 6 years in terms of rutting, fatigue cracking and moisture resistance are presented. For the covering abstract see ITRD E157233