Predicted impact of design parameters in asphalt concrete layers on pavement performance

Abstract

The scope of this study was to assess the predicted impact of design factors (voids percentage (Va), effective binder content (Vbe) and aggregate gradation) in each asphalt concrete (AC) layer on pavement performance for conditions in Izmir, Turkey. Research was conducted on three flexible pavement structures for three traffic levels and three subgrade types using AashtoWare Pavement ME Design software. The results indicated that increasing Vbe (from 8% to 15%) and Va (from 3% to 5%) in the wearing course resulted in, respectively, almost 1.0 mm and 0.2 mm increases in AC rutting depth, 17 m/km and 145 m/km reductions in thermal cracking length and a 55.8 m/km decrease and 85 m/km increase in top-down cracking length. For the binder course, an increase in Vbe (from 7% to 14%) and Va (from 4% to 6%) led to, respectively, nearly 1.0 mm and 0.3 mm increases in AC rutting depth and a 35 m/km increase in top-down cracking length. For the AC base course, an increase in Vbe (from 6% to 12%) and Va (from 5% to 6%) resulted in a 26.3% reduction and 14.2% increase in alligator cracking area, respectively. An increase in the fine aggregate percentage and a decrease in the coarse aggregate gradation in the hot-mix asphalt mixture led to improved performance.