Speaker
Description
Abstract. Dynamic modulus of Hot-Mix Asphalt (HMA) is a primary mechanical property input for flexible pavement design analysis using the AASHTOWare Pavement Mechanistic-Empirical Design (PMED) software. In this research, dynamic modulus inputs were used for design analysis of 21 newly constructed asphalt surface projects with the PMED software to predict asphalt pavement performance and to compare hierarchical Level 1 and Level 3 inputs. Level 1 inputs were obtained from the dynamic modulus tests conducted on mixtures up to 25% recycled asphalt content (RAP) following the AASHTO T 342-22 standard test methods. Level 3 inputs were obtained as defaults in the PMED analysis software. The PMED software predicted two load-related cracks associated with dynamic modulus: asphalt concrete (AC) longitudinal cracking (top-down cracking) and alligator cracking (bottom-up cracking). Roughness in terms of the International Roughness Index (IRI), permanent deformation (rutting), and thermal cracking were also predicted. The results show that for minor arterial projects, in most cases, the projects failed in AC bottom-up fatigue cracking for both Level 1 and 3 input levels. Comparing Level 1 to Level 3 distress prediction, the AC top-down fatigue cracking drastically increased but did not exceed the target value. The other predicted distresses were similar for Level 1 and 3 inputs. These observations regarding top-down cracking and other distress were also observed for the principal arterial projects. With reduced AC thickness, bottom-up fatigue cracking and terminal IRI increased for all minor and principal arterial projects. Other distresses remained the same irrespective of project type or levels of HMA dynamic modulus inputs.
