Field Verification of Superpave Dynamic Modulus

Abstract

In the mechanistic-empirical pavement design guide, prediction of flexible pavement response and performance needs an input of dynamic modulus of hot-mix asphalt at all three levels of hierarchical inputs. This study was intended to find the best way to predict/derive this input. Nine Superpave pavement sections were selected as test sections in this study. Deflection data on all test sections was collected with a Dynatest 8000 falling weight deflectometer shortly after construction. The deflection data, normalized with respect to 40-kN load, were used to back-calculate asphalt layer moduli using three back-calculation algorithms. Laboratory dynamic modulus tests were conducted on asphalt concrete (AC) cores and laboratory-compacted samples. Dynamic modulus was also estimated with the Witczak model, new Witczak model, and Hirsch model. The results show that the AC moduli obtained from various back-calculation programs used in the study are generally comparable. Laboratory dynamic modulus is comparable at