In the Mechanistic–Empirical Pavement Design Guide (M-EPDG), prediction of flexible pavement response and performance needs an input of dynamic modulus of hot-mix asphalt (HMA) at all three levels of hierarchical inputs. This study was intended to verify that this input modulus could be achieved in the field construction. Four newly built Superpave pavements of the Kansas Department of Transportation and four Superpave pavement test sections on the Kansas perpetual pavement project on US-75 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. Normalized deflection data for all new projects and test sections were used to back-calculate asphalt layer moduli using three backcalculation computer programs, EVERCALC, MODCOMP II and MODULUS. Laboratory dynamic modulus tests were conducted on asphalt concrete (AC) cores from four new projects and on laboratory-compacted samples from the US-75 perpetual pavement test sections. Dynamic modulus was also predicted with the Witczak equation, new Witczak model and Hirsch model. The results show that the backcalculated AC moduli from various programs used in the study are generally comparable for all projects and test sections. The backcalculated modulus is highly affected by the FWD test temperature. Laboratory dynamic modulus is comparable for all projects and sections at 40o F but the variation increases as the test temperature increases. The laboratory dynamic modulus is much higher than the backcalculated moduli at 70o F and 25 Hz test frequency. The discrepancy is greater when the dynamic modulus test samples are compacted in the laboratory. The Witczak equation underestimates the dynamic modulus at low temperature and overestimates it at higher temperature. Results from the Hirsch model and new Witczak equation are better. The parameter estimate when the laboratory dynamic modulus is used as a dependent variable and the moduli from other approaches as independent variables is close to 1.0, especially for the AC moduli predicted by various prediction methods. This may indicate that the prediction equations can be used for estimating dynamic modulus of Superpave mixtures.
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