Understanding the changes in the structural characteristics of paving layers with season and asphalt binders type is essential in predicting how well the pavement responds to traffic loads and thus how long it will last. This paper presents a small scale investigation on the seasonal variations in the structural characteristics of pavement layers constructed employing polymer modified asphalt binders. These variations are compared to those of an unmodified binder. Illustrated are the influences of asphalt binder type and seasonal temperature variations on: One) center deflection (D0 ) measured by the falling weight deflectometer (FWD), Two) in situ asphalt concrete modulus (EAC ), Three) in situ base course modulus (Eb ) and Four) in situ subgrade resilient modulus (MmR) Analysis of results for the two polymer modified sectins and the three unmodified control section used in this study indicates that EAC is the parameter most affected by the change in temperature followed by D0 and Eb . The in situ asphalt concrete modulus (EAC ) of the polymer modified sections has shown less sensitivity to temperature changes than other three control sections, especially at high temperature levels (35 0 C -45 0 C). Variations in Eb with temperature are believed to be associated indirectly with variations in EAC with temperature. Changes in EAC with temperature result in changes in stress levels imposed on the underlying layer that causes variations in Eb . Temperature adjustment factors for D0 , EAC and Eb are provided for both polymer modified and unmodified sections. (A)
Abstract