Analysis of reclaimed asphalt blended binders using linear and nonlinear viscoelasticity frameworks

This paper presents a comprehensive analysis of blended asphalt binders extracted from mixtures that contain various amounts of reclaimed asphalt pavements (RAP). The analysis is performed within a thermodynamically consistent non-linear viscoelastic (NVE) modeling framework, which has the advantage of accounting for the contributions of each of the constituents (i.e. virgin binder and RAP binder) to the response of the blended binder. In order to calibrate and validate the NVE model, the RAP blended binders were subjected to different testing protocols: frequency sweep, multiple stress creep and recovery, repeated creep and recovery with multiple stress levels, random creep and recovery, and stress relaxation. For the binders used in this study, linear viscoelasticity (LVE) was suitable to model the frequency sweep and multiple stress creep and recovery data, but it did not capture the repeated creep and recovery with multiple stress levels results that involved higher stress and strain levels. The NVE model, on the other hand, was successful in describing the repeated creep and recovery with multiple stress levels results. The validation was achieved by comparing the NVE model predictions with the random creep and recovery and stress relaxation test results. Finally, the paper recommends a new method, based on the parameters of the NVE model, to evaluate the rutting resistance of blended asphalt binders.