Abstract
The purpose of this research study was to evaluate the effects of plant type and production parameters on the stiffness, performance, and degree of blending between the aged and virgin binders of plant-produced reclaimed asphalt pavement (RAP) mixtures. Mixtures from a batch and a drum plant and the corresponding production information were obtained. The stiffness of each mixture was evaluated by measuring the dynamic modulus. Moisture susceptibility and rutting potential were evaluated with the Hamburg wheel tracking device. Low-temperature cracking characteristics were evaluated with the asphalt concrete cracking device. Finally, the workability of the mixtures was evaluated with an asphalt workability device. Binder was extracted from each mixture to measure the degree of blending between the aged and virgin binder. The degree of blending between the aged RAP and virgin binder in each mixture was evaluated with an analysis approach that used the ratio of the mixture dynamic modulus to the recovered binder shear modulus. Batch and drum plants produced RAP mixtures that performed similarly to the control mixtures and exhibited good blending. None of the RAP mixture tested showed increased susceptibility to moisture damage, rutting, and low-temperature cracking susceptibility as the RAP content was increased. Workability testing identified a potential construction issue as the mixture workability decreased as the amount of RAP in the mixture increased. Finally, the performance data indicated the importance of the proper virgin binder grade selection for mixtures with higher amounts of RAP.
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