Effect of binder in recycled asphalt on cold-mix pavements

This research addresses various notions and perceptions associated with using recycled asphalt pavements for road construction. The research investigates how the residual binder in severely aged recycled asphalt pavements with penetration between 3 and 7 decimillimeter (dmm) influences cold asphalt emulsion mixtures in comparison to moderately aged recycled asphalt pavements with a penetration of about 20 dmm. Cold-mix asphalt specimens were produced using recycled asphalt pavements, recycled asphalt pavements with the residual binder extracted and virgin aggregates. The recycled asphalt pavement was aged to simulate moderately and severely aged asphalt pavement conditions (20 and 5 dmm, respectively). The results show that cold asphalt emulsion mixtures produced using recycled asphalt pavements with residual binder in them had considerably higher stiffness, fatigue and permanent deformation results in comparison to recycled asphalt pavements without the residual binder. The 20 pen recycled asphalt pavements produced the stiffest specimens and gave the greatest fatigue lives, although the 5 pen recycled asphalt pavements gave the best resistance to permanent deformation. Specimens with recycled asphalt pavements from which the binder had been removed performed poorly. This research study shows that the residual binder in recycled asphalt pavements adds valuable mechanical and performance properties to cold-mix asphalt.