Reintroducing the intrinsic self-healing properties in reclaimed asphalt by rejuvenation

Abstract

Reclaimed Asphalt (RA) is one of the largest fractions of raw materials used in road construction today. Probably over 90% of the total RA in the Netherlands is being reused in new asphalt constructions. RA contains aggregates coated with very hard bitumen (penetration grade of 10-20). During service, the bituminous binder loses its flexibility and its intrinsic self-healing capability because of ageing. These parameters are critical for reconstructing new durable surface layers. Therefore it is very important to reintroduce the flexibility and the intrinsic self-healing capability of the RA. In order to achieve this goal, rejuvenation technology is developed in this paper to re-compound to the aged bitumen in the RA. A preliminary research has been conducted to evaluate the effect of different potential rejuvenators on aged bituminous binders by means of laboratory blending. Two types of laboratory aged bitumen and six types of rejuvenators were developed. The rheological properties were evaluated by using the Dynamic Shear Rheometer (DSR), and the chemical compositions were evaluated using the Infrared Spectrometry (FT-IR). The thermodynamic properties of the blended bitumen were evaluated using the Differential Scanning Calorimetry (DSC) measurements. It is shown that with the blending of the rejuvenator into the laboratory aged bitumen is a physical process, the bitumen can regain its flexibility with a lower complex shear modulus, a higher phase angle and a lower glass transition temperature. A softer rejuvenator shows a higher potential. No significant chemical change can be observed for the rejuvenated bitumen. This research is on-going to investigate the diffusion capabilities of rejuvenators on the field aged reclaimed asphalt and the fatigue and healing evaluation.