Laboratory and In-Plant Validation of Hot Mix Recycling Using a Rejuvenator

This paper shows an experimental investigation developed in laboratory and in mix-plant for the validation of an asphalt concrete (AC) produced through the hot mix recycling (HMR) technique. A specific rejuvenator was used to improve the mechanical characteristics of the AC containing reclaimed asphalt (RA). The optimum dosage of the rejuvenator was selected on the basis of the viscosity of the bitumen recovered from RA. The AC produced with the optimum dosage of rejuvenator and 30% of RA was characterized in laboratory by means of indirect tensile strength (ITS) and indirect tensile stiffness modulus (ITSM). The results obtained in laboratory were validated by testing the AC produced in a mix-plant. The Fourier transform infrared spectrometry (FT-IR) was used to evaluate the interaction between rejuvenator and bitumen and to check the presence of the rejuvenator to produce the AC in the mix-plant.