Innovative hot recycling of wearing course layers: laboratory characterization of 100% RAP asphalt concretes.

In the road paving sector as “recycling” is meant the possibility to recover and reuse the milled material (Reclaimed Asphalt Pavement - RAP) from the old paving and to produce new bituminous conglomerate out of it. From the environmental and energetic point of view this would represents an incredible reduction of impacts, and consequently it will provide remarkable savings also from the financial side. For these reasons it must be pursued the maximization of the recycled materials’ share. The present study has the aim to characterize in laboratory a mixture produced with 100% RAP in an innovative hot recycling technique for wearing course layers. No new virgin aggregates will be added in the mixture, but will be employed three different chemical additives at different dosages. The performed experimental activities can be divided in two main types: the first one involves the characterization of the available milled material, in terms of particle distribution and volumetric characteristics; the second one concerns the optimization of the final mix’s design: both volumetric (Curve density, air voids content) and mechanical (ITSM, ITS, ITSR, Particle loss tests) characterization will be performed. The results of the different samples tests will be compared in order to define the most performing additive and its correct dosage, but most importantly will be verified their compliance with the current legislation. This work is organized in 6 chapters: after this first introductive one, the second chapter will deal with the theoretical background on the different pavement’s recycled materials; the third one will explain the many possible recycling techniques available for the bituminous conglomerate production, and how can they be modified in order to process RAP; the fourth will introduce every step of the experimental program in detail, while the fifth will be dedicated to the exposition of the results. The sixth and last chapter will be reserved to the conclusions.