Asfalti tappabuche e Green Deal

This article presents the first results of a study conducted as part of the european research project InfraROB, whose aim is to increase the safety of workers and road users at road maintenance sites. In particular, as part of the project, a system for repairing small potholes by means of an autonomous device is currently being studied. A 3D printer will be installed on this device in order to extrude a mixture suitable for the pothole to be repaired, without the prior cleaning and compaction of the backfill. In particular, this article presents the laboratory and in situ study aimed at defining the optimal characteristics for the mixture to be used to power the 3D printer. Grain size, Marshall stability, void content, indirect tensile strength and material loss were studied in the laboratory using the Cantabro test. These characteristics were evaluated by varying the additive content in the range of 1.5-3.5 per cent and the water content in the range of 3.1-5%. The maximum aggregate size was limited to 8 mm, because the InfraROB project only deals with the repair of small potholes, with a maximum size of 5 cm depth and 20 cm diameter. From the point of view of sustainability, the technology involves the use of 100% rejuvenated RAP (Iterlene ACF 1000 HP Green) with blending at room temperature. A total of eight mixtures were tested. Laboratory tests gave very good results in terms of indirect tensile strength, Marshall stability and particle loss; the mixture proved to be very stable during in-situ tests. Other cold asphalt mixtures are still being studied within the InfraROB project, but at the moment, the mixture presented in this article seems to meet all the requirements of consistency, homogeneity, fluidity and internal structure necessary to be used with a 3D printer.