## 1 Introduction  
The first applications of waste rubber form end of Life tires (ELT) for the production of bituminous mixtures date back to the 1960s'. Since then, this field of research has gained popularity and the production technologies have gradually tried to couple both material performances and sustainability [1]. The wet method was the first production process developed by [PERSON] in the United States. The addition of recycled rubber to a bituminous mixture resulted in the so-called asphalt rubber (AR), characterized by great elasticity and viscosity at high temperatures [2; 3; 4]. However, AR binders showed issues related to production stability and storage properties [5]. Specific bitumen modification plants have been developed to solve these problems, allowing the continuous motion of the rubber particles, spreading them uniformly in the binder volume [6]. However, the environmental impact of this technology is still consistent, considering the high temperatures needed during the in-plant production and paving operations. As stated by [PERSON] et al. [7], despite its well-known advantages, AR technology has never been applied extensively. Furthermore, as highlighted in the last few international asphalt rubber conferences, a well-defined track in the use of this rubberized bituminous mixture has still to come. Thus, despite that AR technology was developed around 60 years ago, it is still not considered as a common practice in many countries. In Europe, apart from Spain and Portugal, AR was mainly adopted for research purpose. Experimental applications highlighted the advantages of the material. However, the downsides related to the high binder viscosity [8] as well as the need of special plants and specific productions operations prevented its development on a large scale. For these reasons, the potential addition of recycled rubber for the production of asphalt concretes (ACs) has been continuously investigated in the last 30 years. Most of the issues related to AR were overcome with the introduction of the dry technology [9; 10], in which the crumb rubber (CR) is added to the bituminous mixture in substitution of the fine part of the aggregates [11; 12]. However, this requires a specific mix design in order to have benefits from the addition of rubber within an AC [13]. In recent years, some novel technologies have been developed in Italy and Spain in order to merge the benefits given by polymer modified binders (PmBs) and the properties of a rubberized asphalt [14; 15]. In Italy, the new technology is called \"dry-hybrid\" and it is based on the addition of CR as partial substitution of the traditional limestone filler. Furthermore, this technology provides for the use of modified bitumen with SBS (styrene-butadiene-styrene) polymer and paraffinic wax. Thus, it is possible to reduce the production and working temperatures. As showed in previous studies [7; 8] the final aim is to add the recycled CR, without a significant modification in the asphalt plant and in the production process of a common modified AC. The proposed novel technology has been used for the production of a stone music asphalt (SMA) considering its high stones content. This creates a gap-graded skeleton-like stone structure that can be filled with a high viscosity bituminous mastic of PmB bitumen and filler [16; 17]. The positive outcomes of the dry hybrid technology have been shown in several recent studies. Researchers have highlighted the benefits given by this production method with experimental applications on bituminous mastics, mortars and ACs. [PERSON] et al. [18] analyzed bituminous mastics containing both filler and fine CR through rheological tests and discrete element methods (DEM) modelling. Results showed that the combination of fine CR and limestone filler enhances the mastic stiffness at high temperatures, increasing its rutting resistance.