## 1 Introduction  
Sustainability in construction is one of the Sustainable Development Goals (SDGs) established by the United Nations (UN) [1]. In order to prevent the negative environmental impacts of this industry, it is necessary to address the problem both from the point of view of building sustainable infrastructures and cities and from a vision of responsible production and consumption. In general, construction uses non-renewable materials, requiring a high consumption of natural resources for its production and generates a large amount of waste at the end of its useful life [2]. In Europe, construction and demolition waste (CDW) accounts for between 25% and 30% of all waste generated in the European Union, amounting to 800 million tonnes per year [3]. In Spain, 14,341,183 tonnes of waste were produced annually on average in the period of 2018-2020 from construction [4]. The main component of CDW is concrete [5], responsible for 4-8% of the world's CO\({}_{2}\) emissions [6]. In turn, waste concrete infrastructure comes mainly from Public Works, which is supervised by the transport minister. Supervision is the responsibility of government administration and amounts to 6,140,009 tonnes on average per year, representing 39.76% of total production. Therefore, one of the main solutions proposed is the use of recycled materials in the production of concrete. This solution reduces the use of virgin aggregates and eliminates the presence of waste in landfills [7]. European guidelines indicate the need for a sustainable use of resources, as well as the need to ensure recycling of at least 70% of CDW [8]. Nevertheless, country regulations for the manufacture of structural concrete significantly restrict the use of recycled aggregates, limiting it to a portion of coarse aggregates and preventing the use of fine recycled aggregates [9]. Consequently, most studies for the re-use of CDW have focused on applications requiring lower mechanical performance with non-structural concretes [10; 11; 12; 13]. Nevertheless, exhaustive research into the properties of recycled concrete aggregates [14] has demonstrated their viability for use in higher performance applications when properly treated [15] or when sourced from higher quality elements such as precast structural elements [16]. This type of element generally presents a characteristic concrete strength of more than 40 MPa, so its waste allows obtaining recycled aggregates of higher quality to be used in structural concretes [17]. The use of these recycled aggregates makes it possible to achieve strength and bonding properties comparable or superior to those of other structural concretes [18] whose minimum strength value is 20 MPa for mass concretes and 25 MPa for reinforced or prestressed concretes [19]. In addition, the use of precast concrete rejects as recycled aggregate results in up to 15% less energy consumption and carbon dioxide emissions compared to other recycled materials [20]. Due to regulatory constraints, studies in structural concrete are not very common. Nevertheless, research such as that of [PERSON] et al. [21] affirms the potential of these rejects from precast elements even for self-consumption in the same precast plants. [PERSON] et al. [22] validate this theory by manufacturing new building blocks from precast block rejects on an industrial scale. [PERSON] et al. [23] agree that this type of recycled aggregates have a higher quality than average, allowing them to achieve similar characteristics to conventional concrete and propose the elimination of restrictions on their use. Regarding the amount of aggregates to be used, [PERSON] et al. [24] highlight in their research that substitution percentages up to 20% do not affect the properties of the concrete, and higher substitution percentages cause an increase in the amount of cement.