Although construction has existed since the origin of civilization (Greek and Roman temples serve as an example), construction with structural elements of precast concrete is more recent. The origins of these precast elements date back to the early nineteenth century when, in Chicago, the first blocks based on lime cements and limestone aggregates were used in masonry walls, as an alternative to natural stone. Prefabrication is the industrialized version for construction and its many advantages include greater reliability (quality), dimensional precision, speed of execution, optimization of sections, greater work safety and longer useful life. Hence, in recent decades, many countries, such as the USA, Japan or The Netherlands, are promoting the prefabrication industry, consolidating the use of precast elements. However, and as with other activities related to construction, the precast sector requires a large amount of natural resources, since almost 80% of the total volume of concrete is aggregates. This is leading to a progressive depletion of natural resources, forcing all countries to adopt more sustainable construction. In this regard, it is worth highlighting the “Precast Sustainability Strategy and Charter” of the British Precast Concrete Federation [1
] where measures to reduce energy consumption, eliminate waste and implement environmental and sustainable management systems were introduced. Furthermore, they have recently approved new targets in line with the Sustainable Concrete industry Strategy targets and the construction industry Low Carbon Route map to 2050.
Therefore, taking into account that construction and all activities related to cement consume a large amount of natural resources, the recovery of concrete and its subsequent treatment to re-incorporate as a substitute for natural aggregate has taken on great importance. Since 2011, all precast sector companies in the European Union, complying with EU Regulation 305/2011 [2
] have had to use natural resources sustainably.
The use of recycled aggregates (RA) from concrete can be an alternative to natural aggregates for the manufacture of different types of concrete, which has a positive impact on the environment by reducing the continuous exploitation of natural aggregate quarries that produce an important environmental impact and also has a favourable impact on the economy. Numerous investigations have been carried out to find ways to use this type of RA in the manufacture of concrete [3
], generally observing a decrease in the properties and durability of concrete. A possible cause of this reduction may be a consequence of the greater absorption of the recycled aggregate with respect to the natural aggregate, producing a reduction in the water/cement (w
) ratio, which reduces the workability of the concrete and, therefore, its fresh properties. As has been shown in different studies, the use of superplasticizer additives can be an alternative to correct the workability and can be beneficial in terms of durability and mechanical resistance since it optimizes the w
]. In this regard, Sainz-Aja [10
] analysed the optimal amount of superplasticizer additive in the manufacture for self-compacting concrete. Regarding the use of RA, Thomas et al. [8
] analysed the possibility of incorporating multi-recycled aggregate for the manufacture of a multi-recycled concrete. The results showed that it was possible to incorporate this type of RA, but limiting recycling to a 3rd generation aggregate.
Regarding the mechanical properties, it has been shown that the quality of the recycled aggregate influences the compressive strength, especially when it is desired to obtain strengths greater than 30 MPa. Sami and Tabsh [12
] showed that when using high quality RA, the results obtained can be better than those obtained for control concrete. The results obtained by Pérez Benedicto when replacing 100% of the aggregate with waste from precast parts were in the same line [13
]. Likewise, Sainz-Aja [14
] demonstrated the viability of using recycled aggregate from out-of-service railway superstructure wastes for the manufacture of a more ecological SCC that also fulfils the mechanical requirements of slab tracks.
Another property that is usually affected by the incorporation of RA is the durability of concrete. In general, the incorporation of RA reduces the durability of concrete [15
], although López-Gayarre [17
] considers that the influence of RA is not significant since the durability is more dependent on the w
ratio. Thomas [18
] investigated the influence of the curing conditions of concrete with RA on its durability, observing a decrease in terms of permeability when the concrete is exposed to an aggressive environment.
The use of recycled aggregate causes a greater shrinkage in concrete compared to natural aggregate [19
]. However, the greater or lesser variation in shrinkage can be influenced by other factors such as the dosage method, manufacturing procedure and curing conditions. For example, for a 100% substitution, Limbachiya [19
] and Ravindraraja [20
], found an increase of between 10–35%, while the results obtained by Domingo [21
] showed increases greater than 70% with respect to the control concrete. The results obtained in different studies have shown that the incorporation of AR, can affect other physical processes related to the durability of concrete, such as resistance to frost [22
] or resistance to erosion [19
It can be seen that numerous studies have examined the use of concrete waste in the manufacture of new concrete, however, few studies relate to the use waste from the precast sector [6
]. These studies are mainly focused on examining the influence of these wastes on the physical and mechanical properties of concrete [5
]. Taking these data into account, the objective of this work was to analyse the influence that the use of RA from precast elements has on the durability of SCC under physical actions such as shrinkage, freeze-thaw cycles, thermal shock cycles and abrasion. This study can be considered innovative since, as mentioned above, the studies carried out to date have mainly focused on analysing the influence of these RAs on the mechanical properties of concrete. A SCC has been manufactured with a minimum compressive strength of 30 and 45 MPa for use in precast elements. The degrees of substitution analysed were 20%, 50%, 100% of the natural aggregate. The results of this research show that it is possible to use the recycled aggregate coming from precast pieces in order to the manufacture of self-compacting recycled concrete in the same precast industry.