Environmental evaluation of applications of concrete with recycled material from tyres

Alternatives for using end-of-life tyres as a component of concrete are currently being studied. Particularly, granulated rubber and steel fibres from tyres can generate relevant technical benefits in concrete. However, it is not clear what environmental benefits these alternatives can provide. Hence, a study was carried out to evaluate, from an environmental perspective, applications of concrete with recycled materials from tyres. For this purpose, a streamlined life-cycle assessment was developed to compare the impact of the use of concrete with tyre materials and traditional concrete for safety barriers, railway sleepers, pavements and masonry mortar. Furthermore, the analysis was based on energy-thermal simulations, experimental work and collected studies. The results indicated that a safety barrier and a railway sleeper with tyres can reduce the harmful impact by 60 and 50%, respectively. For masonry mortar and concrete pavement applications, the impact reduction was between 4 and 10%. Moreover, one case was observed where, to comply with the technical requirements, it was necessary to incorporate more material into the concrete mix. This had a significant impact on the results, which meant that no environmental benefits were generated. Therefore, the study showed that to ensure the benefits of an application, it was required to consider not only the technical advantages but also the environmental savings that contributed to sustainable construction.