The concept of circularity in construction is being increasingly applied with the primary objective of reducing the extraction of natural resources and mitigating the disposal of waste in landfills. In the context of mortars and concrete, this can entail a reduction in the utilization of natural aggregates (NA) and an increase in the incorporation of recycled aggregates (RA), thereby promoting more sustainable construction.
The principal objective of this paper is to ascertain the environmental consequences of incorporating RA into mortars and concrete produced at an industrial scale in Portugal. In order to achieve this, it is first necessary to determine the environmental impacts (EI) of the mortars and concrete that are currently produced by the industry. This is followed by an assessment of the impact of partially replacing NA with RA, which also involves an analysis of the consequent change in transport distances.
An environmental and economic comparison between NA and RA is presented. Several life cycle assessment (LCA) studies are then conducted, taking into account the national context. The initial stage comprises a pre-feasibility study on the supply of RA to the Portuguese industry. Subsequently, two comparative studies are presented, examining the introduction of RA into two mortar factories and two concrete plants.
In general, it may be concluded that the impacts associated with the production of RA are lower than those associated with the production of NA. Therefore, the incorporation of RA into mortars and concrete results in a reduction in the EI of their production. It should be however noted that these impacts are considerably dependent on the EI associated with cement production, as well as on the transportation distances of raw materials.