Environmental and Economic Comparison of Natural and Recycled Aggregates Using LCA

Abstract

Recycled aggregates (RAs) have been playing an important role in replacing natural aggregates (NAs) in concrete production, thereby contributing to a reduction in the extraction of natural resources and the promotion of a circular economy. However, it is important to assess the global impacts of this replacement, in both environmental and economic terms. In this study, an overview of the impacts of the production of natural and recycled aggregates is presented, using the life cycle assessment (LCA) methodology. Through this methodology, products with the same function are compared and information about the best solutions is given, considering their environmental and economic impacts. Studies with data collected from specific producers were compared, as well as environmental product declarations (EPDs) and generic databases, regarding the production of natural and recycled, coarse and fine, and rolled and crushed aggregates. This study intends therefore to provide the environmental and economic impact comparison at the global level through LCA from different data sources. According to this literature review, the best and worst environmental results are assigned to lower and higher transport distances, respectively. Regarding EPDs, the lowest environmental impacts are related to recycled coarse aggregates and the highest to natural coarse crushed aggregates. In terms of generic databases, the results are similar, with the lowest impacts associated with natural fine rolled aggregates and the highest to natural coarse crushed aggregates. In what concerns the economic impacts, in general, recycled aggregates are associated with the lowest costs. However, these results are highly dependent on transport distances and costs.

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“…It is worth noting that numerous LCA studies (e.g. de Brito et al, 2022;Dias et al, 2022) have demonstrated discrepancies in natural resource consumption between NAC and RAC, as evident by indicators such as abiotic depletion. However, the current study's calculation Fabric filter à Fresh-water is pumped from a river by electricity.…”

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“…Grabois et al [18] analyzed the performance of RCA mortars through different impact categories and observed that high levels of Natural Aggregate (NA) replacement by RCA was less detrimental to the environment and that the RCA evaluation was strongly influenced by long transport distances. Transport distance is also mentioned by Dias et al [19] as a crucial parameter in RCA LCA.…”

Special Issue “Feature Papers in Recycling 2022”

“…The LCA approach is a methodology widely used in waste management studies to find the best option in terms of environmental and economic impact. In [8], the authors used LCA results from different sources to compare the production of natural and recycled aggregates for concrete. The authors considered the following parameters to perform the comparison: global warming potential, non-renewable energy consumption, and the cost of 1 tonne of natural and recycled aggregates from cradle to gate.…”