Environmental life cycle assessment of coarse natural and recycled aggregates for concrete.

Purpose:To present a comparative life cycle assessment (LCA) of natural and recycled coarse aggregates used in concrete production.Methods:LCA was used to compare the environmental impacts of three alternative of procurement of coarse aggregates for concrete production: extraction and processing of natural aggregates; recycling of demolished concrete either using a fixed or a mobile plant. Site-specific data supplied by companies were used to model the life cycle of these aggregates. A sensitivity analysis was also made for the critical stages of these three life cycles.Results and conclusion:This paper presents and analyses innovative LCA data of production of coarse aggregates, both natural and recycled (from mobile or fixed recycling plants). The recycling process of aggregates has to be optimised, following a selective demolition of buildings that maximises waste recovery, reuse and recycling. The use of these aggregates in the production of concrete is more favourable than natural aggregates only in terms of land use and respiratory inorganics, but coarse recycled aggregates can present a better environmental performance than natural ones if fine recycled aggregates are also used in concrete production instead of being sent to a landfill. These results are, however, very sensitive to the transportation distances. [ABSTRACT FROM AUTHOR]