Methodology for the environmental analysis of mortar doped with crumb rubber from end-of-life tires

The construction sector is in a process of improvement towards sustainability. The study of the use of a waste as raw materials is an opportunity. This article aims to evaluate the environmental viability of incorporating recycled crumb rubber from end-of-life tires into a mortar. To this end, a life cycle assessment tool is implemented by applying the EPD methodology to assess the various categories of impact. A series of mortar alternatives were analyzed in which fine aggregate is replaced by a percentage of crumb rubber ranging from 10% to 40%: the proportion increases by 5% in each solution. The scope of the LCA is from cradle to gate as it is during the various stages that the greatest environmental impacts are incurred: including the extraction of raw materials, their transport, as well as the production process. The functional unit is that of producing 1 m3 of mortar. The results obtained in this study show that the primary contributor to environmental impact is the cement production phase. On the other hand, the various alternatives evaluated achieved a 37.04% reduction in emissions of kg of CO2, as well as a 41.83% reduction of abiotic depletion of fossil fuels when 40% of fine aggregate was replaced by crumb rubber. This study also demonstrates that the transport distance of recycled materials from their point of production to the mortar production plant is a decisive factor. Depending on that distance, the proposed solution can be rendered environmentally unviable. On a final note, it is important to underscore that the appropriate use of recycled aggregates in mortar is not only determined by strength but also environmentally. This research generates knowledge about the environmental benefits of using recycled materials in construction.