# Life Cycle Carbon Assessment of Mortars with Carbonated and Non-Carbonated Recycled Aggregates
## 1 Introduction
[13] analysed the mechanical behaviour and environmental impacts of concrete mixtures containing high amounts of fly ash (FA) and RAs. Life cycle assessment (LCA) methodology was used to determine the influential factors, non-renewable energy consumption (PE-NRe) and global warming potential (GWP) for different scenarios in central Portugal. The study concluded that the GWP and PE-NRe of RA concrete are not considerably affected, contrary to previous studies where transportation scenarios played a significant role. The LCA of concrete decreases substantially with the use of FA, regardless of transportation scenario. [PERSON] et al. [14] reviewed the LCA of several mortars produced with different aggregates assuming that the use of alternative materials in mortar production, such as recycled or earth-based, can provide environmental benefits quantified through LCA. These alternatives can promote the circular economy and enhance mortar performance, while reducing energy-intensive processing and transportation compared to conventional materials. Other authors [15; 16; 17] studied the LCA of mortars with recycled industrial waste aggregates, finding out that these performed better environmentally in several environmental impact categories compared to natural aggregate mortars, reaching benefits of up to 20% in some environmental impacts. In sum, several studies have generally found that the use of RAs can lead to a reduction in the environmental impact of the final product, primarily due to the avoidance of the energy-intensive extraction and processing of natural aggregates. Nonetheless, the specific environmental benefits of using RAs from CDW that have undergone forced carbonation, a process that can further enhance their properties, have not been extensively explored. Forced carbonation is a technique that can improve the quality of recycled aggregates by reducing their water absorption and increasing their strength, potentially leading to improved performance and reduced environmental impacts in mortar and concrete applications [18]. In the work of [PERSON] et al. [18], the RCA properties were improved by CO\({}_{2}\) treatment, as were the old and new interfacial transition zones (ITZ) of the new composites with treated RCAs. In previous studies, the carbon dioxide capture capacity of construction and demolition waste (CDW) was determined. [PERSON] et al. [19] concluded that mixed recycled aggregates that came from recycling plants were still able to capture 0.66% of their weight of CO\({}_{2}\). Concrete aggregates from recycling plants and from selective demolition sites can capture between 0.88% and 0.97%. Concrete aggregates from industrial wastes are lowly carbonated and, in this sense, the results pointed out that they are able to capture 4.09%. Finally, a reference concrete produced in a laboratory was able to capture 4.9%. All the materials were submitted to forced carbonation at 23 \({}^{\circ}\)C, 60% relative humidity and 25% CO\({}_{2}\) at different exposure times. After subjecting CDW recycled aggregates to high levels of CO\({}_{2}\), they were incorporated in mortars. [PERSON] et al. [20] evaluated these mortars in terms of their mechanical performance. This paper aims to address the gap in assessing the environmental impacts of the use of RAs subjected to forced carbonation by conducting a focus on the life cycle carbon impact assessment (LCCA) of mortar formulations in a cradle-to-gate boundary. In order to quantify the benefits of the use of carbonated RAs in mortars, a life cycle carbon assessment focused on global warming potential (GWP), that corresponds to the emissions of a CO\({}_{2}\) equivalent to the atmosphere, is presented in this study. The paper's objective is to quantify the GWP of these mortars and compare them to those made with natural aggregates and with RAs from CDW not subjected to forced carbonation, providing valuable insights into the environmental benefits of using recycled aggregates in the construction industry.