# Life Cycle Carbon Assessment of Mortars with Carbonated and Non-Carbonated Recycled Aggregates
## 1 Introduction  
The cement industry is responsible for several environmental impacts, including the extraction of natural resources and burning of fossil fuels. Among several environmental impacts, carbon dioxide (CO\({}_{2}\)) emissions are the major environmental impact associated with cement production [1, 2]. CO\({}_{2}\) is part of a set of gases that contribute to global warming. The high concentration of CO\({}_{2}\) in the atmosphere, together with other greenhouse gases, is responsible for a greater reflection of the radiation emitted by the earth's surface, which results in an incremental increase in the planet's average temperature [3, 4] and has significant consequences for various ecosystems, namely the increase in water levels due to the thawing of glaciers. Therefore, global warming is one of the important issues that the world is confronting today. For this reason, cement plants need to become carbon neutral by 2050, in accordance with the 13 th United Nations Sustainable Development Goals. This neutrality can be achieved by a reduction in CO\({}_{2}\) emissions complemented with capture and utilization of the remaining CO\({}_{2}\). In parallel, the generation of construction and demolition waste (CDW) has also emerged as a significant environmental challenge, particularly in the European Union. It is estimated that CDW accounts for 25-30% of all waste generated in the EU, making it one of the largest waste streams [5]. The disposal of this waste in landfills or through incineration can further contribute to greenhouse gas emissions and environmental concerns [6]. To address these two major concerns, studies have been made regarding the potential of using recycled aggregates from CDW as a substitute for natural aggregates in concrete and mortar production. Several studies have investigated the global warming potential (GWP) and life cycle assessment (LCA) of mortars and concrete containing recycled aggregates [7; 8]. Comparing the environmental and economic impacts of concrete with natural and recycled coarse aggregates from a cradle-to-gate perspective, [PERSON] et al. [7] conducted a LCA of 216 concrete mixes from 24 references. The results show that using coarse recycled concrete aggregates can significantly reduce environmental impacts and costs compared to natural aggregates, with cement identified as the main contributor to both impacts. Therefore, the referred study proved the viability of using recycled concrete aggregates as a more sustainable alternative to natural aggregates in concrete production, with the potential to reduce environmental impacts and costs for the construction industry. [PERSON] et al. [9] used LCA to compare the environmental and economic impacts of using recycled aggregates (RAs) to replace natural aggregates (NAs) in concrete production. It was concluded that transport distances significantly impact the environmental results, with shorter distances favouring the use of RAs. Also, environmental product declarations (EPD) show that recycled coarse aggregates have the lowest impacts, while natural coarse crushed aggregates have the highest. [PERSON] et al. [10; 11] studied the environmental assessment of masonry mortars with the incorporation of recycled fine aggregates from CDW. The results showed that the use of recycled fine aggregates reduced the environmental impacts in most categories, analysed by avoiding the impacts of disposing in landfills. However, some environmental impacts were slightly increased, namely ecotoxicity, due to a higher transport distance of the RAs when compared to the location of NAs used in the referred study. Additionally, [PERSON] et al. [12] studied the environmental performance of cement-based mortar considering the incorporation of recycled aggregates from a site demolition. The life cycle assessment was carried out based on a cradle-to-gate scope. The authors analysed different replacement ratios and concluded that the environmental impacts were reduced with the increase in RA incorporation. In another study, [PERSON] et al.