# Life Cycle Carbon Assessment of Mortars with Carbonated and Non-Carbonated Recycled Aggregates
## 4 Life Cycle Impact Assessment  
The life cycle impact assessment of this research is focused on the global warming potential (GWP) environmental impact of powder mortars. The mortars present a mixing ratio of 1:4 cement-sand by volume. The LCA of the powdered mortars was based on cradle-to-gate analysis, meaning it includes the environmental impacts associated with raw and recycled materials, transport distances and mortar manufacturing process All the rendering of mortars with the incorporation of recycled aggregates from CDW presented a lower GWP than the usual rendering of mortars with natural aggregates (Table 8 and Figure 2). The reduction is between 3.3% and 7.5%. This means that these mortars emit less CO\({}_{2}\) equivalent to the atmosphere, reducing the environmental impact associated with GWP. RCA-RP 50% and MRA-RP 50% presented a reduction in GWP of about 3.3-3.8%. Higher benefits were noticed for the mortars with 100% of incorporation of recycled aggregates. RCA-IS 100%, RCA-IW 100% and CA-L 100% are mortars with a reduction in GWP of more than 6%; respectively, 7.5%, 6.5% and 6.3%. \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Product Stage** & **GWP (kg CO\({}_{2}\) eq.)** \\ \hline \multirow{3}{*}{A3} & Powder mortars packaging (A3.1) & 2.78 \(\times\) 10\({}^{1}\) \\  & Mortars manufacturing (A3.2) & 2.16 \(\times\) 10\({}^{-3}\) \\  & Production and disposal of packaging waste (A3.3) & 7.57 \(\times\) 10\({}^{-5}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 7: GWP environmental impact of the production process of 1 m\({}^{3}\) of powder mortar [3]. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Mortars** & **GWP (kg CO\({}_{2}\) eq.)** &
\begin{tabular}{c} **GWP Reduction (In** \\ Comparison with REF)** \\ \end{tabular} \\ \hline REF & 1.56 \(\times\) 10\({}^{2}\) & 0.00\% \\ MRA-RP\({}_{50\%}\) & 1.50 \(\times\) 10\({}^{2}\) & 3.86\% \\ MRA-RP\({}_{100\%}\) & 1.47 \(\times\) 10\({}^{2}\) & 5.64\% \\ RCA-IS\({}_{50\%}\) & 1.49 \(\times\) 10\({}^{2}\) & 4.80\% \\ RCA-IS\({}_{100\%}\) & 1.44 \(\times\) 10\({}^{2}\) & 7.52\% \\ RCA-RP\({}_{50\%}\) & 1.51 \(\times\) 10\({}^{2}\) & 3.34\% \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Global warming potential impact (1 m\({}^{3}\) of powder mortar). In Figure 3, the same recycled aggregates are presented but submitted to forced and accelerated carbonation. As can be noted, carbonated recycled aggregates improved the mortars' GWP performance, compared with the mortars with non-carbonated recycled aggregates. The improvements vary from 4.2% to 36.8%, depending on the mortar. The benefits are greater with the increase in CO2 absorption capacity. CA-L and RCA-IW are the recycled aggregates with higher CO2 absorption capacities, resulting in mortars with 36.8% and 30.9% lower emissions of CO2 equivalent when compared with a REF mortar, respectively, considering a 100% replacement of the sand. Comparing the reduction in GWP through the carbonation of recycled aggregates, it is noted that carbonation further reduces the carbon footprint, thereby enhancing the environmental performance of the mortars. Even though the use of non-carbonated RAs also reduces the environmental impacts of the mortars (Figure 2) when compared to mortars with natural aggregates, those with carbonation get a more significant reduction. Mortars with carbonated recycled aggregates can reduce the GWP impact by up to 37%. Figure 2: Global warming potential of mortars with non-carbonated recycled aggregates in comparison with REF mortar. Other studies have also investigated the environmental performance of cementitious materials with the use of RAs. The work of [PERSON] et al. [13] indicated that the GWP of concrete is not significantly influenced by the incorporation of recycled aggregates. The authors tested 50% and 100% of replacement, and the results showed that the use of RAs did not affect this environmental impact, probably due to the transportation scenario. In addition to this, [PERSON] et al.