# Life Cycle Carbon Assessment of Mortars with Carbonated and Non-Carbonated Recycled Aggregates
## 2 Goal and Scope Definition
### LCA Assumptions  
The LCA approach considered the following assumptions:  
* Global warming potential was selected as the environmental impact category to consider in the LCA, since it is the most affected by RA carbonation;
* The LCA of the powdered mortars was considered as cradle-to-gate. Construction, use and end-of-life stages were not taken into account;
* The mortar plant, cement plant and recycled aggregate recycling plant were considered in specific locations. Different locations would affect the transport distances and, consequently, the transport environmental impacts and the overall results;
* The data used to obtain the environmental impacts of the processing of recycled aggregates from CDW were collected from Portuguese companies that produce limestone aggregates. The energy used to crush these recycled aggregates can differ from that of limestone aggregates;
* The recycled aggregates are carbonated in a rotary equipment to promote carbonation. However, it was considered that the energy spent in this process is negligible by comparison with the other processes under analysis. Hence, the environmental impacts of the carbonation process were not considered;
* The data used to obtain the environmental impacts of the mortars production were collected from a specific Portuguese company. The energy used can differ if a different company is chosen;  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Life Cycle Assessment Boundaries** & **Life Cycle Stages** & **Life Cycle Stages Designation and Description** \\ \hline \multirow{4}{*}{Cradle-to-gate} & \multirow{4}{*}{Product stage (A1–A3)} & \multirow{4}{*}{A1} & Raw material extraction and processing, processing of secondary material input \\ \cline{3-3}  & & & A2 & Transport to the factory \\ \cline{3-3}  & & & A3 & Manufacturing \\ \hline \multirow{4}{*}{Cradle-to-gate} & \multirow{4}{*}{Construction process stage (A4–A5)} & \multirow{4}{*}{A4} & Transport to the building site \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Detailed life cycle stages of building materials from EN 15804.  
* The environmental impacts of the mortar production were considered dependent only on the mortars' bulk density, and other aspects could change these impacts;
* In some cases, it was not possible to use an environmental product declaration (EPD), a site-specific data collection or scientific research to estimate the environmental impacts of a product or process, as discriminated in Section 3.1. In those cases, databases from SimaPro software (Ecoinvent 3 and ELCD) were used. The data from these databases present some uncertainty because they are generic.