## 5 Case Study--LCA Results and Discussion
### Environmental Assessment

Table 3: Environmental impacts for waste deposition in the landfill following column production. To change the impacts generated in the linear model options, a circular model was developed where the waste was used as an alternative raw material in the production of precast concrete. The impacts resulting from the linear model waste management operations (Table 3) do not exist in the circular model, because the impact of landfill was eliminated and, in addition, the lime ash does not require any treatment operation to be incorporated as an alternative raw material in the precast concrete industry. Although present in a small percentage (4.4%), the natural filler is entirely replaced by the lime ash waste and the other components in the concrete formulation (gravel, cement sand, superplasticiser and water) remain the same as the concrete formulation in the linear model (Table 1). Thus, the impacts of gravel, sand, cement and superplasticiser remain the same as in the previous case (Table 4). On the other hand, the impacts resulting from the use of natural filler disappear in this circular case and impacts of transporting lime ash are approximately reduced by 28% of the impacts of filler transportation. In other words, the use of lime ash makes it possible to reduce raw material transport impacts by 72% \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Category** & **Unit** & **Landfill** & \
\begin{tabular}{c} **Precast Concrete** \\ **(Reference)** \\ \end{tabular} &
\begin{tabular}{c} **Total Impacts of** \\ **Linear Model** \\ \end{tabular} \\ \hline GWP & kg CO\({}_{2}\) eq & \(4.27\times 10^{-1}\) & \(2.46\times 10^{2}\) & \(2.46\times 10^{2}\) \\ ODP & kg CFC\({}^{-11}\) eq & \(7.01\times 10^{-8}\) & \(1.04\times 10^{-5}\) & \(1.05\times 10^{-5}\) \\ AP & kg SO\({}_{2}\) eq & \(3.11\times 10^{-3}\) & \(5.48\times 10^{-1}\) & \(5.51\times 10^{-1}\) \\ EP & kg PO\({}_{4}\)\({}^{3-}\) eq & \(1.08\times 10\) & \(1.40\times 10^{-1}\) & \(1.09\times 10\) \\ POFP & kg NMVOC & \(5.31\times 10^{-3}\) & \(5.50\times 10^{-1}\) & \(5.55\times 10^{-1}\) \\ ADP & kg Sb eq & \(1.07\times 10^{-8}\) & \(3.34\times 10^{-5}\) & \(3.34\times 10^{-5}\) \\ ADP (fossil fuels) & MJ & \(5.89\) & \(1.21\times 10^{3}\) & \(1.22\times 10^{3}\) \\ WU & m\({}^{3}\) & \(2.00\times 10^{-2}\) & \(8.91\times 10\) & \(8.92\times 10\) \\ CED & MJ & \(6.34\) & \(1.50\times 10^{3}\) & \(1.50\times 10^{3}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Environmental impacts for landfill plus precast concrete and total impacts of linear model. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Category** & **Unit** & \
\begin{tabular}{c} **Coarse Aggregate** \\ **(12/25 mm)** \\ \end{tabular} &
\begin{tabular}{c} **Coarse Aggregate** \\ **(8/12 mm)** \\ \end{tabular} & **Coarse Sand** & **Fine Sand** \\ \hline GWP & kg CO\({}_{2}\) eq & \(9.87\) & \(5.67\) & \(5.45\) & \(3.20\) \\ ODP & kg CFC\({}^{-11}\) eq & \(1.08\times 10^{-6}\) & \(6.18\times 10^{-7}\) & \(8.02\times 10^{-7}\) & \(4.70\times 10^{-7}\) \\ AP & kg SO\({}_{2}\) eq & \(5.48\times 10^{-2}\) & \(3.14\times 10^{-2}\) & \(3.35\times 10^{-2}\) & \(1.96\times 10^{-2}\) \\ EP & kg PO\({}_{4}\)\({}^{3-}\) eq & \(1.45\times 10^{-2}\) & \(8.31\times 10^{-3}\) & \(7.04\times 10^{-3}\) & \(4.13\times 10^{-3}\) \\ POFP & kg NMVOC & \(5.44\times 10^{-2}\) & \(3.13\times 10^{-2}\) & \(3.97\times 10^{-2}\) & \(2.33\times 10^{-2}\) \\ ADP & kg Sb eq & \(1.02\times 10^{-6}\) & \(5.83\times 10^{-7}\) & \(2.98\times 10^{-7}\) & \(1.75\times 10^{-7}\) \\ ADP (fossil fuels) & MJ & \(1.20\times 10^{2}\) & \(6.89\times 10\) & \(7.22\times 10\) & \(4.23\times 10\) \\ WU & m\({}^{3}\) & \(9.75\) & \(5.60\) & \(3.36\times 10\) & \(1.97\times 10\) \\ CED & MJ & \(1.45\times 10^{2}\) & \(8.33\times 10\) & \(8.21\times 10\) & \(4.81\times 10\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Environmental impacts for aggregates in precast concrete formulation.