# Performance of Ore Sand as Aggregate for Interlocking Blocks
## 3 Results
### Transportation Impacts  
Within the predefined boundaries for life cycle assessment in this study, transportation is an important determinant of the environmental impact of aggregates used in the production of pavers. Figure 7 summarizes the impacts of production and transportation of the conventional aggregates, namely, natural sand, limestone sand, and gravel (detailed in Section 3.2). In this scenario, the environmental assessment includes the impact of the  
Figure 6: Relative contribution to environmental impacts by each aggregate type used in conventional blocks and ore-sand blocks (excluding impacts related to the transportation of aggregates). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Impact Category** & **Unit** & **Conventional Block** & **OS Block** & **Reduction** \\ \hline \hline \multicolumn{2}{c}{Abiotic depletion} & kg Sb eq & \(3.6\times 10^{-4}\) & \(2.3\times 10^{-4}\) & 35\% \\ \multicolumn{2}{c}{Abiotic depletion (fossil fuels)} & MJ & \(9.3\times 10^{3}\) & \(7.2\times 10^{3}\) & 23\% \\ \multicolumn{2}{c}{Global warming (GWP100a)} & kg CO\({}_{2}\) eq & \(7.2\times 10^{2}\) & \(5.5\times 10^{2}\) & 24\% \\ \multicolumn{2}{c}{Ozone-layer depletion (ODP)} & kg CFC-11 eq & \(1.1\times 10^{-4}\) & \(0.86\times 10^{-4}\) & 22\% \\ \multicolumn{2}{c}{Human toxicity} & kg 1,4-DB eq & \(9.2\times 10^{1}\) & \(6.4\times 10^{1}\) & 31\% \\ \multicolumn{2}{c}{Freshwater aquatic ecotoxicity} & kg 1,4-DB eq & \(5.9\times 10^{1}\) & \(3.9\times 10^{1}\) & 33\% \\ \multicolumn{2}{c}{Marine aquatic ecotoxicity} & kg 1,4-DB eq & \(1.7\times 10^{5}\) & \(1.1\times 10^{5}\) & 35\% \\ \multicolumn{2}{c}{Terrestrial ecotoxicity} & kg 1,4-DB eq & \(2.4\times 10^{-1}\) & \(1.7\times 10^{-1}\) & 31\% \\ \multicolumn{2}{c}{Photochemical oxidation} & kg C\({}_{2}\)H\({}_{4}\) eq & \(1.8\times 10^{-1}\) & \(1.2\times 10^{-1}\) & 30\% \\ \multicolumn{2}{c}{Acidification} & kg SO\({}_{2}\) eq & \(1.1\times 10^{1}\) & \(0.77\times 10^{1}\) & 32\% \\ \multicolumn{2}{c}{Eutrophication} & kg PO\({}_{4}\) eq & 2.7 & 1.8 & 33\% \\ \hline \hline \multicolumn{2}{c}{Sb (antimony); CFC (chlorofluorocarbons); DB (dichlorobenzene); C\({}_{2}\)H\({}_{4}\) (ethylene); SO\({}_{2}\) (sulfur dioxide); PO\({}_{4}\) (phosphate).} \\ \end{tabular}
\end{table} 
Table 3: Environmental impacts of aggregates for the production of 60,000 blocks. transportation of conventional aggregates. The average contributions of transportation to diesel burning for the conventional and alternative blocks were 22.7% and 25.6%, respectively. Figure 8 and Table 4 show only the impact of transporting such aggregates according to their type and quantity (Table 2). The greatest impact comes from the transportation of natural sand due to the large amount needed and the distance of this resource from the block factory site, which together result in higher diesel consumption. Gravel and limestone are transported the same distance, but the amount of gravel needed is greater than the amount of limestone needed, so gravel has a greater impact. Among the materials used in the block manufactured with ore sand, the transportation of natural sand had the greatest impacts across all the categories evaluated. To capture the complete environmental impact of the alternative block, it is essential to consider the transportation of ore sand from the storage or mining site to the block factory. More specifically, the break-even point, or the distance up to which the ore-sand block has a lower environmental impact than the conventional block considering the transportation of this waste, needs to be identified. Figures 9a and 10a show the impacts for different transportation distances for the block manufactured using ore sand (in combination with the transportation impacts for the block constructed with conventional aggregates) by train and truck, respectively. The overall impact for each distance was calculated using the Score Indicator.