# Performance of Ore Sand as Aggregate for Interlocking Blocks
## 3 Results
### Transportation Impacts
Figure 7: Environmental impact of the production and transportation of conventional aggregates (natural sand, limestone sand, and gravel). For example, for the global-warming category, the conventional block generates 7.2 \(\times\) 10\({}^{2}\) kg of CO\({}_{2}\) (Table 3) from the production of aggregates and an additional 4.14 \(\times\) 10\({}^{2}\) kg of CO\({}_{2}\) (Table 4) from transportation, totaling 11.4 \(\times\) 10\({}^{2}\) kg CO\({}_{2}\) (_Vt_). The block manufactured with ore sand generates 5.5 \(\times\) 10\({}^{2}\) kg of CO\({}_{2}\) from the aggregates and 3.5 \(\times\) 10\({}^{2}\) kg of CO\({}_{2}\) from transportation. Transporting ore sand (100 km) entails the burning of an additional 14.1 L of diesel, which generates 0.43 \(\times\) 10\({}^{2}\) kg of CO\({}_{2}\) (3.06 kg CO\({}_{2}\)/L), for a total of 9.4 \(\times\) 10\({}^{2}\) kg CO\({}_{2}\) (_V_). The ratio between the two results (\(V/V_{t}\)) for this category is 0.82. This process was carried out for all impact categories. Next, the ratios were summed and divided by the number of categories (\(n\)). For 100 km, the _SI_ result was 0.75; for 200 km it was 0.78, etc., as shown in Figure 9a. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{1}{c}{**Impact Category**} & \multicolumn{1}{c}{**Unit**} & \multicolumn{1}{c}{**Transport of Ordinary Aggregates**} \\ \cline{3-4}  & & **Conventional Block** & **Ore-Sand Block** \\ \hline Abiotic depletion & kg Sb eq & 2.20 \(\times\) 10\({}^{-5}\) & 1.86 \(\times\) 10\({}^{-5}\) \\ Abiotic depletion (fossil fuels) & MJ & 5.77 \(\times\) 10\({}^{3}\) & 4.86 \(\times\) 10\({}^{3}\) \\ Global warming & kg CO\({}_{2}\) eq & 4.14 \(\times\) 10\({}^{2}\) & 3.49 \(\times\) 10\({}^{2}\) \\ Ozone-layer depletion (ODP) & kg CFC-11 eq & 7.40 \(\times\) 10\({}^{-5}\) & 6.23 \(\times\) 10\({}^{-5}\) \\ Human toxicity & kg 1,4-DB eq & 2.57 \(\times\) 10\({}^{1}\) & 2.17 \(\times\) 10\({}^{1}\) \\ Fresh water aquatic ecotox. & kg 1,4-DB eq & 4.33 & 3.65 \\ Marine aquatic ecotox. & kg 1,4-DB eq & 1.78 \(\times\) 10\({}^{4}\) & 1.50 \(\times\) 10\({}^{4}\) \\ Terrestrial ecotox. & kg 1,4-DB eq & 6.79 \(\times\) 10\({}^{-2}\) & 5.72 \(\times\) 10\({}^{-2}\) \\ Photochemical oxidation & kg C\({}_{2}\)H\({}_{4}\) eq & 6.28 \(\times\) 10\({}^{-2}\) & 5.29 \(\times\) 10\({}^{-2}\) \\ Acidification & kg SO\({}_{2}\) eq & 3.20 & 2.70 \\ Eutrophication & kg PO\({}_{4}\) eq & 7.17 \(\times\) 10\({}^{-1}\) & 6.04 \(\times\) 10\({}^{-1}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Environmental impact of the transportation of conventional aggregates (natural sand, limestone sand, and gravel) for the production of blocks. Figure 8: Contribution of conventional aggregates to transportation impacts. At distance zero, the environmental impact of the conventional block is compared to the alternative payer block without ore-sand transportation. The environmental per  
Figure 10: Environmental-impact score for the ore-sand block: (**a**) impact for different transportation distances for OS materials by truck; (**b**) point at which the ore-sand block breaks even with the conventional block. Figure 9: Environmental impact score for the ore sand block: (**a**) impact for different transportation distances for OS materials by train; (**b**) break-even point with the conventional block. formance of the paver measured by the Score Indicator at distance zero is 0.728 (\(\sim\)0.73), indicating reduced environmental impacts due to the use of ore sand in block production, as described in the previous section. Therefore, the OS block starts at an advantage over the conventional block, with an SI less than 1. This difference decreases when ore-sand transportation is considered. For a transportation distance of 1,147 km by train and 217 km by truck for the ore sand, the alternative block has the same potential environmental impacts as the conventional block (Figures 9b and 10b) considering the impacts of the and production and transportation of all aggregates.