# Performance of Ore Sand as Aggregate for Interlocking Blocks
## 4 Discussion  
In assessing the environmental performance of only the aggregates used to manufacture the interlocking paver blocks, the ore-sand block has a significant environmental advantage over the conventional block and has similar load capacity. This difference is explained by the replacement of 24% of the aggregate (by mass) with IOTs (a leftover), which creates an alternative with a lower environmental footprint in all eleven impact categories. In the context of this work, from a materials point of view, the ore-sand block has an advantage over the conventional block. However, the iron-mining areas are strategically located for iron extraction, in contrast to the areas for commercial natural-sand extraction, which are typically situated close to block factories. This feature demonstrates the importance of the transportation analysis performed here for the environmental appraisal of this alternative solution. Transportation represented an average of 22.7% of the environmental impact across the eleven impact categories evaluated for blocks constructed with conventional aggregates. This finding highlights the fact that the transportation of materials is important in assessing environmental performance. [PERSON] [53] identifies the main contributors to the total environmental burden of concrete over its life cycle as the raw materials and transportation. The Score Indicator enabled a comparison of the impacts of different transportation distances for the leftover ore sand. As the distance increases, the consumption of diesel burned by rail or road transport increases. The increase in the burning of fossil fuel leads to increases in the several categories, all of which were considered to have the same weight in this work. Figure 11 shows that \(SI=1\) for the \(V/V_{t}\) ratio, which corresponds to the distance values obtained with Equation (2) (1147 km) and 3 (217 km) for both transportation types. This figure shows the categories (photochemical oxidation, ozone layer depletion, global warming, and abiotic depletion-fossil fuels) that have an increase in impact (\(V/V_{t}>1\)) in comparison to traditional blocks for distances above 1,147 km for train and 217 km for truck. However, for the other seven categories, the burning of diesel had a smaller impact compared to construction of conventional blocks (\(V/V_{t}<1\)). The sum of the values (\(V/V_{t}\)) in the impact categories divided by the number of categories (\(n=11\)) results in a value of 1.0, where the increase in certain categories is counterbalanced by categories with lower impacts compared to the conventional block. This result confirms that the equations developed from the SI were effective in determining the best distance for ore-sand transportation. The evaluation of several impact categories enhances the understanding of environmental trade-offs between analyzed systems [54, 55]. Evaluating the performance of two products through the ratio of the impacts across environmental categories (\(V/Vt\)) is an established practice in life cycle assessment studies [56, 57, 58]. This approach provides an objective metric by which to identify categories with better or worse performance. Calculating category ratios simplifies complex environmental data, allowing for easier result interpretation through this metric. The Scoring Indicator used in this study proved to be a useful and efficient tool for determining the increase in impacts due to transportation. It provides an equation that supports decision-making regarding the distance allowed for incorporating ore sand into interlocking paving blocks. Alternative models, such as the normalization and ranking of environmental indicators for decision-making [59] and MIVES (Spanish Integrated Value Model for the Sustainability Assessment) [60], are applicable, although they are complex. However, the latter model allows for the inclusion of broader considerations from studies that incorporate assessments in the environmental, social, and economic fields.