# Performance of Ore Sand as Aggregate for Interlocking Blocks
## 1 Introduction
Despite the applicability of IOTs in construction, it is necessary to evaluate the environmental benefits of replacing aggregates with mining waste. For example, [PERSON] et al. [25], verified that the use of IOTs as raw material in the production of sodium silicate for soil stabilization reduces environmental impacts because it avoids the extraction of natural sand. The focus of that work was on the production of sodium silicate using IOT as a source of silicates in the production of a binder. [PERSON] et al. [26] studied concrete produced with mining waste. Using life cycle analysis, the author examined the replacement of natural sand with tailings at different content levels (5% to 100%). A 3% reduction in the carbon footprint was found in the case of 100% replacement of sand by tailings. However, the environmental impact associated with the transportation of materials represents a possible restriction in the search for environmentally friendly concrete produced using waste [27]. [PERSON] et al. [28] used IOTs as a cementitious composite to improve the mechanical properties of the composite while helping to reduce the environmental burden of production. These authors evaluation LCA in five impact categories: photochemical ozone-creation potential, acidification potential, global-warming potential, ozone-depletion potential and nitrification potential, and found that incorporation of IOTs into concrete reduces the environmental impact of production, which consolidates the possibility of achieving clean production with the use of IOTs to prepare cementitious composites. Nevertheless, that work is more focused on the mechanical and microstructural aspects of using tailings in concrete, with the LCA being used superficially. [PERSON] et al. [29] also briefly evaluated the environmental impacts of using molybdenum mining tailings to replace fine aggregates in structural concrete. Additionally, in both studies, the life cycle assessment is focused on the completed concrete (cement and aggregates), not just the aggregates that compose the blend. A comparative LCA between aggregates highlights the environmental importance of using waste. In general, LCA studies of the use of IOT have focused mainly on cement mortars. Evaluations of their use as an aggregate for interlocking blocks are still lacking. Brazil alone has the potential to consume around 2.5 million tons of ore sand per year as fine aggregate in the paving of its roads [23]. In this context, no studies were found that carried out a more focused environmental life cycle assessment for the replacement of conventional aggregates by ore tailings in interlocking concrete paving blocks, along with the influence and limits imposed by the transportation of the alternative aggregate for the production of this civil construction product. Hence, this study investigates the environmental impact of utilizing ore sand in constructing interlocking paver blocks and assesses how the distance from the source of tailings generation impacts the life cycle environmental footprint of these materials. The application of LCA to the construction sector is part of a wide effort to implement LCA as a decision-support tool for industry and policy [30]. Therefore, research on the mechanical feasibility of using mining tailings to replace natural resources and on their environmental impact (considering other relevant categories beyond CO2 emissions) is key to developing more sustainable products. The objective of this research is to assess sustainability by considering the environmental benefits of utilizing ore sand as a substitute for conventional aggregates (natural sand and limestone sand) in the production of interlocking concrete block pavement and to evaluate the impact of ore-sand transportation on environmental assessment. The compressive strength of both alternatives (conventional and ore-sand blocks) was evaluated and compared.