A geração de resíduos está aumentando em função do crescimento da população, urbanização e desenvolvimento econômico, especialmente nos países em desenvolvimento. O conhecimento do quantitativo de resíduo de construção e demolição gerado por meio de previsões pode auxiliar os tomadores de decisões a adotarem práticas mais eficientes de gestão, sendo fundamentais para prevenir o desenvolvimento dos problemas ambientais. O objetivo deste artigo foi desenvolver um modelo de previsão de geração dos resíduos de construção e demolição para cidades brasileiras de médio porte populacional, utilizando como estudo de caso o munícipio de Varginha (MG). Foi elaborado um modelo linear múltiplo (R² = 0,880), empregando como variáveis independentes a expansão urbana, o Produto Interno Bruto (PIB) e o PIB per capita para prever o quantitativo de resíduo de construção e demolição gerado em 2020 e a quantidade de resíduo que será produzida em 2040 no município. Os resultados da aplicação do modelo indicaram aumento de 18,27% no quantitativo de resíduo de construção e demolição gerado no município, quando comparados o cenário de 2020 (39.940 t) e de 2040 (47.238 t). Também foi verificada a eficiência do modelo ao aplicá-lo em outras seis cidades brasileiras de similar porte populacional e que possuíam pesquisas sobre a geração de resíduo de construção e demolição. A diferença do quantitativo de resíduo de construção e demolição obtido pelos autores e os calculados pelo modelo foram inferiores a 13%. Os resultados desta pesquisa podem contribuir para o desenvolvimento de estratégias de gestão de resíduos de construção e demolição eficientes, já que fornece uma ferramenta para resolução dos problemas ambientais atuais e também permite a adoção de ações proativas para a correta gestão em cenários futuros.

This article presents a study on the performance of semi-empirical methods based on the Standard Penetration Test (SPT) for the prediction of bearing capacity already disseminated in the practice of Brazilian Foundation Engineering (Aoki and Velloso, 1975; Décourt and Quaresma, 1978, 1996; Teixeira,1996), together with the recent method proposed by Pereira (2020), and the theoretical method known as a Method (disseminated around the world). These were applied to precast concrete piles based on sandy clay in the Uberlândia-MG region. In the performance analysis, the ultimate shaft and tip resistances and the bearing capacity values, which were utilized as references, were mobilized in the dynamic loading tests performed on ten piles. The results of these tests were compared with those obtained using the mentioned methods. In general, both methods yielded robust results, with relatively accurate predictions, except the a Method, which was found to perform below the semi-empirical methods considered. The research still highlights the need for discretion in the application of semi-empirical/theoretical methodologies because there are certain scenarios wherein these methods can yield inaccurate results.

The extraction of slate generates large volumes of waste that could be applied in paving. The dynamic Resilient Modulus (RM) test provides important data for the structural analysis of pavements. Although several studies have been carried out to evaluate RM for pavement applications, few refer to the analysis of the effects of the percentage increase of wastes in mixtures. In this paper, it was possible to verify, through physical-mechanical characterization and MR tests of mixtures with clayey soil containing percentages (60, 70 and 80% by mass) of slate waste (SLT) and aggregate of gneiss (REF), which there is similar physical behavior of the SLT and REF mixtures. It was observed that the California Bearing Ratio (CBR) and MR values of the SLT increased by 16.1% and 40.9%, respectively, with the addition of the slate waste between SLT 60/40 and SLT 80/20. The MR results obtained are within the range reported in the bibliographic references for recycled and natural materials used in paving. Finally, the software MeDiNa was used to prove the possibility of using SLT mixtures as base and subbase paving layer. Thus, it is important to develop studies that allow a better analysis of the applicability of waste as a substitute for conventional paving materials.

The railway industry is increasingly pressured to adopt sustainable practices, seeking alternatives to virgin natural aggregates that reduce environmental impact and lifecycle costs. The extraction of slate for ornamental purposes generates significant waste, approximately 30% by mass, which is typically disposed of in landfills, causing environmental and economic concerns. This study comprehensively investigates the potential of slate waste as a primary component in sub-ballast layers for railways. Laboratory tests were conducted on mixtures of slate waste and a clayey soil, with granular contents ranging from 60% to 90%. The key geotechnical parameters evaluated included the California Bearing Ratio (CBR), Resilient Modulus (RM), compaction characteristics, granulometry and Atterberg limits. In addition, the DNIT ISF-212 standard was used to verify compliance with the Brazilian requirements for the use of materials in sub-ballast layers. The results indicate that mixtures with slate waste (SLT) exhibit performance comparable to conventional gneiss aggregate mixtures (REF); however, verification against the DNIT ISF-212 standard showed that only the SLT 80/20 and SLT 90/10 mixtures fully meet the requirements for use as railway sub-ballast. The RM and CBR values for the SLT mixtures increased by 48.5% and 38.4%, respectively, when the slate waste content was raised from 60% to 90%. A non-linear relationship was found between RM and CBR for both material types. Furthermore, the study integrates findings from related research on recycled ballast and tropical soils, highlighting the synergistic benefits of using industrial by-products. It concludes that slate waste presents a viable, high-performance, and sustainable solution for railway sub-ballast, contributing to circular economy principles in railway infrastructure.

Purpose: This paper provides a comprehensive analysis of the Brazilian freight railway system, examining the efficacy of the current concession renewal model in light of persistent structural problems such as market concentration, cargo dependence on export commodities and underutilization of the network. Situating Brazil within the broader international debate on railway reforms, the paper evaluates whether the ongoing early renewal of concessions can deliver a more diversified and competitive freight system. Design/methodology/approach: The study adopts a sequential mixed-methods research design that integrates longitudinal quantitative analysis with qualitative institutional and policy evaluation. The quantitative component examines time-series indicators published by ANTT, DNIT and INFRA S.A. from 1999 to 2023 to identify structural patterns in traffic growth, investment, safety and market concentration. The qualitative component employs a process-tracing logic to reconstruct the evolution of concession renewals and the implementation of Railway Law 14.273/2021, drawing on concepts from regulatory economics, institutional theory and industrial organization. These empirical streams are synthesized through an analytical framework that connects three dimensions - regulatory design, market structure and system performance - allowing for a systematic assessment of how Brazil's institutional configuration shapes incentives, competitive dynamics and network utilization. Findings: The analysis confirms that the early renewal of concessions has successfully secured substantial private investment for capacity expansion on existing trunk lines. However, it has perpetuated the vertically integrated model, reinforcing the market power of incumbent operators and failing to significantly promote intramodal competition or cargo diversification. The system remains dominated by iron ore and agricultural commodities, with general cargo representing a minuscule share. The new authorization regime and short-line railway policies present a viable pathway for market opening but face significant operational and institutional barriers to implementation. Originality/value: This research offers a timely and critical assessment of a pivotal moment in Brazilian railway policy. It moves beyond a simplistic evaluation of volume growth to a structural analysis of market failures and the interplay between concession renewal and regulatory innovation. The findings provide actionable insights for policymakers in Brazil and other emerging economies seeking to balance private investment with public interest goals in railway infrastructure, highlighting the necessity of complementary, pro-competitive measures alongside financial investment.