The main objective was to determine the deleterious potential of quartzite mining tailings subjected to different ASR alkali–silica reaction tests. The studies included petrographic analysis, chemical analysis of cements, expansion tests in mortar bars and concrete prisms, and microstructural analysis. Petrographic analysis of quartzites indicated high percentages of deformed quartz (95%), and were classified as potentially reactive. Two types of HES high early strength cement with alkaline equivalents of 0.749% and 0.61%, respectively, were selected. Of the 8 samples analyzed by the accelerated method in mortars, only 2 quartzite samples and 1 diabasium sample indicated potentially reactive behavior. The accelerated and long-term methods in concrete prisms proved to be effective and were consistent with the deleterious potential of the samples. All analyzed samples were diagnosed with the ASR gel. In the microstructural analysis, in addition to the ASR products, other expansive products of late ettringite were detected. Reaction mitigation methods are proposed so that quartzite waste can be used as an alternative aggregate in concrete, and thus contribute to the reduction of mine tailings and, consequently, reduce the negative environmental impact from mining.

Gerais: Estudo da fração fina para a produção de concretos de pós reativos e diagnóstico da reação álcali-agregado São Carlos 2022 IVAN FRANCKLIN JUNIOR Rejeitos de quartzitos do Sul de Minas Gerais: Estudo da fração fina para a produção de concretos de pós reativos e diagnóstico da reação álcali-agregado Versão Corrigida Original encontra-se disponível na unidade que aloja o programa

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Resumo: Objetivou-se com esse trabalho analisar e propor soluções para os problemas do sistema de microdrenagem da Avenida Fernão Dias, localizada em Três Corações -MG. Nesse estudo, averigou-se o motivo das patologias na pavimentação e alagamentos que ocorrem nessa via. Foram utilizadas pesquisas bibliográficas, visitas in loco para levantamento e análise do sistema atual, levantamento de dados hidrológicos e a delimitação e caracterização da bacia de contribuição através de imagens de satélite e curvas de nível. A análise e os cálculos realizados da vazão pluvial trecho a trecho nessa bacia provaram que, apesar do grande número de bocas de lobo existentes, ocorrem diversos trechos superdimensionados e outros em que há uma insuficiência de dispositivos para captação de águas pluviais. Observou-se também falta de manutenção dada aos dispositivos já existentes, que com isso, estão com sua vazão de captação limitada, fato esse que agrava a situação dos trechos localizados em cotas mais baixas. Palavras-chave: Análises hidrológicas. Enchentes. Chuvas.Abstract: The objective of this work was to analyze and propose solutions to the problems of the Fernão Dias Avenue microdrainage system, located in Três Corações -MG. In this study, we investigated the reason for the pathologies in paving and flooding that occur on this road. Bibliographic searches, on-site visits were used to survey and analyze the current system, hydrological data survey and the delimitation and characterization of the contribution basin through satellite images and contours. The analysis and calculations of the run-by-run rainwater flow in this basin proved that, despite the large number of existing wolf mouths, there are several oversized stretches and others where there are insufficient rainwater catchment devices. There was also a lack of maintenance given to existing devices, which, as a result, have their limited intake flow, a fact that aggravates the situation of stretches located at lower levels.