This article assesses the use of sewage sludge as a raw material in the ceramic industry, specifically in the manufacture of soft-mud bricks, to determine the maximum incorporation of sludge that results in technically sound and environmentally friendly bricks. The results obtained confirm that there was no alteration in the odor of the bricks, even at high proportions of sludge; however, high concentrations of sludge had a negative influence on certain properties, such as mechanical strength and absorption. Compressive strength was significantly diminished with the addition of sludge: the bricks with 5% sludge lost an average of 45% of the strength obtained by the control brick; the bricks manufactured with 15 and 20% lost around 70% of maximum strength; however, they still met minimum strength standards. For the specified conditions of this study, it was concluded that 20% was the maximum proportion of sludge that could be incorporated into a ceramic mass and still meet technical and environmental requirements.
No litoral oriental do Estado do Rio Grande do Norte, localiza-se a área de estudo nos limites do Centro de Lançamentos da Barreira do Inferno, que possui características naturais preservadas e onde foram avaliadas as unidades e classes temáticas do meio físico, com vistas à elaboração do mapa de suscetibilidade do solo à erosão, entre as quais: geologia, geomorfologia, pedologia, cobertura
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RESUMO Na atualidade, os resíduos de mineração vem sendo considerados como matéria prima nos programas de sustentabilidade ambiental, com o objetivo de minimizar os impactos decorrentes da atividade mineradora. Diante disso, o presente trabalho propõe analisar os resíduos de mineração de pegmatito para uso em agregado para concretos. As amostras foram caracterizadas petrograficamente, segundo seu potencial reativo à Reação Álcali-Agregado sob a norma ABNT 15577-3 e foram realizados ensaios para avaliação dos índices físicos e da resistência mecânica. Verificou-se entre as amostras de pegmatitos que duas delas obtiveram inocuidade para a reação álcali-agregado, por conter teores de fases deletéreas à RAA abaixo do limite aceitável pela norma. Entretanto, as demais amostras apresentaram potencial reatividade à RAA, por conter ora quartzo deformado, ora ambas as fases deletéras identificadas de acordo com a norma utilizada: quartzo deformado e microgranular. Os valores de resistência mecânica assumiram valores abaixo dos valores médios apresentados pela literatura consultada. Esse fato se justifica pelo grau de alteração observado nas amostras estudadas. Comprovou-se que os resíduos de lavra foram submetidos às ações intempéricas, tendo como resultado uma queda nos valores de resistência mecânica esperados. Considerando os índices físicos, as amostras apresentaram bons resultados no que diz respeito à capacidade de absorção de umidade.
The present paper analyzes the feasibility of using septic tank sludge subsequently treated in an anaerobic pond as raw material in the ceramic industry. An experiment was conducted involving the manufacture of 500 bricks using 6.5% (dry weight) of sludge at a ceramic plant in the Northeast of Brazil. To reproduce the methodologies, the same conditions and methods used by the local ceramic industry were adopted. To evaluate the bricks produced and environmental risk, compressive strength, water absorption and lixiviation tests were carried out, obeying current Brazilian norms, according to international standards. Results show the technical feasibility of using sludge as raw material in the red ceramic industry, highlighting the firing temperature of the bricks as a determinant variable. Moisture content of the sludge-clay mixture emerges as limiting factor in the manufacturing process. The moisture value determined as acceptable in the study was 22%.
The aim of this study is to assess the volumetric and mechanical behavior of concrete asphalt mixtures, using natural sludge as a partial substitute for the tiny aggregate and calcined sludge as filler. This assessment was performed based on technical and environmental parameters, using laboratory tests obeying current Brazilian norms, according to international standards. The addition of natural sludge to the mixtures has increased stability, increased air voids contents of the mixtures. The addition has compromised mixture adhesiveness. With respect to the addition of calcined sludge to the mixtures, the mixtures with calcined sludge displayed the same behavior as those with cement. It was observed decrease in empty space volume of the mixtures and consequent increase in empty space-bitumen relation and increased stability. The mixture addition of natural sludge that has the best mechanical and volumetric performance is the one with 7.5% of natural sludge in the granulometric composition of the mixture. The mixture with 1% of calcined sludge had the best volumetric and mechanical performance.
The aim of the present study is to assess the incorporation of kaolin processing waste as partial substitute for aggregates in asphalt concrete. Mixtures elaborated from the conventional mixture with the gradual incorporation of kaolin processing waste (5 to 40%) were evaluated by volumetric composition, mechanical behavior and susceptibility to moisture tests, obeying current Brazilian norms, according with international standards. The results show that the coarse kaolin waste displays grains with varying diameters, and, as such, can substitute part of the conventional aggregates and filler used in an asphalt mixture. Moreover, its mineralogical composition showed the same minerals in the composition of conventional aggregates used in paving. The assessment of the mechanical behavior of these mixtures indicate that the increased waste levels in the mixtures studied caused an increase in stability and a reduction in tensile strength. When susceptibility to moisture was considered, the results indicate that up to 25% of residue can be used as a substitute for conventional aggregates.
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