The state of Para is one of the greatest producers of mineral substances in Brazil. Kaolin for paper coating industry and bauxite for alumina and aluminium production are amongst the most important commodities. The latter is responsible for the generation of red mud, a well-known residue from Bayer process. The kaolin processing plants are also responsible for the generation of large amounts of wastes, in this case, very fine-grained kaolinite (white mud). The research aimed to find a final destination for such residues by developing new building materials. The proposed material is a pozzolanic pigment produced through calcination and grinding of mixtures of red mud and kaolin waste. The pozzolanic pigments provided increased mechanical strength and color stability of the colored mortars relative to the inert pigment. The pozzolanic characteristics of the pigments reduced the leaching of the mortars. The new material has proven to be promising in its application as an innovative construction material, with the possibility of using these residues in a market that is little explored in Brazilian civil construction: colored mortars and concrete.
The use of permeable concrete pavements can mitigate flooding in densely populated areas by serving as a functional and sustainable mechanism for surface water absorption and drainage. However, it is found that the performance of the pavement is often limited to low and moderate flows and that the absorption capacity of the concrete matrix decreases as the flow rate increases. Therefore, the present study was developed aiming to evaluate the potential to reduce runoff in permeable concrete pavements subjected to simulations of successive events of heavy rainfall. For this purpose, 2 binary combinations of coarse aggregates were used, varying the cement consumption and the water/cement (w/c) ratio. The samples were submitted to simulations of heavy and sequential rainfall, with evaluation of the volume of water absorbed and the runoff. The mechanical and hydraulical properties of the permeable pavements were evaluated, as well as the characteristics of the area and volume of the internal and superficial pores. Among the results, specific weight stands out as the parameter that showed the highest linear correlation with the mechanical and hydraulic behavior of the specimens. It was also found that the runoff coefficient had a moderate negative linear correlation with the average pore size of the surface of the pavement. Finally, the permeable concrete pavements investigated were found to have the potential to reduce surface runoff in densely populated areas that are prone to frequent flooding, thus playing a critical role in mitigating the problems associated with stormwater runoff.
RESUMOO estudo se resume em a comparação dos resultados dos Ensaios, in loco, Dinâmico e de Carregamento Lento (este último que necessitou ser extrapolados pelo método de Van Der Veen, de acordo com a NBR 6122), com os métodos de cálculo semiempíricos de Aoki-Velloso e Decourt-Quaresma. Para tal, foram usadas como dados dez estacas de perfil metálico tipo I na fundação de um prédio comercial na região sul da cidade de Belém do Pará, onde a estratigrafia é composta por camadas intercaladas de areias compactadas à compactas medias e argilas mole à rijas. A metodologia do estudo se deu pela comparação dos valores de carga mobilizada perante os parâmetros de transferência de carga. Com base nos resultados foram gerados gráficos de força mobilizada em relação ao deslocamento. Foram atingidos resultados satisfatórios, levando-se em comparação o
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