DECIV - Departamento de Engenharia Civil
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/496
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4 resultados
Resultados da Pesquisa
Item Coating mortars based on mining and industrial residues.(2020) Mendes, Júlia Castro; Barreto, Rodrigo Rony; Vilaça, Vanessa de Freitas; Lopes, Amanda Vitor; Souza, Henor Artur de; Peixoto, Ricardo André FiorottiThe present work assesses the feasibility of using mining and industrial residues as aggregates of coating mortars in terms of building thermal performance. For this purpose, we investigated four types of aggregates (river sand—REF, iron ore tailings—IOT, friable quartzite—QTZ, and steelmaking slag—SLG). Initially, the specifc gravity (density) and thermal conductivity of the residue-based mortars were experimentally obtained. Subsequently, a sensitivity analysis was performed through energy simulations of two existing dwellings. Mortars with SLG and IOT presented the best performance due to their low thermal conductivity and, more importantly, their high density. Mortars with SLG presented 64% of thermal performance classifcations as “superior” and “intermediate”, versus an average of 53% for the other aggregates. They were followed by those with IOT, REF and lastly those with QTZ. Therefore, these mortars are cost-efective and sustainable solutions to passively improve the thermal performance of buildings, as well as to mitigate the impacts of the disposal of these residues.Item Factors affecting the specific heat of conventional and residue-based mortars.(2020) Mendes, Júlia Castro; Barreto, Rodrigo Rony; Castro, Arthur Silva Santana; Silva, Guilherme Jorge Brigolini; Peixoto, Ricardo André FiorottiThe present work investigates the specific heat of cement-based composites and the factors influencing it. To this purpose, coating mortars with Portland cement and hydrated lime were investigated, along with four types of aggregates: river sand, friable quartzite (QTZ), steelmaking slag (SLG), and iron ore tailings (IOT). Initially, the aggregates were characterised chemically and physically. Subsequently, the mortars were evaluated according to their physical and thermal properties. Adiabatic calorimetry was used to measure the specific heat of the samples in two conditions: oven-dried and saturated. The advantages and limitations of the method were discussed. Results showed that the microstructure of the mortars was more significant to the resulting specific heat than their chemical composition or density. Mortars with high specific heat and density, such as those with IOT and SLG, have great potential as sensible heat storage. Therefore, for application purposes, the specific heat should preferably be obtained through techniques that maintain the structure of the composite mostly intact, such as adiabatic calorimetry.Item On the relationship between morphology and thermal conductivity of cement-based composites.(2019) Mendes, Júlia Castro; Barreto, Rodrigo Rony; Paula, Ana Carolina Barbieri de; Elói, Fernanda Pereira da Fonseca; Silva, Guilherme Jorge Brigolini; Peixoto, Ricardo André FiorottiThe present work discloses the factors related to the morphology of the matrix that affect the thermal conductivity of cement-based composites. For this purpose, we investigated three mortar mixes with cement and hydrated lime (1:3, 1:1:6 and 1:2:9); and three types of aggregates (river sand, iron ore tailings, friable quartzite). We studied how the chemical composition and particle characteristics of the aggregates affect the overall properties of the mortars. In this sense, physical and chemical characterisation of the aggregates were performed; along with the physical, thermal and morphological evaluation of the resulting mortars. It is concluded that the morphology of the matrix is more relevant to the thermal conductivity of mortars than the chemical composition of its components. Also, the pore system generated by the aggregates in the mortar is more correlated to its thermal conductivity than its total porosity and specific gravity.Item Reuse of iron ore tailings from tailings dams as pigment for sustainable paints.(2018) Galvão, José Lucas Barros; Andrade, Humberto Dias; Brigolini, Guilherme Jorge; Peixoto, Ricardo André Fiorotti; Mendes, Júlia CastroIn order to minimise the environmental, social and economic impacts caused by the mining activity, this work proposes the use of iron ore tailings from tailings dams (IOT) as pigment in the production of a paint for buildings e the Sustainable Paint. The waste originates from the mining activity in the state of Minas Gerais. For this work, it was used in its raw state, subjected only to drying and lump breaking. In addition to IOT and water, four types of binders were tested: polyvinyl acetate (PVA) resin (in the form of ordinary white glue), acrylic resin, hydrated lime for painting and high early strength Portland cement. Binder contents ranged from 0% to 50% over the mass of IOT. For the evaluation of the mixtures, four main parameters were used: cost, colour homogeneity, abrasion resistance, and durability to external exposure, using the colour difference methodology DE (Delta-E). The results of binder evaluations were compared among themselves and with conventional paints from a brand recognised by the Brazilian Association of Paint Manufacturers. The Sustainable Paint presented reddish colour; suitable opacity; satisfactory results regarding durability at a significantly lower cost. In general, the blends with IOT, especially those using PVA as binder, have proved to be promising alternatives for paintings prepared in situ. It is noticeable the wide potential of use of this pigment by communities affected by iron ore tailings dams throughout Brazil and worldwide.