DECIV - Departamento de Engenharia Civil
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/496
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3 resultados
Resultados da Pesquisa
Item Residues in cement-based composites : occurrence mapping in Brazil.(2023) Lopes, Carolina de Melo Nunes; Mendes, Vítor Freitas; Garcia, Danielle Rios; Mendes, Júlia CastroScientific articles related to the incorporation of residues in civil construction materials are growing worldwide, although their practical application is still incipient. In this scenario, this paper produced an occurrence map of the most studied residues in Brazil when incorporated in cement-based composites. Initially, the most relevant residues were identified through a bibliometric analysis on the Scopus database, using the software VOSviewer. This analysis included scientific papers from Brazilian institutions published from 2001 to 2022 regarding the development of cement-based composites using residues, wastes, or tailings. Subsequently, to map the occurrence of these materials in each Brazilian state, we used public and private data on the country’s industrial production and waste disposal. From 1272 articles analyzed, we identified 49 residues with at least 2 citations. Among the most cited residues in Brazilian publications are construction and demolition waste, rice husk, glass waste, sugarcane bagasse, and tire rubber residue. The authors noticed the heterogeneity of the occurrence of the residues across the large Brazilian territory and found gaps on research trends involving them. These and other observations facilitate the decision-making process regarding logistics and investments related to the reuse and recycling of these materials.Item Correlation between ultrasonic pulse velocity and thermal conductivity of cement-based composites.(2020) Mendes, Júlia Castro; Barreto, Rodrigo Rony; Costa, Laís Cristina Barbosa; Silva, Guilherme Jorge Brigolini; Peixoto, Ricardo André FiorottiThe thermal conductivity of construction materials is among the main factors influencing the thermal performance of buildings. This property is, thus, extensively demanded for design purposes. The thermal conductivity is especially related to the pore system and the composition of cement-based composites, the same factors that affect their Ultrasonic Pulse Velocity (UPV). In this sense, the present work evaluates the correlation between thermal conductivity and UPV. To this purpose, mortar specimens were investigated, with varying mix proportions, fine aggregate types, and dosages of air-entraining admixture. A satisfactory determination coefficient (R2 > 0.9) was obtained between thermal conductivity and UPV of the mortars when they were grouped under similar components and pore structure. It was observed that the pore system of the mortars tested is more influential to the UPV than their overall porosity. In this sense, a better correlation was found between UPV and thermal conductivity than between thermal conductivity and specific gravity. Additionally, the fine aggregate type presents a significant impact—not only due to its chemical and mineralogical properties but also as a result of the morphology that each aggregate generates within the matrix. In conclusion, this technique potentially presents high applicability to the thermal characterisation of cement-based composites.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.