EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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2 resultados
Resultados da Pesquisa
Item Compressive strength of reduced concrete specimens considering dimensional distortion of coarse aggregates.(2020) Azevedo, Carlos Felipe de; Carvalho, José Maria Franco de; Mendes, Júlia Castro; Castro, Arthur Silva Santana; Barreto, Rodrigo Rony; Peixoto, Ricardo André FiorottiThe present study investigates the mechanical behavior of small cylindrical specimens (£50 100 mm) in relation to the minimum standard size (£100 200 mm) recommended by ASTM and Brazilian codes. Statistical and dimensional analyses were performed for three different classes of compressive strength (20, 30, and 40 MPa), and four grades of coarse aggregates (Dmax 9.5, 12.5, 19, and 25 mm). To this purpose, the Student’s t-Test for two means and equations from the Similitude Theory were applied. The following evaluations were performed: a) influence of the dimensional distortion of aggregates on the compressive strength of small concrete specimens; b) analyses through hypothesis testing between strength means; c) the use of prediction coefficients with statistical reliability for correcting the dimensional distortion of aggregates; and d) influence of the wall effect for different specimen sizes and concrete mixes. The results showed that the reduced and the standard specimens have similar compressive strengths, despite the reduced ones having presented higher variability of results. Also, innovative quantitative results from Wall Effect analysis show agreement with the strength results and illustrate the phenomena from a new perspective.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.