A Influência de fatores socioeconômicos na determinação do perfil de risco de alunos universitários

O estudo das finanças comportamentais vem ocupando espaço na área de finanças e, ao mesmo tempo, ensejando e estimulando trabalhos acadêmicos com vistas à explorar e desenvolver esta área de estudo. O objetivo principal deste trabalho consiste na análise da influência dos fatores socioeconômicos dos estudantes de Graduação de Administração na Mesorregião do Centro-Sul do Paraná na determinação do perfil de risco. O estudo caracteriza-se como exploratório, ex post facto, dimensão temporal transversal e escopo quantitativo. Os dados foram coletados dados por meio de questionário estruturado aplicado à uma amostra de 309 estudantes, em um universo de 648. O estudo testou a influência de três aspectos socioeconômicos: gênero, idade e renda – que consistiram as hipóteses da pesquisa. Concluiu-se que o gênero e a idade são aspectos determinantes do perfil de risco, evidenciando-se que os homens são mais propensos ao risco que as mulheres e que, à medida que aumenta a idade do indivíduo, diminui a propensão ao risco.  A renda não se mostrou significativa

Determination Of Volume And Distribution Of Pores Of Concretes According To Different Exposure Classes Through 3D Microtomography And Mercury Intrusion Porosimetry

Diagnosing and understanding the properties of concrete structures allows its use in more effective ways that neither compromise application nor impose safety risks or waste materials. Several tests can be performed for this purpose, differing with regards to diagnostic precision, complexity of execution, costs, need of specific apparatus, and others. Specifications from standards must be followed to assure the durability of concrete structures, such as Eurocode 1 (EN 1992-1) and EN 206 in Europe. This study determined the volume and the distribution of pores of four concrete compositions with distinct water/cement ratio, cement consumption, and compressive strength, through tests of mercury intrusion porosimetry (MIP) and 3D microtomography. Results showed high correlation coefficients between the tests for assessing voids and compressive strength. Comparatively, the 3D microtomography test presented linear relation to the specifications of mixtures, although MIP indicated discrepancies for mixture 2

Comparative study of concrete panels' fire resistance

There is still a concern regarding concrete structures' fire safety, mostly due to the occurrence of concrete spalling. Although many tests have already been carried out, there is no clear definition about the parameters of the factors that influence its occurrence. This paper aimed to compare three different types of concrete panels, with dimensions of 300 x 315 x 10 cm (124.0 x 39.4 x 3.9 in.), composed of reinforced concrete (RC), prestressed concrete, and polypropylene microfiber RC. The panels were exposed to the standard fire curve based on ISO 834, aged 28 days, measuring the temperatures in panels' surfaces. Prestressed concrete panels experienced explosive spalling 18 minutes after the test began. RC panels and the panels with polypropylene microfiber addition maintained their integrity and structural stability for 240 minutes, failing in the thermal insulation criteria at 210 and 140 minutes, respectively. Although polypropylene microfiber concrete panels presented no spalling of concrete, conventional concrete panels attended the standardized criteria for a longer period due to its better thermal insulation

Influência da adição de fibras metálicas em concreto autoadensável no estado endurecido

[PT] A utilização do concreto autoadensável reforçado com fibras (CAARF) permite um grande avanço nas propriedades do concreto convencional. As fibras são adicionadas à mistura com a finalidade de melhorar suas propriedades mecânicas no estado endurecido. Esse compósito apresenta uma dispersão mais uniforme das fibras dentro dos elementos estruturais devido à eliminação de compactação e vibrações, o que pode causar a segregação e orientação das fibras. Assim, é possível executar elementos estruturais de espessuras reduzidas com alta qualidade, majorando sua resistência à tração na flexão e suavizando a curva de tensão-deformação quando comparados ao concreto sem incorporação de fibras. De modo a verificar a influência da utilização da adição de fibras nas propriedades do material, foi dosado um traço de concreto autoadensável com fibras de aço de três fatores de forma, nas porcentagens de 0,25%, 0,5% e 1,0%, em relação ao volume total da mistura. Após a avaliação dos resultados foi possível afirmar que a mistura com melhores resultados possui uma taxa de 1,00% da fibra com maior fator de formal, apresentando perda de 9,1% na resistência à compressão, aumento de 261% da resistência à tração na flexão e mais de 31 vezes o acréscimo do valor de fator de tenacidade, em relação à mistura referência.Cristofoli, T.; Silva, G.; Tutikian, B.; Christ, R. (2018). Influência da adição de fibras metálicas em concreto autoadensável no estado endurecido. En HAC 2018. V Congreso Iberoamericano de hormigón autocompactable y hormigones especiales. Editorial Universitat Politècnica de València. 445-454. https://doi.org/10.4995/HAC2018.2018.5369OCS44545

Verification of the influence of loading and mortar coating thickness on resistance to high temperatures due to fire on load-bearing masonries with clay tiles

Masonry has been widely used as a construction method. However, there is a lack of information on its fire behavior due to the multitude of variables that could influence this method. Thispaperaimedtoidentifytheinfluenceofloadingandmortarcoatingthicknessonthefirebehavior of masonry. Hence, six masonries made of clay tiles laid with mortar were evaluated. The mortar coatinghadathicknessof25mmonthefacenotexposedtohightemperatures,whilethefire-exposed face had thicknesses of 0, 15, and 25 mm. For each mortar coating thickness, two specimens were tested, with and without loading of 10 tf/m. The real-scale specimens were subjected to the standard ISO 834 fire curve for four hours, during which the properties of stability, airtightness, and thermal insulation were assessed. Results showed that loaded specimens yielded smaller deformations than unloadedones. Samplesthatlackedmortarcoatingonthefire-exposedfaceunderwentfireresistance decreaseof27.5%,whiletheoneswith15mmdecreasedby58.1%,andtheoneswith25mmdecreased by 41.0%. As mortar coating thickness increased, the plane deformations decreased from 40 mm to 29 mm and the thermal insulation properties of the walls improved significantly. For specimens with mortarcoatingthicknessof25mm,theloadapplicationresultedinareductionof23.8%ofthethermal insulation, while the unloaded specimen showed a decrease of 43.3%, as well as a modification of its fire-resistance rating

Evaluating steel fiber‐reinforced self‐consolidating concrete performance

The fiber‐reinforced self‐compacting concrete (FR‐SCC) is considered a high‐performance material, clustering characteristics of SCC combined with steel fibers. This paper assessed fresh and hardened state properties of a reference SCC and a FR‐SCC with fibers of three types and three quantities of reinforcement, totalizing 10 mixtures. Fresh state properties of the mixture were evaluated through the tests of slump‐flow, flow rate, filling ability, plastic viscosity by V‐funnel, passing ability by J‐ring and by L‐box; and hardened properties comprised compressive strength, flexural strength, and flexural toughness. Overall, it was observed that increasing the amount and length of fibers hindered the mixture workability. Also, the flexural strength and flexural toughness increased as the length and the amount of fibers increased. Regarding mechanical properties, it was not possible to identify an equivalence between the types of fibers evaluated and the compressive strength of mixtures. The flexural was proportional to the amount of fibers, with increases of up to 30% for concretes with fibers

Analysis of the influence of thickness on fire reaction performance in polyisocyanurate core sandwich panels

Sandwich panels (also known as insulated panels) have been traditionally used for industrial buildings and warehouses, but nowadays are being increasingly a favorable choice in building construction, mainly in wall cladding and roofing systems. This paper presents the results of an experimental and statistical comparative analysis of Fire Reaction development in sandwich panels consisting of steel sheeting and Polyisocyanurate (PIR) foam core. All these PIR core sandwich panels with joints kept the same dimensions (1000 mm × 1500 mm) + (500 mm × 1500 mm), but different thicknesses (30, 50, 100 and 150 mm). Five Single Burning Item (SBI) tests were carried out on individual PIR sandwich panels with vertical joints and their results were compared between themselves. It was possible to observe through an analysis of variance that there is an influence of the sample thickness in the individual results of the SBI test parameters; however, this variability has no significant influence on the Fire Reaction performance of the samples. Overall, the importance of these alternative sandwich panels is the increase in performance in the constructive processes and the offered comfort through its thermal insulation characteristics