ANÁLISE EXPERIMENTAL DA INFLUÊNCIA DA ESPESSURA DA ARGAMASSA DE ASSENTAMENTO NO DESEMPENHO MECÂNICO DE PRISMAS DE BLOCOS DE CONCRETO

A alvenaria estrutural traz um conjunto de vantagens técnicas e econômicas à indústria da construção civil, devido a ampliação da sua função de exclusivamente vedação para suporte da edificação, sendo cada vez mais resistente e eficiente. Além disso, tem-se a simplificação das técnicas construtivas o que permite maior rapidez de execução e reduz a diversidade de mão de obra especializada. Entretanto, muito ainda deve ser estudado para um melhor aproveitamento deste sistema construtivo. Este trabalho apresenta ensaios experimentais com o objetivo de verificar como a variação da espessura da camada de argamassa de assentamento pode influenciar na resistência de prismas de blocos de concreto estruturais e por conseguinte na resistência de paredes de alvenaria. Com os resultados dos ensaios à compressão dos prismas, conseguiu-se constatar a influência notável da espessura da junta e se verificar que a espessura proposta pelas normas brasileiras de alvenaria estrutural são adequadas e prudentes

AVALIAÇÃO DE ENSAIOS EM ARGAMASSAS PARA USO EM PISOS E REVESTIMENTOS – ANÁLISE COMPARATIVA ENTRE AS NORMAS

A indústria construção civil é uma grande consumidora de argamassas e, de acordo com o uso, suas propriedades assumem mais ou menos relevância em função da aplicação, podendo, ser determinadas no estado fresco e/ou endurecido. As propriedades das argamassas devem ser criteriosamente analisadas, de modo que o surgimento de patologias seja minimizado e a vida útil potencializada. Dentro deste contexto, este trabalho verifica o comportamento mecânico das argamassas em função dos seguintes parâmetros: resistência à compressão axial utilizando corpos de prova cilíndricos e prismáticos, resistência à tração na flexão e por compressão diametral. Analisaram-se argamassas com duas consistências distintas, conforme o uso (piso e revestimento/assentamento), nas idades de 7, 14 e 28 dias e nos traços 1:0:3 e 1:1:6 (cimento: cal hidratada: areia). Finalmente, obteve-se as correlações entre os parâmetros analisados onde constatou-se um aumento da resistência a compressão avaliada nos corpos de prova cilíndricos em relação aos prismáticos (10%), a evolução das resistências mecânicas com a idade e a interdependência das propriedades em relação aos materiais constituintes da mistura

Carbon fiber-reinforced polymers as a tensile reinforcement of the Pinus elliotti and Manilkara huberi wood species

In wood structures, the elements subjected to bending stresses, such as the beams, present a fracture initiated in the tensile region, and under these conditions, the use of laminated composite materials is presented as an alternative solution in the form of repair or reinforcement. This research aimed to evaluate the influence of the use of carbon fibers laminated composites in tensile reinforcement in the direction parallel to grain of Pinus elliotti and Manilkara huberi wood species. The Viapol two-component epoxy adhesive was used in the lamination and fixation of the unidirectional carbon fiber in the wood species. Ten specimens with no defects (reference) and 10 specimens were prepared for each crack length (25 and 50mm) with and without the reinforcement (60mm × 50mm) by the laminated composite. The tensile tests were performed in accordance with the requirements of the Brazilian standard ABNT NBR 7190 (1997). From the results of the statistical analysis, the use of the carbon fiber composite was able to restore the tensile strength of the cracked samples (partial or total) in relation to samples without defects, demonstrating the potential of the laminates in carbon fibers as an alternative solution in repair for both wood species

<b>Shear and longitudinal modulus of elasticity in wood: relations based on static bending tests

Improve quality of timber structures design is an aim that must be systematically sought by engineers in this area. An important topic that can contribute directly to be achieved in this subject is the more consistent knowledge related to structural properties of wood. Know values of longitudinal modulus of elasticity (E) and shear modulus (G) is essential for proper evaluation of plate structures performance, as example. It has been usual to adopt statistical equivalence for E and G values in plans longitudinal-radial and longitudinal-tangential, although experimental confirmation of this hypothesis is required. In this context, the aim of this work is to determine values of ELR, ELT, GLR and GLT, based on static bending tests, to five dicotyledonous species. Results showed statistical equivalence between the elastic properties in both plans, and the relation E = 35G was obtained for the five wood species here considered

Carbon fiber-reinforced polymers as a tensile reinforcement of the "Pinus elliotti" and "Manilkara huberi" wood species

In wood structures, the elements subjected to bending stresses, such as the beams, present a fracture initiated in the tensile region, and under these conditions, the use of laminated composite materials is presented as an alternative solution in the form of repair or reinforcement. This research aimed to evaluate the influence of the use of carbon fibers laminated composites in tensile reinforcement in the direction parallel to grain of Pinus elliotti and Manilkara huberi wood species. The Viapol two-component epoxy adhesive was used in the lamination and fixation of the unidirectional carbon fiber in the wood species. Ten specimens with no defects (reference) and 10 specimens were prepared for each crack length (25 and 50mm) with and without the reinforcement (60mm × 50mm) by the laminated composite. The tensile tests were performed in accordance with the requirements of the Brazilian standard ABNT NBR 7190 (1997). From the results of the statistical analysis, the use of the carbon fiber composite was able to restore the tensile strength of the cracked samples (partial or total) in relation to samples without defects, demonstrating the potential of the laminates in carbon fibers as an alternative solution in repair for both wood species

Estimation of Toughness as a Function of Compression Strength Parallel to the Grain of Tropical Woods

Tropical species are widely used in construction, and their physical and mechanical properties have been important characteristics with direct impact on the design of structures, especially the strength and stiffness of wood applied in them. Tests to obtain both parameters are conducted under ABNT NBR 7190 (1997) guidelines in Brazil, being rarely found in some research centers because of the higher costs of testing equipment. For instance, the toughness test depends on equipment with a pendulum, whose device requires accuracy and maintenance for reliable analyses. This paper aims to estimate toughness through another property more easily found, given by the compression strength parallel to the grain. For this, 20 tropical wood species of the South American region were used to obtain initial values of these properties. The characteristic values of the compression strength parallel to the grain as well as linear and quadratic regression models were obtained. Statistical analysis was performed and confirmed that a linear model gave better predictions than a quadratic model