Angela Borges Masuero

Concrete Performance With Admixtures of Electrical Steel Slag and Copper Copper Concerning Mechanical Properties

The generation of solid residues and an adequate final destiny for them is a subject that has attracted more and more research. The recycling of solid by-products as construction materials can be an alternative to reduce costs of the latter and it can also reduce the impact on the environment. Nevertheless, it is fundamental that the characteristics of these new materials be equivalent to the traditional ones or even better, if possible. In this context, the use of electric steel slag and copper slag can be a potential alternative to the admixtures used in concrete and mortars. Results of physical, chemical and physical-chemical characterizations of electric steel slags from Rio Grande do Sul and copper slags from Bahia, both in Brazil, are presented in this work. Also presented are results of compressive tests, flexural tests and Brazilian tests in concrete specimens with these admixtures, indicating the viability of their use.

Analysis of main parameters affecting substrate/mortar contact area through tridimensional laser scanner

This study assesses the influence of the granulometric composition of sand, application energy and the superficial tension of substrates on the contact area of rendering mortars. Three substrates with distinct wetting behaviors were selected and mortars were prepared with different sand compositions. Characterization tests were performed on fresh and hardened mortars, as well as the rheological characterization. Mortars were applied to substrates with two different energies. The interfacial area was then digitized with 3D scanner. Results show that variables are all of influence on the interfacial contact in the development area. Furthermore, 3D laser scanning proved to be a good method to contact area measurement.

The Wind-Driven Rain and the Buildings: Directional Driving Rain, Experimental Simulation and Quantification of Wetness Areas

The theme involving the driving rain has been the subject of various studies that seek to contribute to the understanding of this phenomenon and its interaction with the buildings. In this sense, research discusses some aspects related to driving rain, such as the development and application of a methodology for quantifying wetting areas on models exposed to experimental driving rain, and the determination to the direction of the driving rain, in Porto Alegre city—Brazil, through the use of semi-empirical method, more specifically, a wind-driven rain relationship formula. The findings of this study demonstrate that the building facades oriented to the East/South quadrant have higher incidence level of driving rain, considering the Porto Alegre City-RS-Brazil. Furthermore, considering the application of the methodology, it was found, based on the images obtained in the experimental tests that both the building shape and the surroundings influence the degree of driving rain wetting on the models facades. In this way, the model with a square base and without surroundings showed the least amount of wet area when compared to the others.

Proposta de elemento de integração para a interface entre alvenaria estrutural e esquadria

A utilizacao de sistemas modulares na industria da construcao tem crescido de forma acentuada nos ultimos anos no Brasil, sendo que, dentre estes, se destaca o sistema construtivo de alvenaria estrutural. Entretanto, diversos estudos apontam uma alta incidencia de manifestacoes patologicas relacionadas a este sistema. A interface entre alvenaria e esquadria e um dos locais de maior incidencia de problemas, alem de representar um gargalo construtivo, pela necessidade de realizacao de inumeras atividades que dependentes da mesma. O presente artigo apresenta o processo de desenvolvimento de uma nova solucao para este problema, denominada elemento de integracao, incluindo sua definicao geometrica, funcional e conceitual, bem como a producao de prototipos virtuais e fisicos (com diferentes materiais). Ao longo do desenvolvimento de diferentes modelos, foram realizadas avaliacoes pela equipe de projeto, a partir das quais foram introduzidas melhorias. Ao todo, foram produzidos 4 modelos virtuais, 3 modelos fisicos na escala 1:1, e uma parede experimental. Os principais resultados apontam para a viabilidade e adequacao da proposta ao sistema construtivo, bem como identificam o possivel aumento de construtibilidade do sistema como um todo a partir da aplicacao do elemento desenvolvido.

Analysis of Main Parameters that Affect Contact Area Between Mortar Rendering and Substrate: Use of 3D Laser Scanning Technique

The objective of this research is to analyze the influence of granulometric composition of sand, application energy, and substrates superficial tension on the contact area of rendering mortars. Three different substrates were selected with distinct wetting behaviors: polyethylene, acrylic, and glass. The contact angle of drop water was measured by goniometer. Mortars were prepared with cement:lime:sand ratios of 1:0:3, 1:1:6, and 1:2:9, by content converted in mass, with sand composition of 25 % of each 0.15, 0.3, 0.6, and 1.2 mm grain sizes. Characterization tests in fresh and hardened mortars were performed to provide the technological control of mortars and concretes, as well as the characterization of the different rheological behaviors of the mortars by squeeze-flow and rotational rheometer methods. Mortars were applied to substrates with two different energies, and after curing time were parted from substrates and submitted to scanner 3D digitalization of interfacial area. Results showed that both mortar proportion and substrate superficial tension exercise influence on interfacial contact area development. Additionally, interaction between application energy and substrates superficial tension was significantly influent on contact area. Finally, 3D scanning is a promising new method that shows good performance to measure contact area to improve the understanding of bond strength.

Concreto usinado: análise da variação da resistência à compressão e de propriedades físicas ao longo da descarga do caminhão betoneira

The common practice, in construction sites of the region of Porto Alegre, to collect samples for testing, of the first portion of the concrete discharged from the truck mixer, and the lack of standardization to measure the quality of the mixer and uniformity of mixing and the importance of quality control testing of concrete, this paper aims to examine the uniformity of ready mixed concrete. To achieve the aim was collected samples at five different points along the discharge of ready mixed concrete, for 13 lots of conventional concrete. There was not the formation of a representative profile of compressive resistance as the different collection point and there was not significant variation between the collection points.

O limite de tempo especificado pela NBR 7212, para mistura e transporte do concreto, pode ser ultrapassado?

A norma NBR 7212, para execucao de concreto dosado em central, estipula o tempo maximo para que o concreto seja descarregado (aplicado) completamente em 150 min; porem, na pratica, ocorrem situacoes onde caminhoes ficam carregados por tempos bem acima desse limite. O objetivo principal deste artigo consiste na avaliacao do comportamento do concreto em relacao a sua resistencia a compressao, quando utilizado posterior ao tempo maximo de mistura e transporte especificado pela norma. Para tal, adotou-se como procedimento o restabelecimento do abatimento a condicao inicial com aditivo superplastificante por um periodo de 6 horas. Os resultados mostram que nao houve perda de resistencia a compressao para esse tempo de mistura prolongada, nas condicoes dessa pesquisa.