Desempenho térmico de coberturas: Um estudo comparativo entre as telhas de material reciclado, de fibra e betume, fibrocimento e cerâmica

This study aims to compare the thermal performance of tiles made from recycled material (waste packaging cardboard with aluminized film) with the tiles of fiber and bitumen, fiber cement and red ceramic with the aim of verifying the suitability of tile to be used in hot and humid climate of low latitude. The samples were selected according to the availability from Natal - RN market, as they are sold to the consumers. The methodology was based on studies that used experimental apparatus composed of thermal chambers heated by banks of incandescent bulbs, to analyze the thermal performance of materials. The tiles in the study were submitted to analysis of thermal performance, thermophysical properties and absorptance, using chambers of thermal performance, measuring the thermophysical properties and portable spectrometer, respectively. Comparative analysis of thermal performance between two samples of the recycled material with dimple sizes and different amounts of aluminum were made, in order to verify, if these characteristics had some interference on the thermal performance of them; the results showed no significant performance differences between the samples. The data obtained in chambers of thermal performance and confirmed by statistical analysis, showed, that the tile of recycled material have similar thermal performance to the tile of fiber cement. In addition to these tests was carried out the automatic monitoring of a building covered with tiles of recycled material, to verify its thermal performance in a real situation. The results showed that recycled shingles must be used with technical criteria similar to those used for fiber cement tiles, with regard to the heat gain into the building. Within these criteria should be taken into account local characteristics, especially in regions with hot and humid climate, and its use must be associated, according to the literature, to elements of thermal insulation and use of passive techniques such as vented attics, ceilings and right foot higher

Estudo da adição de resíduo de scheelita em matriz cerâmica: formulação, propriedades físicas e microestrutura

Extractivism mineral is considered an activity highly degrading, due to the large volume of material that he moves in the form of ore and residues. The vast majority of mining companies do not show any technology or economically viable application that will allow the recycling of mineral residue, these being launched in areas receiving located the "open skies" degrade the environment. In Rio Grande do Norte to the production of ceramic red restricts their activities to the production of products such as: solid bricks, ceramic blocks, tiles, among others. Seeking to unite experiences and technical information that favor sustainable development, with important benefits to the construction sector and civil society in general, the present work studies the incorporation of the residue of scheelite in ceramic matrix kaolinitic, coming from the municipality of Boa Saúde - RN, in percentage of 5 %, 10 %, 20 %, 30% 40% and 50 %, by evaluating its microstructure, physical properties and formulation. The raw materials were characterized through the trials of X ray fluorescence, Diffraction of X rays, Differential Thermal Analysis and Termogravimetric Analysis. The samples were formed and fired at temperatures of 850o, 900o, 1000o, 1050o, 1100o, 1150o and 1200 oC, with isotherm of 1 hour and heating rate of 10 oC/min. Assays were performed technological of loss to fire, Water Absorption, Apparent Porosity, Apparent Density, Mass Loss in Fire and Bending Resistance; in addition to the Scanning Electron Microscopy, analyzing their physical and mechanical properties. The use of residue of scheelite in ceramic mass kaolinitic provided a final product with technological properties that meet the technical standards for the production of bricks and roofing tiles, with the percentage of 20% of waste that showed the best results

Aplicação da metodologia de planejamento de experimentos para formulação de massas cerâmicas para telhas

Rio Grande do Norte State stands out as one great producer of structural clay of the brazilian northeastern. The Valley Assu ceramic tiles production stands out obtained from ilitics ball clays that abound in the region under study. Ceramics formulation and the design of experiments with mixture approach, has been applied for researchers, come as an important aid to decrease the number of experiments necessary to the optimization. In this context, the objective of this work is to evaluate the effects of the formulation, temperature and heating rate in the physical-mechanical properties of the red ceramic body used for roofing tile fabrication of the Valley Assu, using design of mixture experiments. Four clays samples used in two ceramics industry of the region were use as raw material and characterized by X-ray diffraction, chemical composition, differential thermal analysis (DTA), thermogravimetric analysis (TGA), particle size distribution analysis and plasticity techniques. Afterwards, they were defined initial molded bodies and made specimens were then prepared by uniaxial pressing at 25 MPa before firing at 850, 950 and 1050 ºC in a laboratory furnace, with heating rate in the proportions of 5, 10 e 15 ºC/min. The following tecnologicals properties were evaluated: linear firing shrinkage, water absorption and flexural strength. Results show that the temperature 1050 ºC and heating rate of 5 ºC/min was the best condition, therefore presented significance in all physical-mechanical properties. The model was accepted as valid based of the production of three new formulations with fractions mass diferents of the initial molded bodies and heated with temperature at 1050 ºC and heating rate of 5 ºC/min. Considering the formulation, temperature and heating rate as variables of the equations, another model was suggested, where from the aplication of design of experiments with mixtures was possible to get a best formulation, whose experimental error is the minor in relation to the too much formulations

Relación entre la calificación de los elementos de un sistema de gestión y los indicadores de accidentalidad en empresas del sector de la construcción en Colombia

El presente estudio tiene como objetivo determinar la relación que existe entre la implementación de un sistema de gestión de seguridad y salud en el trabajo (SGSST), y la frecuencia y la severidad de la accidentalidad en la industria de la construcción en Colombia. Para ello se seleccionaron 35 empresas que realizan actividades relacionadas con la edificación, infraestructura e interventoría, que hubiesen implementado un SGSST para la intervención de los riesgos de accidentes y que contaran con la evaluación del mismo. La evaluación del SGSST está enmarcada en cinco dimensiones o criterios: planeación, política, implementación, manejo integral del accidente y revisión por la gerencia. Cada una evaluada a través de diferentes requisitos y se presentan en una escala de 1 a 10, siendo 10 el nivel más alto del cumplimiento por requisito. Teniendo los resultados de esta calificación, la tasa (proporción entre los accidentes reportados y los trabajadores de cada empresa) y los días de incapacidad (ausentismo por accidente de trabajo), se realizó un análisis de las medidas descriptivas consolidado por las empresas del estudio: tendencia central y dispersión para número de trabajadores, tasa de accidentalidad, días de incapacidad y el resultado de los totales de cada criterio de la evaluación y el gran total. Para estudiar la relación entre los resultados de la evaluación y los indicadores de tasa y días, se llevó a cabo un análisis de correlación y regresión lineal entre los indicadores de accidentalidad y los resultados de las puntuaciones de los criterios. Esta correlación se realizó tanto para la primera evaluación como para la segunda. En las dos mediciones las correlaciones fueron negativas mostrando que existe una disminución en la tasa de accidentalidad y días de incapacidad entre una evaluación y la otra. En el análisis de regresión, en la primera evaluación por cada unidad que aumentó la calificación global, se presentó una reducción de la tasa de frecuencia de 0.140. En la segunda evaluación por cada unidad que aumentó la calificación global, la tasa se redujo en 0.159. Ambos hallazgos soportan la necesidad de implementar un SGSST para ayudar a reducir el número inaceptable de lesiones y enfermedades en la industria de la construcción.

THERMAL EFFICIENCY OF INDIVIDUAL SHELTERS FOR GIROLANDO CALVES IN BRAZILIAN SEMI-ARID REGIONS

The objective of this research was to evaluate the thermal efficiency of roofs used on individual shelters during milk-feeding stage of Girolando calves. The research was conducted at a farm located in a dry region of Pernambuco state, Brazil. The experimental design was completely randomized, with 27 Holstein × Gir dairy crossbred calves housed in shelters with three roofing materials (fibre cement tile, recycled tile, and thatched roofs). The recycled tiles and thatched roofs provided reductions of 18.7 and 14.6% in radiant thermal load, respectively. Regardless the roofing material, all animals increased their respiratory rate to maintain thermal equilibrium.