Rosemary Bom Conselho Sales

Thermal comfort of seats as visualized by infrared thermography

Published studies that deal with the question of how the temperature of chair seats influences human activities are few, but the studies considering such a factor, a function of the type of material, could contribute to improvements in the design of chairs. This study evaluates seat temperatures of 8 types of chairs made of different materials. The parts of the furniture that people come into contact with, and the thermal response of the material to heating and cooling have been evaluated. Infrared thermography was used for this, as it is a non-contact technique that does not present any type of risk in the measurement of temperatures. Seats made of synthetic leather (leatherette), wood and polyester fabric were found to have the highest temperatures, and the plywood seat showed the lowest. The study has also revealed that thermography can contribute to studies of thermal comfort of chair seats in addition to determining the most suitable material.

Durability of Mortar Made with Fine Glass Powdered Particles

Different studies investigate the use of waste glass in Portland cement compounds, either as aggregates or as supplementary cementitious materials. Nevertheless, it seems that there is no consensus about the influence of particle color and size on the behavior of the compounds. This study addresses the influence of cement replacement by 10 and 20% of the colorless and amber soda-lime glass particles sized around 9.5 μm on the performance of Portland cement mortars. Results revealed that the partial replacement of cement could contribute to the production of durable mortars in relation to the inhibition of the alkali-aggregate reaction. This effect was more marked with 20% replacement using amber glass. Samples containing glass microparticles were more resistant to corrosion, in particular those made of colorless glass. The use of colorless and amber glass microparticles promoted a reduction in wear resistance.

Study of the Influence of Chemical Composition on the Pozzolanicity of Soda-lime Glass Microparticles

The use of residues, in partial or total substitution of aggregates or binders in concrete, presents interesting possibilities for obtaining eco-efficient concretes. Research has investigated the use of glass residue in Portland cement composite, whether as an aggregate or a supplementary cementitious material. However, there is still no consensus on the influence of the chemical composition of glass on the behaviour of the composites in which it is used. This paper analyse the influence of this composition on the performance of cement composites produced with microparticles of colourless and amber glass. Pozzolanicity was assessed by direct (Modified Chapelle, electrical conductivity) and indirect test (chemical characterization, X-ray diffraction, thermogravimetric analysis, differential thermal analysis and Strength Activity Index testing. The results show that microparticles of both glass display pozzolanic activity, with no significant differences between them. This confirms the potential for the use of glass microparticles as a supplementary material in cement composites.

The Use of Infrared Thermography in the Analysis of Engineered Cementitious Composites

Non-destructive testing using infrared thermography has been used in civil construction basically in situations involving electrical conductors or mechanical wear that normally generate heat. In the specific case of materials, the application of thermography to metal stud is well documented, but there are few reports in the literature covering thermography in concrete; these are usually limited to the inspection of cracks and to the localization of water infiltration in prefabricated concrete structures. The present report evaluates the potential of the active infrared thermography method in the detection of changes in the macrostructure of engineering cementitious composite, as well as in order to estimate its thermal performance. The results show that thermography is able to detect changes in the macrostructure and is sensitive to temperature differences among the constituents of concrete.

Concrete Study Using Infrared Thermography and Forced Resonant Frequency

The performance of materials made from Portland cement is usually evaluated by tensile strength under compression loads, elastic modulus and porosity. Modulus of elasticity is usually determined from compression tests, and the results show large dispersions. With the advances in data acquisition and signal processing, the infrared thermography and forced resonant frequency have been increasingly used in the study of materials. However, these studies are devoted almost entirely to metals. In this paper it is evaluates the use of the method of forced longitudinal resonance frequency and infrared thermography as a tool for characterization of the buildings cementitious materials. The results show that thermography and forced resonant frequency are Able to detect changes in concrete macrostructure as well as the nature of its constituents.