Materials Science Forum Vol. 1012

Abstract: This paper evaluated the use of the pitcher, a ceramic waste obtained through the quality process of a sanitary ware industry, in the development of a material for usage in the manufacture of sintered parts. The pitcher was obtained through powder technology and is composed, according to the chemical analysis obtained by X-ray fluorescence spectrometry, of clayey minerals (clay and kaolin), quartz, and feldspar, which may include ceramic rocks such as granite, pegmatite and phyllite; that is, it has proved to be a potential raw material due to the minerals that can still be reused. The pitcher passed through a granulometry-based selection process, sieving about 20kg using the following sieve sequence: 18 MESH, 25 MESH, 30 MESH, 120 MESH and 400 MESH; with around 70% of the residue being retained in the sieves of 120 and 400 MESH, which were selected to be used in the evaluation. The samples were compacted in a manual press with different pressures, between 300 and 1000 kgf, and after were sintered at a temperature of 1100oC in a resistive furnace. To characterize the material, the apparent and green density, as well as the compressibility curve, were determined to identify the best compression pressure. The microstructure of the test specimen and the pitcher homogeneity were evaluated using Scanning Electron Microscopy (SEM). Both particle sizes presented the typical compressibility curve, in which the density increases with increasing compaction pressure, while the curve slope decreases with increasing pressure. The density increase with the increasing compaction pressure indicates a good densification for the temperatures, independent of the sample granulometry. The sintering porosity decreased proportionally to the particle size in the sintered samples. The analysis showed that the particle size of 400 MESH sintered at 1100oC obtained more porous surfaces, thus indicating a promising future for the manufacture of parts using powder technology, especially for the development of filters.

Abstract: This study aims to characterize slag and from a steel mill and clays from in the state of Pará, aiming at its incorporation into clays for tiles production. The waste passed through the processing step X-ray diffraction (XRD) and X-ray fluorescence (XRF) were performed. Besides that, strong and weak clays from state of Pará were also analyzed by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and XRD. The results showed that hematite, magnetite and wustite are the predominant phases. The chemical analysis by XRF showed that the residue presents low levels of silica (SiO₂) and alumina (Al₂O₃) associated with elevated levels of iron oxide. Thus, the characterization of steel slag showed that this residue presents itself as a potential ceramic constituent and can contribute to the formation of liquid phase during which it would lead to improvement of technological properties such as water absorption and mechanical resistance.

Abstract: This work has as its objective to evaluate the effect of incorporation of 10 wt% of a powder waste from the sintering stage of an integrated steel-making plant in the physical and mechanical properties of bricks produced in industrial scale. Environmental tests of leaching and solubilization were performed. The results indicated that the waste slightly increased the water absorption of the ceramic and also increased in 35% its compressive strength. The sulfate parameter was above the maximum limit established by the norm for solubilization test. It was observed a strong efflorescence in the massive bricks and a smooth efflorescence in the perforated bricks.

Abstract: Residues incorporation into construction building materials is a promising sustainable alternative for the correct disposal of this kind of material. Brazil is one of the largest world producers of ornamental stones. Nevertheless, the disposal of these residues usually is made outside the industry, which contributes to environmental pollution. This work aimed to evaluate the incorporation of residues from the marble industry into ceramic bricks. Specimens of clay ceramic containing 10, 20, 30 and 40 wt.% of marble residue were prepared and fired at 900oC. The evaluation of the ceramic bricks added with marble residue was based on linear shrinkage, water absorption and mechanical resistance. These properties were compared with Brazilian standards. It was concluded that the incorporation of marble residues, with up to 20 wt%, into the ceramic body is technically feasible and positively influences the properties of the material.

Abstract: This work evaluates mortars using sewage sludge calcined at temperatures of 600°C and 700°C as a hydraulic binder replacing the cement. The percentages incorporated by mass to replace the Portland cement were 10%, 20% and 30%, using the 1:3:0,60 (cement: sand: factor a/c) trace. Sludge ash was characterized and tensile strength at flexion as well as tensile strength (pullout test) were evaluated. As a way of performing a comparison with conventional mortars, the same tests were carried out using reference mortar. The results of the flexural tensile strength tests indicated that results were higher than the reference traces of the mortars with the calcined sludge at a temperature of 700°C, a factor related to the increase of the calcination temperature and the incorporated percentage. With respect to the tests on the determination of tensile strength, it was observed that the specimens submitted to the test suffered rupture in the mortar, and that the calcination temperature of the sewage sludge was not influenced. The results obtained with the mortars using sewage sludge ash with partial replacement of the cement are shown within the normative standards and approximate to the results obtained with the tests executed with the reference mortar.

Abstract: The incorporation of industrial waste in cementitious materials is an alternative for its adequate disposal. Among the residues that do not yet have adequate disposal are the residues created by the ornamental rock industries. In this context, this work aims to identify and characterize clays of the region where the ornamental rock industry is dominant and to verify the performance of the ceramic masses with the incorporation of the marble and granite residue. Physical and chemical characterization tests were performed on both clay and residues. After the identification of the two best clays, ceramic masses were prepared where it was possible to evaluate the performance of the clays with each of the residues in incorporations up to 20 wt.%. The results indicated that CI-A with 15 wt.% marble incorporation obtained the best performance.

Abstract: Ashes from sugar cane’s residues is quantitively the greatest mineral residue generated from sugar ethanol industries which represent high calorific value, being able to be employed in a variety of products. In this present paper, it is proposed as final objective to analyze the viability of the partial substitution of this residue in mortar, study the resistance to axial compression and determine the influence of the residue utilization as alternative source to construction materials. Based on these mechanical tests, the results reveal the substitution of up to 10% (T1) of the cbc results in the production of a mortar within the developed standards in the experiment, fitting in the P6 Class of resistance to compression mortar for settlement and lining and roofs in the Technical Norm NBR 13.281:2005, leading towards superior values higher than 8MPa.

Abstract: Structural concretes must have a set of chemical characteristics to present a satisfactory resistance to the degradation in environment conditions. Besides the several types of mineralogical compositions, the calcium-rich sulfates, silicates and aluminates phases appear as majority components, but the gypsum one seems to play the most important rule in morphological changes during the concrete cure. In this work, it was carried out several characterizations in commercial Portland cement and the structural concrete sample. Nitrogen adsorption isotherms at 77 K for Portland cement showed the thermal treatment at 500 oC does not undergo significant decreasing in surface area due the high content of porous silicates and aluminates components. The additional resistance to the corrosion of structural concretes exposed at environment conditions can be associated to presence of slag metallic aggregates, which could be characterized successfully by thermal analysis. The amount of embedded metallic component in concrete sample was detected by typical weight gain originated form oxygen incorporation above 700 oC.

Abstract: Human bone has a complex geometry, varying its structure and composition. Additive manufacturing processes, such as selective laser sintering (SLS), can produce bone scaffolds with a wide range of biomaterials. Through SLS a complex structure with highly interconnected porous can be fabricated from a combination of materials. Composites made from biopolymers and bioceramics have shown promising results for bone regeneration, although some properties still must be enhanced. Finding suitable processing parameters is mandatory to achieve required final properties. This review paper is focused on polymer/ceramics using SLS machines in the last 10 years.

Abstract: The influence of citric acid in the properties of high strength Portland cement pastes and mortars, both in fresh and hardened condition, was evaluated. The content of citric acid varied from 0 to 0.8 wt%. Tests were carried out in cement pastes to determine the water required for normal consistency and initial and final setting times. Mortars cements were tested to define bulk density, consistency index, air content in the fresh condition and compressive strength after 7, 14, and 28 days. Analysis by XRD was also performed. The results showed that the use of citric acid as a retardant additive is a viable procedure, because it increased the mechanical strength after 14 days and improved the mortar workability.