Veronica Scarpini Candido

Production of Synthetic Ornamental Marble as a Marble Waste Added Polyester Composite

The worldwide demand for ornamental stones in building construction is motivating the use of their wastes, generated during fabrication, to produce synthetic stones. This work has as its objective to investigate the production of a synthetic ornamental marble (SOM) under vacuum and vibro-compression processing of a polyester matrix composite with addition of marble waste as a filler. Rectangular SOM composite plates were subjected to compression and flexural mechanical tests. Samples were analyzed to obtain the density, water absorption, and microstructure. The SOM composites presented properties within the expected range of an artificial stone, which indicates that the applied process is suitable for production of this type of material.

Weibull Analysis to Characterize the Diameter Dependence of Tensile Strength in Sugarcane Bagasse Fibers

Fibers obtained from de sugarcane bagasse are being investigated as possible engineering materials. Their application as reinforcement of polymer composites is of interest due not only to environmental benefits associated with a waste recycling but also to their biodegradable and renewable characterisitics. Since it is known that many lignocellulosic fibers present a tensile strength inverse dependence with the diameter, this possibility was investigated on bagasse fibers. By means of the Weibull analysis, it was found that the thinner the bagasse fiber, the greater the strength. Fracture observation of bagasse fibers by scanning electron microscopy, indicated possible mechanisms related to this inverse correlation.

Microstuctural Evaluation of a Clay Ceramic Incorporated with Granite Rejects from Stone Sawing Using Diamond Wire

The Brazilian sector of ornamental stones is concentrated in the country’s southeast part. This sector has both the social and economical relevance because of the magnitude of the production, including that for exportation, in association with a large number of job positions. In particular, the state of Espirito Santo (ES) is responsible for more than half of the Brazilian exportation of ornamental stones. Consequently a huge amount of wastes and rejects is generated in this ES industrial activity. The present work evaluated the microstructure of red clay ceramics incorporated with a reject from the sawing of granite blocks using the technology known as diamond wire. The clay ceramic was incorporated with 40 wt% of reject and fired at 750 and 1050oC. The microstructure was evaluated by optical and scanning electron microscopy as well as X-ray diffraction. The results indicated that the incorporation sensibly changed the microstructural aspects in which more consolidated characteristics are observed at 1050oC.

Characterization of a Granite Waste for Clay Ceramic Addition

Wastes generated by processing ornamental stones are an increasing environmental problem in Brazil. Recycling alternatives are being investigated for the different types of wastes. The addition into clay ceramic is a possibility as long as the stone waste presents compatible characteristics. Therefore the objective of this work was to characterize a waste obtained from the sawing operation of granite by a steel multi-wire equipment as well as to evaluate its effect on the plasticity of clayey formulations. This characterization was performed in terms of chemical composition, X-ray diffraction and particle size distribution. The results indicated not only similar chemical and physical aspects but also a potential for addition into clay bodies of Campos dos Goytacazes in the state of Rio de Janeiro, Brazil, by the adjustment of the excessive plasticity of the clay.

Clay Ceramic Incorporated with Granite Waste Obtained from Diamond Multi-Wire Sawing Technology

The technology of subdividing stone blocks by diamond multi-wire sawing has recently been used by the ornamental stone industrial sector in the state of Espirito Santo, southeast of Brazil. The waste generated by this sawing procedure is iron free and relatively clean as compared to other stone processing operations. In principle, the diamond multi-wire sawn waste could be a viable alternative of incorporation into clays ceramics. The possibility of incorporating up to 40 wt% of a granite waste generated from diamond multi-wire sawing into clay ceramics, fabricated in the neighbor state of Rio de Janeiro, was investigated in this work. The incorporated ceramics were fired at 750, 950 and 1050oC. The apparent density, liner shrinkage and flexural strength were evaluated. The results indicated that the incorporation of the waste improved the ceramic properties, particularly at 1050oC.

A Study on Public Opinion of Structural Concrete Blocks Incorporated with Ornamental Stone Residue

The municipal area of Cachoeiro de Itapemirim, state of Espirito Santo, Brazil, is a major producer of ornamental stones. The sawing process of these stones generates a considerable amount of residues, which is disposed in open air piles, contributing to pollution and landscape degradation. A current solution being investigated for these residues is their incorporation into civil construction products such as clayey ceramics, lining mortars and concrete blocks. However, this incorporation is still subjected to doubt not only by the producers in the industry but also the intermediate seller as well as the final consumer. In order to verify the degree of personal acceptance of concrete structural blocks incorporated with ornamental stone residue, a field poll was conducted by means of questionnaires for inquiring the three directly related segments. The results showed distinct degrees of acceptance, especially by the sellers who fear rejection by the consumer. The acceptance of the residue incorporated block was, in some cases, positive as long as supported by a research work conducted in R&D centers and Universities.

Microstructural Analysis of Clay Ceramic Added with Blast Furnace Sludge

The microstructure of a clay ceramic added with blast furnace sludge, a residue generated at integrate steel making plants, has been analyzed. This analysis was performed by means of optical microscopy and scanning electron microscopy coupled with energy dispersive spectroscopy. The green clay body was added with 5 and 10 wt% of blast furnace sludge. A pure clay body was also considered as reference. These clay bodies were fired at 750°C and 950°C. The results indicated that the ceramic microstructure is non-uniform with both residue particles and pores dispersed throughout the clay matrix. Microcracks are also observed as a consequence of weak adhesion of the residue to the clay. At the higher firing temperature of 950°C the microstructure displayed a smoother surface due to the formation of low melting phases.

Characterization of Elephant Grass Ash as a Potential Clay Ceramic Addition

The elephant grass (Pennicetum purpureum) is traditionally used both as fresh feedstock for cattle and, dried, as fuel for ceramic production in Campos dos Goytacazes, Brazil. In the present work the bottom ash generated after dry grass incineration in a ceramic furnace was characterized for a possible addition into red clay ceramics. The characterization comprised the ash morphology by laser microscopy, scanning electron microscopy coupled with EDS and thermal behavior by thermogravimetry as well as differential thermal analysis. These results indicated that the elephant grass ash could be added into a clay body not only as a fluxing agent but also to improve the particles compaction before firing.

Technical Feasibility of Using Lightweight Concrete with Expanded Polystyrene in Civil Construction

The civil construction sector is considered among one of the most polluting to the environment because of the huge amount of wastes generated in its processes. Lighter and more rational structures not only reduces the amount of waste but also decrease the final price of the buildings and thus become more accessible to lower income population. One possible solution for reducing the weight of building structures is the application of light materials to the concrete, which represents a relatively larger part of the construction cost. Therefore, this study aimed to assess the compressive resistance of a concrete using expanded polystyrene (EPS), as an addition, by replacing the sand. This addition was found to provide lightness as well as economy and flexibility to structures. However, the highest strength obtained was 8.86 MPa. According to the results, it is recommended that the use of EPS should be restricted to non-structural concretes, for which the required strength is below 20 MPa, following the standards prescribed by the regulations.

Chacterization of Tensile Strength Dependence with Diameter of Sponge Gourd Fibers by Weibull Statistical Analysis

Lignocellulosic fibers with relatively unknowns mechanical properties such as those extracted from the sponge gourd, are being investigated as polymer composites reinforcement. The use of natural fibers are related to environmental , technical, economical and social advantages. An important possibility of improving the mechanical properties is the fact that lignocellulosic fibers may present tensile strength inversely correlated with their diameter. Therefore, this possibility was investigated in the present work regarding sponge gourd fibers by means of the Weibull statistic analysis. The results supported a hyperbolic inverse correlation between the strength of sponge gourd fibers with their diameter. Scanning electron microscopy observation of fibers with different diameters revealed possible mechanisms for the strength inverse correlation with diameter.