Abstract
The use of solid waste for the development of new building materials has been an alternative to reduce environmental impacts through the preservation of natural resources. In this context, this paper evaluates the possibility of using agate gemstone waste, called rolled powder, which basically consists of silica (SiO2), in the manufacture of aerated foamed concrete blocks completely replacing the natural sand. Preformed foam was used as the air entrained by mechanical stirring with a mixture of natural foaming agents derived from coconut. To produce test specimens, the water/cement ratio and foam concentrations were varied, with three and four levels, respectively. The specimens were left for 28 days at room temperature to be cured, and then underwent analysis to determine their compressive strength, density, and the distribution of air-voids. The experiments demonstrated that the best water/cement ratio was 1.28 for 18% (of total solid mass) addition of foam, which generated a sample with a density of 430 kg/m3, and a compressive strength of 1.07 MPa. The result for compressive strength is 11% smaller than the requirements of the Brazilian standard (NBR 13438) for autoclaved aerated concrete blocks, but the results are promising.
Highlights
The state of Rio Grande do Sul, located in the south of Brazil, stands out nationally and internationally for its wealth of precious stones, such as agate and amethyst, which are exported to several countries in the world
The results showed that the major constituent of the Rolled Powder (RP) is SiO2, at approximately 92.5%
aerated foamed concrete blocks (AFCB) was developed with the addition of RP waste as a substitute aggregate of natural sand
Summary
The state of Rio Grande do Sul, located in the south of Brazil, stands out nationally and internationally for its wealth of precious stones, such as agate and amethyst, which are exported to several countries in the world. The town of Soledade/Rio Grande do Sul (RS) was a pioneer in extracting, processing, and commercializing precious stones. It has only one industrial and commercial area of gemological asset, which accounts for a large part of its economy; 71% of companies in this area are exporters [3]. Other minerals are found in these deposits, such as quartz, rock crystal, rosy quartz, calcite, apophyllite, zeolites, onyx, jasper, opal, gypsite, and barite. Brum [7] identified that the agate coming from these deposits is formed by granular and fibrous microcrystalline quartz, known as chalcedony
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