Avaliação de misturas de solo de resíduo de polimento de porcelanato para emprego em obras rodoviárias

Abstract

The solid waste management has become a constant challenge in the modern society as a result of the increase in industrial production. This scenario is also a fact in Brazilian industries, including those producing ceramic materials. The polishing step in the production of porcelain tiles in ceramic industries produces large amounts of a residue consisting of ceramics remains, water and traces of abrasive discs used in the polishing step. This residue corresponds to a white powder of fine grain and variable chemical composition, known as Porcelain Tile Polishing Residue (RPP), and it was collected in a company located in Conde / PB. In this study, blends of a sandy-clayey soil and RPP were evaluated for use in road construction. Different dosages of residue were studied, specifically, 0% (pure soil) 5%, 10%, 15%, 20% and 40%, added in relation to the dry mass of soil. The materials were evaluated conducting tests to determine Atterberg limits, grain size distribution and specific solid weight. In addition, compaction tests, tests to determine the CBR (California bearing ratio) and oedometer consolidation tests were also carried out. A plate load test was also conducted in the laboratory with the 10% blend. Because of the chemistry of the material, a preliminary study was conducted on the influence of pozzolanic activity on the results. Finally, an environmental analysis was performed based on the collection and chemical analysis of solubilized extract obtained from a sample of pure residue. The mechanical tests were conducted under inundated conditions, in order to reduce the influence of soil suction. The evaluation of the California Bearing Ratio was made using normal and modified proctor energy. The tests showed a reduction of the average resistance of the blends compared to that of the pure soil. For the consolidation tests, it was observed that the blend with 5% of RPP had a smaller deformation than the specimen of pure soil in the same stress values, unlike the others mixtures which were more deformable. The results of the plate load test showed that the 10% blend presented a lower bearing capacity than the pure soil and the 5% blend, with bigger settlements for the same stress values. Considering all the data obtained in this research, it can be said that the residue did not significantly change the mechanical behavior of soil to levels up to 10% of RPP. For higher values, there is a worse mechanical performance. However, depending on the intended use in road construction, this behavior does not preclude the application of mixtures with more than 10% of RPP. In fact, all studied mixtures can be considered as potential materials for road construction. The pure soil and 5% blend compacted using the modified energy can also be used as sub-base material for pavement layers. The other mixtures can be used as subgrade improvement layer, if their CBR value is higher than the subgrade in question. Regarding the chemical analysis of the solubilized extract of the residue, it was observed the concentrations of the studied parameters were below the limits suggested by Brazilian standard NBR 10004.