Otimização da produção de agregados leves com resíduo do polimento do porcelanato por métodos estatísticos

Abstract

Studies on synthetic lightweight aggregates using industrial and agricultural waste are of interest for reducing environmental impacts by reusing waste materials, promoting sustainable practices, and conferring commercial value to the residues. Additionally, its various applications are appealing: concrete, masonry, pavement, geotechnics, water treatment, among others. The main objective of this research was to investigate the production of lightweight aggregates using porcelain polishing waste and clays, utilizing the Taguchi method to evaluate the main variables influencing the process and possible applications of the obtained aggregates in engineering services. To achieve this, the aggregates were produced based on an experimental program defined by the Taguchi method, with controllable variables including the heating rate (ranging from 10 ºC/min to 40 ºC/min), the sintering time (from 10 min to 25 min), the type of clay used (white or red), and the sintering temperature (ranging between 1180 ºC and 1240 ºC). Subsequently, the samples were subjected to laboratory tests that made it possible to determine the expansion index, mass loss, unit mass, apparent specific mass, water absorption, crushing resistance, mineralogical composition and morphology. Statistical analyses were also performed using the Taguchi method and analysis of variance ANOVA, followed by the creation of surface graphs and classification regarding the possible applications of the aggregates. With this, it was possible to obtain aggregates with expansion ranging from -40.84% (shrinkage) to 91.69%, mass loss between 3.67% and 7.62%, unit mass from 0.81 g/cm³ to 2.43 g/cm³, specific mass with values between 0.99 g/cm³ and 2.36 g/cm³, water absorption from 0% to 3.29%, and compressive strengths between 4.57 MPa and 39.87 MPa. In general, the variables that most influenced the processes were the type of clay used and the sintering temperature. Out of the 16 experiments carried out, 9 were configured as lightweight aggregates and were used for the 3 main engineering applications (concretes). This research concluded that it is possible to generate lightweight aggregates using clays from the coast of Paraíba and porcelain polishing waste by varying the sintering factors, such as heating rate, temperature and time depending on the desired property. It was possible to verify the relevance of using statistical methods to identify the parameters that influence production which, if controlled, can result in cost reduction and improvement in product quality.