Estudo da expansão por umidade (EPU) em peças cerâmicas obtidas com massas alternativas contendo resíduos de granito e caulim.

Abstract

ME is the phenomenon experienced by ceramic materials when in contact with water in liquid or vapor. This increase is due to the adsorption of surface water in stages and glassy amorphous and crystalline, increases the dimensions of the parts and gretamento, compromising the structure and reaching to collapse. In this study we used mass incorporated with waste from kaolin and granite in the preparation of ceramic bricks and tiles, in order to study the EPU. The raw materials were processed and submitted to physical and mineralogical characterization. Were then formulated compositions using experimental design and the specimens were uniaxially pressed and extruded and fired at temperatures of 800º, 900º and 1000ºC, for blocks and 1125°C, 1150°C for the coatings. After firing, the bodies of the test piece was subjected to determination of physical-mechanical properties, to determine the following properties: water absorption, apparent porosity, apparent density and modulus of rupture and underwent induction by autoclaving, boiling and immersion. The results showed that the residues of kaolin and granite have characteristics similar to conventional ceramic materials and non-plastic composition of the ceramic bodies with a higher content of granite residue had a tendency to reduce the moisture expansion, especially at temperatures above 1000°C, whereas those with higher levels of kaolin waste provided EPU values higher, especially at lower temperatures.