Abstract The self-healing capacity of a ceramic material produced by uniaxial pressing with alumina (Al2O3), silicon carbide (SiC), and magnesium oxide (MgO) was evaluated. To assess self-healing, a discontinuity was generated on the surface of the specimens. The healing time in the oven, at a temperature of 1000 ºC, was 1, 30, and 60 min. The specimens were analyzed by physical and mechanical tests. The results showed that, for the mixture containing 15% SiC, the specimens healed at 60 min had an increase in flexural strength of 84.9% when compared to the specimens that were only indented while for the specimens containing 20% SiC, this increase was 61.1% at 30 min. For the 30 min healing time, there was a reduction in the size of the discontinuity in the specimens by about 19.1% and 14.8%, for the formulation containing 15% and 20% of SiC, respectively.

O resíduo (lodo) gerado nos decantadores das Estações de Tratamento de Água (ETA) possui composição variada, de acordo com a região onde ela está localizada, com o mês de coleta e com o coagulante usado. Neste trabalho foram feitas caracterizações, física, química e mineralógica, deste lodo e ensaios tecnológicos em corpos de prova, com a finalidade de avaliar a possibilidade de incorporação deste resíduo em massa cerâmica para produção de tijolos. Retração linear, absorção de água, porosidade e massa específica aparente e ensaios de resistência à flexão em corpos-de-prova, com diferentes concentrações de lodo, foram avaliadas. Também, foi avaliado o efeito do tipo de floculante usado na ETA, sobre as propriedades dos corpos-de-prova. A análise mineralógica mostrou que estes lodos apresentaram composição parecida com as das argilas usadas pelas cerâmicas. Em geral, a adição destes materiais à massa cerâmica piorou suas propriedades, entretanto, os valores obtidos para as propriedades tecnológicas ainda permaneceram dentro dos valores limites aceitáveis para a produção de tijolos, dependendo da temperatura de queima e da concentração na mistura. O lodo obtido com floculante à base de alumínio, em geral, prejudicou mais as propriedades cerâmicas do que aqueles à base de ferro. Os resultados indicaram que o lodo de ETA pode ser incorporado à massa cerâmica para produzir material cerâmico.

The residue (sludge) produced in the decantation ponds of Water Treatment Plants (WTP) has variable composition according to the regional WTP localization, the month of collection and the chemical used to flocculation. In this work the sludge was submitted to physical, chemical and mineralogical characterization. Also, technological trials were realized on ceramic probes to evaluate the possibility of sludge incorporation in ceramic mass used to produce bricks. Linear shrinkage, water absorption, mechanical resistance to flexion, apparent porosity and density were evaluated in samples with different sludge concentration. Also, the effect of the chemical product used by the WTP to flocculate the solid particles on the probe ceramic properties was evaluated. The mineralogical analysis showed that the sludge and the ceramic mass had equivalent composition. As a general rule the sludge incorporation make worse the ceramic properties of the probes. Depending on the temperature of firing and the sludge concentration, the measured values can be in accordance with the limit-accepted values to produce bricks. The sludge flocculated by chemicals with aluminum is more deleterious than that obtained by using chemicals with iron. The results indicated that ETA sludge can be mixed to the raw material to produce massive bricks.