Fabricação de tijolos prensados com agregados reciclados de telhas cerâmicas, cimento portland e cinza de casca de arroz

Abstract

The red ceramic industry sector stands out as a major consumer of natural resources and energy. It is responsible for considerable greenhouse gas emissions that cause the greenhouse effect. It has also been considered as large generator of waste. Estimates indicate that in 2009, these industries produced in Brazil, 76 billion pieces, accounting for 75% of blocks / bricks and 25% of tiles. Concerning these findings, the ceramic industries consumed 3,500 GWh of energy, 152 million tons of clay; emitted 185 kg of CO2/tons of material produced and these sectors generated and discarded between 4.5 and 6.7 million tons of waste. Similarly, the beneficiary industries of rice, when using the method of burning the bark of this cereal in the parboiling processes generates about 20% of ash, if improperly discarded cause serious damage to the environment. Furthermore, it is known that Rice Husk Ash (RHA) when properly processed develop pozzolanic properties. This study aimed at producing a pressed brick from Ceramic Tile Recycled Aggregates of (CTRA), Portland cement and Rice Husk Ash (RHA). The importance of the research is justified by the fact that the resulting bricks do not require extraction of clay, nor require burning, consequently without spending energy in their production, there are no gases emissions which cause greenhouse effect. Initially it was done the procedure of crushing the tiles, after it was initiated the process of separating the particle sizes corresponding to fine aggregates defined by ABNT. It was used two types of RHA: the natural type, collected in the industry and the type produced in the laboratory, both of them used in partial substitution of 20, 25 and 30% of Portland cement. After physical, chemical and mineralogical characterizations of these wastes the bricks were molded using traces 1:9 [binder (cement + RHA): aggregate]. The results of the compressive strength tests revealed that the partial replacement of cement by RHA according to the percentages set forth in research impaired the mechanical performance of the bricks which had, however, a satisfactory performance to be used as sealing elements on the internal walls above the ground level. The results also indicated that the association of these two residues can contribute in order to give an environmentally friendly destination for both.