Tijolos de solo-cimento produzidos com manipueira em substituição à água

Abstract

The construction industry is recognized as one of the largest consumers of natural resources on the planet. The number of researches aimed at reducing the impacts caused by the sector has grown considerably in recent years. The development of new construction materials, which contribute to reducing environmental impacts, satisfying current standards, has been debated and studied by researchers. One of these materials is the soil-cement brick which is considered to be ecological and presents a great potential of incorporation of residues of several industries that need studies for treatment and/or reuse, such as ceramic waste, rice husks, bottle waste PET, etc. An environmental liability that requires research to be reused is cassava water, an industrial byproduct (effluent), from the pressing of cassava in flour house, highly polluting, due to its toxicity and concentration of organic matter. Some authors have proposed alternative solutions for treatment or disposal of this waste, and the production of bricks is one of them. Thus, this study aimed to evaluate the physical, mechanical, and microstructural properties of solid bricks soil-cement produced with cassava instead of water. After characterization of the raw materials of the soil-cement formulations, 3 complete 2k factorial experimental designs with 3 replicates at the central point were elaborated to reduce the number of samples. The cement was used in the proportions 6%, 9%, and 12%, and the cassava wastewater 0%, 50% and 100% instead of water. Thus, 5 formulations were produced. The compressive strength tests were performed at 7, 28, and 49 days. The water absorption and modified durability tests were performed at 7 days. Subsequently, the microstructure of the bricks with 12% cement and 0% and 100% of cassava wastewater and 9% of cement and 50% of cassava wastewater was studied by means of X-ray diffraction and scanning electron microscopy (SEM). All formulations showed results of compressive strength above 1MPa. In the water absorption test, all the samples obtained results below 20%. And in the modified durability test, all compositions showed mass loss below 1%. In the X-ray diffraction tests the kaolinite, quartz, calcite, CASH (calcium aluminate silicate hydrated) and CSH (calcium silicate hydrated) phases were identified in all samples analyzed. In the SEM, it was possible to verify the soil particles and typical structures of the CSH. It is worth mentioning that the bricks produced with cassava wastewater presented similar results to those obtained in the formulations that did not use the waste. It is possible to conclude that the results demonstrate the technical feasibility of using cassava waste water instead of water in the production of soil-cement bricks for use in masonry without structural function.