Análise do desempenho de concretos com cinza de casca de arroz, areia de descarte de fundição e efluente tratado de aterro sanitário

Abstract

Anchored in the environmental impacts caused by the civil construction sector in the production of concrete, with high demand for materials, high cost and large generation of waste, the need to implement sustainable systems becomes clear and necessary so that it is possible to live with quality of life. life in the coming years. In this context, this research aimed to use foundry sand contaminated by phenolic resin or also known as foundry waste sand, rice husk ash (RHA) and treated landfill effluent, as inputs for the concrete mix. Traces with different substitution contents were made and they were compared to conventional concrete. As a way of evaluating the product generated from the use of waste, the concrete was subjected to axial compression strength tests, X-ray diffraction and ACMI (Accelerated Corrosion by Modified Immersion). It was concluded that it is possible to reuse the waste studied in the research, with substitutions of up to 75% of natural sand by phenolic foundry sand, 25% of cement by rice husk ash and using treated effluent as mixing water, considering the particularities of each of these components. The mix that presented the best alternative in terms of resistance to axial compression was the mix with 50% replacement of foundry sand, followed by the mix with 100% replacement of mixing water by treated effluent. In X-ray diffraction, it was observed that there was a tendency for quartz to remain at approximate levels in all mixtures, since it comes from the fine aggregate. When alite was evaluated, which reacts before belite, it was observed that the samples with RHA had much lower levels of alite. If the XRD test had been carried out at 91 days, the tendency would have been for an increase in alite levels, since there was consumption of CH by the pozzolanic reaction. With regard to the reinforcement corrosion test, the mixture with RHA showed the best result, which can be used in concrete with the presence of steel, while the other mixtures must be used for purposes that do not show interaction with steel.