Reciclagem de resíduos sólidos eletrônicos como agregado na fabricação de concreto para a construção civil, visando a redução de impactos ambientais

Abstract

Electronic solid waste, commonly erroneously discarded in ordinary waste, has metals in its composition, meaning a high degree of contamination of water and soil, as well as presenting risks to human health. This work aimed at replacing the portion of small or large aggregates with solid electronic residues in the concrete. Mechanical tests were carried out, comparing resistance values for conventional (pure) concrete and for samples with electronic waste as an aggregate, as well as environmental analyzes, where the potential for reducing environmental contamination was evaluated after encapsulation, with leaching tests and solubilization of heavy metals. For sample composition, the recycled material replaced 2 and 5% of the conventional aggregate and the simple compression tests were performed for 28 days of resistance, with the following values: Pure concrete - 4.27MPa; Replacement of 2% sand - 5,26MPa; 5% of the sand - 3.51MPa; 2% of the gravel - 4.44MPa and 5% of the gravel - 3.92MPa. It was observed that, for the substitution of 2% of residue for both aggregates, there was an improvement in the resistance, which did not occur for the substitution in 5% of the aggregate, proving mechanically that incorporating the E-trash in the cementitious matrix can be a good alternative for the destination of the same. Regarding the environmental analysis, from the leaching test, the elements Al, Cu, Fe, Mn and Zn could not be evaluated, considering that the norm NBR 10004/04, does not present limit values for such concentrations. As for the Ag, Ba and Cr elements, their respective concentrations were below the defined limits. On the other hand, the elements As, Mn, Pb, presented with concentrations greater than the allowed limit, characterizing a toxic material, being normatively a hazardous waste Class I. In the analysis, it is observed that, in the samples where the electronic waste was considerably lower concentrations were found than in the raw electronic waste sample, presenting potential reduction of toxic contaminants, thus proving the effectiveness of its incorporation in the concrete for use in civil construction.