Incorporação do pó de conchas de ostra provenientes do processo de ostreicultura na produção de argamassa para revestimento

Abstract

The aquaculture is one of the industries that has grown up the most in the past few years, surpassing the fishery, producing 114.5 million tons in 2048 and with a projection of growth of another 109 million tons by 2030. Modern aquaculture must be based on three pillars: economically viable production, environmental conservation and social development. The environmental impacts caused by oyster farming are considered low compared to other aquaculture modalities. However, solid wastes generated by this activity includes problems such as silting, when discarded at sea or beaches, and when discarded in vacant lots problems may include the appearance of diseases caused by pathogenic animals and insects that feed on organic matter present in these wastes, also contributing with the visual pollution. The purpose of the present research was evaluate the technical feasibility of laying and coating mortar production through substitution of different percentages of the aggregate by oyster shell powder from oyster farming conducted by an association located in Tibau do Sul, Rio Grande do Norte, Brazil. The shells of Crassostrea brasiliana oyster were cleaned and directed to the grinding process in a ball mill. The material reduced in the grinding process was subjected to granulometric, thermogravimetric analysis, X-ray fluorescence and diffraction, so that a physical-chemical characterization could be performed. Subsequently, it was used in modeling clay specimens for cladding, replacing the aggregate with the percentages of 0%, 10%, 20%, 30%, 40% and 100% of oyster shell powder. The mortar specimens were subjected to technological tests of compressive strength and water absorption. The partial replacement of aggregate by the by-product of oyster farming in the manufacture of mortar provides an increase in compressive strength, reaching an average of 18 MPa for a reduction of 100% of the by-product, above the values required by Brazilian Standards. The water absorption rate was higher for the specimens with a greater amount of the by-product, when compared to the reference samples, although still within the BRS. Based on these results, we concluded that the use of mortar production residue proves to be viable.