Argamassas produzidas a partir da substituição do agregado miúdo pelo resíduo do beneficiamento da scheelita e da água de hidratação por manipueira

Abstract

Mortars are homogeneous mixtures between fine aggregate, binder and water, being one of the materials most consumed by the construction industry, presenting main uses in masonry laying and coating. Aggregates account for 60 to 80% of material consumption in ready-mixed mortars, in addition to high consumption of treated water. In this sense, research has been developed to replace the constituent materials with residues that contribute to the properties of the mortars, reduce the consumption of the finite natural resources and present a destination for the residues. In this scenario the Rio Grande do Norte (RN) presents high levels of commercialization of minerals, such as tungsten that is found in the ore of scheelite. In Brazil, the main scheelite ore deposits are located in the Província Scheelitífera do Seridó. The process of beneficiation of the scheelite produces about 18,000m3 of waste/year (fine and coarse). On the other hand, the cassava processing process (Manihot esculenta Crantz) also produces some residues, such as cassava wastewater, a milky-looking liquid that flows from the roots of cassava during the pressing process to obtain starch or for the production of flour. This liquid has high content of hydrocyanic acid and high biochemical oxygen demand (BOD). Brazil is the fourth largest producer of manioc (21.08 million tons) and it is estimated the production of cassava wastewater in the proportion of 3: 1, in which for every 3 kg of manioc roots pressed, 1 liter of cassava wastewater. Both residues lack technology for their use and reduction of environmental impacts, such as visual degradation of landscape, soil, relief, air pollution and groundwater contamination. In this way, mortars for bricklaying will be analyzed with replacement of the fine aggregate by residue of scheelite (fine and coarse) and water of hydration by cassava wastewater. The residues and materials will be characterized for use in mortar in the proportion of 1: 3 (cement: aggregate) and 1: 1: 6 (cement: lime: aggregate), in volume. Afterwards, mortars will be analyzed for their freshness properties (consistency, mass density, entrained air content and water retention) and hardened (tensile strength, compression, immersion absorption, capillary absorption, bulk density and dynamic modulus of elasticity), as well as MEV analyzes to verify its technical feasibility of substitution. The expected results are the obtaining of properties, using the residues, with values within those expected for use as mortar for bricklaying.