Banca de DEFESA: JEANDSON WILLCK NOGUEIRA DE MACEDO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JEANDSON WILLCK NOGUEIRA DE MACEDO
DATE: 28/07/2021
TIME: 14:00
LOCAL: https://meet.google.com/ocz-cdaa-uns
TITLE:

Coating mortar produced from the replacement of natural aggregate with scheelite residue and stone dust

KEY WORDS:

Mortar. Residue. scheelite. Grit. Systematic review

PAGES: 91
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Construção Civil
SPECIALTY: Materiais e Componentes de Construção
SUMMARY:

The exploration of aggregates involves the extraction of non-renewable natural resources, and with that, it modifies the environment, causing environmental impacts. In 2019 alone, Brazil produced around 312 million tons of sand, an aggregate that is usually extracted from river beds, causing various damages to the environment, such as erosion, siltation of rivers, and soil contamination. In this context, the reuse of waste is an alternative that connects the economy to sustainability, mainly due to its ability to reduce production costs and, at the same time, promote the reduction of consumption of natural resources, as well as providing adequate management for by-products from various industries, such as those from the scheelite beneficiation process and rock crushing. The state of Rio Grande do Norte concentrates the largest reserves of scheelite in Brazil, which are explored to obtaining tungsten, one of the most used minerals in the production of various industrial segments. During the extraction of this element, tons of solid waste are generated and stored outdoors, occupying large areas, providing impacts to the environment. Stone dust is the fine by-product originating from the rock crushing process to obtain gravel for civil construction, which, in turn, is usually deposited in the quarries yard, in large volumes, providing various environmental impacts and respiratory diseases. In Brazil, this by-product is used mainly in the production of concrete and industrialized mortar, however, its use in the production of mortar and concrete in construction works is still very limited. Faced with this problem, this research aims to study the performance of coating mortars produced with total replacement of natural aggregate by residual binary sands consisting of stone dust and scheelite by-products. For this, the characterization of waste and materials used in the manufacture of mortars was carried out, including FRX, DRX, and SEM analyses. Then, mortars were formulated at a ratio of 1:3 in volume, with total replacement of natural sand by residual scheelite sand and crushing.  The mortars were analyzed for their properties in the fresh state (consistency, mass density, incorporated air content, and water retention) and hardened (tensile strength, compression strength, immersion absorption, capillary absorption, bulk density, and microstructure). In the end, coatings were performed, which in turn, were evaluated for adherence to traction. The study of the packing and particle size distribution of the aggregates allowed the production of high-quality residual sand from the combination of stone dust and coarse scheelite residue, which are significant environmental liabilities of mining in the state of Rio Grande do Norte, Brazil. The mortar produced with this composition, in the fresh state, although denser, had better consistency, greater water retention, and incorporated air content similar to the reference mortar. In the hardened state, the formulation achieved high mechanical strength, higher mass density, lower absorption, both by immersion and capillarity, among all the evaluated mortars, as well as a tensile adhesion performance close to the reference mortar and, above the minimum values established by Brazilian standards for mortar coatings, which confirms the feasibility of using the composition of crushing sand and scheelite as an aggregate for mortars.

BANKING MEMBERS:
Presidente - 1149564 - WILSON ACCHAR
Interna - 1717461 - LUCIANA DE FIGUEIREDO LOPES LUCENA
Externa à Instituição - JAQUELIGIA BRITO DA SILVA
Externa à Instituição - SHEYLA KAROLINA JUSTINO MARQUES - IFAl
Externo à Instituição - VAMBERTO MONTEIRO DA SILVA - IFPB