Evaluation of the microstructure and micromechanics properties of structural mortars with addition of iron ore tailings.
Nenhuma Miniatura disponível
Data
2023
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
The Interfacial Transition Zone (ITZ) between the cement paste and aggregates is a region of great
interest for concretes because it is the composites’ weakest region. ITZ presents a great amount of
large calcium hydroxide and ettringite crystals, with the porosity being able to be up to 2.5
greater than that the rest of the paste. The microstructure, and consequently the ITZ, can be
improved by mineral addition. These materials fill the pores in the composite, influence the
hydration process and densify the matrix. Therefore, mineral additions, such as iron ore tailings
(IOT), can modify microstructure of composites. There are few studies on the assessment of IOT
heterogeneity on the microstructure and hardness of structural mortar. Thus, the present study
analyzes the properties influences of four IOT types on the microstructure, porosity, and thickness
of the structural mortars’ Interfacial Transition Zone (ITZ) with IOT addition, by different evaluation methods. The composites were characterized through the Scanning Electron Microscope by
backscattered electrons (SEM-BSE), line scan by Energy Dispersive Spectroscopy and nanoindentation. Results presented that IOT improved particle packing and tended to reduce the ITZ.
The IOT improved nucleation since it reduces the amount of anhydrous cement particles and
increases the amount of calcium hydroxide particles in the cement matrix. The nanoindentation
showed that IOT-added matrix presented greater hardness and indentation module. It can be
concluded that the IOT heterogeneity may affect microstructural properties and that the methods
presented can be good ways to evaluate the parameters.
Descrição
Palavras-chave
Iron ore tailings, Microstructure, Waste heterogeneity, Interfacial transition zone, Structural mortars
Citação
ALMADA, B. S. et al. Evaluation of the microstructure and micromechanics properties of structural mortars with addition of iron ore tailings. Journal of Building Engineering, v. 63, artigo 105405, 2023. Disponível em: <https://www.sciencedirect.com/science/article/pii/S2352710222014115>. Acesso em: 15 mar. 2023.