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Effects of Dolomitic Limestone on the Properties of Magnesium Oxysulfate Cement.
Molano, Juan Camilo Adrada; Azevedo, Adriano Galvão Souza; Freitas, Taís Oliveira Gonçalves; Silva, Gabriela Casemiro Da; Savastano, Holmer.
Afiliação
  • Molano JCA; Department of Biosystems Engineering, University of São Paulo, Pirassununga 13635-900, SP, Brazil.
  • Azevedo AGS; Department of Biosystems Engineering, University of São Paulo, Pirassununga 13635-900, SP, Brazil.
  • Freitas TOG; Department of Biosystems Engineering, University of São Paulo, Pirassununga 13635-900, SP, Brazil.
  • Silva GCD; Polytechnic School, University of São Paulo, São Paulo 05508-010, SP, Brazil.
  • Savastano H; Department of Biosystems Engineering, University of São Paulo, Pirassununga 13635-900, SP, Brazil.
Materials (Basel) ; 17(18)2024 Sep 18.
Article em En | MEDLINE | ID: mdl-39336321
ABSTRACT
This study investigated the effects of substituting magnesium oxide (MgO) with dolomitic limestone (DL) on the mechanical and physical properties of magnesium oxysulfate (MOS) cement. Additionally, the hydration formation phases and the influence of the molar ratio on the MOS cement's performance were examined. The corresponding action mechanisms were identified and explored by compressive strength tests, scanning electron microscopy (SEM), X-ray diffraction (XRD), isothermal calorimetry, and a thermogravimetric analysis (TGA). The results showed that replacing MgO with DL decreased the reaction speed and heat release rate generated in the hydration process of the MOS cement. This substitution also reduced the quantity of non-hydrated MgO particles and delayed the formation of Mg(OH)2. The diminished formation of Mg(OH)2 contributed to an increase in the apparent porosity of pastes containing DL, thus alleviating internal stresses induced by Mg(OH)2 formation and enhancing their mechanical strength after 28 days of curing. Conversely, the increased porosity improved the CO2 diffusion within the structure, promoting the formation of magnesium carbonates (MgCO3). Through the characterization of the cement matrix (XRD and TGA), it was possible to identify phases, such as the brucite, periclase, and 318 phases. The obtained results revealed the potential of incorporating mineral fillers like limestone as a promising approach to producing MOS cement with a reduced environmental impact and better properties at higher curing ages.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: Materials (Basel) Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Brasil País de publicação: Suíça

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: Materials (Basel) Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Brasil País de publicação: Suíça