Magnesia (MgO) Production and Characterization, and Its Influence on the Performance of Cementitious Materials: A Review

Nobre, José; Ahmed, Hawreen; Bravo, Miguel; Evangelista, Luís; Brito, Jorge de

doi:10.3390/ma13214752

Cited by 71 publications

(31 citation statements)

References 49 publications

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“…The formation of Mg(OH)2 during f-MgO hydration leads to inner stresses, causing a reduction in the compressive strength [55]. Nevertheless, generally, as observed for OPC, there was a decrease in the compressive strength with increased f-MgO contents (> 3 wt.%), especially at later ages [55][56][57]. At the same time, there was a compressive strength reduction with an increased f-MgO content, relative to a reference paste without additional f-MgO (ordinary Portland cement mix), mainly attributed to the increase in porosity and lower hydration of f-MgO mixtures compared to MgO-free mixtures [58].…”

Section: Compressive Strengthmentioning

confidence: 99%

The Incorporation of Steel Slag into Belite-Sulfoaluminate Cement Clinkers

et al. 2021

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The potential use of steel slag from treated steel slag in belite-sulfoaluminate cements was investigated in this study. Cement clinkers with two phase compositions were synthesized, allowing the incorporation of different amounts of steel slag. The phase composition and microstructure of cement clinkers at three different sintering temperatures were studied by X-ray powder diffraction and the Rietveld method, as well as scanning electron microscopy with energy dispersive spectrometry. The results showed that the targeted phase composition of clinkers was achieved at a sintering temperature of 1250 °C. However, a higher amount of perovskite instead of ferrite was detected in the clinker with a higher content of Ti-bearing bauxite. Apart from the main phases, such as belite, calcium sulfoaluminate, and ferrite, several minor phases were identified, including mayenite, perovskite, periclase, and alkali sulfates. In both clinker mixtures, a higher content of MgO in the steel slags resulted in the formation of periclase. Furthermore, the hydration kinetics and compressive strength at 7 and 28 days were studied in two cements prepared from clinkers sintered at 1250 °C. As evidenced by the results of isothermal calorimetry, the hydration kinetics were also influenced by the minor clinker phases. Cement with a higher content of calcium sulfoaluminate phase developed a higher compressive strength.

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Section: Compressive Strengthmentioning

confidence: 99%

The Incorporation of Steel Slag into Belite-Sulfoaluminate Cement Clinkers

et al. 2021

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“…The temperature and calcination time produce changes in the crystalline structure of MgO. For example, with the increase of temperature and calcination time, MgO suffers a reduction in its surface area increasing the size of the crystalline structure and reducing its reactivity [5][6][7]. The calcination process in obtaining MgO can be identified according to the calcination temperature.…”

Section: Introductionmentioning

confidence: 99%

“…The existing references show that the use of reactive MgO in concrete leads to higher initial expansion and lower shrinkage [7,26]. However, the MgO incorporation effect is dependent on the MgO reactivity [27] and MgO content [13].…”

Section: Introductionmentioning

confidence: 99%

Fracture Behaviour of Concrete with Reactive Magnesium Oxide as Alternative Binder

et al. 2021

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This research evaluates the fracture behavior of concrete with reactive magnesium oxide (MgO). Replacing cement with MgO is an attractive option for the concrete industry, mainly due to sustainability benefits and reduction of shrinkage. Four different MgO’s from Australia, Canada, and Spain were used in the concrete mixes, as a partial substitute of cement, at 5%, 10%, and 20% (by weight). The fracture toughness (KI) intensity factor and the stress–strain softening parameters of the wedge split test were evaluated after 28 days. The experimental results showed that the replacement of cement with MgO reduced the fracture energy between 13% and 53%. Moreover, the fracture energy was found to be correlated with both compressive strength and modulus of elasticity. A well-defined relationship between these properties is important for an adequate prediction of the non-linear behavior of reinforced concrete structures made with partial replacement of cement with MgO.

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“…In addition, concrete produced with MgO can allow permanent sequestration of CO 2 over its lifetime, thus partly offsetting the CO 2 emitted in its production phase [ 7 ]. As well as this environmental advantage, concrete with reactive MgO may behave better in some aspects, e.g., in terms of shrinkage [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Performance of Mortars with Commercially-Available Reactive Magnesium Oxide as Alternative Binder

et al. 2021

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This paper intends to analyze the performance of mortars with reactive MgO, as a sustainable alternative to cement. Six different MgOs from Australia, Canada, and Spain were used in the production of mortars as partial substitutes for cement, namely 5%, 10%, 15%, 20%, and 25% (by weight). MgOs with different levels of reactivity were used to analyze its influence on the performance of MgO mortars. In order to evaluate the mechanical performance of these mortars, compressive strength, flexural strength, dynamic modulus of elasticity, and ultrasonic pulse velocity tests were performed. Compressive strength tests showed that the use of 25% reactive MgO can cause a decrease of this property of between 28% and 49%. The use of reactive MgO affected the other mechanical properties less. This paper also intends to analyze the durability performance of mortars with reactive MgO. To that effect, water absorption by capillarity was assessed. In this research, the effect of using MgO on the shrinkage was also analyzed. It was found that shrinkage may decrease by more than a half in some cases.

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Magnesia (MgO) Production and Characterization, and Its Influence on the Performance of Cementitious Materials: A Review

Cited by 71 publications

References 49 publications

The Incorporation of Steel Slag into Belite-Sulfoaluminate Cement Clinkers

The Incorporation of Steel Slag into Belite-Sulfoaluminate Cement Clinkers

Fracture Behaviour of Concrete with Reactive Magnesium Oxide as Alternative Binder

Performance of Mortars with Commercially-Available Reactive Magnesium Oxide as Alternative Binder

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