Research on the properties of magnesium oxychloride cement prepared with simulated seawater

Huang, Qing; Xiao, Xueying; Liu, Ying; An, Shi; Chang, Chenggong; Wen, Jing; Zheng, Weixin; Dong, Jinmei

doi:10.1680/jadcr.17.00127

Cited by 13 publications

(8 citation statements)

References 15 publications

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“…7 MOC had obvious advantages with respect to strength, wear resistance, high and low temperature resistance, salt-brine resistance, and so on. [8][9][10][11][12][13] Further, MOC is a nonhydraulic cementitious materials prepared by mixing magnesium chloride and magnesia in certain proportions. 7,14 The research on MOC focused primarily on the ternary system (MgO-MgCl 2 -H 2 O), the phase transition process of the ternary system and application of MOC, among others.…”

Section: Introductionmentioning

confidence: 99%

“…A sketch of the electrochemical corrosion process in concrete is shown in Figure 2. 24 The research on MOC products has focused primarily on the properties of the paste and the mortar, [8][9][10][11][12][13][14][15][16] while relatively less research has been conducted on the properties of MOCC was, and has focused mainly on the effects of the MgCl 2 concentration, fly ash, molar ratio of MgO, and MgCl 2 , and so on, on the strength and water resistance of MOCC. 25,26 However, in recent years, some experts have begun to study rebar corrosion in MOCC.…”

Section: Introductionmentioning

confidence: 99%

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Time‐dependent model and life prediction for reinforcement corrosion in magnesium oxychloride cement concrete

Gong

Wang

Zhang

et al. 2020

Structural Concrete

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An effective approach to make better use of the salt-brine resistance of magnesium oxychloride cement concrete (MOCC) and reduce "magnesium damage" (the concentrate of magnesium resources) that destroys the ecological balance in salt lake areas is to apply MOCC widely. However, the first problem is the high chloride ion content in MOCC, which corrodes reinforcement easily. Concrete cover depth, the experimental environment, and surface treatment of rebar were considered factors study in reinforcement corrosion in MOCC. Based on the tests conducted, a time-dependent model for reinforcement corrosion in MOCC was proposed, and its life time (initial corrosion and initial cracking time) was calculated and verified in tests. The results showed that proper coating could inhibit reinforcement corrosion and increase the service life of rebar significantly. Further, the salt lake environment had little influence on reinforcement corrosion in MOCC. For exposed rebar in MOCC, the larger the concrete cover depth, the more serious the reinforcement corrosion, while, for coated rebar, the converse was true. All cases of reinforcement corrosion in MOCC conformed to the logarithmic-type time-dependent model before concrete cracking. Accordingly, reinforcement corrosion in MOCC and the excess of magnesium resources are expected to be solved.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Time‐dependent model and life prediction for reinforcement corrosion in magnesium oxychloride cement concrete

Gong

Wang

Zhang

et al. 2020

Structural Concrete

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“…The molar ratio of the active MgO/MgCl 2 /H 2 O of MOC cement preparation was 7 : 1 : 15, which is the same as the previous reference [18,19]. To prepare the neat MOC specimens, bischofite was firstly dissolved into the water before mixing it with the light-burned magnesia.…”

Section: Specimen Preparationmentioning

confidence: 99%

“…To evaluate the water resistance of the MOC, the specimens cured for 28 days in the air environment were dipped in water at 20 ± 3 °C, and the compressive strength of the samples after the different immersion times in the water was measured and used to calculate the strength retention coefficient (R f) as follows [18,19]:…”

Section: Specimen Analysismentioning

confidence: 99%

Effect of Ethyl Silicate on the Water Resistance of Magnesium Oxychloride Cement

Huang¹

2019

Ceramics - Silikaty

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In this paper, fly ash (FS), phosphoric acid (H 3 PO 4), ferrous sulfate (FeSO 4 •7H 2 O) and ethyl silicate (TEOS) were incorporated to devote effort for the further improvement of the water resistance of magnesium oxychloride cement (MOC). The strength retention coefficient was tested to evaluate the water resistance of the MOC, in which the addition of FS + H 3 PO 4 + + FeSO 4 •7H 2 O + TEOS resulted in a remarkable improvement. The characterisation of the hydration products before and after the water immersion was carried out using X-ray diffraction (XRD), a thermogravimetric (TG) analysis, Fourier-transformed infrared spectroscopy (FTIR) and a scanning electron microscope (SEM). Through the XRD, TG and FTIR analysis, the results showed that the addition of FS + H 3 PO 4 + FeSO 4 •7H 2 O + TEOS resulted in the generation of the amorphous phase during the water immersion. This amorphous gel was identified as a mixture of a magnesium-chloride-silicate-hydrate gel (M-Cl-S-H gel) and an insoluble magnesium-chloride-hydrate gel (M-Cl-H gel) by Energy Dispersive Spectrometer (EDS). The generation of the insoluble M-Cl-S-H gel and M-Cl-H gel and the densification of the microstructure contributed to the valuable and long-term improvement of the water resistance in the MOC. Then the transformation of the morphology might be due to the interaction performance and superposed effect of FS, H 3 PO 4 , FeSO 4 •7H 2 O and TEOS.

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“…In this experiment, the molar ratio of the fixed MOC to MgOa/MgCl 2 /H 2 O is 7:1:15 according to references [10,[18][19][20]. Meanwhile, 0 %, 5 %, 10 % and 15 % of the compound admixture Q101 are added to prepare a homogeneous slurry.…”

Section: Specimen Preparationmentioning

confidence: 99%

The Compressive Strength Development of a Magnesium Oxychloride Cement Comprising a Composite Additive in Brine

Huang¹

2019

Ceramics - Silikaty

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In this paper, the performance of magnesium oxychloride cement (MOC) in brine environment after the addition of an anticorrosion admixture (Q101) was investigated. The compressive strength, compressive strength retention, crystal composition and microstructure were analysed in detail. The results show that the compressive strength of the MOC with the Q101 admixture maintains a high compressive strength of more than 100 MPa in air, and decreases slightly in the raw brine and the aging brine, but the decreases are not significant with the compressive strength of 80 MPa. This demonstrates the excellent salt brine resistance in brine environment of the MOC. One reason is that the high content of Mg 2+ and Clin brine suppress the dissolution rate of main hydration product in the MOC. The other is the addition of an anti-corrosion additive that improves the salt brine resistance by about 30 %. However, the compressive strength and strength retention of the MOC after the raw brine immersion are higher than the aging brine immersion. The reason may be that the salts fill the surface and the pores in the samples that prevented water erosion to some extent. Meanwhile, the MOC pastes have the biggest compressive strength retention when the Q101 was up to 10 % over the long run. As a result, the optimum dosage of Q101 is 10 % in this experiment.

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Research on the properties of magnesium oxychloride cement prepared with simulated seawater

Cited by 13 publications

References 15 publications

Time‐dependent model and life prediction for reinforcement corrosion in magnesium oxychloride cement concrete

Time‐dependent model and life prediction for reinforcement corrosion in magnesium oxychloride cement concrete

Effect of Ethyl Silicate on the Water Resistance of Magnesium Oxychloride Cement

The Compressive Strength Development of a Magnesium Oxychloride Cement Comprising a Composite Additive in Brine

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