Tuning the phase structure and mechanical performance of magnesium oxychloride cements by curing temperature and H2O/MgCl2 ratio

Ye, Qianqian; Wang, Wen; Zhang, Wei; Li, Jianzhang; Chen, Hui

doi:10.1016/j.conbuildmat.2018.05.257

Cited by 48 publications

(20 citation statements)

References 24 publications

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“…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. 15,16 If the magnesium chloride used to produce MOC derived from salt lake areas, it could obviously alleviate "magnesium damage" and resources waste. However, unfortunately, because of the high chloride ion content of MOC, 17 the rebar in concrete in which MOC was used as the cementitious material corroded so easily that it reduced the service life of the new concrete structure significantly.…”

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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“…Among superior properties of MOC cement composites are: early compressive strength, excellent fire resistance, low alkalinity (pH of 8-10), short setting time, and anti-abrasion performance [8,9]. MOC cements are also known by their ability to incorporate a higher amount of various fillers compared to PC, namely granite waste [10], fly ash [10,11], cenospheres derived from the fly ash [12], biomass ash [13], wood [6], recycled tire rubber [14], and waste plastics [15].…”

Section: Introductionmentioning

confidence: 99%

“…The production of MgO from magnesite releases more CO 2 per ton than in the production of Portland cement (1.7 t of CO 2 /t of MgO vs. 1 t CO 2 /t of PC) [3]. However, taking into account the carbonation of the MOC cement composites, when MOC is able to sequestrate more than half of the CO 2 produced during MgCO 3 calcination (the resulting CO 2 emissions decreased therefore to around 0.5-0.6 t of CO 2 /t), and given the total environmental impact during the life cycle of MgO ascertained by LCA, the MOC cement can be considered as environmentally friendly material [3].Among superior properties of MOC cement composites are: early compressive strength, excellent fire resistance, low alkalinity (pH of 8-10), short setting time, and anti-abrasion performance [8,9]. MOC cements are also known by their ability to incorporate a higher amount of various fillers compared to PC, namely granite waste [10], fly ash [10,11], cenospheres derived from the fly ash [12], biomass ash [13], wood [6], recycled tire rubber [14], and waste plastics [15].…”

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confidence: 99%

Influence of Waste Plastic Aggregate and Water-Repellent Additive on the Properties of Lightweight Magnesium Oxychloride Cement Composite

et al. 2019

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Featured Application: The results obtained in the paper can find use in the design and development of low-energy and low-carbon construction composites with the incorporation of waste expanded polypropylene. The developed "green materials" possess good thermal insulation function, minimum water absorption, sufficient permeability for water vapor, and resistance against the harmful water action. The mechanical strength of the lightened composites is acceptable for non-bearing purposes but if required, it can be further improved to meet the technical requirements of construction practice. Abstract:The aim of the present study is to improve the thermal and hygric performance of magnesium oxychloride (MOC) cement composites by the incorporation of waste plastic-based aggregate and the use of the inner and surface hydrophobic agents. The crushed waste expanded polypropylene particles were used as a full replacement of natural silica sand. The aggregate properties were evaluated in terms of their physical and thermal parameters. The caustic calcined magnesite was studied by SEM, XRF, and XRD spectroscopy. The MOC cement composites were characterized by SEM/EDS, XRD, and FT-IR spectroscopy and measurement of their structural properties, strength parameters, thermal conductivity, and volumetric heat capacity. Assessment of water-and water vapor transport properties was also conducted. The results show significantly improved thermal parameters of MOC cement composite containing expanded polypropylene (EPP) as aggregate and indicate high efficiency of surface hydrophobic agent (impregnation) as a barrier against the transport of liquid and gaseous moisture. The resulting lightweight EPP-MOC cement composite with improved thermal insulation function and suitable mechanical properties can be used to produce thermal insulation floors, ceilings, or wall panels reducing the operational energy demand of buildings. volume of CO 2 emissions can be attributed to building industry, whether related to construction materials production or energy needed for heating and cooling of insufficiently insulated buildings [1,2]. For example production of Portland cement (PC) contributes to circa 5-7% of the global CO 2 emissions [3,4].At present, there are efforts to find an alternative to PC that would have a low carbon footprint. One of the candidates may be cements based on the magnesium oxide (MgO). Magnesium oxychloride cement (also known as Sorel cement) is formed by the reaction of a light-burnt MgO powder with a solution of magnesium chloride (MgCl 2 ) [5], where the light-burnt (also called caustic c) MgO is produced by calcination of magnesite (MgCO 3 ) at a temperature of circa 750 • C [6]. This lower temperature, compared to~1450 • C used in the production of Portland clinker, allows the use of alternative fuels [3]. MOC cement-based composites are able to absorb high amount of CO 2 from the atmosphere during their service life to form carbonates and hydroxycarbonates, which leads to their denser microstructure and to higher streng...

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“…SD was encapsulated into EG by physical impregnation to obtain composite phase change energy storage material (SD/E). Magnesium oxychloride cement (MOC) is one of the most attractive building materials owing to its short setting time, good mechanical strength and high flame resistance [31,32], so we designed a house-like model that was made of SD/E and MOC to simulate the indoor environment to detect the insulation effect of SD/E and explore the possibility of application in building materials.…”

Section: Introductionmentioning

confidence: 99%

Design of Eutectic Hydrated Salt Composite Phase Change Material with Cement for Thermal Energy Regulation of Buildings

Liu

Yang

et al. 2020

Materials

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An energy-efficient eutectic hydrated salt phase change material based on sodium carbonate decahydrate and disodium hydrogen phosphate dodecahydrate (SD) was prepared. Then, SD was encapsulated into expanded graphite (EG) to produce form-stable composite phase change materials (SD/E), which indicated a positive effect on preventing the leakage of SD, decreasing the supercooling and improving the thermal conductivity. SD/E was further tested for thermal efficiency by simulating the indoor environment with a house-like model which was composed of SD/E and magnesium oxychloride cement. The results showed an excellent thermal insulation effect. This exciting porous composite phase shift material reveals possible architectural applications because of the attractive thermos-physical properties of SD/E.

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Tuning the phase structure and mechanical performance of magnesium oxychloride cements by curing temperature and H2O/MgCl2 ratio

Cited by 48 publications

References 24 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

Influence of Waste Plastic Aggregate and Water-Repellent Additive on the Properties of Lightweight Magnesium Oxychloride Cement Composite

Design of Eutectic Hydrated Salt Composite Phase Change Material with Cement for Thermal Energy Regulation of Buildings

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