scholarly journals Environmental Assessment of Magnesium Oxychloride Cement Samples: A Case Study in Europe

2019 ◽  
Vol 11 (24) ◽  
pp. 6957 ◽  
Author(s):  
Gediminas Kastiukas ◽  
Shaoqin Ruan ◽  
Cise Unluer ◽  
Shuang Liang ◽  
Xiangming Zhou
Keyword(s):  
Portland Cement ◽  
Environmental Impacts ◽  
Construction Material ◽  
Dry Process ◽  
Molar Ratios ◽  
Process Route ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Reactive Magnesia ◽  
Oxychloride Cement

This study is the first in the literature to systematically assess the environmental impacts of magnesium oxychloride cement (MOC) samples, which are regarded as a more eco-friendly construction material than Portland cement. The environmental impacts of MOC samples prepared with various molar ratios of MgO/MgCl2∙6H2O and sources of reactive magnesia were obtained via a life cycle assessment (LCA) approach (from cradle to grave), and the obtained outcomes were further compared with the counterparts associated with the preparation of Portland cement (PC) samples. Meanwhile, a sensitivity analysis in terms of shipping reactive magnesia from China to Europe was performed. Results indicated that the preparation of MOC samples with higher molar ratios led to more severe overall environmental impacts and greater CO2 sequestration potentials due to the difference of energies required for the production of MgO and MgCl2∙6H2O as well as their various CO2 binding capacities, whereas in terms of CO2 intensities, the molar ratios in MOC samples should be carefully selected depending on the strength requirements of the applications. Furthermore, various allocation procedures and MgO production processes will greatly influence the final outcomes, and allocation by mass is more recommended. Meanwhile, the environmental impacts associated with the transportation of reactive magnesia from China to Europe can be ignored. Finally, it can be concluded that MOC concrete is no longer a type of ‘low-carbon’ binder in comparison with PC concrete in terms of CO2 emissions, and in view of the single scores and mixing triangles for weighing, MOC concrete can only be identified as a type of more sustainable binder than PC concrete when the main component MgO in MOC samples is obtained through the dry process route rather than the wet process route.

Magnesium Oxychloride Cement Concrete with Recycled Tire Rubber

1996 ◽  
Vol 1561 (1) ◽  
pp. 6-12 ◽  
Author(s):  
Timothy D. Biel ◽  
Hosin Lee
Keyword(s):  
Tensile Strength ◽  
Portland Cement ◽  
Shear Failure ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Rubber Concrete ◽  
Concrete Matrix ◽  
Oxychloride Cement

Either portland cement or magnesium oxychloride cement was used as binders for concretes that incorporated fine rubber aggregate, ranging from 0 to 25 percent by volume. The concretes were tested for their compressive and split tensile strengths to determine whether the use of a magnesium oxychloride cement along with recycled tire rubbers would improve concrete properties. Failure of the concrete around the rubber particles was attributed to tension failure, leading to weak shear failure of the concrete matrix. Both portland and magnesium oxychloride cement concretes lost 90 percent of their compressive strength with 25 percent rubber by volume. The portland cement concrete retained 20 percent of its tensile strength, and the magnesium oxychloride cement concrete retained 35 percent of its tensile strength. Both compressive and tensile strengths of magnesium oxychloride cement rubber concrete were significantly higher than rubberized portland cement rubber concrete.

scholarly journals Synthesis, Structure, and Thermal Stability of Magnesium Oxychloride 5Mg(OH)2∙MgCl2∙8H2O

2020 ◽  
Vol 10 (5) ◽  
pp. 1683 ◽  
Author(s):  
Adéla Jiříčková ◽  
Michal Lojka ◽  
Anna-Marie Lauermannová ◽  
Filip Antončík ◽  
David Sedmidubský ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Compressive Strength ◽  
Portland Cement ◽  
Mass Spectroscopy ◽  
Carbon Footprint ◽  
X Ray ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Thermal Stability Of ◽  
Oxychloride Cement

Today, low-energy and low-carbon footprint alternatives to Portland cement are searched because of huge CO2 emissions coming from Portland clinker calcination. Because of some superior properties of magnesium oxychloride cement (MOC) and the lower carbon footprint of its production, MOC became an intensively studied material with high application potential for the design and development of construction products. In this contribution, magnesium oxychloride with stoichiometry 5Mg(OH)2∙MgCl2∙8H2O (Phase 5) was prepared and characterized. The kinetics of formation and the phase composition of the material were determined using X-ray diffraction and consequent Rietveld analysis. The morphology was studied by scanning electron microscopy, and the chemical composition was determined by both energy-dispersive spectroscopy and X-ray fluorescence. Moreover, the simultaneous thermal analysis in combination with mass spectroscopy and Fourier-transform infrared spectroscopy was employed to study the thermal stability. Using mass spectroscopy, we were able to clarify the mechanism of water and hydrochloric acid release, which was not previously reported. The observed structural and chemical changes induced by exposure of studied samples to elevated temperatures were linked with the measured residual macro and micro parameters, such as bulk density, specific density, porosity, water absorption, compressive strength, and pore size distribution. The Phase 5 revealed a needle-like crystalline morphology which formed rapidly and was almost completed after 96 h, resulting in relatively high material strength. The four-day compressive strength of magnesium oxychloride cement was similar to the 28-day compressive strength of Portland cement. The thermal stability of Phase 5 was low as the observed disruptive thermal processes were completed at temperatures lower than 470 °C.

scholarly journals Magnesium Oxychloride Cement Composites with Silica Filler and Coal Fly Ash Admixture

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2537 ◽  
Author(s):  
Adam Pivák ◽  
Milena Pavlíková ◽  
Martina Záleská ◽  
Michal Lojka ◽  
Ondřej Jankovský ◽  
...  
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Coal Fly Ash ◽  
Cement Industry ◽  
Silica Sand ◽  
Great Decrease ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
And Storage ◽  
Oxychloride Cement

Worldwide, Portland cement-based materials are the most commonly used construction materials. As the Portland cement industry negatively affects the environment due to the excessive emission of carbon dioxide and depletion of natural resources, new alternative materials are being searched. Therefore, the goal of the paper was to design and develop eco-friendly, low-cost, and sustainable magnesium oxychloride cement (MOC)-based building material with a low carbon footprint, which is characterized by reduced porosity, high mechanical resistance, and durability in terms of water damage. To make new material eco-efficient and functional, silica sand which was used in the composition of the control composite mixture was partially replaced with coal fly ash (FA), a byproduct of coal combustion. The chemical and mineralogical composition, morphology, and particle morphology of FA were characterized. For silica sand, FA, and MgO, specific density, loose bulk density, and particle size distribution were measured. Additionally, Blaine specific surface was for FA and MgO powder assessed. The workability of fresh mixtures was characterized by spread diameter. For the hardened MOC composites, basic structural, mechanical, hygric, and thermal properties were measured. Moreover, the phase composition of precipitated MOC phases and their thermal stability were investigated for MOC-FA pastes. The use of FA led to the great decrease in porosity and pore size compared to the control material with silica sand as only filler which was in agreement with the workability of fresh composite mixtures. The compressive strength increased with the replacement of silica sand with FA. On the contrary, the flexural strength slightly decreased with silica sand substitution ratio. It clearly proved the assumption of the filler function of FA, whereas its assumed reactivity with MOC cement components was not proven. The water transport and storage were significantly reduced by the use of FA in composites, which greatly improved their resistance against moisture damage. The heat transport and storage parameters were only slightly affected by FA incorporation in composite mixtures.

scholarly journals Magnesium Oxychloride Cement Composites with MWCNT for the Construction Applications

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 484
Author(s):  
Michal Lojka ◽  
Anna-Marie Lauermannová ◽  
David Sedmidubský ◽  
Milena Pavlíková ◽  
Martina Záleská ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Mechanical Resistance ◽  
Cement Composites ◽  
Multi Walled Carbon Nanotubes ◽  
The Subject ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Phase And Chemical Composition ◽  
Walled Carbon Nanotubes ◽  
Oxychloride Cement

In this contribution, composite materials based on magnesium oxychloride cement (MOC) with multi-walled carbon nanotubes (MWCNTs) used as an additive were prepared and characterized. The prepared composites contained 0.5 and 1 wt.% of MWCNTs, and these samples were compared with the pure MOC Phase 5 reference. The composites were characterized using a broad spectrum of analytical methods to determine the phase and chemical composition, morphology, and thermal behavior. In addition, the basic structural parameters, pore size distribution, mechanical strength, stiffness, and hygrothermal performance of the composites, aged 14 days, were also the subject of investigation. The MWCNT-doped composites showed high compactness, increased mechanical resistance, stiffness, and water resistance, which is crucial for their application in the construction industry and their future use in the design and development of alternative building products.

Study on corrosion and anticorrosion of rebar in magnesium oxychloride cement concrete

2019 ◽  
Vol 8 (1) ◽  
pp. 94-104 ◽  
Author(s):  
Wei Gong ◽  
Hongfa Yu ◽  
Haiyan Ma ◽  
Hongxia Qiao ◽  
Guangfeng Chen
Keyword(s):  
Cement Concrete ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Oxychloride Cement
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