Experimental Analysis of MOC Composite with a Waste-Expanded Polypropylene-Based Aggregate

Záleská, Martina; Pavlíková, Milena; Jankovský, Ondřej; Lojka, Michal; Pivák, Adam; Pavlík, Zbyšek

doi:10.3390/ma11060931

Cited by 35 publications

(14 citation statements)

References 40 publications

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“…The lower alkalinity (pH~10) allows the usage of MOC together with glass fibers, preventing the aging process. Moreover, the MOCs are suitable for use with a variety of aggregates [4,5] such as tire rubber [6,7], fly ash [8], synthetic resin, and wood particles [9]. A wide variety of applications for magnesium oxychloride cements were found, primarily as a flooring material for its elastic and acoustic properties, resistance to a charge accumulation, and decorative ivory-like appearance [10].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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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.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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“…At the same time, these materials have also some disadvantages, especially when they come into contact with water [18,19]. MOC has a low water resistance due to magnesium chloride leaching, a corrosive compound that causes severe damage when it comes in contact with metals [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Carbon Dioxide Uptake by MOC-Based Materials

et al. 2020

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In this work, carbon dioxide uptake by magnesium oxychloride cement (MOC) based materials is described. Both thermodynamically stable magnesium oxychloride phases with stoichiometry 3Mg(OH)2∙MgCl2∙8H2O (Phase 3) and 5Mg(OH)2∙MgCl2∙8H2O (Phase 5) were prepared. X-ray diffraction (XRD) measurements were performed to confirm the purity of the studied phases after 7, 50, 100, 150, 200, and 250 days. Due to carbonation, chlorartinite was formed on the surface of the examined samples. The Rietveld analysis was performed to calculate the phase composition and evaluate the kinetics of carbonation. The SEM micrographs of the sample surfaces were compared with those of the bulk to prove XRD results. Both MOC phases exhibited fast mineral carbonation and high maximum theoretical values of CO2 uptake capacity. The materials based on MOC cement can thus find use in applications where a higher concentration of CO2 in the environment is expected (e.g., in flooring systems and wall panels), where they can partially mitigate the harmful effects of CO2 on indoor air quality and contribute to the sustainability of the construction industry by means of reducing the carbon footprints of alternative building materials and reducing CO2 concentrations in the environment overall.

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“…Among the extensively studied recycling pathways are the incorporation of plastics waste particles as aggregate into Portland cement-based construction materials, which generally led to decrease of the unit weight and to improvement of the thermal insulation performance of the resulting material, but it is also associated with the reduction of the strength parameters [29][30][31][32]. The research on the replacement of natural silica aggregate in MOC cement composites with plastics waste aggregate reported, e.g., by Záleská et al [15] is rather rare.…”

Section: Introductionmentioning

confidence: 99%

“…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]. Currently, MOC cement is used for the production of industrial floors, for ornamental applications, stucco, grinding wheels, and for different types of panels used for fire protection, as decoration or for sound and thermal insulation [7,16].…”

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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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Experimental Analysis of MOC Composite with a Waste-Expanded Polypropylene-Based Aggregate

Cited by 35 publications

References 40 publications

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

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

Carbon Dioxide Uptake by MOC-Based Materials

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

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