scholarly journals Mechanical Properties and Pore Structure Characteristics of Magnesium Oxychloride Cement Modified by Highland Barley Straw Ash

2021 ◽  
Author(s):  
Feng Cao ◽  
Hongxia Qiao ◽  
Penghui Wang ◽  
Weijia Li
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Pore Diameter ◽  
Barley Straw ◽  
Diameter Distribution ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Straw Ash ◽  
Highland Barley ◽  
Oxychloride Cement

Abstract Highland barley straw ash contains a large amount of silica, and the ash calcined and ground under certain conditions has a higher pozzolanic effect. In order to study the effect of HBSA added into magnesium oxychloride cement mortar (MOCM) on the mechanical properties and pore structure, the activity of highland barley straw ash was studied firstly through the macroscopic mechanical properties test. Nuclear magnetic resonance (NMR) and Brunner−Emmet−Teller (BET) were used to test the distribution of full pore and micropore for MOCM respectively. The microstructure of MOCM was characterized by scanning electron microscope (SEM). The results illustrate that the highest activity of HBSA was obtained by calcining at 600℃ for 2h and grinding for 2h. The addition of HBSA has a significant effect on the mechanical properties and pore diameter distribution of MOCM. A large amount of M-S-H gel was generated in MOCM added with 10% HBSA content, and had a consequence of decreased proportion of larger pores and the increased proportion of micropores as well as the better mechanical properties and pore structure.

Effect of EVA Emulsion on the Properties of Corn Stalk Magnesium Oxychloride Cement Composites

2017 ◽  
Vol 863 ◽  
pp. 71-77
Author(s):  
Si Qi Li ◽  
Ying Liang Tian ◽  
Chang Wei Xu ◽  
Jian Heng Wang ◽  
Shi Bing Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Water Absorption ◽  
Water Resistance ◽  
Cement Composites ◽  
Corn Stalk ◽  
Coefficient Of Thermal Conductivity ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Oxychloride Cement

By the method of EVA emulsion coating, cron stalk-magnesium oxychloride cement composites (C-MOC) was modified to study the effect of EVA emulsion content on C-MOC density, the coefficient of thermal conductivity, water resistance and mechanical properties. Furthermore microstructure of C-MOC was analyzed by SEM. The results show that: with the increase of EVA emulsion content, the coefficient of thermal conductivity and softening of C-MOC increase, but water absorption reduces. When the content is 80%, the flexural strength after 28 days could reach 3.65 MPa and the compressive strength is 4.69 MPa, reaching the maximum. At the same time, C-MOC density is 816 kg/m3 and thermal conductivity is 0.111 W/(m·k). Water absorption is 36% and softening coefficient was 0.47. It is believed that EVA emulsion could form a thin film on the outer surface of the corn stalk by microscopic analysis, increasing the roughness of the straw surface and reducing the gap between the stalk. Since the EVA emulsion has good compatibility with the magnesium oxychloride cement, they could constitute a whole jointly with glue liquid, crystal and fiber, playing the role of enhancing the surface. Therefore, water resistance, thermal conductivity and mechanical properties of C-MOC have been improved effectively.

scholarly journals Influence of Rubber Powder Modification Methods on the Mechanical and Durability Properties of Rubberized Magnesium Oxychloride Cement

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1323
Author(s):  
Dongqing Zhong ◽  
Shuguang Wang ◽  
Yu Gao ◽  
Luming Wang ◽  
Yanbo Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cement Composite ◽  
Acrylic Emulsion ◽  
Rubber Powder ◽  
Water Washing ◽  
Waste Rubber ◽  
Modification Effect ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Oxychloride Cement

In the present study, three modification methods, including water washing, sodium hydroxide (NaOH), and styrene–acrylic emulsion, were used to modify waste rubber powders. The influence of rubber powders on the mechanical properties and frost resistance of magnesium oxychloride cement was examined, and the different modification mechanisms were also analyzed. Based on the analysis of hydrophilic properties after modification, styrene–acrylic emulsion achieved the best modification effect, while water washing produced the least modification effect; regarding mechanical properties, magnesium oxychloride cement mixed with NaOH modified rubber powders achieved the best modification effect, in which the 28 d flexural strength and compressive strength increased by 41.2% and 59.6%, respectively. During the freeze-thaw cycles, the mass loss of specimens was reduced with an increase in the content of rubber powders. In addition, after 300 cycles, the relative dynamic modulus of elasticity of the blank sample was about 28.12%, while that of the magnesium oxychloride cement mixed with NaOH modified rubber powders was approximately 42.38%. In general, the properties of the modified rubber powder–magnesium oxychloride cement composite material can meet the requirements for engineering materials, which provides a theoretical basis and technical support for the application of rubberized magnesium oxychloride cement.

Effect of fly ash on mechanical properties of magnesium oxychloride cement under water attack

2019 ◽  
Vol 21 (3) ◽  
pp. 1181-1199 ◽  
Author(s):  
Yingying Guo ◽  
Yixia Zhang ◽  
Khin Soe ◽  
Wayne D. Hutchison ◽  
Heiko Timmers ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Oxychloride Cement

scholarly journals Effect of Calcination Temperature on Mechanical Properties of Magnesium Oxychloride Cement

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 607
Author(s):  
Chenggong Chang ◽  
Lingyun An ◽  
Rui Lin ◽  
Jing Wen ◽  
Jinmei Dong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Calcination Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Scanning Electron ◽  
Oxychloride Cement

In order to make full use of magnesium chloride resources, the development and utilisation of magnesium oxychloride cement have become an ecological and economic goal. Thus far, however, investigations into the effects on these cements of high temperatures are lacking. Herein, magnesium oxychloride cement was calcinated at various temperatures and the effects of calcination temperature on microstructure, phase composition, flexural strength, and compressive strength were studied by scanning electron microscopy, X-ray diffraction, and compression testing. The mechanical properties varied strongly with calcination temperature. Before calcination, magnesium oxychloride cement has a needle-like micromorphology and includes Mg(OH)2 gel and a trace amount of gel water as well as 5 Mg(OH)2·MgCl2·8H2O, which together provide its mechanical properties (flexural strength, 18.4 MPa; compressive strength, and 113.3 MPa). After calcination at 100 °C, the gel water is volatilised and the flexural strength is decreased by 57.07% but there is no significant change in the compressive strength. Calcination at 400 °C results in the magnesium oxychloride cement becoming fibrous and mainly consisting of Mg(OH)2 gel, which helps to maintain its high compressive strength (65.7 MPa). When the calcination temperature is 450 °C, the microstructure becomes powdery, the cement is mainly composed of MgO, and the flexural and compressive strengths are completely lost.

Long-term mechanical properties and micro mechanism of magnesium oxychloride cement concrete

2020 ◽  
Vol 32 (8) ◽  
pp. 371-378 ◽  
Author(s):  
Chenggong Chang ◽  
Jinmei Dong ◽  
Xueying Xiao ◽  
Weixin Zheng ◽  
Jing Wen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cement Concrete ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Oxychloride Cement
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