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 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 Superhydrophobic Coating on the Water Resistance of Foundry Dust/Magnesium Oxychloride Cement Composite

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3431
Author(s):  
Fajun Wang ◽  
Xiantao Zhu ◽  
Huangjuan Liu ◽  
Sheng Lei ◽  
Daqi Huang
Keyword(s):  
Compressive Strength ◽  
Water Resistance ◽  
Cement Composite ◽  
Superhydrophobic Coating ◽  
X Ray Diffraction ◽  
Aqueous Emulsion ◽  
The Matrix ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Oxychloride Cement

In this work, magnesium oxychloride cement (MOC) was used to realize the resource use of foundry dust (FD). Portland cement (PC)-based superhydrophobic coating was prepared on the surface of FD/MOC composite to improve the water resistance of the composite. First, the FD/MOC composites with different contents of FD were prepared. The phase structure of the composite was analyzed using X-ray diffraction (XRD). The microstructure of the cross-section and surface of the composite was observed using field emission scanning electron microscope (FE-SEM). The mechanical properties of the FD/MOC composites with different FD contents at different ages were tested and analyzed. Secondly, the superhydrophobic coating was prepared on the surface of MOC composite using silane/siloxane aqueous emulsion as the hydrophobic modifier, PC as the matrix and water as the solvent. The microstructure and chemical composition of the PC-based superhydrophobic coating were tested and analyzed. The results show that FD can significantly improve the early strength of the FD/MOC composite. The 28-day compressive strength of the FD/MOC composite decreases with increasing FD content. When the FD content is 30%, the 28-day compressive strength of the FD/MOC composite is as high as 75.68 MPa. Superhydrophobic coating can effectively improve the water resistance of the FD/MOC composite. The softening coefficient of the FD/MOC composite without superhydrophobic coating is less than 0.26, while that of the composite modified by superhydrophobic coating is greater than 0.81.

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 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.

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