Experimental study on properties of magnesium oxychloride cement

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Experimental study on properties of magnesium oxychloride cement To cite this article: Hao Sun et al 2018 IOP Conf. Ser.: Earth Environ. Sci. 153 022016

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2018 2nd International Workshop on Renewable Energy and Development (IWRED 2018) IOP Publishing IOP Conf. Series: Earth and Environmental Science 153 (2018) doi:10.1088/1755-1315/153/2/022016 1234567890 ‘’“” 022016

Experimental study on properties of magnesium oxychloride cement Hao Sun1, a, Xiao Yang1, a, Shun Wang1, a, Zhanhua Kou1, a, Silu Xie1, a 1 a

School of Shandong Jianzhu University, Shandong 250101, China

463960047@qq.com

Abstract. Magnesium oxychloride cement is an air-hardening cementitious material formed by the reaction of magnesium oxide and magnesium chloride solution. This kind of cement has high strength and high folding pressure ratio, which is the unmatched performance of ordinary cement concrete. This article tests the modification status of magnesium oxychloride cement after adding organic solution, and provides reference for the processing and design of magnesium oxychloride cement components in the future.

1. Introduction Magnesium oxychloride cement is an air-hardening cementitious material mixed with MgO powder and MgCl2 solution, and has a series of excellent properties [1]: ①fast setting and hardening; ②good mechanical strength; ③weak alkaline and low corrosive; ④Good abrasion resistance; ⑤Good adhesion; ⑥Flame retardant performance; ⑦Strong heat insulation; ⑧Good impermeability and low price. However, the water resistance is poor, the fluidity of the magnesium oxychloride cement and the permeability to the carbon fiber must be further improved. Currently, the reaction mechanism of the magnesium oxychloride cement has been studied [2-4]. This article tests the compressive and flexural properties of magnesium oxychloride cement by adding organic solution [5] to magnesium oxychloride cement. Through the work of this paper, the structural strength of modified magnesium oxychloride cement was tested to provide reference for the processing and design of magnesium oxychloride cement components in the future [6]. 2. Principle and proportion of experiments The raw materials of magnesium oxychloride cement (MOC cement) used in the experiment: magnesium oxide, magnesium chloride, water, silica fume (SF), potassium Potassium dihydrogen phosphate crystals (KDP), and the raw material ratios are shown in Table 1.

Material

TABLE 1. Magnesium oxychloride cement Quantity

MgO+SF (solid) MgCl2 (solid) KDP (solid) Water Compressive strength (MPa)

Stirring time (1’30” ~2’) 1000g 454g 23.6g 200g 70~130

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Flexural strength（MPa）

15~20

Additional：MgO: SF=10:1 (weight ratio) The test required material equipment: epoxy emulsion, styrene-acrylic emulsion, concrete mixer, electro-hydraulic servo universal testing machine. 3. experiments situation According to the formula of magnesium oxychloride cement (Figure 1), we first pour MgO and SF powder into the stirred pot, add water, add MgCl2, add KDP solid and finally add different proportion of epoxy emulsion and styrene acrylic emulsion. The proportion is 2% and 5%. Prepare the cement slurry, use the concrete mixer (Figure 2), stir the material to make a cement test block (Figure 3), the cement test block made after curing in 28 days after the electro-hydraulic servo. The universal testing machine (Figure 4) was tested to measure the compressive and flexural properties of the cement test block.

Figure 1.

Figure 2.

Figure 3.

Figure 4.

4. Test results and analysis First, the cement test block was subjected to a flexural test and there was no significant change during the loading process. The pressure surface suddenly broke down. The cement test block broke into two pieces and its section was smooth and there was no obvious damage, see Figure 5. Then the compressive test was carried out. The fractured cement test pieces were gradually damaged during the loading process and the loading surface was suddenly destroyed. The cement sample blocks were crushed and stopped loading. For each set of tests, two blocks were taken for data measurement. The specific failure load and shear strength are shown in Table 2 (add styrene-acrylic emulsion), and Table 3 (add epoxy emulsion).

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Figure 5.

Specimen name Styrene-acrylic emulsion2%(1) Styrene-acrylic emulsion2%(2)

TABLE 2. Test results Compressive failure Fracture load/shear strength load/shear strength 144.6KN/19.3MPa

4147.9N/9.7MPa

151.0KN/20.1MPa

4173.5N/9.9MPa

Styrene-acrylic emulsion5%(1)

132.6KN/17.5MPa

3753.6N/8.8MPa

Styrene-acrylic emulsion5%(2)

128.7KN/17.1MPa

3715.4N/8.5MPa

Epoxy emulsion2%(1) Epoxy emulsion2%(2) Epoxy emulsion5%(1)

TABLE 3. Test results Compressive failure Fracture load/shear strength load/shear strength 106.6KN/66.6MPa 6758.2N/15.8MPa 101.8KN/63.7MPa 6066.8N/14.2MPa 85.6KN/53.5MPa 3753.5N/8.8MPa

Epoxy emulsion5%(2)

81.0KN/50.6MPa

Specimen name

2847.7N/6.7MPa

According to the test results, for the epoxy emulsion, the strength of the modified magnesium oxychloride cement is lower than that of the magnesium oxychloride cement without the epoxy emulsion, and the compressive strength and the bending strength are reduced, and the dosage is The bigger, the more the intensity decreases. For the styrene-acrylic emulsion, the strength of the modified magnesium oxychloride cement is lower than that of the magnesium oxychloride cement without the styrene-acrylic emulsion, and the compressive strength and the bending strength are reduced, and the greater the blending amount, the lower the strength is. Many, but compared to the epoxy oxychloride cement added, its modification effect is better than the epoxy emulsion. 5. Conclusion According to the test, it can be seen that adding a small amount of polymer emulsion has better effect, and the more the amount, the worse the modification effect. Because the amount of polymer is small, it cannot form continuous in the system. The polymer film has a poor effect on the cement water resistance modification, and when the amount is large, the water resistance is improved. For the epoxy emulsion, the film formation property of the magnesium oxychloride cement is poor, and the modification effect is not ideal, which is the main reason. The styrene-acrylic emulsion has a stronger modification effect than

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epoxy emulsion. References [1] Wang Yingzi, Qiu Zhenxin, Wang Xiang, on the properties and development of magnesium oxychloride cement products [J]. Shandong Building Materials, 2000, (4): 38-40. [2] CUI Chong, MA Baoguo, CUI Kehao; Study on hydration mechanism and kinetics of magnesium[J]. Journal of Wuhan University of Technology, 1994,16(2):37-41. [3] ZHANG Chuanmei, DENG Dehua. Research on the water-resistance if magnesium oxychloride cement Ⅰ; the stability of the reaction products of magnesium oxychloride cement in water[J]. Journal of Wuhan University of Technology,1994,9(3);51. [4] YZHANG Chuanmei, DENG Dehua. The formation mechanism of the hydrate phases in magnesium oxychloride cement[J]. Cement and Concrete Research,1999,29:1365. [5] Mazuranic C, Bilinski H, Matkovic B. Reaction products in the system MgCl2-NaOH.J Am Cerm Soe, 1982:65(10): 523-526 [6] Zhang Chuanmei, Deng Dehua. The stability of the reaction products of magnesium oxychloride cement in water. Journal of Wuhan University of Technology. 1994:9(3):51

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