Analysis of Hydration Mechanism of New Type Filling Cementitious Materials

2013 ◽  
Vol 753-755 ◽  
pp. 814-818 ◽  
Author(s):  
Shi Qing Nan ◽  
Qian Gao ◽  
Juan Xia Zhang ◽  
Xian Zhang Guo

This paper mainly focuses on revealing the hydration mechanism of new cementitious material of filling body through its microstructure analysis. According to the SEM samples preparation, analysis of different age of filling body microstructure and XRD diffraction mapping, the results showed that the hydration products were with large amount of ettringite, followed by C-S-H gel, calcium and silica. The main reason of strength increasing was the ettringite morphology and the hydration process. It was obtained that the hydration products of different activators were mainly the influence factor of strength, on basis of analyzing the microstructure of different activator materials.

2014 ◽  
Vol 878 ◽  
pp. 171-176 ◽  
Author(s):  
Xu Quan Huang ◽  
Hao Bo Hou ◽  
Min Zhou ◽  
Wei Xin Wang

With new type steel slag-blast furnace slag-fluorgypsum-based cemented material, P O42.5 cement, commonly used cementation agent in China, mechanical properties and microstructure of tailings solidification bodies are studied. The hydration products and morphology tailings concretion body in 60 days are analyzed by SEM and XRD test, which reveals the tailings cementation mechanism solidifying with different cementitious material. Furthermore, a large number of slender bar-like ettringite crystals and filamentous network-like calcium-silicate-hydrate gels bond firmly each other, which is the most important reason why steel slag-blast furnace slag-fluorgypsum base cemented material has the best tailings cementation mechanical properties.


2014 ◽  
Vol 576 ◽  
pp. 57-62 ◽  
Author(s):  
Jun Ping Deng ◽  
Xiao Liang Wang ◽  
Yi Ping Guo

Magnesium slag is a kind of industrial waste during the silicothermic process for magnesium reduction which has potential hydration activity. By adding 20% to 50% of magnesium slag into Portland cement, the influence principle of the additive amount of magnesium slag on the pozzolanic activity is investigated through performance testing and hydration products analysis. During the early period of hydration process, the strength of pozzolanic effectiveness ratio weakens with the increasing additive amount of magnesium slag, while during the later period of hydration process with the additive amount of magnesium slag less than 40%, the strength of pozzolanic effectiveness ratio increases with increasing additive amount of magnesium slag. The activity index of magnesium slag increases with the increase of period and additive amount, and the strength brought by hydration of magnesium slag is a key source of the strength improvement of Portland cement with magnesium slag.


2011 ◽  
Vol 261-263 ◽  
pp. 551-554
Author(s):  
Gong Xun Wang ◽  
Kui Jun Xu ◽  
Ming Qiao Zhu

In order to utilize the waste steel slag effectively, three kinds of alkaline activator such as Na2SO4, Na2SiO3, Na2CO­3 were used to prepare steel slag cementitious material and measure its strength of 28 days and 60 days in the standard wet conditions. Microcosmic structure form of hydration products of cementitious material was analyzed by the test of SEM. The results indicate that: three activators on the strength of steel slag all have certain stimulation effect, and Na2SO4 has the apparent stimulation effect on the strength of steel slag, the analysis and test of SEM also shows that hydration products structure form of steel slag cementitious material added with Na2SO4 is much more than other two activators and is more helpful to improve steel slag strength.


2009 ◽  
Vol 79-82 ◽  
pp. 95-98 ◽  
Author(s):  
Ming Zhang ◽  
Zhu Ding ◽  
Feng Xing ◽  
Peng Liu

An electrodeless resistivity measurement system developed recently can provide a reliable method for monitoring the hydration process of cement-based materials continuously and accurately. Phosphoaluminate cement (PAC) sets quickly and develops high early strength. In order to understand the mechanism, the hydration products and microstructure formation of PAC in early age need to be studied. In the study, early hydration process of PAC with different dosage of retarder was investigated by the electrodeless resistivity equipment. According to resistivity-time curve, resistivity of freshly mixed PAC paste decreases sharply and then rises slowly, some characteristic peaks appear at different hydration stages of PAC. Heat evolution of PAC was also measured. The hydration mechanism and structure formation were studied according to these results. Depending on the dosage of retarder, the hydration process of PAC includes four stages which are dissolution, induction, acceleration and deceleration.


2012 ◽  
Vol 517 ◽  
pp. 363-366 ◽  
Author(s):  
Li Guang Xiao ◽  
Feng Luo ◽  
Rui Bo Li ◽  
Chang Yu Liu

Magnesium slag cementitious material was prepared successfully using the magnesium slag-furnace slag-clinker system and different activators in this paper. The effect of activator on the mechanical property of the material was studied. The hydration and microstructure of this composite cement were analyzed by X-ray diffraction and scanning electron microscopy and the interaction mechanism was researched. The results show that the activity of magnesium slag was enhanced significantly by adding a small amount of activator. Combined activators have the best effect. The hydration products of magnesium slag cementitious materials mortar were C-S-H, Aft and Ca (OH)2 and so on.


Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4794
Author(s):  
Dong Xu ◽  
Pingfeng Fu ◽  
Wen Ni ◽  
Qunhui Wang ◽  
Keqing Li

The use of ammonia soda residue (ASR) to prepare building materials is an effective way to dispose of ASR on a large scale, but this process suffers from a lack of data and theoretical basis. In this paper, a composite cementitious material was prepared using ASR and cement, and the hydration mechanism of cementitious materials with 5%, 10%, and 20% ASR was studied. The XRD and SEM results showed that the main hydration products of ASR-cement composite cementitious materials were an amorphous C-S-H gel, hexagonal plate-like Ca(OH)2 (CH), and regular hexagonal plate-like Friedel’s salt (FS). The addition of ASR increased the heat of hydration of the cementitious material, which increased upon increasing the ASR content. The addition of ASR also reduced the cumulative pore volume of the hardened paste, which displayed the optimal pore structure when the ASR content was 5%. In addition, ASR shortened the setting time compared with the cement group, and the final setting times of the pastes with 5%, 10%, and 20% ASR were 30 min, 45 min, and 70 min shorter, respectively. When the ASR content did not exceed 10%, the 3-day compressive strength of the mortar was significantly improved, but the 28-day compressive strength was worse. Finally, the hydration mechanism and potential applications of the cementitious material are discussed. The results of this paper promote the use of ASR in building materials to reduce CO2 emissions in the cement industry.


2010 ◽  
Vol 129-131 ◽  
pp. 926-930
Author(s):  
Ming Zhang ◽  
Zhu Ding ◽  
Peng Liu ◽  
Ming Ke Wang ◽  
Feng Xing

Electrodeless resistivity and impedance spectroscopy measurement are reliable equipments of test online for monitoring the hydration process of cement-based materials continuously and accurately. Phosphoaluminate cement (PAC) sets quickly and develops high early strength. In order to understand the mechanism, the hydration products and microstructure formation of PAC in early age need to be studied. In the study, early hydration process and impedance spectroscopy characteristics of PAC with different dosage of retarder were investigated. According to the test, resistivity of freshly mixed PAC paste decreases sharply and then rises slowly, some characteristic peaks appear at different hydration stages of PAC, which indicates the hydration process of PAC includes four stages which are dissolution, induction, acceleration and deceleration. Impedance spectroscopy can reflect the change of micro-structure and ion concentribution of PAC matrix by resistance and capacitance.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Zhi Wang ◽  
Weijian Yu ◽  
Fangfang Liu

In this paper, the research background is the filling and mining of the landscape mineral paste body in Baixian State, Guangxi, China. The strength test of the new paste filling material is carried out by the materials of coal zircon, red soil, and cement, the best ratio between the materials is obtained, and the hydration mechanism of the new paste filling material is studied by XRD diffraction instrument and SEM (scanning electron microscopy) test. The types of hydration products and microstructure forms of filling materials in different age periods are revealed. The test results show that the optimal ratio of the new paste filling material in the coal mine is the quality ratio of coal zircon: red soil: cement as 6 : 2 : 1, and the slurry concentration is 80%, which can not only meet the transportation requirements required by the filling process but also reduce the cost of filling, and with the extension of the maintenance age, the filling material produces more gel products, and the overall structure is more encrypted.


2021 ◽  
Vol 8 ◽  
Author(s):  
Zuqian Jiang ◽  
Liwen Zhang ◽  
Junping Zhang ◽  
Zhuo Sun ◽  
Jing Li

Magnesium phosphate cement (MPC), as a new type of inorganic cementitious material, has the advantages of fast curing speed and high early strength. However, MPC still exhibits poor toughness similar to other cementitious materials. Coconut fiber (CF), a renewable plant fiber, was found to have the potential to improve the toughness of MPC in our previous research. As a result, further research should be completed to investigate the mechanical behaviors of MPC mixed with CF. This paper focused on the effect of CF volume dosage on MPC’s flexural performances. Flexural strength, load-deflection (L-D) relationship, fractural patterns, and flexural toughness were obtained by carrying out a three-point bending test. The results showed that flexural strength first increased and then decreased with increasing CF dosage, and the optimal CF dosage for flexural strength was 3%. Besides, it could be observed from the L-D relationship that the toughness increased continuously with increasing CF dosage. Additionally, the technique of scanning electron microscopy (SEM) was employed to analyze the microstructure of MPC mixed with different CF dosages.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4992
Author(s):  
Ruimeng Shi ◽  
Xiaoming Li ◽  
Yaru Cui ◽  
Junxue Zhao ◽  
Chong Zou ◽  
...  

Nickel slags can be produced through ferronickel preparation by the pyrometallurgical processing of laterite nickel ores; however, such techniques are underutilized at present, and serious environmental problems arise from the stockpiling of such nickel ores. In this study, a modification to the process of ferronickel preparation by the direct reduction of carbon bases in laterite nickel ores is proposed. The gangue from the ore is used as a raw material to prepare a cementitious material, with the main components of tricalcium silicate and tricalcium aluminate. By using FactSage software, thermodynamic calculations are performed to analyze the reduction of nickel and iron and the effect of reduction on the formation of tricalcium silicate and tricalcium aluminate. The feasibility of a coupled process to prepare ferronickel and cementitious materials by the direct reduction of laterite nickel ore and gangue calcination, respectively, is discussed under varying thermodynamic conditions. Different warming strategies are applied to experimentally verify the coupled reactions. The coupled preparation of ferronickel and cementitious materials with calcium silicate and calcium aluminate as the main phases in the same experimental process is realized.


Sign in / Sign up

Export Citation Format

Share Document