scholarly journals Mechanism on Activation of Coal Gangue Admixture

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Jixi Chen ◽  
Xiao Guan ◽  
Mengyu Zhu ◽  
Jie Gao
Keyword(s):  
Evaluation Method ◽  
Particle Surface ◽  
Waste Utilization ◽  
Coal Gangue ◽  
Mineral Admixture ◽  
Activation Mechanism ◽  
Activation Effect ◽  
Mortar Strength ◽  
Chemical Activator ◽  
Secondary Hydration

Coal gangue, an industrial waste, is rich in silicon and aluminum phase and may be used as a mineral admixture in concrete after moderately stimulating activity, allowing for efficient solid waste utilization. This study used a mortar strength and activity evaluation method to investigate single or compound activation methods to find the optimum activation method of coal gangue. FLIR, XRD, and SEM were used to investigate the activation mechanism of different modes, providing a theoretical foundation for the study of coal gangue as a concrete admixture. Results showed that mechanical ball milling, microwave, and chemical activator could activate coal gangue, and the composite activation effect was the best. The fineness of the coal gangue powder was more than 300 mesh, according to the optimal compounding method. Accordingly, the particle surface was smooth, the internal defects were reduced, and the microwave irradiation temperature was 700°C–800°C, causing the coal gangue particles to form a bonding surface and gradually agglutinate and densify. Meanwhile, the layered structure of kaolin minerals was destroyed, and a significant amount of glassy active SiO2 and Al2O3 was produced, enhancing the gel ability and activity of coal gangue. Finally, 8% Ca(OH)2 was added in the production of mortar specimens, which increased the alkalinity of the slurry, stimulated the rapid cracking and secondary hydration of the coal gangue, and enhanced the strength of mortar. At this time, the activity rate of coal gangue powder reached the highest, which was 90.5%.

Study of Complex Chemical Activator on Activation Effect of Calcined Coal Gangue

2012 ◽  
Vol 450-451 ◽  
pp. 832-835 ◽  
Author(s):  
Xu Yan Song ◽  
Jing Yun Han ◽  
Zhi Hai Gao
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Coal Gangue ◽  
Activation Effect ◽  
Complex Chemical ◽  
Mortar Strength ◽  
Activated Coal ◽  
Cement System ◽  
Activated Coal Gangue ◽  
Chemical Activator

Three kinds of complex chemical activators were prepared and then introduced into calcined coal gangue cement. Physical and mechanical properties such as mortar fluidity and mortar strength and shrinkage were tested. The results can show that: excitation effects of multiple complex chemical activators may obvious, where with 8% of J1, 50% of cement replaced with activated coal gangue, compressive strength of the system at ages of 28 days can reach 40.7MPa. Compared with coal gangue cement system without exciting agent, in calcined coal gangue cement system with complex activators early shrinkage increased obviously and later shrinkage may be equivalent to that of pure cement.

Cementitious Activity Evaluation of Steel Slag by EDTA-NaOH Solution Extraction Method

2017 ◽  
Vol 893 ◽  
pp. 389-394
Author(s):  
Zai Bo Li ◽  
Tu Sheng He ◽  
Xu Guang Zhao ◽  
San Yin Zhao
Keyword(s):  
Compressive Strength ◽  
Extraction Method ◽  
Evaluation Method ◽  
Steel Slag ◽  
Rapid Evaluation ◽  
Mortar Strength ◽  
Extraction Test ◽  
Naoh Solution ◽  
Cementitious Activity ◽  
The Relationship

In order to establish a rapid evaluation method of steel slag cementitious activity, extraction test of steel slag in EDTA-NaOH solution have been investigated and the relationship between extraction characteristics and cementitious activity expressed as mortar strength has been analyzed. Results show that the linear relationship between the quantity extracted from steel slag and the mortar compressive strength is significant. According to the analysis results of mineral composition and microscopic morphologies, EDTA-NaOH solution can selectively extract the silicate and aluminate minerals of steel slag, which could be used as a rapid evaluation method of steel slag cementitious activity.

Simulation of Microwave Activation Effect of Coal Gangue by ANSYS

2013 ◽  
Vol 838-841 ◽  
pp. 1898-1902 ◽  
Author(s):  
Xiao Mei Zhang ◽  
Zhi Man Zhao ◽  
Chun Jie Wang
Keyword(s):  
Irradiation Time ◽  
Microwave Energy ◽  
Coal Gangue ◽  
Activation Process ◽  
Computer Simulation Model ◽  
Microwave Activation ◽  
Activation Effect ◽  
Complex Process ◽  
Activated Coal ◽  
Activated Coal Gangue

Microwave activated coal gangue is a complex process, which is bound up with irradiation time, fineness, composition and other factors.Coal gangue is not easily absorbed substances,so it could be get microwave energy for activation from strong wave absorbing materials. In this paper,as influence of the activation process of coal gangue by microwave irradiation time, establish the computer simulation model by ANSYS.As a reference to modify the activation process,improve and perfect the model of microwave activated coal gangue.

An Experimental Study on the Electrical Properties of Fly Ash in the Grounding System

2006 ◽  
Vol 7 (2) ◽  
Author(s):  
Shin-Der Chen ◽  
Li-Hsiung Chen ◽  
Chih-Kun Cheng ◽  
Jiann-Fuh Chen
Keyword(s):  
Fly Ash ◽  
Power Systems ◽  
Power Plants ◽  
Bottom Ash ◽  
Waste Utilization ◽  
Mineral Admixture ◽  
Attractive Alternative ◽  
Grounding System ◽  
Grounding Resistance ◽  
Resistance Reduction

A good grounding system is the fundamental insurance to keep the safe operation of power systems. The grounding resistance reduction additive-fly ash is proposed in this study. Fly ash is the byproduct of coal-fired power plants. A pulverized coal boiler generates approximately 80% fly ash and only 20% bottom ash. Furthermore, the study of these materials will assume greater importance. Waste utilization is an attractive alternative to disposal in that disposal cost and potential pollution problems are reduced. Extensively used as an additive in Portland cement or as a mineral admixture in concrete in recent years, we have found that fly ash has a low resistivity, and so can be used as an agent for reducing resistance to grounding. Also, an effort is made to investigate the effect of water-to-cement(W/C) and temperature on the resistivity of the test specimens. The grounding resistance reduction agent was determined by considering various proportions of water, cement and salt. Experimental results demonstrate that the proposed approach can effectively reduce the grounding resistance.

scholarly journals Seismic Vulnerability Analysis of Rural Modified Raw-Soil Structures

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Shiwei Hou ◽  
Hao Zhang ◽  
Yuzhe Zhang ◽  
Xin Chen ◽  
Suyun Meng
Keyword(s):  
Seismic Vulnerability ◽  
Waste Utilization ◽  
Coal Gangue ◽  
Calcined Clay ◽  
Response Characteristics ◽  
Soil Model ◽  
Structural Resistance ◽  
Soil Structures ◽  
Probabilistic Seismic Demand ◽  
Modified Soil

Based on the concept of environmental protection of solid waste utilization, material testing is conducted to achieve native improvement using coal gangue-based limestone-calcined clay cement (LC3). Finite element (FE) models of rural raw-soil architecture with a colored-steel roof (RACSR) were established. The effect of modified soil type and seismic character on the vulnerability of single-story raw-soil structures was investigated using probabilistic seismic demand (PSD) analysis. The seismic response characteristics of 80 representative sequences were comparatively investigated when subjected to northwest clay (raw soil) of China, fiber and stone-improved clay (modified soil), and coal gangue-based limestone-calcined clay cement (LC3 soil). The maximum interstory drift angle (ISDAmax) was lower in the LC3 soil model and the modified soil model compared to the raw-soil model. The use of LC3 soil improves structural resistance and reduces the damage probability of a structure, and the influence of different ultimate failure states on the vulnerability of the raw-soil structure was studied.

Compare of Evaluation Methodology of Activity of Metakaolin

2014 ◽  
Vol 1020 ◽  
pp. 76-79
Author(s):  
Yun Fen Hou ◽  
Si Ru Zhao ◽  
Bo Chao Xu
Keyword(s):  
Evaluation Method ◽  
Pozzolanic Activity ◽  
Evaluation Methodology ◽  
Dissolution Method ◽  
Evaluation Methodologies ◽  
Mortar Strength ◽  
Calcined Temperature

The activity of metakaolin which is thermal activated by kaolin originated from Shandong Zaozhuang in different temperature for 2h is evaluated by mortar strength method and acid-alkali dissolution method. The results show that metakaolin has good pozzolanic activity which is affected by calcined temperature mainly. The mortar strength method is much exact but need more time, and the acid-alkali dissolution evaluation method only need one day to two days. By comparing the results of mortar strength and the acid-alkali dissolution, it is found that the two evaluation methodologies of activity have correlation which means that acid-alkali dissolution evaluation method of metakaolin can be used instead of mortar strength method.

Influence on Activation Property of Calcined Coal Gangue by [SO4]2+

2011 ◽  
Vol 306-307 ◽  
pp. 1757-1760 ◽  
Author(s):  
Chen Chen Gong ◽  
Dong Xu Li
Keyword(s):  
Pore Structure ◽  
Structure Analysis ◽  
Raw Materials ◽  
Pore Distribution ◽  
Coal Gangue ◽  
Experimental Results ◽  
Activation Mechanism ◽  
Hydraulic Activity ◽  
Activation Property ◽  
Pore Structure Analysis

Coal gangue and limestone were used as raw materials with fluorite and gypsum as the mineralizer. The activation mechanism of calcined coal gangue with calcium and the pore structure of its hydrating slurry are discussed. The experimental results show that during calcinations F- and [SO4]2- come into the framework and react deeper with CaO at 850-950°C to create hydraulic-activity C12A7 and C2S. Pore structure analysis of the hydrating slurry indicates that adding gypsum and fluorite into coal gangue is more propitious to strengthen the slurry and optimize the pore distribution than only of gypsum.

Effect of Activator on Mechanical Properties and Porosity of Cement-Base Repair Mortar

2013 ◽  
Vol 830 ◽  
pp. 86-89
Author(s):  
Jian Le Xu ◽  
Long Fei Xue ◽  
Jue Fei Yi
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Total Porosity ◽  
Pozzolanic Reaction ◽  
Mineral Admixture ◽  
Strength Measurement ◽  
Repair Mortar ◽  
Early Strength ◽  
Chemical Activator

This study investigated the different effect of three chemical activators on mechanical properties and porosity of cement-base repair mortar, whose binder consists of 80% cement and 20% mineral admixture. Test of mechanical properties indicate that the addition of 5% chemical activator A increase both the early and later strengths of repair mortar. The presence of 3% chemical activator C increase the early strength but has no significantly affect on the later strength. Measurement of pore structure indicate that repair mortar with chemical activator has lower total porosity and finer pore structure due to the presence of chemical activator which accelerate the pozzolanic reaction and densify the mortar pore structure.

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