scholarly journals Effect of Concentration and Suspension Agent (HPMC) on Properties of Coal Gangue and Fly Ash Cemented Filling Material

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Baogui Yang ◽  
Junyu Jin ◽  
Xindong Yin ◽  
Xiaoyu Wang ◽  
Hongliang Yang
Keyword(s):  
Fly Ash ◽  
Coal Gangue ◽  
Filling Material ◽  
Mixture Ratio ◽  
Bleeding Rate ◽  
Slurry Concentration ◽  
Filling Materials ◽  
Slump Flow ◽  
Underground Openings ◽  
Predicted Values

Cemented coal gangue-fly ash backfill (CGFB) mixtures are utilized as the filling materials for backfilling the underground openings in coal mines. The freshly prepared CGFB slurries are commonly transported into the gobs through a pipeline. The mixture ratio of slurry concentration and suspending agent (HPMC) plays an essential role in transporting the slurry to goaf smoothly and efficiently. In this paper, the influence of slurry concentration and HPMC on the performance of coal gangue-fly ash cemented filling material was studied based on the response surface method. The prediction model of CGFB slurry slump flow, segregation rate, and bleeding rate was constructed. It is concluded that the segregation rate and slump flow of slurry are more sensitive to the variation of concentration. On the other hand, the bleeding rate of slurry is more sensitive to the change of HPMC content. Based on the established model, the reasonable mix proportion range of slurry concentration and suspending agent (HPMC) was obtained. In addition, three new CGFB mixtures have been tested, and the experimental results are in good agreement with the predicted values.

scholarly journals Study on Filling Material Ratio and Filling Effect: Taking Coarse Fly Ash and Coal Gangue as the Main Filling Component

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Changxiang Wang ◽  
Yin Liu ◽  
Hao Hu ◽  
Yangyang Li ◽  
Yao Lu
Keyword(s):  
Fly Ash ◽  
Material Selection ◽  
Orthogonal Experiment ◽  
Coal Gangue ◽  
Environmental Benefits ◽  
Filling Material ◽  
Range Analysis ◽  
Filling Materials ◽  
Filling Simulation ◽  
Main Component

Filling mining is an effective way to settle the dilemma of “Three Down and One Above” in coal mining. Fly ash and coal gangue can be used as filling materials with significant social, economic, and environmental benefits. Using coarse fly ash base as cementing material and coal gangue as aggregate, orthogonal experiment of filling paste was conducted in this study. The range analysis was performed for the strength and transportation requirements of filling paste, and the optimum proportion was determined by the comprehensive balance method. In order to verify the filling effect, a dynamic filling simulation device was designed, and a comparative simulation test of caving mining and dynamic filling mining was carried out. Results show that the filling paste with fly ash and coal gangue as the main component can meet the requirements of filling design and application. This research provides a reference for the material selection and proportion design of paste filling.

The Microstructure Research on Interfacial Transition Zone of Filling Material Containing FA and Coal Gangue

2011 ◽  
Vol 287-290 ◽  
pp. 1125-1129 ◽  
Author(s):  
Yan Yao ◽  
Hao Wu ◽  
Ling Wang
Keyword(s):  
Fly Ash ◽  
Transition Zone ◽  
Concrete Structure ◽  
Interfacial Transition Zone ◽  
Coal Gangue ◽  
Mineral Admixture ◽  
Filling Material ◽  
Filling Materials ◽  
Durability Performance

Interfacial transition zone (ITZ) is the weakest part in concrete structure because of the interrelation between its special characters and the performance of concrete, and adding mineral admixture in concrete is a feasible and effective way to improve ITZ. The workability, mechanical and durability performance of filling materials with Fly ash and Coal gangue has been invesitgated, and the interrelation has been research in a micro view by means of SEM and EDS.

scholarly journals Influential Factors in Transportation and Mechanical Properties of Aeolian Sand-Based Cemented Filling Material

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 116 ◽  
Author(s):  
Nan Zhou ◽  
Haobin Ma ◽  
Shenyang Ouyang ◽  
Deon Germain ◽  
Tao Hou
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Cement Content ◽  
Ash Content ◽  
Influential Factors ◽  
Filling Material ◽  
Aeolian Sand ◽  
Early Hydration ◽  
Filling Materials ◽  
Slag Content

Given that normal filling technology generally cannot be used for mining in the western part of China, as it has only a few sources for filling gangue, the feasibility of instead using cemented filling materials with aeolian sand as the aggregate is discussed in this study. We used laboratory tests to study how the fly ash (FA) content, cement content, lime–slag (LS) content, and concentration influence the transportation and mechanical properties of aeolian-sand-based cemented filling material. The internal microstructures and distributions of the elements in filled objects for curing times of 3 and 7 days are analyzed using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The experimental results show that: (i) the bleeding rate and slump of the filling-material slurry decrease gradually as the fly ash content, cement content, lime–slag content, and concentration increase, (ii) while the mechanical properties of the filled object increase. The optimal proportions for the aeolian sand-based cemented filling material include a concentration of 76%, a fly ash content of 47.5%, a cement content of 12.5%, a lime–slag content of 5%, and an aeolian sand content of 35%. The SEM observations show that the needle/rod-like ettringite (AFt) and amorphous and flocculent tobermorite (C-S-H) gel are the main early hydration products of a filled object with the above specific proportions. After increasing the curing time from 3 to 7 days, the AFt content decreases gradually, while the C-S-H content and the compactness increase.

Study on the Properties of Pumping Gangue Filler

2011 ◽  
Vol 287-290 ◽  
pp. 1164-1167
Author(s):  
Yue Zhong Lin ◽  
Dong Cai Lin
Keyword(s):  
Fly Ash ◽  
Research And Development ◽  
Portland Cement ◽  
Coal Gangue ◽  
Filling Material

As reinforcement of goaf filling needs, filling material mined area become the focus of research and development. This study used PO42.5 Portland cement, fly ash, coal gangue, preparation meets the requirements of good performance out of the strength of pumping gangue filler.

An Environmentally Sound Usage of both Coal Mining Residue and Sludge

2011 ◽  
Vol 183-185 ◽  
pp. 595-599 ◽  
Author(s):  
Kui Mei Qian ◽  
Li Zhang ◽  
Li Ping Wang
Keyword(s):  
Fly Ash ◽  
Arbuscular Mycorrhiza ◽  
Coal Mining ◽  
Experimental Research ◽  
Toxic Element ◽  
Coal Gangue ◽  
Mixture Ratio ◽  
Arbuscular Mycorrhiza Fungi ◽  
Environmentally Sound ◽  
Wasteland Reclamation

This study reported the test done on coal gangue-fly ash-sludge mixture for mine wasteland reclamation in pot experiments. According to the characteristic of coal gangue, fly ash and sludge, they were mixed as the complex substrate for reclamation of mine wasteland; meanwhile, arbuscular mycorrhiza fungi (AMF) was also introduced to the reclamation of mine wasteland. The experimental research of the complex substrate and AMF in mine wasteland reclamation was conducted. The results indicated that coal gangue-fly ash-sludge mixture ratio studies revealed that 2: 6: 2 fly ash-coal gangue-sludge mixtures was the optimum mixture ratio that minimized toxic element and provided sufficient nutrients. It resulted that appropriate ratio of the three composite can effectively promote the reclamation, and increase the nutrients absorption of plants, providing a reference for ecological utilization of coal gangue, and fly ash and sludge. In addition, inoculation with AMF in the presence of sludge in mining reclamation was essential for the promotion of plant absorption of nutrients.

Study on Proportioning Test of Coal Solid Waste Paste Filling Material

2012 ◽  
Vol 524-527 ◽  
pp. 1086-1091
Author(s):  
Xin Guo Zhang ◽  
Ji Wen Bai ◽  
Heng Wang ◽  
Ning Jiang
Keyword(s):  
Fly Ash ◽  
Solid Waste ◽  
High Efficiency ◽  
Filling Material ◽  
Confined Water ◽  
Bleeding Rate ◽  
Mining Technique ◽  
Comprehensive Mechanization ◽  
Early Strength ◽  
Cementing Material

In order to excavate coal resourses which is under buildings, water bodies, railways and above confined water, a complete technology of new pumping paste comprehensive mechanization mining technique which is safety, high efficiency, high mining rate and environmental protection has been formed, the study on filling material is very important. In this thesis, the uniform experiment is used comprehensively on the proportioning test of mine solid waste such as coal gangue, fly ash etc. The results showed: (1) the collapsed slump of paste will increase obviously with the increase of the content of fly ash; (2) the paste stratified degree will decrease regularly with the increase of the content of fly ash; (3) the paste bleeding rate will reduce obviously with the increase of the content of fly ash; (4) the paste strength will increase gradually with the the increase of cementing material; (5) early strength agent can improve the early strength of filling test blocks to some extent, but the later strength growth is not obvious.

scholarly journals Performance of Coal Gangue-Based Cemented Backfill Material Modified by Water-Reducing Agents

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yuxia Guo ◽  
Peng Wang ◽  
Guorui Feng ◽  
Tingye Qi ◽  
Guoyan Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Yield Stress ◽  
Reducing Agents ◽  
Plastic Viscosity ◽  
Coal Gangue ◽  
Bleeding Rate ◽  
Backfill Material ◽  
Slump Flow ◽  
Cemented Backfill

Coal gangue-based cemented backfill material (CGCBM) is developed for backfilling the goaf in coal mines. As fresh CGCBM slurry is generally transported into underground openings through a pipeline, and after hardening, it plays the role of supporting the overlying strata. The fluidity, stability, and mechanical (compressive strength) of CGCBM become the most important properties. Adding water-reducing agents (WRAs) is considered to improve the fluidity, stability, and mechanical properties of CGCBM, but there is a risk of increased bleeding. So, two types of WRA (naphthalene series (WRA1) and poly carboxylic acid (WRA2)) are used at different contents (1.0%-2% for WRA1, 0.2%–0.6% for WRA2) by mass of binder. Slump, slump flow, yield stress, and plastic viscosity test are used to evaluate the fluidity properties of CGCBM after adding WRA. Bleeding rate test is used to evaluate the stability of CGCBM after adding WRA. Compressive strength is the most important factor in measuring the mechanical properties. SEM and XRD tests are used to analyse the mechanism of strength change. Results show that the slump, slump flow, and plastic viscosity increase after adding WRA, which reduces the yield stress and improves the fluidity. The bleeding rate increases with the increase of WRA content, leading to a decrease in stability. Adding WRA increases the compressive strength, and it increases first and then decreases with the increase of the content at the later stage. Considering the effects of WRA on the fluidity, stability, and compressive strength properties of CGCBM, the reasonable content of WRA1 and WRA2 is 1.5% and 0.4%, respectively. The research results provide guidance for the design and preparation of CGCBM with favourable performance in practical production.

scholarly journals Development of Filling Material with Fly Ash and Slag as Lubricant in Pipe Jacking Under Acid Sulfate Soils

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Kazuki MAEHARA ◽  
Hideki SHIMADA ◽  
Takashi SASAOKA ◽  
Akihiro HAMANAKA
Keyword(s):  
Fly Ash ◽  
Frictional Resistance ◽  
Filling Material ◽  
Acid Sulfate Soils ◽  
Acid Sulfate ◽  
Filling Materials ◽  
Pipe Jacking ◽  
Negative Impacts ◽  
Trenchless Construction ◽  
Sulfate Soils

The pipe jacking method is relatively reasonable among trenchless construction methods.For the application of this method, the acid sulfate soils have negative impacts on filling materials (one of the cement materials) injected into the tail-void which are over-cutting areas formed to reduce the friction between the pipes and the surrounding soils. In thisstudy, the application of fly ash and slag is discussed to minimize the effect of sulfur acid to filling materials. As the results of the experiments, the addition of fly ash and slag can control the gelling time and prevent the reduction of uniaxial strength of filling materialsunder the acid sulfate soils. In addition, the filling materials added slag lowered frictional resistance compared to that of fly ash. Fillingmaterials with the lower frictional resistance are preferred to apply for the smooth pipe jacking constructions. Therefore, filling materials added slag would show better performance than that of fly ash under the acid sulfate soils due to its lower frictional resistance.

Tissue Reaction to Subcutaneous Implantation of SuperEBA (Reinforced Zinc Oxide Cement) Used as Root-End Filling Material: A Histological Study in Rats

2016 ◽  
Vol 695 ◽  
pp. 247-251
Author(s):  
Alexandru Andrei Iliescu ◽  
Cristian Marian Petcu ◽  
Ileana Cristiana Petcu ◽  
Irina Maria Gheorghiu ◽  
Andrei Iliescu ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Histological Study ◽  
Tissue Reaction ◽  
Tissue Response ◽  
Successful Outcome ◽  
Filling Material ◽  
Clinical Value ◽  
Filling Materials ◽  
Retrograde Filling ◽  
Specific Tissue

The retrograde filling is a critical step to a successful outcome of the endodontic surgery. Despite the progress in the technology of novel root-end filling materials, zinc oxide-eugenol cement superEBA is still preserving its clinical value on long-term basis. The study aimed to reconsider the tissue response to the initial irritating effect of this material. Silicon tubes filled with superEBA were subcutaneously implanted for 120 days in white Wistar rats which were afterwards sacrificed. The connective tissue surrounding the superEBA implants revealed fibroblast proliferation and a definite reparatory process without inflammatory reaction. A non-specific tissue healing in progress around the implants, without calcifications, necrosis, and apoptosis was also described after 4 months. SuperEBA proved on animal model that its cytotoxicity is reducing gradually in time until no adverse reaction is observed. The reduced content in eugenol compared to other surgical zinc oxide cements and the benefic effect of o-ethoxybenzoic acid are the support to reconsider SuperEBA as a biocompatible retrograde filling material.

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