Research on Mining Water-Rich Fly-Ash-Based Filling Material

2014 ◽  
Vol 988 ◽  
pp. 201-206 ◽  
Author(s):  
Wei Xin Chen ◽  
Feng Yi Li ◽  
Xian Hua Guan ◽  
Lei Chen ◽  
Wen Bo Nie
Keyword(s):  
Fly Ash ◽  
Industrial Waste ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Filling Material ◽  
Metal Mine ◽  
Early Strength ◽  
The Cost ◽  
Cementing Material ◽  
Early Activity

It had decades of history that cementing material was used for filling in coal mine or metal mine goaf, which was a common filling material in recently filling mining. Paste and high water material have excellent performance, but the price was too high, which restricted the development of cemented filling technology severely. Later, fly ash and other industrial waste were mixed into the cementing material in order to reduce the cost, but because of which early activity was low, the early strength was reduced by mixing too much fly ash and other industrial waste, the setting time was extended, which affected the filling effect seriously. Therefore, it becomes a key problem that how to excite the early activity of fly ash. It was a breakthrough to select the appropriate activator and activation method, because of the difference mechanism of action and effects for different activators of fly ash, the complexity composition of filling material mixed with large number of fly ash, and the early and late physical and mechanical properties [1,2].Four salts are used for activators in this paper, which are mixed with fly ash and water, and a display method was selected to maximum activate the activity of fly ash, increase the early strength of the material, and reduce the cost of the material.

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.

Influence of Alkaline Activator on the Strength of Fly Ash-Cement Gel Sand Material

2014 ◽  
Vol 937 ◽  
pp. 472-475 ◽  
Author(s):  
Hai Yan Huang ◽  
Ai Min Gong ◽  
Kun Yuan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Test Specimen ◽  
Rupture Strength ◽  
Setting Time ◽  
Alkaline Activator ◽  
Early Strength ◽  
Sand Material ◽  
Early Activity ◽  
Better Than

Influence of different kinds and mixing amount of the alkaline activators on the strength of fly ash-cement gel sand materials is discussed through experiment wit 29 group test specimen. The rupture strength and the compressive strength with the age of 3 and 28 days of test blocks mixed with NaOH or CaO are compared each other. The early activity of fly ash can be activated by mixing the alkaline activator. The early activity of fly ash can be activated by mixing with the alkaline activators. The setting time of fly ash-cement binders becomes better. And the early strength can be improved. The activated effect of fly ash-cement binders by different type of the alkaline activators is affected by the age of test blocks. The activated effect mixed with CaO is better than the effect mixed with NaOH.

scholarly journals Optimization and Hydration Mechanism of Composite Cementing Material for Paste Filling in Coal Mines

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Jinxiao Liu ◽  
Wenxin Li ◽  
Feng Zhang ◽  
Xinguo Zhang ◽  
Lianjun Chen ◽  
...  
Keyword(s):  
Early Stage ◽  
Uniform Design ◽  
Setting Time ◽  
Coal Mines ◽  
Hydration Products ◽  
Hydrated Calcium Silicate ◽  
Sulphoaluminate Cement ◽  
Final Setting Time ◽  
Early Strength ◽  
Cementing Material

The low early strength of materials for paste filling in mines caused by low early strength of composite cementing material has been a severe issue. In this study, the effects of sulphoaluminate cement and gypsum on strengths of composite cementing material were investigated experimentally by employing the constrained formulation uniform design. With the content of the sulphoaluminate cement below 14% and the content of the gypsum below 16%, the compressive strengths of composite cementing materials increased, especially early strength. However, the initial and final setting time does not meet the engineering requirements in this case. Optimization tests of composite additives demonstrated that H2BO3(0.3%) + Na2SO4(0.1%) and H2BO3(0.3%) + NaNO2(0.1%) were ideal setting retarding and early strengthening composite additives as they can both reduce the initial and final setting time and enhance compressive strengths of composite cementing material. Investigations by XRD and SEM revealed that the hydration products of composite cementing material were dominated by AFt (ettringite) at the early stage and by C-S-H (hydrated calcium silicate) gel + CH (calcium hydroxide) gel at the middle and late stages. The hydration products of ratio-optimized composite cementing material do not restrain each other due to the generation sequence. Instead, they grew interactively and were coupled, thus facilitating the growth of the hardened body. This study can provide references for optimization of composite cementing material for paste filling in coal mines.

Physical Properties of Volcanic Ash Based Geopolymer Concrete

2016 ◽  
Vol 841 ◽  
pp. 1-6 ◽  
Author(s):  
Puput Risdanareni ◽  
Adjib Karjanto ◽  
Febriano Khakim
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Physical Properties ◽  
Volcanic Ash ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Ash Content ◽  
Geopolymer Concrete ◽  
Split Tensile Strength ◽  
Time Test

This paper describes the result of investigating volcanic ash of Mount Kelud as fly ash substitute material to produce geopolymer concrete. The test was held on geopolymer concrete blended with 0%, 25%, 50% and 100% fly ash replacement with volcanic ash. Natrium Hidroxide (NaOH) with concentration of 12 molar and Natrium Silicate (Na2SiO3) were used as alkaline activator. While alkali-activator ratio of 2 was used in this research. The physical properties was tested by porosity and setting time test, while split tensile strength presented to measure brittle caracteristic of geopolymer concrete. The result shown that increasing volcanic ash content in the mixture will increase setting time of geopolymer paste. On the other hand increasing volcanic ash content will reduce split tensile strength and porosity of geopolymer concrete. After all replacing fly ash with volcanic ash was suitable from 25% to 50% due to its optimum physical and mechanical properties.

Study on Basic Experiment of Coal Waste Paste Filling Material

2012 ◽  
Vol 174-177 ◽  
pp. 384-389 ◽  
Author(s):  
Xin Guo Zhang ◽  
Ning Jiang ◽  
Heng Wang ◽  
Yang Yang Li
Keyword(s):  
Fly Ash ◽  
Coal Mine ◽  
Coal Waste ◽  
Hydration Reaction ◽  
Filling Material ◽  
Hydration Products ◽  
Xrd Diffraction ◽  
Speed Up ◽  
Diffraction Patterns ◽  
Cementing Material

Based on present situation that coal mining under buildings, water bodies and railways, and solid wastes mainly including coal waste, fly ash in coal mine of our country, optimization proportioning of paste filling material and hydration reaction mechanism is systematicaly researched combining with project practice of paste filling in Daizhuang Coal Mine, Zibo Mining Group. The result shows that: Proportioning design P10 can be used as the optimal proportion results, the rate of cementing material is that the proportion: fly ash: coal waste is 1:4:6, quantity concentration is 74%; Coal waste paste XRD diffraction patterns of different instar shows that its hydration products at different instar stage are mainly gelation of CH, Aft and C-S-H; Relative content of each material in hydration products is different at different instar stage; With scanning electron microscope a certin ettringite is producted after coal waste paste hydrated 8h, and content of C-S-H gelation and CH gelation is increased gradually; Hydration process of portland cement is speed up and the strength of paste is enhanced.

scholarly journals Effect of fly ash on physical and mechanical properties of mortar

2019 ◽  
Vol 17 (6) ◽  
pp. 35
Author(s):  
Vu-An Tran
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Water Absorption ◽  
Thermal Power ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Flow Density ◽  
Control Specimen

This research investigates the physical and mechanical properties of mortar incorporating fly ash (FA), which is by-product of Duyen Hai thermal power plant. Six mixtures of mortar are produced with FA at level of 0%, 10%, 20%, 30%, 40%, and 50% (by volume) as cement replacement and at water-to-binder (W/B) of 0.5. The flow, density, compressive strength, flexural strength, and water absorption tests are made under relevant standard in this study. The results have shown that the higher FA content increases the flow of mortar but significantly decreases the density of mixtures. The water absorption and setting time increases as the samples incorporating FA. Compressive strength of specimen with 10% FA is approximately equal to control specimen at the 91-day age. The flexural strength of specimen ranges from 7.97 MPa to 8.94 MPa at the 91-day age with the best result for samples containing 10% and 20% FA.

scholarly journals Development of Coal Mine Filling Paste with Certain Early Strength and Its Flow Characteristics

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Feng Zhang ◽  
Jinxiao Liu ◽  
Haiming Ni ◽  
Wenxin Li ◽  
Yongle Liu
Keyword(s):  
Fly Ash ◽  
Coal Mine ◽  
Setting Time ◽  
Flow Characteristics ◽  
Coal Gangue ◽  
Practical Significance ◽  
Range Analysis ◽  
Factors Affecting ◽  
Early Strength ◽  
Backfill Strength

In coal mine paste filling technology, geomaterials like coal gangue and fly ash are used as the main component, and cement is applied as the cementing material. In the mining production, mining-and-filling is a cyclic work, where the filling immediately after mining and mining immediately after filling. Long solidification time after filling will affect mining; consequently, the paste should have early strength. In addition, the prepared paste will be conveyed to goaf through the pipeline. The paste flow characteristics will change to some extent in the conveying process, and there is uncertainty about whether the paste can meet the requirements of pumpability and strength. Therefore, the influence of pipeline conveying on flow characteristics of paste before filling the goaf should be taken into consideration. Based on the above two points, this paper studies the paste strength, backfill strength, and pumpability parameters in coal mine paste filling and determines the early and later strength of coal mine paste, as well as the pumpability parameters such as slump degree, segregation degree, setting time, and paste gradation. With the determined mass proportion of coal gangue, fly ash, and silicate cement, the orthogonal test was carried out with three factors including gypsum content, the content of early strength agent (Na2SO4), and the mass concentration, and at three levels. The factors affecting paste flow characteristics were determined by range analysis, and the factors affecting the paste’s early strength were determined by the XRD test and SEM test on its microstructure. With paste proportioning and pipeline conveying simulation system, taking slump, segregation degree, backfill strength, and other parameters as indicators, we obtain the influence law of pipeline conveying on the flow characteristics of paste. The research has great theoretical and practical significance for developing coal paste with early strength and its flow characteristics.

Review on Development and Application of Gelled Material Filling Mined-Out Area

2016 ◽  
Vol 852 ◽  
pp. 1366-1370
Author(s):  
Yong Liu ◽  
Jie Chen
Keyword(s):  
Fly Ash ◽  
Solid Waste ◽  
Future Development ◽  
High Water ◽  
General Situation ◽  
Filling Material ◽  
Industrial Solid Waste ◽  
Development Direction ◽  
Cementing Material ◽  
Great Development

With the development of the cementing filling technology,the research and application of filling cement materials technology has also made great development. This paper introduces the high water quick-setting filling cementing material, fly ash filling gel material, slag cementing filling material new filling gel materials such as the general situation of the research and application in mine industry analyses the characteristics of different filling cementing materials and limitations, and puts forward the development potential the activity of potential of industrial solid waste to reduce filling gelled material cost and improve the gel material performance will be filling material of the future development direction.

scholarly journals Properties and Engineering Applications of a New Goaf Grouting Filling Material

Geofluids ◽  
2022 ◽  
Vol 2022 ◽  
pp. 1-14
Author(s):  
Xiao Feng ◽  
Chong Xia ◽  
Sifeng Zhang ◽  
Chuangui Li ◽  
Hongkui Zhao ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Silicate ◽  
Traffic Engineering ◽  
Setting Time ◽  
Microstructural Analysis ◽  
Volume Ratio ◽  
Skeletal Structure ◽  
Filling Material ◽  
Technical Problems

In the treatment of goafs in traffic engineering, technical problems such as those related to large-volume grouting and the precise control of material properties are often encountered. To address these issues, we developed a new composite material comprising cement-fly ash-modified sodium silicate (C-FA-MS). The setting time, fluidity, unconfined compressive strength, and microstructure were varied for different proportions of cement-sodium silicate (C-S) slurry, cement-fly ash-sodium silicate (C-FA-S) slurry, and C-FA-MS slurry, and their performances were compared and analysed. The experimental results showed that the initial setting time of the slurry was the shortest when both the original sodium silicate volume ratio ( V S ) and modified sodium silicate volume ratio ( V MS ) were 0.2. The final setting time of the C-S and C-FA-S slurries tended to decrease but then increased with decrease in V S , while that of the C-FA-MS slurry increased with lower V MS . The fluidity of the C-FA-S and C-FA-MS slurries decreased with decrease in V S or V MS at different fly ash admixture ratios. The consolidation compressive strength of C-S increased with decreasing V S , while that of C-FA-S showed a considerable increase only when V S decreased from 0.4 to 0.2. Meanwhile, the compressive strength of the C-FA-MS concretions first increased and then decreased with decrease in V MS . Microstructural analysis revealed that there were more cracks in the C-S agglomerate, the fly ash in the C-FA-S agglomerate reduced the relative density of the skeletal structure, and the stronger cross-linking in the C-FA-MS agglomerate improved the strength of the agglomerate. Under the condition of unit grouting volume, the cost of the C-FA-MS slurry was approximately 44.7% and 31.3% lower than that of the C-S and C-FA-S slurries, respectively. The new C-FA-MS material was applied for the treatment of the goaf in the Wu Sizhuang coal mine. Core drilling detection and audiofrequency magnetotelluric survey revealed that the goaf was sufficiently filled.

Influence of the Variability of Limestone and Fly Ash on the Setting and Mechanical Properties of a Moroccan Composite Cement

2022 ◽  
Author(s):  
Nisrine El Fami ◽  
Hind Agourrame ◽  
Nacer Khachani ◽  
Ali Boukhari ◽  
Adeljebbar Diouri
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
High Energy ◽  
Pozzolanic Reaction ◽  
Cement Industry ◽  
Chemical Compositions ◽  
Significant Prolongation ◽  
Cement Manufacturing

The Moroccan cement industry is looking for new processes to effectively minimize the high energy costs associated to cement manufacturing. This work presents the effect of three types of limestone with different chemical compositions and different CaCO3 contents on the physical and mechanical properties of resulting composite cements by the addition of fly ash in the proportions by weight of: 5 % and 10 %. The samples are studied in order to evaluate the interaction between different types of limestone and fly ash. Ternary cements based on fly ash-limestone-clinker induce a significant prolongation of the setting time compared to binary cements based on limestone-clinker. The substitution of clinker by limestone induces an improvement in mechanical strength compared to ternary cements in the first days; at 28 days, cements prepared with fly ashes reach significant strength due to their pozzolanic reaction.

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