Experimental Research on Coal Gangue Grouting Material for Gob Filling

2013 ◽  
Vol 357-360 ◽  
pp. 1158-1166
Author(s):  
Tian Feng Gu ◽  
Zhong Di Sun ◽  
Feng Tao Luo ◽  
Kang Guo ◽  
Ya Ming Liu ◽  
...  
Keyword(s):  
Fly Ash ◽  
Compression Strength ◽  
Raw Materials ◽  
Setting Time ◽  
Blended Cement ◽  
Coal Gangue ◽  
Activation Process ◽  
Initial Setting Time ◽  
Wide Range ◽  
Coal Gob

Grouting fill is one of the main methods of coal gob treatment. The grouting properties directly affect the effect of grouting treatment. Cement-fly ash grout is widely used in the treatment of coal gob. But in many gob grouting fill projects, due to the lack of fly ash, we need to look for other low-cost grouting materials. Study was made through laboratory experiment on the properties of cement-coal gangue materials used for the gob grouting. In this paper, the correlation of water-solid ratio, cement content, admixture, concretion compression strength, setting time, viscosity, water segregation rate and hardening rate is discussed in the case of use of large gangue content cement. The test results show that compared with the grout not go through the activation process, the blended cement grout mixed with coal gangue powder activated by low temperature and mechanical crushing has high concretion compression strength. Water glass has a great effect on the viscosity, initial setting time and final setting time, which can be used to adjust the grout properties to accommodate grouting environment requirements. This grout has the advantage of wide range sources of raw materials, and can be used to solve the lack of fly ash and gangue resource utilization problems.

Effect of Fly Ash and Slag on the Resistance to H2S Attack of Oil Well Cement

2009 ◽  
Vol 79-82 ◽  
pp. 71-74
Author(s):  
Qi Wang ◽  
Lin Qiao ◽  
Peng Song
Keyword(s):  
Fly Ash ◽  
Compression Strength ◽  
Blended Cement ◽  
Oil Well ◽  
X Ray Diffraction ◽  
X Ray ◽  
Curing Period ◽  
Oil Well Cement ◽  
Xrd Patterns ◽  
Well Cement

In this paper, the resistance to H2S attack of pastes made from slag-fly ash blended cement used in oil well (SFAOW) was studied, in which fly ash (FA) was used at replacement dosages of 30% to 60% by weight of slag. Samples of SCOW and SFAOW pastes were demoulded and cured by immersion in fresh water with 2 Mp H2S insulfflation under 130oC for 15 days. After this curing period, compression strength and permeability of the samples were investigated. The reaction mechanisms of H2S with the paste were carried out through a microstructure study, which included the use of x-ray diffraction (XRD) patterns and scanning electron microscope (SEM). Based on the obtained data in this study, incorporation of FA into SCOW results in the comparable effects in the resistance to H2S attack. When the replacement dosage of slag is about 40%, the paste exhibits the best performance on resistance to H2S attack with compression strength 36.58Mp.

Utilization of Circulating Fluidized Bed Combustion (CFBC) Fly Ash and Coal-Fired Fly Ash in Portland Cement

2014 ◽  
Vol 629-630 ◽  
pp. 306-313 ◽  
Author(s):  
Mao Chieh Chi ◽  
Ran Huang ◽  
Te Hsien Wu ◽  
Toun Chun Fou
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Building Materials ◽  
Circulating Fluidized Bed ◽  
Setting Time ◽  
Fluidized Bed Combustion ◽  
Initial Setting Time ◽  
Cfbc Fly Ash ◽  
Circulating Fluidized Bed Combustion

Circulating fluidized bed combustion (CFBC) fly ash is a promising admixture for construction and building materials due to its pozzolanic activity and self-cementitious property. In this study, CFBC fly ash and coal-fired fly ash were used in Portland cement to investigate the pozzolanic and cementitious characteristics of CFBC fly ash and the properties of cement-based composites. Tests show that CFBC fly ash has the potential instead of cementing materials and as an alternative of pozzolan. In fresh specimens, the initial setting time of mortars increases with the increasing amount of cement replacement by CFBC fly ash and coal-fire fly ash. In harden specimens, adding CFBC fly ash to replace OPC reduces the compressive strength. Meanwhile, CFBC fly ash would results in a higher length change when adding over 30%. Based on the results, the amount of CFBC fly ash replacement cement was recommended to be limited below 20%.

scholarly journals Properties of non-standard fly ash – slag cements containing calcareous fly ash

2013 ◽  
Vol 12 (3) ◽  
pp. 215-222
Author(s):  
Katarzyna Synowiec
Keyword(s):  
Fly Ash ◽  
Blast Furnace Slag ◽  
Strength Class ◽  
Setting Time ◽  
Heat Of Hydration ◽  
Initial Setting Time ◽  
Granulated Blast Furnace Slag ◽  
Unfavorable Effect ◽  
Initial Setting ◽  
Furnace Slag

The paper presents the tests results of the properties of non - standard fly ash - slag cements composition. Both natural (unprocessed) and activated by grinding calcareous fly ash was used. It was found that the calcareous fly ash next to the granulated blast furnace slag may be a component of low - clinker cements (ca. 40%). Those cements are characterized by low heat of hydration and overdue of initial setting time in comparison with Ordinary Portland Cement, moreover they have an unfavorable effect on consistency and its upkeep in time. Production of fly ash - slag cements is possible for strength class 32,5 N when the component of cement is raw fly ash, and for strength classes 32,5 N, 32,5 R and 42,5 N when ground fly ash was used. Fly ash activated by grinding was characterized by higher activity.

scholarly journals Preparation of Portland Cement with Gold Ore Tailings

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Qiang Wang ◽  
Geng Yao ◽  
Xiangnan Zhu ◽  
Junxiang Wang ◽  
Peng Wu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Raw Materials ◽  
Setting Time ◽  
Hydration Product ◽  
Difficult Problem ◽  
Initial Setting Time ◽  
Gold Ore ◽  
Curing Age

The disposal of gold ore tailings (GTs) has been a very difficult problem for a long time. Thus, this study explored a new approach to the management of GTs by preparing Portland cement. Physical properties, reaction mechanisms, and hydration product types of cement prepared with GTs (C-GTs) and ordinary Portland cement (C-SS) were compared. X-ray diffraction (XRD), thermogravimetric (TG), and scanning electron microscope energy-dispersive spectroscopy (SEM-EDS) analysis techniques were used to study the mineralogical phases of the clinker and raw materials, hydration product types, and microtopography. The consistency, setting time, flexural strength and compressive strength values of the cement samples (C-GTs and C-SS), and burnability of the raw materials were also studied. The burnability analysis indicated that GTs provided a higher reactivity. The XRD results showed that the clinker phases of the C-GTs were C3S, C2S, C3A, and C4AF. The XRD, TG, and SEM-EDS results showed that the hydration products were flaky calcium hydroxide, rod-shaped ettringite, and granular C-S-H gels. Its compressive strength and flexural strength were, respectively, 30.4 MPa and 6.1 MPa at the curing age of 3 days and 59.1 MPa and 9.8 MPa at the curing age of 28 days, which were slightly higher than those of the C-SS. Furthermore, the results showed that the consistency, initial setting time, and final setting time for the two kinds of cement were similar, which further suggested that GTs could be used to prepare Portland cement.

Study on the Anti-Static Desulphurization Gypsum Fiberboard

2013 ◽  
Vol 772 ◽  
pp. 156-160
Author(s):  
Yan Long Liu ◽  
Chao Fa Tang ◽  
Wen Hao Shen ◽  
Ji Wen Han ◽  
Hong Shuang Du
Keyword(s):  
Raw Materials ◽  
Setting Time ◽  
Market Demand ◽  
Initial Setting Time ◽  
Application Range ◽  
Dry Process ◽  
Biomass Resources ◽  
Initial Setting ◽  
Forestry Industry ◽  
Positive Effect

The fiber of the agriculture and forestry biomass resources and the processing residues is main raw materials as a reinforcing material, the calcinated calcium sulfate hemihydrates by industrial flue gas desulfurization waste is a binder, adding efficient composite retarder to increase the initial setting time of gypsum and meet the production process requirements, adding conductive carbon black to reduce system resistance gypsum fiber to produce and meet the requirements of antistatic products. By semi-dry process, we produced the retardant, waterproof, environmental friendly and anti-static desulfurization gypsum fiberboard. Desulfurization gypsum antistatic fiberboard can meet the market demand for functional products used widely in antistatic floor, antistatic wall panel etc. The production of anti-static desulfhurization gypsum fiberboard expands the application range of desulfhurization gypsum, at the same time, which changes the structure of the forestry industry and has a positive effect on improving the forestry economic operation quality, efficiency and international competitiveness.

Evaluation of Fresh Properties and Rheology of Mortar Using Carbon-Free Fly Ash and Normal Fly Ash

2020 ◽  
Vol 1005 ◽  
pp. 76-81
Author(s):  
Ghawsaddin Nazari ◽  
Shunya Yamanaka ◽  
Shigeyuki Date
Keyword(s):  
Fly Ash ◽  
Setting Time ◽  
Great Influence ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Fresh Properties ◽  
Initial Setting Time ◽  
Usual Solution ◽  
Initial Setting ◽  
Flow Loss

Usage of mineral admixture and chemical admixture in concrete or mortar is a usual solution to reach full compaction, particularly where reinforcement blockage and lack of skilled labor happen. In this paper effect of mineral admixtures (Carbon-free fly ash, hereafter CfFA, and normal fly ash) on fresh properties and rheology of mortar have been investigated. As a result, it was confirmed that CfFA increased significantly the fluidity and air content of mortar in comparison to normal fly ash, both in 15% and 30% replacement; however, the flow loss and air stability within one hour were almost equal. In addition, the initial setting time has also been affected by variation of materials. The two mixing of 30% and 15% of CfFA had a shorter setting time in comparison to the mortar with normal fly ash. Furthermore, CfFA based mortar had a great influence on rheology of mortar. Compared to normal fly ash, CfFA Considerably decreased the plastic Viscosity and increased the productivity of the mortar, both in non-vibrated and vibrated condition, particularly those with 30% replacement.

Environmental Friendly Sulphoaluminate Cement Based Rapid Hardening and Repair Materials

2014 ◽  
Vol 548-549 ◽  
pp. 12-15 ◽  
Author(s):  
Meng Jie Lu ◽  
Ming Fang Ba ◽  
Dan Yi Man ◽  
Si Yuan Ma ◽  
Jie Yang ◽  
...  
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Setting Time ◽  
Mass Ratio ◽  
Rapid Hardening ◽  
Initial Setting Time ◽  
Sulphoaluminate Cement ◽  
Repair Materials ◽  
Initial Setting ◽  
Working Performance

In order to save the costs of the rapid hardening and repair sulphoaluminate cement and improve its working performance, the effects of slag, fly ash, silica fume in different contents and different adding ways on the initial setting time and working performance of sulphoaluminate cement are studied. The results show that the initial setting time of single-doped slag and fly ash both meet the requirements of repair materials, but silica fume significantly cuts the cement’s initial setting time short, which does not meet the construction conditions for rapid hardening and repair. Ultimately it is determined that the mechanical properties of sulphoaluminate cement are the best when slag and fly ash are compound added by the content of 30% at 4:1 mass ratio and simultaneously the initial setting time meets the conditions for rapid hardening and repair.

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