scholarly journals Characterization of Macro Mechanical Properties and Microstructures of Cement-Based Composites Prepared from Fly Ash, Gypsum and Steel Slag

Minerals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 6
Author(s):  
Jiajian Li ◽  
Shuai Cao ◽  
Erol Yilmaz
Keyword(s):  
Computed Tomography ◽  
Fly Ash ◽  
Laboratory Experiments ◽  
Steel Slag ◽  
Solid Wastes ◽  
Curing Time ◽  
Tensile Shear ◽  
Microscopic Studies ◽  
Scanning Electron

Using solid wastes (SWs) as backfilling material to fill underground mined-out areas (UMOAs) solved the environmental problems caused by SWs and reduced the backfilling cost. In this study, fly ash (FA), gypsum and steel slag (SS) were used to prepare cement-based composites (CBC). The uniaxial compression, computed tomography (CT) and scanning electron microscope (SEM) laboratory experiments were conducted to explore the macro and micromechanical properties of CBC. The findings showed that the uniaxial compressive strength (UCS) of CBC with a curing time of 7 d could reach 6.54 MPa. The increase of SS content reduced the UCS of CBC, while the gypsum and FA content could increase the UCS of CBC. Microscopic studies have shown that the SS particles in CBC have noticeable sedimentation, and the increase of SS content causes the failure mode of CBC from tensile to tensile-shear. These research results can provide a scientific reference for the preparation of backfilling materials.

Study on Microstructure of Long-Age Concrete with HCSA Expansive Agent

2017 ◽  
Vol 744 ◽  
pp. 40-44 ◽  
Author(s):  
Fang Fang Hou
Keyword(s):  
Fly Ash ◽  
High Volume ◽  
Hydration Product ◽  
Curing Time ◽  
Average Ratio ◽  
Expansive Agent ◽  
Binding Material ◽  
High Volume Fly Ash ◽  
Energy Dispersion Spectrum ◽  
Scanning Electron

The microstructure of high-volume fly ash and long-age concrete with HCSA expansive agent at different curing time is studied by means of scanning electron microscope and energy dispersion spectrum analysis. The result shows that wet curing is benefit to the generation of ettringite which is the hydration product of HCSA expansive agent, and also is benefit to the hydration of cement and fly ash, which can fundamentally improve compactness of concrete. For the concrete which mix 6% amount of HCSA expansive agent a 60% amount of fly ash, when it is not cured, the average ratio of Ca to Si is 1.8, and the value is 0.36 after 28d curing. Since the ration of Ca to Si is lower, the hydration rate of binding material is faster.

Synthesis and characterization of geopolymer composites based on gasification coal fly ash and steel slag

2019 ◽  
Vol 211 ◽  
pp. 646-658 ◽  
Author(s):  
Yuchi Chen ◽  
Xian Zhou ◽  
Sha Wan ◽  
Rui Zheng ◽  
Jun Tong ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Steel Slag ◽  
Synthesis And Characterization ◽  
Geopolymer Composites

Preparation and Characterization of the Ceramsites with Microscale Pores from Iron Tailing and Fly Ash

2020 ◽  
Vol 12 ◽  
Author(s):  
Zeyang Xue ◽  
Zi Wang ◽  
Chunhu Yu ◽  
Yajing Mao ◽  
Lizhai Pei
Keyword(s):  
Fly Ash ◽  
Mechanical Performance ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sintering Time ◽  
Duration Time ◽  
Important Significance ◽  
Scanning Electron

Background: Iron tailing causes great environmental and social problems which contaminate water, air and soil. Therefore, it is of important significance to prepare iron tailing ceramsites with microscale pores which can recycle the deposited iron tailing. Objective: The aim of the research is to obtain iron tailing ceramsites with microscale pores and good mechanical performance. Methods: The iron tailing ceramsites have been characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). Influence of the content of iron tailing, temperature and duration time on the mechanical performance of the obtained ceramsites was performed and the optimal sintering parameter was determined. The bulk density, apparent density and cylinder compressive strength of the obtained ceramsites increase obviously as improving the iron tailing content, temperature and sintering time. Results: Duration time and sintering temperature play important roles in the formation and size of the pores of the ceramsites. The optimal iron tailing content and sintering parameter are 70wt.%, 1100 ℃ for 40 min. The iron tailing ceramsites mainly consist of orthorhombic CaAl2Si2O8, monoclinic CaSiO3, hexagonal Ca7Si2P2O16, triclinic MgSiO3, triclinic Al2SiO5 and triclinic Ca2Fe2O5 phases. Iron tailing ceramsites from 1100 ℃ for 40 min are composed of irregular particles with several hundreds of micrometers improving the density and strength of the ceramsites. Conclusion: Iron tailing ceramsites containing microscale pores were prepared using iron tailing and fly ash, and exhibit excellent potential for the application in the field of construction.

Use of Fly Ash and Cu-Slag from Mexico to Make Alkali Cements and Hybrid Cements

2016 ◽  
Vol 1813 ◽  
Author(s):  
M. Rendón Belmonte ◽  
A. Palomo Sánchez ◽  
A. Fernández Jiménez ◽  
A. Torres Acosta ◽  
M. Martínez Madrid ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fly Ash ◽  
Chemical Characterization ◽  
Copper Slag ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naoh Solution ◽  
Scanning Electron

ABSTRACTThis paper focus on evaluating the ability to use Mexican fly ash (FA) and copper slag (CS) to produce alkali cements (0% OPC) or hybrid cements (20% OPC + 80% fly ash). The alkali activators used were two: 8 M NaOH solution for alkali cements and NaCl with sodium silicate for hybrid cement (HYC). Results of mechanical testing and characterization of the reaction products formed after 2 and 28 days are presented and discussed. Mechanical strength in some cases exceeded 20 MPa, at 2 days curing. The chemical characterization techniques used were X-Ray Diffraction (XRD) and scanning electron microscopy (SEM).

scholarly journals Compressive Strength of High-Volume Fly Ash (HVFA) Concrete as a Function of Lime Water and Curing Time

2021 ◽  
Author(s):  
Chin Mei Yun ◽  
Md. Rezaur Rahman ◽  
Kuok King Kuok ◽  
Mohd Elfy Mersal ◽  
Colin Ngu Ker Liing ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
High Volume ◽  
Partial Replacement ◽  
Curing Time ◽  
Additional Information ◽  
Lime Water ◽  
High Volume Fly Ash

Abstract The compressive strength of high-volume fly ash (HVFA) concrete with varied volume percentages of 40%, 50%, and 60% was examined utilizing low calcium fly ash (Class-F) as a partial replacement for regular Portland cement in this study. On the 7th, 28th, and 56th days, the compressive strength is tested. At the 7th and 28th days, the influence of saturated lime water on the compressive strength of HVFA concrete is evaluated. The inclusion of fly ash as a replacement for Portland cement reduces the compressive strength of the HVFA concrete, according to the findings. At the 56th day, the HVFA concrete with 40% fly ash substitution has a compressive strength equivalent to the regular weight concrete. At the 28th day, it was discovered that saturated lime water was helpful in maximizing the strength of HVFA concrete with 50% fly ash substitution. There was additional information about the characterization of HVFA concrete.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Characterization of Sputtered Films using the Scanning Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 44-45
Author(s):  
R. F. Schneidmiller ◽  
W. F. Thrower ◽  
C. Ang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Sputtered Films ◽  
Plasma Sputtering ◽  
Microelectronic Devices ◽  
Control Film ◽  
Scanning Electron

Solid state materials in the form of thin films have found increasing structural and electronic applications. Among the multitude of thin film deposition techniques, the radio frequency induced plasma sputtering has gained considerable utilization in recent years through advances in equipment design and process improvement, as well as the discovery of the versatility of the process to control film properties. In our laboratory we have used the scanning electron microscope extensively in the direct and indirect characterization of sputtered films for correlation with their physical and electrical properties.Scanning electron microscopy is a powerful tool for the examination of surfaces of solids and for the failure analysis of structural components and microelectronic devices.

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