Effect of Chemical Composition on the Properties of Reconstructed Steel Slag

2019 ◽  
Vol 944 ◽  
pp. 1163-1171
Author(s):  
Ying Xu ◽  
Qiao Ling Wang ◽  
Chen Guang Hu ◽  
Shan Shan Yang

The steel slag is not widely or extensively used because of its poor volume stability and low cementitious activity. In this paper, the solid waste fly ash, quicklime and slag discharged from iron and steel enterprises are used as conditioning components in the experiment. In order to improve the cementitious activity and volume stability of steel slag, the high temperature reconstruction experiment of steel slag was completed. The effects of C/S (2.50~3.14), S/A (4.5~17. 81) on the cementitious activity and volume stability of reconstructed steel slag were investigated by means of the tests of compressive strength, scanning electron microscope, X-ray diffraction, lithofacies test, stability test and so on. The results showed that the cementitious activity and volume stability of the reconstructed steel slag were improved in the higher C/S or lower S/A. The cementitious activity and volume stability of the reconstructed steel slag were improved with the increase of CaF2 content. By analyzing the cementitious activity and volume stability of the reconstructed steel slag, the optimum technological parameters are obtained as follows: C/S is 2.70 , S/A is 5.78, the content of CaF2 is 4%.

2011 ◽  
Vol 306-307 ◽  
pp. 961-965
Author(s):  
Chao Nan Yin ◽  
Ling Chao Lu ◽  
Shou De Wang

The influence of P2O5on the properties of alite-calcium strontium sulphoaluminate cement was researched by means of X-ray diffraction, scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) and petrographic analysis. The results show that the optimal content of P2O5is 0.3% and the compressive strength of the cement at 1, 3, 28d are 27.0, 59.1, 110.9MPa when the calcining temperature is 1350°C. P2O5mainly exists in the belite and a suitable amount of P2O5can promote the formation of C1.5Sr2.5A3and alite. When the content of P2O5is higher than 0.3%, the formation of C1.5Sr2.5A3and alite can be hindered. P2O5can enhance the hydration heat evolution rate in the acceleration period and the hydrate heat of cement containing P2O5increases slightly.


2017 ◽  
Vol 12 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Siriporn Sirikingkaew ◽  
Nuta Supakata

This study presents the development of geopolymer bricks synthetized from industrial waste, including fly ash mixed with concrete residue containing aluminosilicate compound. The above two ingredients are mixed according to five ratios: 100:0, 95:5, 90:10, 85:15, and 80:20. The mixture's physico-mechanical properties, in terms of water absorption and the compressive strength of the geopolymer bricks, are investigated according to the TIS 168-2546 standard. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses are used to investigate the microstructure and the elemental and phase composition of the brick specimens. The results indicate that the combination of fly ash and concrete residue represents a suitable approach to brick production, as required by the TIS 168–2546 standard.


Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 672
Author(s):  
Dimitris Kioupis ◽  
Aggeliki Skaropoulou ◽  
Sotirios Tsivilis ◽  
Glikeria Kakali

One of the areas of priority in a circular economy, regarding waste management, regards the valorization of construction and demolition wastes (CDW). This study suggests the synthesis of geopolymeric binders based almost entirely on construction and demolition wastes. Ceramic waste was used as the aluminosilicate precursor of the geopolymer synthesis, while glass waste was applied in the preparation of the activation solution. A fractional experimental design defined the optimum synthesis parameters, based on compressive strength values. The final products were characterized by means of X-Ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The glass waste was appropriately processed in order to prepare the activation solution for the geopolymerization of brick waste. In this work, CDW-based geopolymers were produced with a compressive strength in the range 10–44 MPa. The developed products contained 80–90 wt.% CDWs, depending on the method of activator preparation.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Wenwei Lin ◽  
Fan Fei ◽  
Qunjie Li

The sulfur concrete samples were prepared by the optimized process, which were mixed with cement, fly ash and slag, respectively. The influence of the type and content of filler on the compressive strength of sulfur concrete was studied. The phase and micromorphology of filler and sulfur mixture were characterized by X-ray diffraction and scanning electron microscope, and the bonding mode was studied. The results show: the cement filler has the best effect on the compressive performance of sulfur concrete,and the compressive strength is 87.2 MPa by adding cement filler with the same quality as sulfur; there is no chemical reaction between filler and sulfur, and the filler is physically bonded to sulfur matrix.


2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Tsai-Lung Weng ◽  
Wei-Ting Lin ◽  
An Cheng

This study investigated the basic mechanical and microscopic properties of cement produced with metakaolin and quantified the production of residual white efflorescence. Cement mortar was produced at various replacement ratios of metakaolin (0, 5, 10, 15, 20, and 25% by weight of cement) and exposed to various environments. Compressive strength and efflorescence quantify (using Matrix Laboratory image analysis and the curettage method), scanning electron microscopy, and X-ray diffraction analysis were reported in this study. Specimens with metakaolin as a replacement for Portland cement present higher compressive strength and greater resistance to efflorescence; however, the addition of more than 20% metakaolin has a detrimental effect on strength and efflorescence. This may be explained by the microstructure and hydration products. The quantity of efflorescence determined using MATLAB image analysis is close to the result obtained using the curettage method. The results demonstrate the best effectiveness of replacing Portland cement with metakaolin at a 15% replacement ratio by weight.


2013 ◽  
Vol 357-360 ◽  
pp. 1353-1357
Author(s):  
Xiao Li Ji ◽  
Zhuo Chen

High-temperature foam ceramics were produced from sludge, Zhongxiang porcelain sand, shale and sand, with addition of SiC 0.15%~0.40% as foaming agent, respectively, sintered at 1130°C~1160°C. The phase composition and micro structure of sintered samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and density, compressive strength and thermal conductivity were evaluated. The results showed that the main phase of amorphous phase plagioclase in sintered samples and interior of samples with a large number of uniformly distributed closed pores, rose sintering temperature and increased SiC addition leading to pores size enlarged and density, compressive strength and thermal conductivity diminished.


2020 ◽  
Vol 8 (1) ◽  
pp. 93-100
Author(s):  
Ediman Ginting Suka ◽  
◽  
Ira Sudarsono Putri ◽  
Reka Puspitasari ◽  
Reza Arsela ◽  
...  

Composite of rice husk and asphalt silica was carried out at a ratio of 1: 0.7; 1: 0.8 and 1: 0.9 and heated at 150oC for 3 hours. The characteristics of the phase structure, microstructure, and functional groups were analyzed using X-ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) and Fourier Transform Infrared (FTIR), physical properties analysis (density, porosity) and mechanics (compressive strength). The XRD results showed that the phase in asphalt silica composites detected amorphous carbon at 2θ = 18º and amorphous silica with the amorphous silica peak shifted from 2θ = 22º to 2θ = 20º. Microstructure analysis shows that cracks and clusters are bigger with grain sizes of 7,742 µm, 8,495 µm and 10,921 µm respectively, and the sample composition shows percentage of silicon (Si), Oxygen (O) and sodium (Na), respectively. decreases and the percentage of carbon (C), sulfur (S) increases. The results of FTIR show that the functional groups of Si-OH, Si-O-Si and Si-O bonds are decreasing and the functional groups of C-H bonds are increasing. The addition of asphalt causes the value of density increases, the value of porosity and compressive strength decreases.


Elkawnie ◽  
2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Cut Rahmawati ◽  
Sri Aprilia ◽  
Taufiq Saidi ◽  
Teuku Budi Aulia

Abstract: This study was designed to examine the mineral, microstructural, and mechanical strength properties of fly ash and its feasibility as a raw material for geopolymer cement. The study used an experimental method by examining the characteristics of fly ash by X-ray Fluorescence Spectrometer (XRF), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), hydrometer method, Scanning electron microscopy (SEM), and compressive strength testing. For creating the geopolymer cement paste, a concentration of NaOH 10M was used, with a ratio of water/solid = 0.4 and a ratio of Na2SiO3/NaOH = 1 using curring at room temperature. The results showed the geopolymer pastes have a compressive strength of 18.1 MPa and 21.5 MPa after 7 days and 28 days. The XRD results showed a decrease in the peak of 2θ at 26.54° because the amorphous part had transformed into a C-S-H solution in geopolymer cement. This finding was supported by the FTIR spectra results showing Si-O-Si bending vibration and the functional group of AlO2. It showed that Nagan Raya fly ash-based geopolymer is a potential construction material.Abstrak: Penelitian ini dirancang untuk mendapatkan sifat mineral, mikrostruktural, dan kekuatan mekanis dari fly ash serta kesesuaiannya sebagai material dasar pada semen geopolimer. Metode penelitian yang digunakan adalah metode eksperimen dengan cara  menguji karakteristik dari fly ash dengan pengujian X-ray Fluorescense Spectrometer (XRF), Fourier transform infrared (FTIR) spectoscopy, X-ray diffraction (XRD), hydrometer method, Scanning electron microscopy (SEM) dan kuat tekan.  Untuk pembuatan pasta semen geopolimer digunakan konsentrasi NaOH 10 M, rasio water/solid 0,4 dan rasio Na2SiO3/NaOH = 1 dengan perawatan pada suhu kamar. Hasil menunjukkan setelah 7 hari pasta geopolimer memiliki kuat tekan 18,1 MPa dan 21,5 MPa pada 28 hari. Hasil XRD menunjukkan adanya penurunan puncak 2θ pada 26,54° ini disebabkan karena bagian amorf dari fly ash telah menjadi larutan C-S-H pada semen geopolimer. Hasil ini diperkuat dengan analisis FTIR spectra yang menunjukkan adanya Si-O-Si bending vibration dan gugus fungsi dari AlO2. Hasil menunjukkan fly ash dari Nagan Raya potensial sebagai bahan material konstruksi berbasis geopolimer.


2013 ◽  
Vol 807-809 ◽  
pp. 1266-1269 ◽  
Author(s):  
Atthakorn Thongtha ◽  
Somchai Maneewan ◽  
Chantana Punlek ◽  
Yothin Ungkoon

The comparison of microstructure and mechanical properties between the autoclaved aerated concrete (AAC) and the autoclaved aerated concrete consist of sugar sediment (AAC-SS) was investigated in this work. The microstructure of AAC and AAC-SS was analyzed by the scanning electron microscopy (SEM). The mechanical properties of AAC and AAC-SS were focused on the compressive strength, the density, the water absorption and the flexural strength. To comfirm the tobermorite phase, the phase formation of the samples was tested using X-ray diffraction (XRD). It was found that the microstructure of AAC and AAC-SS surface was the finer needle-like crystalline morphology. The compressive strength (5.9 N/mm2) and flexural strength (1.82 N/mm2) of AAC-SS were higher than that of the AAC (5.0 N/mm2 and 1.64 N/mm2). While, the value of density (0.60 g/cm3) and humidity (23.59%) of AAC-SS had little less than that of the AAC (0.61 g/cm3 and 24.11%). The increasing of the tobermorite phase, which was added by the sugar sediment, had affected to the improvement of the mechanical properties. The specimens of both AAC and AAC-SS were claimed in quality class of 4, which based on the Thai Industrial Standard 1505-1998.


2012 ◽  
Vol 727-728 ◽  
pp. 1535-1540 ◽  
Author(s):  
Adriano da Costa Borges ◽  
Monica Castoldi Borlini Gadioli ◽  
Luiz Alberto Baptista Pinto ◽  
José Roberto de Oliveira

A great amount of granite waste and steel slag is generated daily in Brazil, being those constituted mainly by SiO2and CaO, respectively. The objective of this work was to characterize the material formed after melting and cooling of the mixture of granite waste and LD steel slag, with basicity (CaO/SiO2) of 1.0, aiming to evaluate the technical feasibility of this to the Portland cement production. Two samples were prepared and melted. After the melting of the mixture, one sample was cooled in water and another in the furnace. The samples characterization was carried out through X-ray diffraction and scanning electron microscopy. The results showed that the new material formed presented amorphous state, to the samples cooled in water and akermanite and gehlenite phases, considered ideals for the hydraulic activity of the slags, in the sample cooled in the furnace. Therefore, the mixture of those two wastes can be a new alternative for the use of both, allied to the decrease of the environmental impact.


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