scholarly journals Thermal Resistance Evaluation of Raffia Palm Ash Concrete

2021 ◽  
Vol 25 (3) ◽  
pp. 461-467
Author(s):  
U.N. Wilson ◽  
J.E. Sani ◽  
A.A. Adefila ◽  
I.S. Mohammed
Keyword(s):  
Electron Microscopy ◽  
Compressive Strength ◽  
Thermal Resistance ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Minimum Loss ◽  
X Ray ◽  
Average Loss ◽  
Sem Imaging ◽  
Scanning Electron

T: This research attempts to empirically investigate the behavior of Raffia Palm Ash (RPA) concrete under elevated temperature of different percentages of RPA inclusion in the concrete. Raffia palm ash was obtained after the calcination of the raffia palm for 3 hours at 5500C. X-ray Florescence (XRF) analysis performed revealed that the sample of Raffia Palm Ash (RPA) is a Class C pozzolana, which contains 51.8% of (SiO2 + Al2O3 + Fe2O3) and has a specific gravity of 2.8. The compressive strengths were determined at 0 0C, 718 0C and 821 0C at 0 minutes, 15 minutes and 30 minutes respectively. The result revealed that workability of the concrete declined with the increment in the percentage of raffia palm ash in the concrete. The compressive strength of the concrete cubes as well decreased with the rise in temperature for the entire samples tested. The average loss in strength of the control (0% RPA) is about 15.3% at 7180Cand 25.3% at 8120C while for Raffia palm ash concrete with 5% (optimum replacement) gives a minimum loss in strength of about 21.3% at 7180C and 28.5% at 8120C, which is about 6% at 7180C and 13.2% at 8120C, more than the control. The Scanning Electronic Microscopy (SEM) imaging indicates that the concrete subjected to temperature of about 821oC produces fewer flakes when compared to the concrete subjected to temperature of about 7180C. Keywords: Compressive strength, Raffia Palm Ash (RPA), Scanning Electron Microscopy (SEM), Thermal resistance, X-ray Florescence (XRF)

scholarly journals The Use of Calcium Lactate to Enhance the Durability and Engineering Properties of Bioconcrete

2021 ◽  
Vol 13 (16) ◽  
pp. 9269
Author(s):  
Saddam Hussein Abo Sabah ◽  
Luis Hii Anneza ◽  
Mohd Irwan Juki ◽  
Hisham Alabduljabbar ◽  
Norzila Othman ◽  
...  
Keyword(s):  
Calcium Lactate ◽  
Engineering Properties ◽  
Optimal Conditions ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Sem Images ◽  
X Ray ◽  
Predicted Values ◽  
Potential Option ◽  
Scanning Electron

This study investigated the optimization of the bioconcrete engineering properties and durability as a response of the calcium lactate (CL) content (0.22–2.18 g/L) and curing duration (7–28 days) using the response surface methodology (RSM). Scanning electronic microscopy (SEM) was conducted to evaluate the microstructure of calcium precipitated inside the bioconcrete. The results indicated that the optimal conditions for the engineering properties of concrete and durability were determined at 2.18 g/L of CL content after 23.4 days. The actual and predicted values of the compressive strength, splitting tensile strength, flexural strength, and water absorption were 43.51 vs. 43.43, 3.19 vs. 3.19, 6.93 vs. 5.50, and 7.55 vs. 7.55, respectively, with a level of confidence exceeding 95%. The scanning electron microscope (SEM) images and energy-dispersive X-ray spectroscopy (EDX) proved that the amount of calcium increased with the increase in CL content up to 2.81 g/L at 23.4 days, reducing the pores inside the concrete and making it a great potential option for healing of concrete structures.

UTILIZATION OF FLY ASH AND CONCRETE RESIDUE IN THE PRODUCTION OF GEOPOLYMER BRICKS

2017 ◽  
Vol 12 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Siriporn Sirikingkaew ◽  
Nuta Supakata
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Phase Composition ◽  
Fly Ash ◽  
Industrial Waste ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

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.

scholarly journals Valorization of Brick and Glass CDWs for the Development of Geopolymers Containing More Than 80% of Wastes

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 672
Author(s):  
Dimitris Kioupis ◽  
Aggeliki Skaropoulou ◽  
Sotirios Tsivilis ◽  
Glikeria Kakali
Keyword(s):  
Electron Microscopy ◽  
Compressive Strength ◽  
Circular Economy ◽  
X Ray Diffraction ◽  
Glass Waste ◽  
X Ray ◽  
Optimum Synthesis ◽  
Synthesis Parameters ◽  
Construction And Demolition Wastes ◽  
Scanning Electron

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.

APPLICATION OF SCANNING ELECTRONIC MICROSCOPY FOR THE PURPOSE OF STUDYING CANDIDA ALBICANS BIOFILM ON THE SURFACE OF BASIC PLASTICS OF REMOVABLE ORTHOPEDIC DESIGNS

2019 ◽  
Vol 64 (5) ◽  
pp. 308-313 ◽  
Author(s):  
M. G. Chesnokova ◽  
V. A. Chesnokov ◽  
A. Yu. Mironov
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Candida Albicans ◽  
Electron Microscope ◽  
Biofilm Formation ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Orthopedic Rehabilitation ◽  
Candida Albicans Biofilms ◽  
Scanning Electron

The most common pathology in the clinic of orthopedic dentistry is the presence of partial adentia in patients, manifested in the form of defects of dentition of various localization and length. Removable orthopedic structures in the oral cavity are a potential place for adhesion and colonization of microorganisms. The aim of the research was to study Candida albicans biofilms on the surface of base plastics of removable orthopedic structures using scanning electron microscopy. 175 cultures of C. albicans were isolated and identified from the oral mucosa of patients at various stages of orthopedic rehabilitation. When studying the surface of samples of plastics of hot and cold type polymerization and Candida biofilms using a JEOL JCM 5700 scanning electron microscope (JEOL, Japan), features of biofilm formation were established. An assessment of the nature of the manifestation of the hemagglutinating activity of clinical strains of Candida fungi in the hemagglutination test with human erythrocytes I (O), II (A) of the human and guinea pig blood groups was carried out. The total number of hemagglutinating strains was 37.14%, with the prevalence of the proportion of manna-resistant (MRHA) cultures - 23.43% of cases. Micrographs of the C. albicans yeast-like biofilm biofilm were obtained on the surface of hot and cold-type plastics in incubation dynamics. Scanning electron microscopy revealed the most pronounced changes in the surface of hot plastics of polymerization compared to cold plastics with long incubation of C. albicans, which characterize the loosening of plastics and the appearance of cracks on the surface, and the cracking of a yeast-like fungus biofilm was noted.

Observing of Surface Microstructure Pearl in Bionic Materials by Scanning Electron Microscopy

2012 ◽  
Vol 531 ◽  
pp. 379-382 ◽  
Author(s):  
Wei Lin Shi ◽  
Ye Fei Jin ◽  
Qian Xu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Microstructure ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
High Quality ◽  
Regular Shape ◽  
Scanning Electron

We present the surface microstructure of pearls in bionic materials investigated by means of scanning electronic microscopy (SEM). We found that surface microstructure of pearls in bionic materials with superior luster and quality are built up by aragonite blocks with regular shape, such as around, polygon or diamond, while pearls high luster are composed of by spindly shaped blocks, and pearls with weak luster and quality are made of some undefined aragonite blocks. Clearly, the regular shaped aragonite blocks are the most idea blocks in crystallography for building high quality pearls. The study of surface microstructure pearl in bionic materials will be helpful for the development of bionic materials.

scholarly journals Karakteristik Struktur Mikro dan Gugus Fungsi Komposit Silika Sekam Padi dan Aspal

2020 ◽  
Vol 8 (1) ◽  
pp. 93-100
Author(s):  
Ediman Ginting Suka ◽  
◽  
Ira Sudarsono Putri ◽  
Reka Puspitasari ◽  
Reza Arsela ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Functional Groups ◽  
Amorphous Silica ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Sample Composition ◽  
Scanning Electron

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.

scholarly journals Mineralogical, Microstructural and Compressive Strength Characterization of Fly Ash as Materials in Geopolymer Cement

Elkawnie ◽  
2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Cut Rahmawati ◽  
Sri Aprilia ◽  
Taufiq Saidi ◽  
Teuku Budi Aulia
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Fourier Transform ◽  
Fly Ash ◽  
X Ray Diffraction ◽  
Bending Vibration ◽  
X Ray ◽  
Geopolymer Cement ◽  
Scanning Electron

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.

scholarly journals Evaluación de la acción del fuego en una estructura de hormigón armado mediante XRD, SEM y Espectroscopía infrarroja

2013 ◽  
Vol 3 (1) ◽  
pp. 29-38
Author(s):  
Susana B. Gea ◽  
P. D. Chacón
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Infrared Spectroscopy ◽  
Reinforced Concrete ◽  
Reinforced Concrete Structure ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
X Ray ◽  
Identidad Nacional ◽  
Scanning Electron

RESUMENEl Monumento a los Héroes de la Independencia situado en Humahuaca (norte de Argentina) es una obra inaugurada en 1950 que representa magníficamente las razas autóctonas y europeas que conforman la identidad nacional. Las esculturas de bronce de 40t se encuentran sustentadas por una estructura de hormigón armado, la cual incluye instalaciones adecuadas para vivienda de un cuidador. El subsuelo de esta vivienda sufrió la acción de un incendio cuya carga y tiempo de duración se desconocen. A fin de evaluar los efectos en el hormigón producidos por el fuego, fueron tomadas muestras de un sector de la estructura que luego fueron analizadas por diversas técnicas: difracción por rayos X, microscopía electrónica de barrido y espectroscopia infrarroja. El estudio permitió inferir la temperatura a la que estuvieron sometidas las muestras analizadas y la profundidad alcanzada por el daño. Se proponen los pasos a seguir para evaluar la totalidad de la estructura.Palabras Clave: hormigón armado; fuego; microscopía electrónica; difracción por rayos X; espectroscopia infrarroja.ABSTRACTThe Monument to the Independence Heroes in Humahuaca (northern Argentina) was built in 1950 and represents magnificently the native and European people which shape the national identity. A reinforced concrete structure bears the bronze sculptures of 40tons and includes a dwelling for the monument keeper. The basement of this dwelling underwent a fire whose load and duration are unknown. A few samples from a sector of the structure were taken in order to assess the effects that fire produced in the concrete. They were analyzed by different techniques: X-ray diffraction, scanning electron microscopy and infrared spectroscopy. The study allowed to infer the temperature experimented by the analyzed samples and the depth of the damage. The following steps to assess the whole structure are proposed.Keywords: reinforced concrete; fire; electronic microscopy; X-ray diffraction; infrared spectroscopy.

scholarly journals Compressive strength and microstructure of modified coffee exocarp cement-based composites

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9059-9074
Author(s):  
Zehua Zhu ◽  
Cheng Cheng ◽  
Debin Zhu ◽  
Dewen Liu ◽  
Yafei Zhang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Portland Cement ◽  
Vacuum Extraction ◽  
X Ray Diffraction ◽  
Extraction Technology ◽  
X Ray ◽  
Scanning Electron

Portland cement-based composites were prepared with coffee exocarp (pretreated with water or NaOH) via vacuum extraction technology. An orthogonal test was adopted to analyze the influence of various factors on mechanical properties of the composite. The morphology and composition of the pretreated coffee exocarp and composites were analyzed via environmental scanning electron microscopy and X-ray diffraction, respectively. The results showed that the coffee exocarp content and vacuum extraction time significantly affected the compressive strength. An addition of 10% coffee exocarp had a slight negative effect on the mechanical properties but enhanced the crack inhibition and overall toughness of the composite. The scanning electron microscopy and X-ray diffraction results showed that the composite containing coffee exocarp pretreated with 4% NaOH solution had the highest density and exhibited the best properties due to mechanical interlocking between the coffee exocarp and cement. After 28 d of curing, the composites exhibited a maximum compressive strength of 15.72 MPa, a mass that was approximately 37% less than that of ordinary Portland cement samples, and a bulk density of 1.5 g/cm3 to 1.6 g/cm3. Hence, the produced biocomposites could be used for low-load pavements, providing a new type of economical building material.

scholarly journals Influence of the gypsum dehydration temperature and alkali additives on the properties of anhydrite cement

2010 ◽  
Vol 42 (2) ◽  
pp. 233-243 ◽  
Author(s):  
V. Leskeviciene ◽  
I. Sarlauskaite ◽  
D. Nizeviciene ◽  
N. Kybartiene
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Crystalline Structure ◽  
Alkali Activation ◽  
Glass Waste ◽  
X Ray ◽  
Gypsum Dehydration ◽  
Scanning Electron ◽  
Sem Analyses

While dehydrating gypsum with additives at the temperatures of 800?C and 900?C the influence of alkali additives on both the crystalline structure of anhydrite and properties of anhydrite binder was investigated. The industrial and household wastes including other lowcost materials were used as additives. Having heated them with gypsum the anhydrite with alkali activation properties was obtained. The properties of such substances were evaluated using the methods of chemical, diffractive X-ray scanning and scanning electron microscopy (SEM) analyses. Some additives, e.g. 5 % ground glass waste, were found to increase crystal agglomerate formation of anhydrite binder, accelerate the hydration process of anhydrite and double the compressive strength of hydrated samples compared to samples without additives.

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