The document summarizes research into problems occurring during the production of cellular concrete blocks (Thermostone) in Iraq. Key findings include:
1) No pore formation can result from insufficient reaction between lime and aluminum powder below 40°C, requiring more aluminum powder or alkali additives to reach the necessary temperature.
2) Hydrogen bubble escape causes denser blocks and is addressed by using finer 50-100μm aluminum powder. This also improves thermal insulation and compressive strength.
3) X-ray diffraction identified phases like tobermorite, ettringite and thaumasite that influence mechanical properties and moisture retention. Proper phase formation through curing improves block quality.
Corrosion Behaviour of Titanium Anodized Film in Different Corrosive Environm...IJERA Editor
Anodizing is an electrochemical process in which thickness of the natural oxide layer is increased and converted it into a decorative, durable, corrosion-resistant film. Titanium is used as a biocompatible material in human implants due to its excellent corrosion and wears resistance. Stable, continuous, highly adherent, and protective oxide films can be developed on titanium using various acid or alkaline baths. Anodizing of titanium generates a spectrum of different color without use of dyes. This spectrum of color dependent on the thickness of the oxide, voltage ranges, interference of light reflecting off the oxide surface and reflecting off the underlying metal surface. The anodized film of Titanium is mainly consists of TiO2 or mixtures of TiO2 & Ti2O3 etc. In the present work, Pure Titanium plate has been anodized using bath of Chromic Acid at different voltage range. The anodized film is characterized by visual observation, SEM & EDAX analysis & A.C Impedance Spectroscopy, while the corrosion studies were performed using Potentiodynamic studies were performed in 3.5% NaCl & 0.1N H2SO4. The Results show that the anodized film of Titanium show different spectrum of colors from Brown-Violet-Tea or Peacock. SEM & EDAX analyses show that the anodized film of Titanium is mainly made up of TiO2 and Ti2O3. Potentiodynamic study implies that the film developed on Titanium using the bath of Chromic Acid exhibits good corrosion resistance. The A.C. Impedance study shows that the film is more compact, adherent and more uniform in chromic acid bath.
Production of light-weight porous ceramic media from metakaolin and waste glass
powder with sodium silicate as foaming agent in batch1 and without sodium silicate in
batch 2 was investigated. Different weight percentages of yeast (0.1-0.5) as pore
forming agent have been added to both batches. All samples were formulated by wet
milled, dried, shaped and fired at 700°C for batch 1and at 850°C for batch 2.
Chemical and mineralogical analysis, identification and calculation of crystalline to
amorphous ratio phases by XRD, microstructure and mechanical and physical
properties were investigated to specify the resulting porous article. The predominant
closed porosity is found in batch 1 whereas open pores are prevalent in batch 2. The
size of pores ranges from 3.794mm to 58μm in batch No. 1 and from 67.5 μm to 1.6
μm in batch No. 2 (millimeter to sub-micron) with approximately spherical shape
were found in both batches
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Corrosion Measursement, Friction testing and XRD Analysis of Single Layer CrN...IJAEMSJORNAL
The purpose of present study was to investigate the erosive corrosive wear behavior of single layer (CrN) coatings on AISI 304 Stainless Steel samples with varying coating thickness (0-200 nm) in the range of 50 nm. The slurry jet erosive test was conducted on Slurry Jet Erosion Tester in saline slurry (3.5wt% salt) under the different working conditions with varying impact velocity (10-25 m/s), impingement angle (30°-75°) and erodent discharge (160-280 gm/min). Corrosion tests were conducted in 3.5 wt. % NaCl solution using a Potentiostat, in order to analyze the corrosion behavior of the coated samples in sea water environment. Coefficient of friction was measured using a Scratch Tester. XRD analysis of the eroded samples indicated the presence of both CrN and Cr2N (200) in the coatings.
Taguchi analysis of single layer CrN coatings on AISI 304 Stainless Steel to ...IJAEMSJORNAL
The purpose of present study was to investigate the erosive corrosive wear behavior of single layer (CrN) coatings on AISI 304 Stainless Steel samples with varying coating thickness (0-200 nm) in the range of 50 nm. The slurry jet erosive test was conducted on Slurry Jet Erosion Tester in saline slurry (3.5wt% salt) under the different working conditions with varying impact velocity (10-25 m/s), impingement angle (30°-75°) and erodent discharge (160-280 gm/min). Taguchi analysis was applied to find optimum parameters for the minimization of erosion rate of various coated and uncoated samples. The results of Taguchi experiments also indicated that among all the factors, impact velocity became least significant when samples were coated with CrN whereas it was most significant for uncoated samples. Coating thickness was the second most significant factor in the case of CrN coated samples. PVD- CrN coatings reduced the wear rate by nearly 2 times.
SIMONA CAVALU_Surface Modification of Alumina/ Zirconia Ceramics Upon Differe...Simona Cavalu
The aim of this study was to prepare and to characterize the structure of Al2O3–3YSZ composites with 5% TiO2 addition
as well as the surface modification upon treatments with SnF2 and NaBF4, respectively. SEM micrographs showed the
controlled densification of the composites as an effect of 3YSZ and TiO2 addition to alumina matrix. By FTIR and XRD,
the characteristics of Al-O and Zr-O vibrations, respectively, the diffractions lines related to a-corundum and zirconia in
tetragonal phase were discussed. Qualitative and quantitative results obtained by XPS and ATR FTIR demonstrated that the
proposed materials are more sensitive to SnF2 than to NaBF4 treatment.
Corrosion Behaviour of Titanium Anodized Film in Different Corrosive Environm...IJERA Editor
Anodizing is an electrochemical process in which thickness of the natural oxide layer is increased and converted it into a decorative, durable, corrosion-resistant film. Titanium is used as a biocompatible material in human implants due to its excellent corrosion and wears resistance. Stable, continuous, highly adherent, and protective oxide films can be developed on titanium using various acid or alkaline baths. Anodizing of titanium generates a spectrum of different color without use of dyes. This spectrum of color dependent on the thickness of the oxide, voltage ranges, interference of light reflecting off the oxide surface and reflecting off the underlying metal surface. The anodized film of Titanium is mainly consists of TiO2 or mixtures of TiO2 & Ti2O3 etc. In the present work, Pure Titanium plate has been anodized using bath of Chromic Acid at different voltage range. The anodized film is characterized by visual observation, SEM & EDAX analysis & A.C Impedance Spectroscopy, while the corrosion studies were performed using Potentiodynamic studies were performed in 3.5% NaCl & 0.1N H2SO4. The Results show that the anodized film of Titanium show different spectrum of colors from Brown-Violet-Tea or Peacock. SEM & EDAX analyses show that the anodized film of Titanium is mainly made up of TiO2 and Ti2O3. Potentiodynamic study implies that the film developed on Titanium using the bath of Chromic Acid exhibits good corrosion resistance. The A.C. Impedance study shows that the film is more compact, adherent and more uniform in chromic acid bath.
Production of light-weight porous ceramic media from metakaolin and waste glass
powder with sodium silicate as foaming agent in batch1 and without sodium silicate in
batch 2 was investigated. Different weight percentages of yeast (0.1-0.5) as pore
forming agent have been added to both batches. All samples were formulated by wet
milled, dried, shaped and fired at 700°C for batch 1and at 850°C for batch 2.
Chemical and mineralogical analysis, identification and calculation of crystalline to
amorphous ratio phases by XRD, microstructure and mechanical and physical
properties were investigated to specify the resulting porous article. The predominant
closed porosity is found in batch 1 whereas open pores are prevalent in batch 2. The
size of pores ranges from 3.794mm to 58μm in batch No. 1 and from 67.5 μm to 1.6
μm in batch No. 2 (millimeter to sub-micron) with approximately spherical shape
were found in both batches
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Corrosion Measursement, Friction testing and XRD Analysis of Single Layer CrN...IJAEMSJORNAL
The purpose of present study was to investigate the erosive corrosive wear behavior of single layer (CrN) coatings on AISI 304 Stainless Steel samples with varying coating thickness (0-200 nm) in the range of 50 nm. The slurry jet erosive test was conducted on Slurry Jet Erosion Tester in saline slurry (3.5wt% salt) under the different working conditions with varying impact velocity (10-25 m/s), impingement angle (30°-75°) and erodent discharge (160-280 gm/min). Corrosion tests were conducted in 3.5 wt. % NaCl solution using a Potentiostat, in order to analyze the corrosion behavior of the coated samples in sea water environment. Coefficient of friction was measured using a Scratch Tester. XRD analysis of the eroded samples indicated the presence of both CrN and Cr2N (200) in the coatings.
Taguchi analysis of single layer CrN coatings on AISI 304 Stainless Steel to ...IJAEMSJORNAL
The purpose of present study was to investigate the erosive corrosive wear behavior of single layer (CrN) coatings on AISI 304 Stainless Steel samples with varying coating thickness (0-200 nm) in the range of 50 nm. The slurry jet erosive test was conducted on Slurry Jet Erosion Tester in saline slurry (3.5wt% salt) under the different working conditions with varying impact velocity (10-25 m/s), impingement angle (30°-75°) and erodent discharge (160-280 gm/min). Taguchi analysis was applied to find optimum parameters for the minimization of erosion rate of various coated and uncoated samples. The results of Taguchi experiments also indicated that among all the factors, impact velocity became least significant when samples were coated with CrN whereas it was most significant for uncoated samples. Coating thickness was the second most significant factor in the case of CrN coated samples. PVD- CrN coatings reduced the wear rate by nearly 2 times.
SIMONA CAVALU_Surface Modification of Alumina/ Zirconia Ceramics Upon Differe...Simona Cavalu
The aim of this study was to prepare and to characterize the structure of Al2O3–3YSZ composites with 5% TiO2 addition
as well as the surface modification upon treatments with SnF2 and NaBF4, respectively. SEM micrographs showed the
controlled densification of the composites as an effect of 3YSZ and TiO2 addition to alumina matrix. By FTIR and XRD,
the characteristics of Al-O and Zr-O vibrations, respectively, the diffractions lines related to a-corundum and zirconia in
tetragonal phase were discussed. Qualitative and quantitative results obtained by XPS and ATR FTIR demonstrated that the
proposed materials are more sensitive to SnF2 than to NaBF4 treatment.
Erosive Corrosive Wear Performance of Single Layer CrN Coatings on AISI 304 S...IJAEMSJORNAL
The purpose of present study was to investigate the erosive corrosive wear behavior of single layer (CrN) coatings on AISI 304 Stainless Steel samples with varying coating thickness (0-200 nm) in the range of 50 nm. The slurry jet erosive test was conducted on Slurry Jet Erosion Tester in saline slurry (3.5wt% salt) under the different working conditions with varying impact velocity (10-25 m/s), impingement angle (30°-75°) and erodent discharge (160-280 gm/min). Steady state analysis was applied to find optimum parameters for the minimization of erosion rate of various coated and uncoated samples. The finding of steady state condition tests indicated that the erosion rate increased with the increase in impact velocity and erodent discharge but decreased with the increase in coating thickness. The results also indicated that erodent discharge was the most significant factor, followed by impingement angle and impact velocity for the CrN coated samples. The SEM characterization of the eroded samples was carried out in order to analyze the topography of the eroded surface to investigate the wear mechanisms induced by slurry jet erosion test.
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity
The ladle nozzle filling compound is critical to the production of “clean” steel. Failure of a “free” opening severely compromises the cleanliness of liquid steel. Chemical, X-ray diffraction, and thermal analyses of the nozzle filling compounds in commercial use were carried out to identify the nature of phases present and to establish the influence on the “free' opening of the ladle in each case. The samples showed evidence of partial fusion as well as volume expansion due to phase change when heated under conditions simulating the nozzle well of a filled ladle. The wetting behavior of ceramic powders is also being investigated by a physically simulating a model of ladle nozzle mold. Investigation of the adhering nature of ceramic powder & penetration depth of liquid steel is also done by the use of killed & un-killed liquid steel condition.
Combination of urea-Sn+2 in SCP solution was examined as a corrosion inhibitor for concrete reinforced steel by potentiodynamicpolarization, surface synergist parameter and cyclic voltammetry methods comparing with urea–Zn+2 combination. A synergism parameter (SI) indicated a synergistic effect between urea and Sn+2was exist. Polarization study revealed that formulation consisting of 300 ppm urea+50 ppm Sn+2 in SCP solution provided inhibition efficiency (IF) of 85.93% while 300 ppm urea +50 ppm Zn+2 provided 82.3% IF, and this combination acts as anodic type inhibitor. Cyclic voltammetry curves showed that the steel samples immersed in this formulation has low tendency to pitting corrosion. From these results it can be concluded that urea – Sn+2 inhibitor formulation is a good corrosion n inhibitor for concrete reinforced steel, it can maintain stable passive film on steel surface even in the presence of aggressive chloride ions so it can be used instead of the high toxicityZn+2 inhibitor to improve the corrosion inhibition of urea fertilizer inhibitor.
Experimental and Analytical Investigation on Strength Properties of Concrete ...HARISH B A
The experiment work carried out by micro silica as a supplementary material for cement and evaluate
cement for M20 grade of concrete. We are adding 0%, 5%, 10%, 15%, and 20% by weight of cement in concrete. The
material chosen for structural up gradation should not pollute the environment. They should be accessible to the
ordinary people and low monetary cost. Coconut fibre is abundant, versatile, renewable, cheap and more resistant
thermal conductivity. Coconut fibres have the highest toughness amongst natural fibre. They have potential to be used
as reinforcement in low cost concrete structures, especially in tropical earth quake region. The aim of investigation is
study the possibilities to use coconut fibre in addition to other constituents of concrete and strength properties. The
influence of 1%, 2% and 3% fibre content by mass of cement and aspect ratio 125, fibre cut length 2.80cm is
investigated. To evaluate the effect of coconut fibres improving the properties of concrete.At 1% addition of coconut
fibre, 5% silica fume with water cement ratio 0.53. compressive strength test and split tensile strength gives best result
in concrete.
TRADITIONAL ingots vs. REMELTED, Comparing Metallurgical ResultsASO Group
As everyone know, remelted ingots are, from a purely metallurgical point of view, preferable to the traditional bottom poured ingots because of a series of reason:
chemical homogeneity
micro inclusions content
ultrasonic results test
absence of segregation
fine and uniform structure.
For a better understanding, we compared characteristics of a remelted ingot around 40tons, with a poly ingot with a similar traversal section of 1500mm and a gross weight near 32tons.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
INVESTIGATION OF OXIDATION RESISTANCE OF NI- TI ELECTROCHEMICAL CODEPOSITION ...IAEME Publication
The effects of Ti particle loading in a plating bath on the morphology and hardness of Ni-Ti composite coatings via an electrochemical codeposition coating were investigated. The Ti-reinforced Ni-matrix composite coatings were codeposited on Austenitic Stainless Steel (316 L) substrates using a Ni-ion electrolytic solution stably suspended with -20 m max. diameter Ti particles and heat treated under vacuum atmosphere for six hours at 950 °C prior to oxidation testing.
Effect of Temperature on Wear Rate of Si-Epoxy- Eglass Polymer composite Mate...IDES Editor
With the increase use of polymer composites in
erosive work environment, it has become extremely important
to investigate their erosion characteristics. The hybrid
composite consisting of a Epoxy resin reinforced with Eglass
fiber and Si particles was developed. The effect of temperature
on wear rate applied to Si – Epoxy – Eglass polymer composite
has been studied. It has been found that the wear rate increases
as the temperature of carrier media (air) is increased.
Temperature of carrier media is one of the significant factor
influencing the erosion wear. The results were compared with
the plain epoxy composite material. Micrographs of eroded
surface are also presented to study the wear rate and Wear
behavior of composite.
Nano-structure TiO2 film coating on 316L stainless steel via sol-gel techniqu...Nanomedicine Journal (NMJ)
Objective(s):
Titanium oxides are known to be appropriate hemocompatible materials which are suggested as coatings for blood-contacting devices. Little is known about the influence of nanometric crystal structure, layer thickness, and semiconducting characteristics of TiO2
on blood hemostasis.
Materials and Methods:
Having used sol-gel dip coating method in this study, TiO2 thin films were deposited on nano-scale electro-polished stainless steel 316L with 1 to 5 nano-sized layers. Surface morphology and structure of the film were studied with X-ray diffraction and atomic force microscopy. Blood compatibility was also determined by measuring the platelet activation (CD62P expression), platelet adhesion (Scanning Electron Microscopy), and the blood clotting time on these samples.
Results:
The films were compact and smooth and existed mainly in the form of anatase. By increasing the number of TiO2 thin layer, clotting time greatly extended, and the population of activated platelet and P-selectine expression changed according to the surface characteristics of each layer.
Conclusion:
The findings revealed that stainless steel 316L coated with nano-structured TiO2 layer improved blood compatibility, in terms of both blood platelet activity and coagulation cascade, which can decrease the thrombogenicity of blood contacting devices which were made from stainless steel.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Erosive Corrosive Wear Performance of Single Layer CrN Coatings on AISI 304 S...IJAEMSJORNAL
The purpose of present study was to investigate the erosive corrosive wear behavior of single layer (CrN) coatings on AISI 304 Stainless Steel samples with varying coating thickness (0-200 nm) in the range of 50 nm. The slurry jet erosive test was conducted on Slurry Jet Erosion Tester in saline slurry (3.5wt% salt) under the different working conditions with varying impact velocity (10-25 m/s), impingement angle (30°-75°) and erodent discharge (160-280 gm/min). Steady state analysis was applied to find optimum parameters for the minimization of erosion rate of various coated and uncoated samples. The finding of steady state condition tests indicated that the erosion rate increased with the increase in impact velocity and erodent discharge but decreased with the increase in coating thickness. The results also indicated that erodent discharge was the most significant factor, followed by impingement angle and impact velocity for the CrN coated samples. The SEM characterization of the eroded samples was carried out in order to analyze the topography of the eroded surface to investigate the wear mechanisms induced by slurry jet erosion test.
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity
The ladle nozzle filling compound is critical to the production of “clean” steel. Failure of a “free” opening severely compromises the cleanliness of liquid steel. Chemical, X-ray diffraction, and thermal analyses of the nozzle filling compounds in commercial use were carried out to identify the nature of phases present and to establish the influence on the “free' opening of the ladle in each case. The samples showed evidence of partial fusion as well as volume expansion due to phase change when heated under conditions simulating the nozzle well of a filled ladle. The wetting behavior of ceramic powders is also being investigated by a physically simulating a model of ladle nozzle mold. Investigation of the adhering nature of ceramic powder & penetration depth of liquid steel is also done by the use of killed & un-killed liquid steel condition.
Combination of urea-Sn+2 in SCP solution was examined as a corrosion inhibitor for concrete reinforced steel by potentiodynamicpolarization, surface synergist parameter and cyclic voltammetry methods comparing with urea–Zn+2 combination. A synergism parameter (SI) indicated a synergistic effect between urea and Sn+2was exist. Polarization study revealed that formulation consisting of 300 ppm urea+50 ppm Sn+2 in SCP solution provided inhibition efficiency (IF) of 85.93% while 300 ppm urea +50 ppm Zn+2 provided 82.3% IF, and this combination acts as anodic type inhibitor. Cyclic voltammetry curves showed that the steel samples immersed in this formulation has low tendency to pitting corrosion. From these results it can be concluded that urea – Sn+2 inhibitor formulation is a good corrosion n inhibitor for concrete reinforced steel, it can maintain stable passive film on steel surface even in the presence of aggressive chloride ions so it can be used instead of the high toxicityZn+2 inhibitor to improve the corrosion inhibition of urea fertilizer inhibitor.
Experimental and Analytical Investigation on Strength Properties of Concrete ...HARISH B A
The experiment work carried out by micro silica as a supplementary material for cement and evaluate
cement for M20 grade of concrete. We are adding 0%, 5%, 10%, 15%, and 20% by weight of cement in concrete. The
material chosen for structural up gradation should not pollute the environment. They should be accessible to the
ordinary people and low monetary cost. Coconut fibre is abundant, versatile, renewable, cheap and more resistant
thermal conductivity. Coconut fibres have the highest toughness amongst natural fibre. They have potential to be used
as reinforcement in low cost concrete structures, especially in tropical earth quake region. The aim of investigation is
study the possibilities to use coconut fibre in addition to other constituents of concrete and strength properties. The
influence of 1%, 2% and 3% fibre content by mass of cement and aspect ratio 125, fibre cut length 2.80cm is
investigated. To evaluate the effect of coconut fibres improving the properties of concrete.At 1% addition of coconut
fibre, 5% silica fume with water cement ratio 0.53. compressive strength test and split tensile strength gives best result
in concrete.
TRADITIONAL ingots vs. REMELTED, Comparing Metallurgical ResultsASO Group
As everyone know, remelted ingots are, from a purely metallurgical point of view, preferable to the traditional bottom poured ingots because of a series of reason:
chemical homogeneity
micro inclusions content
ultrasonic results test
absence of segregation
fine and uniform structure.
For a better understanding, we compared characteristics of a remelted ingot around 40tons, with a poly ingot with a similar traversal section of 1500mm and a gross weight near 32tons.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
INVESTIGATION OF OXIDATION RESISTANCE OF NI- TI ELECTROCHEMICAL CODEPOSITION ...IAEME Publication
The effects of Ti particle loading in a plating bath on the morphology and hardness of Ni-Ti composite coatings via an electrochemical codeposition coating were investigated. The Ti-reinforced Ni-matrix composite coatings were codeposited on Austenitic Stainless Steel (316 L) substrates using a Ni-ion electrolytic solution stably suspended with -20 m max. diameter Ti particles and heat treated under vacuum atmosphere for six hours at 950 °C prior to oxidation testing.
Effect of Temperature on Wear Rate of Si-Epoxy- Eglass Polymer composite Mate...IDES Editor
With the increase use of polymer composites in
erosive work environment, it has become extremely important
to investigate their erosion characteristics. The hybrid
composite consisting of a Epoxy resin reinforced with Eglass
fiber and Si particles was developed. The effect of temperature
on wear rate applied to Si – Epoxy – Eglass polymer composite
has been studied. It has been found that the wear rate increases
as the temperature of carrier media (air) is increased.
Temperature of carrier media is one of the significant factor
influencing the erosion wear. The results were compared with
the plain epoxy composite material. Micrographs of eroded
surface are also presented to study the wear rate and Wear
behavior of composite.
Nano-structure TiO2 film coating on 316L stainless steel via sol-gel techniqu...Nanomedicine Journal (NMJ)
Objective(s):
Titanium oxides are known to be appropriate hemocompatible materials which are suggested as coatings for blood-contacting devices. Little is known about the influence of nanometric crystal structure, layer thickness, and semiconducting characteristics of TiO2
on blood hemostasis.
Materials and Methods:
Having used sol-gel dip coating method in this study, TiO2 thin films were deposited on nano-scale electro-polished stainless steel 316L with 1 to 5 nano-sized layers. Surface morphology and structure of the film were studied with X-ray diffraction and atomic force microscopy. Blood compatibility was also determined by measuring the platelet activation (CD62P expression), platelet adhesion (Scanning Electron Microscopy), and the blood clotting time on these samples.
Results:
The films were compact and smooth and existed mainly in the form of anatase. By increasing the number of TiO2 thin layer, clotting time greatly extended, and the population of activated platelet and P-selectine expression changed according to the surface characteristics of each layer.
Conclusion:
The findings revealed that stainless steel 316L coated with nano-structured TiO2 layer improved blood compatibility, in terms of both blood platelet activity and coagulation cascade, which can decrease the thrombogenicity of blood contacting devices which were made from stainless steel.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Pianist and composer Christopher “Chris” Roberts became president of Universal Music’s Classical and Jazz Music in 1988. Before joining Universal Music and later becoming CEO and president of Robisong Consulting, Christopher Roberts achieved a BA in music and German literature from Lewis and Clark University in Portland, Oregon, his hometown.
Gartner Data and Analytics Summit: Bringing Self-Service BI & SQL Analytics ...Cloudera, Inc.
For self-service BI and exploratory analytic workloads, the cloud can provide a number of key benefits, but the move to the cloud isn’t all-or-nothing. Gartner predicts nearly 80 percent of businesses will adopt a hybrid strategy. Learn how a modern analytic database can power your business-critical workloads across multi-cloud and hybrid environments, while maintaining data portability. We'll also discuss how to best leverage the increased agility cloud provides, while maintaining peak performance.
As a discipline, DevOps brings order to the complex world of application and service development, testing, deployment, scaling and monitoring. DevOps enables a unified approach to enterprise software development and delivery that reflects the needs of the entire application life cycle. DevOps strives for more collaborative, productive relationships between development and operations teams, with faster development cycles and reduced production risks.
How can you make DevOps work for you organisation?
For more insights, visit www.interquestgroup.com
Frabication of an eco-friendly corrosion inhibitor from Terminalia catappa le...IJAEMSJORNAL
Metal corrosion is one of the most challenging problems facing industries. Using corrosion inhibitors is one reasonable approach to protecting metal surfaces. Due to the toxicity of industrial corrosion inhibitors, researchers are continuously searching for green, economical, and friendly alternatives. The present study focuses on the application of Terminalia catappa leaf extract to mitigate the corrosion of concrete reinforcing steel in a simulated seawater environment. The dry product from the Terminalia catappa leaf extraction process was determined to have amino functional groups in polyphenols. Polarization results demonstrate that the corrosion current density decreases from 8.87 A/cm2 (for samples soaked in blank solution) to 5.12 µA/cm2 when adding the optimal concentration of 0.004% of Terminalia catappa leaf extract. 3.5% NaCl solution. Electrochemical impedance spectroscopy (EIS) analysis showed that the inhibition efficiency reached over 90% at this concentration after 24 hours of soaking.
Hot Erosion Experiment on the Blade Material of Dust Contained Gas TurbineIJRES Journal
Gas turbine is the main power plant use dusty gas of high temperature and high pressure produced during the industrial processes. At the same time can effectively bring down nitrogen oxide emissions. High temperature dust gas will erode the surface of turbine blade, not only aerodynamics characteristics of the destruction (cause of affection to the blade profile) but also jeopardizes the strength of the safety blade. Therefore, erosion tests carried out on the blade material at a variety of temperature and angle of attack are very necessary to provide the basis for optimizing blade material. In simulate real conditions reveal the resistance to erosion of different materials. In this paper, erosion tests carried out on three different blade materials(1Cr12Mo、X20Cr13、2Cr12NiMo1W1V)at different angle of attack. Test temperature is 200℃ and 300℃. Experimental results showed that: Accumulate mass loss of materials studied all linearly vary according to the particle quality; 15 ° ~ 25 °, the erosion rate is the highest; 90 °angle of attack shows the lowest erosion rate; The erosion rate of material 2Cr12NiMo1W1V is higher than the other two materials at 200 ℃ and 300 ℃, poor resistance to erosion.
In the material testing laboratory, a Charpy impact test was performed on three different types (hot,cold,and steel alloy)of steels testing each variety at four different temperatures (32°C(RT), 100°C,0°C and -22°C ). From results (shown below), we determined that the a transition is from ductile failures to brittle failures
Corrosion resistance performance of fly ash blended cement concreteseSAT Journals
Abstract Durability of reinforced concrete with respect to corrosion of reinforcement is one of the major aspects to be considered in the management of civil infrastructure systems. An accelerated laboratory test method developed at SERC where the concrete specimen containing rebar is subjected to polarization under a constant voltage in a sodium chloride solution. It is found that the current response with time follows that of a typical service life model indicating depassivation and corrosion propagation. Index terms- Materials, cement, super plasticizer, workability, compressive strength etc.
Corrosion resistance performance of fly ash blended cement concreteseSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
The behavior of hybrid reinforced concrete after heat resistanceIJERA Editor
This study is trying to provide the behavior of concrete when additional fibers are added under the effect of
evaluated temperatures. Three types of polypropylene fibers are used with different length respectively 3 mm, 6
mm and 12 mm and two types of steel fibers are used of length respectively of 3cm and 5 cm. Hybrid specimens
of concrete are prepared by using two different combinations: 0.5% steel fibers in combination with 0.2%
polypropylene fibers by the volume of concrete; and 0.25% of steel fibers in combination with 0.1%
polypropylene fibers by the volume of concrete. The specimens were subject to different temperatures. An
electric furnace was used to heat the specimens up to 200 0C, 400 0C and 600 0C. The mass loss and compressive
strength were determined by using twelve different mixtures.
1-1 Influence of Multi Extrusion Die Process on Mechanical and Chemical Behav...Ahmed Ibrahim Razooqi
INFLUENCE OF MULTI EXTRUSION DIE PROCESS ON MECHANICAL
AND CHEMICAL BEHAVIOR OF 2024-T3 ALLOY.
Ahmed Ibrahim RAZOOQI
Technical Engineering College - Baghdad, Middle Technical University, Baghdad, IRAQ
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
My Master thesis its about how to make a filter for industrial application ( water , waste water, metals and exhaust) by polymeric sponge method A.K.A replica method ., any question u can comment below.
Online aptitude test management system project report.pdfKamal Acharya
The purpose of on-line aptitude test system is to take online test in an efficient manner and no time wasting for checking the paper. The main objective of on-line aptitude test system is to efficiently evaluate the candidate thoroughly through a fully automated system that not only saves lot of time but also gives fast results. For students they give papers according to their convenience and time and there is no need of using extra thing like paper, pen etc. This can be used in educational institutions as well as in corporate world. Can be used anywhere any time as it is a web based application (user Location doesn’t matter). No restriction that examiner has to be present when the candidate takes the test.
Every time when lecturers/professors need to conduct examinations they have to sit down think about the questions and then create a whole new set of questions for each and every exam. In some cases the professor may want to give an open book online exam that is the student can take the exam any time anywhere, but the student might have to answer the questions in a limited time period. The professor may want to change the sequence of questions for every student. The problem that a student has is whenever a date for the exam is declared the student has to take it and there is no way he can take it at some other time. This project will create an interface for the examiner to create and store questions in a repository. It will also create an interface for the student to take examinations at his convenience and the questions and/or exams may be timed. Thereby creating an application which can be used by examiners and examinee’s simultaneously.
Examination System is very useful for Teachers/Professors. As in the teaching profession, you are responsible for writing question papers. In the conventional method, you write the question paper on paper, keep question papers separate from answers and all this information you have to keep in a locker to avoid unauthorized access. Using the Examination System you can create a question paper and everything will be written to a single exam file in encrypted format. You can set the General and Administrator password to avoid unauthorized access to your question paper. Every time you start the examination, the program shuffles all the questions and selects them randomly from the database, which reduces the chances of memorizing the questions.
A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
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Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
2. Kufa Journal of Engineering, Vol.3, No.2, 2012
102
1. Introduction:
The main advantage of manufacturing cellular or autoclaved aerated concrete ( called
Thermostone blocks in Iraq) is to get high thermal insulating material with suitable density and
compressive strength to be used as a lightweight units in masonry works. Unlike many other
concrete products, Thermostone blocks could be drilled, sawed, nailed, or screwed easily by using
conventional carpentry tools .On other hand, cellular concrete blocks may undergoes several
problems during and after manufacturing ,these problems cost both time and money. The cost of
failure for manufacturing companies includes the cost of raw materials, the cost of manufacturing
(fuel, machines , workers cost …..etc.) and the time lost in producing failed blocks.
The main purpose of this work is to determine the main types and causes of failure occurred in
cellular concrete blocks (Thermostone) during and after production process. Physical and
mechanical tests as well as X-ray diffraction technique were conducted to investigate the main
causes of failures and to suggest solutions.
The common raw materials used to manufacturing Thermostone blocks are Portland cement,
hydrated lime (calcium oxide), aluminum fine powder, water, and sand. The raw materials are
mixed into a slurry by a special machine and then poured into greased molds (600 x 120 x 60 cm).
Aluminum reacts with the hydrated lime and free water to evolve millions of tiny hydrogen gas
bubbles(1)
. These macroscopic, unconnected cells cause the material to expand to nearly twice its
original volume with a cellular structure. It takes from 30 minutes to 4 hours for the mixture to
harden enough to be cut by wires into the desired shapes and transported to an autoclave (180o
C
and 10 atmosphere pressure) for curing period of 10 hours.
The present work investigated the main problems occurred in the factory of Najaf Company for
Insulating Materials Industry as a case study. These problems could be classified as follows:
1-The cake failure due to no pores formation after mixing the raw materials.
2-The cake failure due to hydrogen bubble escaping after formation .
3- The product failure due to excessive volume expansion during hydrogen bubble
formation when the product is still green and not hardened or dried .
4- Brittleness due to residual moisture in the cake after drying .
5-The failure of blocks after 10 hours curing in the Autoclave due to excessive expansion or
low compressive strength .
Abdulameer and Muhammed (2)
used experimental-theoretical method to determine the mechanism of
fracture, depending on taking two images. The first one was a stereo microscope with suitable
3. Kufa Journal of Engineering, Vol.3, No.2, 2012
103
magnification, so that all different phases can be seen as possible ,the second one was a video image to
show pores and cracks. A numerical solution (finite element method) was applied on the images. They
found that the existence of pores in Thermostone structure is the source of micro and macrocracks
which in turn reduce the resistance to fracture under loads, or causing damage to the product during
manufacturing processes .
Abdulameer et. al. (3)
investigated the effect of pores characteristics (type of pores - closed and open
- and fineness of the added aluminum powder) on each of thermal conductivity and compressive
strength of cellular concrete blocks (Thermostone).They applied a numerical technique (Finite
Element) to estimate the internal stresses and to get a theoretical cracks pattern. The results showed that
open pores blocks exhibits higher thermal insulation but lower compressive strength than closed pores
blocks. Finer aluminum powder resulted in higher thermal insulation and lower compressive strength
for the two types of pores. 70% of the theoretical crack pattern seemed to be coincide with the actual
crack pattern.
Dariusz, J. (4)
used numerical and experimental methods to measure thermal properties, especially
thermal conductivity of cellular concrete, he found that the most important factor is the initial moisture
content of the test specimens.
Meille,S. et. al. (5)
used a general purpose elastic finite element technique designed for use on
images of random porous composite materials to study the linear elastic and thermal properties of
cellular concrete models. They showed that young's modules, Poisson's ratio and thermal conductivity
depend on each of porosity and properties of individual solid phases.
Justness, H. et. al. (6)
studied pores in concrete and their effect on compressive strength, they
also added accelerator materials through the process of production to increase compressive
strength and to reduce cracking.
2. Materials and Methods:
2.1. Materials:
The proportions of raw materials usually used to manufacture the Thermostone cake are shown
in Table-1.
4. Kufa Journal of Engineering, Vol.3, No.2, 2012
104
Table - 1: proportions of raw materials
The chemical analysis of the above raw materials is shown in table - 2.
Table- 2 : Chemical analysis of raw materials.
2.2.Methods:
In an attempt to solve the problems mentioned previously, Thermostone blocks ( 20 X 20 X 60
cm) with different ratios of additives were made and tested. Each result represents the average of
three tests and the following tests were conducted during the present work:
2.2.1. Compressive strength test: (According to ASTM C 1386)
2.2.2.Dry bulk density test: (According to ASTM C 1386)
2.2.3. Apparent porosity test: ( According to ASTM C-830 )
Component Proportion ( % by wt.)
Sand 25.3%
Lime (Calcium Oxide) 7%
Ordinary
Portland Cement 25.2%
Aluminum
(Powder)
0.04%
Water 40.38
Clay (as impurities) Less than 2%
Chemical analysis (% by
weight)
Portland
Cement
Lime Sand
Loss on Ignition % 0.69 0.78 2.54
CaO 61.52 90.12 3.42
Al2O3 6.02 2.04 3.74
SiO2 20.51 4.09 84.47
MgO 4.66 1.92 1.14
Fe2O3 3.34 0.45 0.92
SO3 2.74 0.65 2.95
5. Kufa Journal of Engineering, Vol.3, No.2, 2012
105
2.2.4.Thermal conductivity test: ( According to ASTM C518 )
2.2.5. Capillary absorption test: According to Iraqi specification for cellular concrete blocks
(Thermostone) No.1441/2000) ,samples were put vertically in a water bath for 24 hours and the
level of water ascendance was measured.
2.2.6. Measuring the reaction temperature:
In order to investigate the problem of no pores formation or weak reaction between lime and
Aluminum powder a special device (Fig.1) was used to measure the reaction temperature after
adding Aluminum. It mainly consists of a mixing motor and a thermometer. Aluminum powder is
added after mixing with small amounts of sand to prevent the powder from floating on the surface
of the mixer, the mixing continues up to 2 minutes, and the whole test time ends within 3 hours .
Fig. 1: Measuring the temperature of reaction of lime and aluminum.
2.2.7. X-Ray diffraction technique:
X-ray (powder) diffraction technique and chemical analysis were carried out on raw materials
and Thermostone blocks after autoclaving to determine the phases formed during curing. Analysis
of the samples (powder method) was carried out by XRD with diffractometer DRON-7(the wave
length of radiation λ=17902 nm).
6. Kufa Journal of Engineering, Vol.3, No.2, 2012
106
3.Results and Discussion:
The aim of the present work is to solve some of the problems associated with the production of
Thermostone blocks so the results will be reported according to the problems stated in the
introduction:
Problem No. 1: No pores formation:
The pores formation in cellular concrete is the result of complete chemical reaction between lime
( CaO ) , water ,and aluminum powder due to the liberation of very large number of hydrogen
bubbles according to the following equations.
CaO + H2 O Ca(OH)2
Al + Ca(OH)2 Al CaO2 + H2 gas
The associated temperature is an indication of completion of this reaction. Fig.2 is plotted to
show the required ratio of aluminum powder to get complete reaction ( to get 40-60% porosity )
according to the reaction temperature.
35
40
45
50
55
60
0.04 0.045 0.05 0.055 0.06 0.065 0.07 0.075 0.08 0.085
Al %required to complete reaction
ReactionTemperatureC
Fig.2 : Relationship between temperature and the added ratio of Al-Powder required to get
complete reaction.
During these tests ,it was found that the complete reaction (Hydrogen bubbles formation)
between the lime (CaO) , water ,and Al-powder always occurs when the minimum reaction
7. Kufa Journal of Engineering, Vol.3, No.2, 2012
107
temperature is 43 o
C or more, No observed reaction took place when the hydration temperature was
less than 40 o
C.
It can be seen from this figure that more Aluminum powder is needed to get the required
temperature. For example, 0.075% Al powder was needed to get complete reaction when the
temperature was 40o
C while 0.04% was needed when the temperature was 55o
C.However,
Narayanan (7)
suggested addition of an alkali component like NaOH to get complete reaction when
the temperature is within the critical limit.
Problem No. 2: The cake failure due to hydrogen bubble escaping.
Hydrogen bubble escaping indeed is a result of large bubble size which affect thermal and
mechanical properties. Table- 3 shows the results of thermal and mechanical tests for samples made
with different diameters of Aluminum powder for the same ratio of powder (0.04%).
Table- 3: The effect of Aluminum powder diameter on thermal and mechanical properties
Sample
No.
Aluminum
powder
diameter
(µm)
Density(ρ)
kg/m3
Porosity
ratio%
Thermal
Conductivity
(W/m.° C)
Compressive
Strength (MPa)
1 Without
Aluminum
powder
1250 <6 2.81 5.5
2 200 709 43.28 0.74 2
3 150 652 47.84 0.21 2.1
4 100 601 51.92 0.14 2.5
5 75 540 56.80 0.09 2.7
6 50 538 56.96 0.09 2.9
7 25 512 60 0.09 2.5
Table-3 shows that the density of the product decreases as the radius of the added Al-powder
decreases for the same percentage of aluminum. Large diameters of Al-powder generates larger
bubbles of hydrogen gas, and some of these bubbles can escape out of the mix and this make the
mix more dense . Also it is shown that thermal conductivity (k) decreases with increasing porosity
(i.e. the lower the density the lower the thermal conductivity and the higher is the thermal
insulation).
It can be seen also that compressive strength increases with lower diameter of aluminum powder
and this may be attributed to better distribution of bubbles within the Thermostone block.
8. Kufa Journal of Engineering, Vol.3, No.2, 2012
108
Table-3 shows that the suitable diameter of Aluminum powder is in the range [50-100 µm] to
get both perfect thermal and mechanical properties which are consistent with ASTM C-1386 ,
ASTM C518 and Iraqi standard specifications No. 1441/2000.
The capillary absorption test results for the seven samples are shown in Fig.3
0
1
2
3
4
5
6
7
8
0.5 2 6 15 24
Time (hours)
DepthofWaterAbsorbtion(cm)
Sample1
Sample2
Sample3
Sample4
Sample5
Fig. 3 :The capillary absorption test results for Thermostone samples.
It can be seen from this figure that the difference in water absorption between sample No.1 and
the other samples were in the range (1.5-2.5 cm) which is not significant. Macropores, which are
spherical and large in size, are almost closed and not connected so they possess negligible capillary
suction. Accordingly, capillary suction takes place only through the micropores. Hence the rate of
water penetration through Thermostone is very low. Iraqi standard specification No. 1441/2000
state that the capillary rise for all types of Thermostone should not exceed 12.5 cm. and according
to ASTM C1386 is not exceed 7 cm
X – Ray diffraction results:
X-ray diffraction technique was used to show the final chemical phases of raw materials as well
as green and autoclaved samples. Table- 4 and Table- 5 summarizes the results of XRD for raw
materials and green and autoclaved samples respectively.
9. Kufa Journal of Engineering, Vol.3, No.2, 2012
109
Table -4 :The X-Ray diffraction results of raw materials.
Cement lime Sand
60.13% CaO 90% CaO 85% SiO2
21.38 % SiO2
6.85% Al2O3
3.71% Fe2O3
Table- 5 : X-Ray diffraction results of autoclaved and green samples.
14hr
Autoclaving
10hr
Autoclaving
Problem5
Autoclaved
Samples (volume
expansion)
Problem4
Green
Samples
(moisture
spot)
Problem 3
Green samples
(volume
expansion)
84%Tobermorite75 %
Tobermorite
59.4%Tobermorite31.3%Ca(OH)234.12
%Ca(OH)2
11% Xonotlite11% free
SiO2
13.7% free SiO234.43%
free SiO2
37.43%
free SiO2
2% free SiO28% Ca(OH)29.47% Ca(OH)221.4 %
Ettringite
15.7%Ettringite
2% Hydroxyle
ellestadite
4%
Hydroxyle
ellestadite
4.15% Hydroxyle
ellestadite
9%
Monosulphate
3%
Monosulphate
%3.45 Thaumasite
%2.1Magnesium
silicate hydrates
%2.63 Magnesium
sulfate (MgSo4)
2.48% Brucite
The mechanism of formation of the above components can be summarized as follows: :Ettringite :
(CaO)6(Al2O3)(SO3)3 · 32 H2O : A medium temporary component that formed in the drying stage in
the presence of calcium sulfate.
3CaO.Al2O3+3(CaSO4.2H2O) + 26H2O (CaO)6(Al2O3)(SO3)3 · 32 H2O
Monosulphate : Ca4Al2O6(SO4).14H2O: A brittle detrimental component formed in the presence
of high amount of C3A and high Sulfate ,high ratio of Monosulfate causes moisture to remain in the
cake as combined water after drying process.
3CaO.Al2O3+ CaO+SO3 + 14H2O Ca4Al2O6(SO4).14H2O
Tobermorite Ca5Si6O16 (OH)2. 4H2O: A component with high mechanical and physical properties.
10. Kufa Journal of Engineering, Vol.3, No.2, 2012
110
5CaO + 6SiO2 + 5 H2O Ca5Si6O16 (OH)2. 4H2O
Hydroxyl- ellestadite: Ca10Si3O16.3SO3.H2O
10CaO + 3SiO2 + 3SO3 + H2O Ca10Si3O16.3SO3.H2O
Thaumasite CaSiO3.CaCO3.CaSO4.15H2O which is a brittle component.
2CaO + SiO2 + SO3 + CaCO3 +15 H2O CaSiO3.CaCO3.CaSO4.15H2O
Thermostone is severely affected by Thaumasite formation and can easily be broken by hand
fingers.
Magnesium silicate hydrates MgSiO3. 2H2O : A component causes volume expansion after
autoclaving.
MgO + SiO2+ H2O MgSiO3. H2O
Magnesium Sulfate MgSO4: A brittle component causes volume expansion
MgO + SO3 MgSO4
Brucite :Mg(OH)2 : A white component causes volume expansion
MgO + H2O Mg(OH)2
Xonotlite Ca6Si6O18.H2O: A high quality component formed when the time of autoclaving
increased from 10 to 14 hours ,this component increases the compressive strength of Thermostone
to more than 3 MPa .
6CaO + 6SiO2 + H2O Ca6Si6O18.H2O
Problem No. 3: excessive expansion of green product
Table-5 shows that the formation of Ettringite and Monosulfate which resulted in volume
expansion of the green ( non autoclaved )product.
Problem No. 4: Moisture spots on the green product
Table - 5 shows that the formation of higher ratios of Ettringite and Monosulfate which resulted
in moisture spots on the faces of the blocks because these two phases containing high combined
water (32 H2O in Ettringite and 14 H2O in Monosulfate).
So it can be concluded that the main reason of both problems 3 and 4 is the formation of these
two detrimental compounds (Ettringite and Monosulfate) which may be attributed to the presence of
high ratio of C3A and SO3 in raw materials.C3A as in table - 4 is a main ordinary Portland cement
compound and it is difficult to eliminate this compound during cement manufacturing. So in order
to solve these two problems ( 3 and 4 ) it is strongly recommended to eliminate SO3 in raw
materials other than cement.
Problem No. 5: Excessive expansion and low compressive strength of autoclaved product
Table - 5 shows a formation of relatively high ratio of Tobermorite phase (59.4%) after
autoclaving which leads to high mechanical and physical properties of the product. On the other
11. Kufa Journal of Engineering, Vol.3, No.2, 2012
111
hand, and because there was no control on raw materials ,the results shows a formation of
detrimental phases like Thaumasite ( brittle material), Magnesium silicate hydrate, Magnesium
sulfate, and Brucite (responsible of volume expansion). So , it is again strongly recommended to
control raw materials to avoid presence of detrimental materials.
The results of XRD of 10 hours autoclaved samples ( manufactured with high control on raw
materials) shows higher ratio of Tobermorite which leads to high compressive strength of the
product. No detrimental phases were noted . However, the resulting compressive strength,
sometimes , was lower than the specification requirements and the resulting blocks were considered
as losses materials.
Increasing curing or autoclaving time from 10 to 14 hours improved properties of the resulting
product. XRD results showed higher ratio of Tobermorite and a precence of new phase called
Xonolite which increases the compressive strength to more than 3 MPa. So, when compressive
strength more than 3 MPa is needed it is recommended to increase autoclaving time from 10 to 14
hours.
In an attempt to increase compressive strength of the product , different ratios of limestone
aggregate (4 mm maximum size ) was added to the raw materials. Table -6 shows densities and
compressive strength of Thermostone block samples containing limestone.
Table-6: Effect of added limestone on compressive strength of blocks.
Density
3
kg/mρ Added limestone
ratio (% by wt.)
Compressive Strength (MPa)
540 1% 2.8
543 2% 2.85
557 3% 3.04
563 4% 3.17
568 5% 3.19
According to the above results, adding limestone to the mix of Thermostone improved
compressive strength and reduces cracking. Iraqi specification for Cellular Concrete Block
(Thermostone) requires a compressive strength not less than 2 MPa (Iraqi standard specifications
No.1441/2000),whereas ASTM C 1386 requires a compressive strength not less than 3 MPa. So it
may not be necessary to add more than 5% limestone.
Limestone particles work as a crack arrestor to stop macrocracks and preventing them from
growing together into larger cracks which may cause failure of the product. Carlos(8)
reported that
12. Kufa Journal of Engineering, Vol.3, No.2, 2012
112
addition of limestone has been found to reduce expansion as well as increasing compressive
strength.Fig.4 shows free limestone particles in the structure of Thermostone block.
Fig.4 :Presence of limestone particles in the structure of Thermostone.
3.Conclusions:
Within the limitations of the present work and according to the results shown , the following
conclusions could be reported to eliminate types and causes of failures in cellular concrete blocks
(Thermostone ) :
1- the main types of failure noted in the present study were:
a-The cake failure due to no pores formation.
b-The cake failure due to hydrogen bubble escaping.
c- The product failure due to excessive volume expansion during hydrogen bubble
formation.
d- Brittleness due to residual moisture in the cake after drying.
e-The failure of blocks after 10 hours curing in the Autoclave .
2- The complete reaction (Hydrogen bubbles formation) between lime (CaO) , water ,and Al-
powder always occurs when the minimum reaction temperature is 43 o
C, No observed reaction took
place when the hydration temperature was less than 40 o
C . In low reaction temperatures additional
amounts of Al powder should be added. Uncompleted reaction resulted in failure of no pores
formation.
3- Formation of large bubble size resulted in failure of Hydrogen bubble escaping which affect
thermal and mechanical properties. Compressive strength increases with lower diameter of
Free Particles
of limestone
13. Kufa Journal of Engineering, Vol.3, No.2, 2012
113
aluminum powder for the same Al powder content. The suitable diameter of Aluminum powder
was in the range of [50-100 µm] to get both perfect thermal and mechanical properties as well as
capillary absorption which are consistent with ASTM and Iraqi specifications.
4- XRD (X-Ray diffraction) results showed that the formation of Ettringite and Monosulfate
resulted in volume expansion failure of green ( non autoclaved )product. Higher content of
Ettringite and Monosulfate resulted in moisture spots failure of green product.
5- Excessive expansion failure after autoclaving was noted as a result of no control on raw materials
and presence of detrimental Magnesium compounds and the brittle phase of Thaumasite after 10
hours of curing.
6- In spite of controlling raw materials ,compressive strength of 10 hours curing period may be less
than the requirements of specifications in some cases of failure .Increasing curing time from 10 to
14 hours resulted in more than 3 MPa compressive strength which fulfill the specifications
requirements.
7- Increasing compressive strength and reducing cracking could be achieved by adding up to 5% by
weight limestone aggregate.
Acknowledgments:
The researcher would like to thank the Ministry of Higher Education and Scientific Research/
Directorate of research and development for providing research fund for this study . Thanks are also
directed to the administration of Najaf Company for Insulating Materials Industry for continuous
assistance and cooperation during the period of the work.
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