This paper presents a review of the properties of fresh concrete including workability, heat
of hydration, setting time, bleeding, and reactivity by using mineral admixtures fly ash (FA), silica
fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA).
Comparison of normal and high strength concrete in which cement has been partially supplemented
by mineral admixture has been considered. It has been concluded that mineral admixtures may be
categorized into two groups: chemically active mineral admixtures and microfiller mineral
admixtures. Chemically active mineral admixtures decrease workability and setting time of concrete
but increase the heat of hydration and reactivity. On the other hand, micro filler mineral admixtures
increase workability and setting time of concrete but decrease the heat of hydration and reactivity. In
general, small particle size and higher specific surface area of mineral admixture are favourable to
produce highly dense and impermeable concrete; however, they cause low workability and demand
more water which may be offset by adding effective super plasticizer.
Investigation on Flexural Strength of High Strength Silica Fume ConcreteIRJET Journal
This document investigates the flexural strength of high-strength concrete with different replacement levels of cement with silica fume. Standard prisms were tested to analyze the flexural strength at 7 and 28 days. The results showed that the flexural strength reached a maximum value at 12% cement replacement with silica fume for M40 grade concrete. Workability tests of the mixes found that slump and compaction factor decreased as the amount of silica fume increased, with the lowest values at 15% replacement level. In conclusion, adding silica fume as a partial cement replacement was found to improve the flexural strength properties of high-strength concrete.
The basic components of cement mortar are cement, water and aggregates. But, often, other substances are added to these three in preparing the cement mortar. The purpose of these additional substances is to improve the quality of the mortar. These substances are collectively called admixtures. Admixtures can be broadly classified into two types – chemical admixtures and mineral admixtures.
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.
IPANEX is a liquid admixture added to concrete to make it waterproof by densifying its microstructure. It works by controlling hydration to produce a more homogeneous, fine-grained structure with smaller, more tortuous pores that restrict water penetration. Testing shows IPANEX concrete has significantly reduced permeability and chloride ion ingress. It provides advantages like increased strength, durability, corrosion resistance and waterproofness without organic chemicals that could degrade over time. IPANEX is recommended for applications requiring impermeable concrete under water pressure like foundations, tanks, and marine structures.
This document discusses ways to prevent coatings from peeling on pipelines. It reports on several pipeline coating failures in recent years caused by extreme operating environments and discrepancies between actual service conditions and coating design conditions. Recent case studies show disbonding of coal tar, FBE, and 3LPE coatings. Investigations aim to enhance adhesion between coatings and steel substrates. New coating materials and longer hot water immersion tests provide better adhesion. A silane-based chemical treatment is presented as an environmentally-friendly alternative to chromate treatments for improving coating-steel bonding and corrosion protection. Test results show the silane treatment provides similar adhesion benefits as chromate after hot water immersion.
11 1 wan-brief intro use of mineral admixture in concretedwwpak
This document presents information on the use of mineral admixtures in concrete. It discusses various mineral admixtures including fly ash, blast furnace slag, silica fume, and rice husk ash. Fly ash and blast furnace slag are byproducts that have pozzolanic or cementitious properties. When used as partial replacements for cement in concrete, mineral admixtures can improve workability, reduce heat of hydration, and increase long-term strength and durability. The document also notes that combining different mineral admixtures, such as fly ash and silica fume, can further optimize concrete properties.
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.
IRJET- Utilizing Porous Light Weight Aggregates for Self-Curing Concrete:...IRJET Journal
This document discusses utilizing porous lightweight aggregates for self-curing concrete. It begins with an abstract that outlines how internal curing can increase cement hydration and enhance concrete properties by incorporating materials like pre-wetted lightweight aggregates. The document then provides details on the mechanisms of internal curing, explaining that lightweight aggregates act as reservoirs that supply water throughout the curing process to reduce shrinkage cracking and improve strength. It also discusses practical considerations for implementing internal curing in ready-mix concrete plants and outlines equations for determining the appropriate amount of pre-wetted lightweight aggregates to include.
Investigation on Flexural Strength of High Strength Silica Fume ConcreteIRJET Journal
This document investigates the flexural strength of high-strength concrete with different replacement levels of cement with silica fume. Standard prisms were tested to analyze the flexural strength at 7 and 28 days. The results showed that the flexural strength reached a maximum value at 12% cement replacement with silica fume for M40 grade concrete. Workability tests of the mixes found that slump and compaction factor decreased as the amount of silica fume increased, with the lowest values at 15% replacement level. In conclusion, adding silica fume as a partial cement replacement was found to improve the flexural strength properties of high-strength concrete.
The basic components of cement mortar are cement, water and aggregates. But, often, other substances are added to these three in preparing the cement mortar. The purpose of these additional substances is to improve the quality of the mortar. These substances are collectively called admixtures. Admixtures can be broadly classified into two types – chemical admixtures and mineral admixtures.
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.
IPANEX is a liquid admixture added to concrete to make it waterproof by densifying its microstructure. It works by controlling hydration to produce a more homogeneous, fine-grained structure with smaller, more tortuous pores that restrict water penetration. Testing shows IPANEX concrete has significantly reduced permeability and chloride ion ingress. It provides advantages like increased strength, durability, corrosion resistance and waterproofness without organic chemicals that could degrade over time. IPANEX is recommended for applications requiring impermeable concrete under water pressure like foundations, tanks, and marine structures.
This document discusses ways to prevent coatings from peeling on pipelines. It reports on several pipeline coating failures in recent years caused by extreme operating environments and discrepancies between actual service conditions and coating design conditions. Recent case studies show disbonding of coal tar, FBE, and 3LPE coatings. Investigations aim to enhance adhesion between coatings and steel substrates. New coating materials and longer hot water immersion tests provide better adhesion. A silane-based chemical treatment is presented as an environmentally-friendly alternative to chromate treatments for improving coating-steel bonding and corrosion protection. Test results show the silane treatment provides similar adhesion benefits as chromate after hot water immersion.
11 1 wan-brief intro use of mineral admixture in concretedwwpak
This document presents information on the use of mineral admixtures in concrete. It discusses various mineral admixtures including fly ash, blast furnace slag, silica fume, and rice husk ash. Fly ash and blast furnace slag are byproducts that have pozzolanic or cementitious properties. When used as partial replacements for cement in concrete, mineral admixtures can improve workability, reduce heat of hydration, and increase long-term strength and durability. The document also notes that combining different mineral admixtures, such as fly ash and silica fume, can further optimize concrete properties.
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.
IRJET- Utilizing Porous Light Weight Aggregates for Self-Curing Concrete:...IRJET Journal
This document discusses utilizing porous lightweight aggregates for self-curing concrete. It begins with an abstract that outlines how internal curing can increase cement hydration and enhance concrete properties by incorporating materials like pre-wetted lightweight aggregates. The document then provides details on the mechanisms of internal curing, explaining that lightweight aggregates act as reservoirs that supply water throughout the curing process to reduce shrinkage cracking and improve strength. It also discusses practical considerations for implementing internal curing in ready-mix concrete plants and outlines equations for determining the appropriate amount of pre-wetted lightweight aggregates to include.
Chemical admixtures are added to concrete mixes to modify properties like workability, setting time, strength, and durability. There are five main types of admixtures: retarders which slow setting; accelerators which speed setting; superplasticizers which increase workability; water reducers which decrease water needs; and air-entrainers which introduce tiny air bubbles that improve freeze-thaw resistance. Producers use admixtures to reduce costs, modify hardened concrete properties, and ensure quality during mixing and placement.
This document discusses self-curing concrete, which aims to provide internal moisture to allow for continued hydration of cement without external curing methods. It outlines that self-curing concrete uses saturated lightweight aggregate or polyethylene glycol to reduce moisture loss from the concrete surface. An experimental program tested the compressive strength, splitting tensile strength, and modulus of rupture of concrete mixes with varying dosages of polyethylene glycol added. The optimum dosages were found to be 1% for a M20 mix and 0.5% for a M40 mix, and self-curing concrete achieved strengths comparable to conventionally cured concrete.
Environmental factors affecting durability of concreteArun Sharma
This document discusses the durability of concrete and factors that affect it. It defines durability as a structure's ability to maintain performance over time when exposed to degradation. The main factors that influence concrete durability are the mix design, materials used, and the aggressiveness of the surrounding environment. The three major durability problems discussed are freezing and thawing, alkali-silica reaction, and sulfate attack. The document also provides recommendations from literature and code IS 456:2000 to improve concrete durability.
This document discusses self-curing or internal curing concrete, which provides internal water reservoirs through the use of materials like lightweight aggregates or super absorbent polymers to hydrate cement particles. Proper curing is important for concrete to develop strength and durability. Self-curing concrete reduces the need for external curing and can perform better in areas without sufficient water for curing. The document examines using polyvinyl alcohol as a self-curing agent and finds that it helps retain water in concrete and reduces weight loss compared to conventional mixes without compromising strength. Self-curing concrete offers advantages like reduced cracking, permeability and improved durability.
This document presents a seminar report on the strength behavior of self-curing fly ash concrete using steel fibres. The report was submitted in partial fulfillment of a Master of Technology degree in civil engineering. It provides background on the need for self-curing concrete and potential materials that can enable self-curing such as super absorbent polymers and lightweight aggregates. The report also reviews literature on internal curing methods. It describes the materials and mix proportions used to produce self-curing fly ash concrete. Methods for preparing test specimens and determining workability and strength are also outlined.
IRJET- Design of 300 Years Durable Concrete for Nuclear Confinement Zone ...IRJET Journal
This document discusses the design of a 300-year durable self-compacting concrete for use in nuclear confinement zones and tunnel formworks. The concrete mixture uses materials like cement, silica fume, Alccofine 1203, coarse aggregate, fine aggregate, and an admixture to achieve high durability and self-compaction properties. Silica fume and Alccofine help reduce carbonation and permeability through pozzolanic reactions and fine particle sizes. A water-binder ratio of 0.28 provides sufficient workability while ensuring complete hydration. This concrete is predicted to last 300 years based on durability modeling software.
Experimental Study on Self- Curing ConcreteIRJET Journal
This document presents the results of an experimental study on self-curing concrete. The study investigated the effects of adding shrinkage reducing admixtures like super absorbent polymer and polyvinyl alcohol on the mechanical properties of concrete. Testing was conducted on M30 grade concrete with partial replacement of cement with pond ash ranging from 0-30%. Tests measured the compressive strength, split tensile strength, and flexural strength of specimens at 7, 14, and 28 days. The results showed that compressive strength, tensile strength, and flexural strength increased with the addition of super absorbent polymer up to 0.5% and polyvinyl alcohol up to 0.5% compared to conventional concrete without admixtures.
Durability and permeability of concrete are essential for its ability to withstand weathering and chemical attacks over time. The durability of concrete depends on factors like water-cement ratio, cement and aggregate properties, use of admixtures, age of concrete, and exposure conditions. A more permeable concrete is more porous and allows more water penetration. Permeability decreases with lower water-cement ratio, finer cement, use of waterproofing admixtures, and increased age. Cracks in concrete can form due to temperature changes, drying shrinkage, chemical reactions, weathering, and poor construction practices. Reinforcement corrosion occurs via electrochemical processes and can be limited by restricting chlorides, ensuring proper concrete cover, and
This document summarizes a study that investigated the effect of water-to-cement ratio on sulfate corrosion of fine-grained concrete. Concrete samples with water-to-cement ratios of 0.4, 0.45, and 0.5 were exposed to 0.5% sulfuric acid or a solution simulating wastewater for periods of 1, 3, and 6 months. The pH and sulfate content of layers cut from the samples were measured. After 1 month of exposure, a small decrease in pH was observed only in surface layers, and sulfate penetration was limited to 5 mm. Longer exposure times showed slightly deeper sulfate penetration but did not significantly reduce pH or compromise reinforcement protection. Higher water-to-
This document provides a review of the present status of polymer modified mortar and concrete. It discusses how the addition of polymers can improve the water resistance of cement mortar and concrete by reducing water absorption. It describes the various types of polymer modifiers used, including polymer latexes, redispersible polymer powders, water-soluble polymers, and liquid polymers. The principles of polymer modification are explained for each type, involving cement hydration, polymer film formation, and interactions between polymer and cement particles. Common damages caused by water absorption in concrete structures are also reviewed.
ADMIXTURE ,The major reasons for using
admixtures, Air-Entraining Admixtures, Water-Reducing Admixtures ,Superplasticizers (High-Range Water
Reducers), Retarding Admixtures, Accelerating Admixtures, Corrosion Inhibitors, Shrinkage-Reducing Admixtures, introduction in polymer , types of polymer, classification of polymer , characteristics of polymer, properties of polymer , strength of polymer , application of polymer ,
a brief research about permeability & durability of concrete with helpful images for civil engineering students
fully made by Amira Abdullah (civil engineering student in Ismailia - Egypt)
This document provides an overview of fly ash, its properties, and its use in concrete. Fly ash is a byproduct of coal combustion that is used in concrete for its pozzolanic and cementitious properties. When used in concrete, fly ash contributes to strength gain, improves fresh and hardened concrete properties, and often reduces the cost of construction. The document describes the composition and characteristics of different classes of fly ash, and how fly ash affects the properties of concrete at different stages as well as its uses in concrete construction, products, and other applications.
This document discusses the durability of concrete and factors that affect its longevity. It covers various types of concrete deterioration including abrasion, erosion, frost damage, fire damage, corrosion, alkali-silica reaction, and sulfate attack. It describes how water and various chemical and physical processes can degrade concrete over time. The document also discusses ACI building code standards for concrete durability based on sulfate exposure levels and provides recommendations for improving concrete durability, such as using low water-cement ratio, testing materials, and avoiding aggregates known to cause issues.
Pudlo is a concrete admixture that modifies the microstructure of concrete to improve its durability. It reduces permeability, absorption, and diffusion by densifying the cement paste and reducing porosity and pore size. This makes concrete virtually water-tight and prevents ingress of chloride ions, carbon dioxide, water and other chemicals that can cause corrosion of steel reinforcement or chemical attacks on concrete. Pudlo also autogenously heals microcracks to further improve concrete's resistance to permeation and durability against various degradation mechanisms like corrosion, sulfate attack, and acid attack. Case studies and third party testing show that Pudlo modified concrete outperforms standard concrete in real world exposure conditions and infrastructure projects.
This document provides information on the key ingredients and composition of concrete. It discusses the main components of concrete including cement, aggregates, water, and admixtures. It describes the function of each component and how they contribute to the properties of hardened concrete. It also summarizes the manufacturing process of cement and discusses Bogue's compounds which form due to chemical reactions during cement production.
IRJET- Effect of Sea Water and Strength of ConcreteIRJET Journal
This document describes an experimental study on the effect of sea water and fresh water on the strength of concrete. 27 concrete specimens (cubes, cylinders, beams) were cast and cured using sea water, and another 27 specimens were cast and cured using fresh water. The specimens were tested for compressive strength, split tensile strength, and flexural strength at 7, 14, and 28 days. The study aims to investigate using sea water for mixing and curing concrete as an alternative to fresh water, which is scarce in some coastal areas. The results of the experiment will be presented to analyze how sea water affects the different strengths of concrete compared to using fresh water.
Oil and gas pipelines are critical infrastructure that require effective corrosion protection to ensure long-term operational effectiveness. Internally coating pipelines with epoxy provides benefits like increased gas flow capacity, faster drying times, and reduced operational costs from decreased pumping needs. Externally, fusion-bonded epoxy coatings form an electrical barrier against corrosion and have proven effective for onshore and offshore pipelines. Pipeline coating technologies continue to evolve to meet industry needs for transporting oil and gas from more challenging environments.
Flatline the alkali-silica reaction (ASR) in concrete using pumice-blended cement…at a cost of just pennies per yard. Quantifiable performance backed by ASTM-standard research.
This presentation will take you through a research study of five(5) different kinds of building
materials available on the Botswana market.
The objective of this assignment was to generate interest and facilitate student understanding of
different building materials available and their applications in the building construction environment.
The materials I personally researched about are as follows:
• Wood
• Tile
• Steel
• Glass
• Stone
This document provides an overview of the basic systems of operation for firearms: gas operation, blowback operation, and recoil operation. It describes the key components and cycling processes for each system. Gas operation uses propellant gases tapped from the barrel to operate the action. Blowback operation relies on the energy of the spent casing to cycle the action. Recoil operation uses Newton's Third Law - the equal and opposite reaction of firing a bullet down the barrel causes the bolt and barrel to recoil.
Chemical admixtures are added to concrete mixes to modify properties like workability, setting time, strength, and durability. There are five main types of admixtures: retarders which slow setting; accelerators which speed setting; superplasticizers which increase workability; water reducers which decrease water needs; and air-entrainers which introduce tiny air bubbles that improve freeze-thaw resistance. Producers use admixtures to reduce costs, modify hardened concrete properties, and ensure quality during mixing and placement.
This document discusses self-curing concrete, which aims to provide internal moisture to allow for continued hydration of cement without external curing methods. It outlines that self-curing concrete uses saturated lightweight aggregate or polyethylene glycol to reduce moisture loss from the concrete surface. An experimental program tested the compressive strength, splitting tensile strength, and modulus of rupture of concrete mixes with varying dosages of polyethylene glycol added. The optimum dosages were found to be 1% for a M20 mix and 0.5% for a M40 mix, and self-curing concrete achieved strengths comparable to conventionally cured concrete.
Environmental factors affecting durability of concreteArun Sharma
This document discusses the durability of concrete and factors that affect it. It defines durability as a structure's ability to maintain performance over time when exposed to degradation. The main factors that influence concrete durability are the mix design, materials used, and the aggressiveness of the surrounding environment. The three major durability problems discussed are freezing and thawing, alkali-silica reaction, and sulfate attack. The document also provides recommendations from literature and code IS 456:2000 to improve concrete durability.
This document discusses self-curing or internal curing concrete, which provides internal water reservoirs through the use of materials like lightweight aggregates or super absorbent polymers to hydrate cement particles. Proper curing is important for concrete to develop strength and durability. Self-curing concrete reduces the need for external curing and can perform better in areas without sufficient water for curing. The document examines using polyvinyl alcohol as a self-curing agent and finds that it helps retain water in concrete and reduces weight loss compared to conventional mixes without compromising strength. Self-curing concrete offers advantages like reduced cracking, permeability and improved durability.
This document presents a seminar report on the strength behavior of self-curing fly ash concrete using steel fibres. The report was submitted in partial fulfillment of a Master of Technology degree in civil engineering. It provides background on the need for self-curing concrete and potential materials that can enable self-curing such as super absorbent polymers and lightweight aggregates. The report also reviews literature on internal curing methods. It describes the materials and mix proportions used to produce self-curing fly ash concrete. Methods for preparing test specimens and determining workability and strength are also outlined.
IRJET- Design of 300 Years Durable Concrete for Nuclear Confinement Zone ...IRJET Journal
This document discusses the design of a 300-year durable self-compacting concrete for use in nuclear confinement zones and tunnel formworks. The concrete mixture uses materials like cement, silica fume, Alccofine 1203, coarse aggregate, fine aggregate, and an admixture to achieve high durability and self-compaction properties. Silica fume and Alccofine help reduce carbonation and permeability through pozzolanic reactions and fine particle sizes. A water-binder ratio of 0.28 provides sufficient workability while ensuring complete hydration. This concrete is predicted to last 300 years based on durability modeling software.
Experimental Study on Self- Curing ConcreteIRJET Journal
This document presents the results of an experimental study on self-curing concrete. The study investigated the effects of adding shrinkage reducing admixtures like super absorbent polymer and polyvinyl alcohol on the mechanical properties of concrete. Testing was conducted on M30 grade concrete with partial replacement of cement with pond ash ranging from 0-30%. Tests measured the compressive strength, split tensile strength, and flexural strength of specimens at 7, 14, and 28 days. The results showed that compressive strength, tensile strength, and flexural strength increased with the addition of super absorbent polymer up to 0.5% and polyvinyl alcohol up to 0.5% compared to conventional concrete without admixtures.
Durability and permeability of concrete are essential for its ability to withstand weathering and chemical attacks over time. The durability of concrete depends on factors like water-cement ratio, cement and aggregate properties, use of admixtures, age of concrete, and exposure conditions. A more permeable concrete is more porous and allows more water penetration. Permeability decreases with lower water-cement ratio, finer cement, use of waterproofing admixtures, and increased age. Cracks in concrete can form due to temperature changes, drying shrinkage, chemical reactions, weathering, and poor construction practices. Reinforcement corrosion occurs via electrochemical processes and can be limited by restricting chlorides, ensuring proper concrete cover, and
This document summarizes a study that investigated the effect of water-to-cement ratio on sulfate corrosion of fine-grained concrete. Concrete samples with water-to-cement ratios of 0.4, 0.45, and 0.5 were exposed to 0.5% sulfuric acid or a solution simulating wastewater for periods of 1, 3, and 6 months. The pH and sulfate content of layers cut from the samples were measured. After 1 month of exposure, a small decrease in pH was observed only in surface layers, and sulfate penetration was limited to 5 mm. Longer exposure times showed slightly deeper sulfate penetration but did not significantly reduce pH or compromise reinforcement protection. Higher water-to-
This document provides a review of the present status of polymer modified mortar and concrete. It discusses how the addition of polymers can improve the water resistance of cement mortar and concrete by reducing water absorption. It describes the various types of polymer modifiers used, including polymer latexes, redispersible polymer powders, water-soluble polymers, and liquid polymers. The principles of polymer modification are explained for each type, involving cement hydration, polymer film formation, and interactions between polymer and cement particles. Common damages caused by water absorption in concrete structures are also reviewed.
ADMIXTURE ,The major reasons for using
admixtures, Air-Entraining Admixtures, Water-Reducing Admixtures ,Superplasticizers (High-Range Water
Reducers), Retarding Admixtures, Accelerating Admixtures, Corrosion Inhibitors, Shrinkage-Reducing Admixtures, introduction in polymer , types of polymer, classification of polymer , characteristics of polymer, properties of polymer , strength of polymer , application of polymer ,
a brief research about permeability & durability of concrete with helpful images for civil engineering students
fully made by Amira Abdullah (civil engineering student in Ismailia - Egypt)
This document provides an overview of fly ash, its properties, and its use in concrete. Fly ash is a byproduct of coal combustion that is used in concrete for its pozzolanic and cementitious properties. When used in concrete, fly ash contributes to strength gain, improves fresh and hardened concrete properties, and often reduces the cost of construction. The document describes the composition and characteristics of different classes of fly ash, and how fly ash affects the properties of concrete at different stages as well as its uses in concrete construction, products, and other applications.
This document discusses the durability of concrete and factors that affect its longevity. It covers various types of concrete deterioration including abrasion, erosion, frost damage, fire damage, corrosion, alkali-silica reaction, and sulfate attack. It describes how water and various chemical and physical processes can degrade concrete over time. The document also discusses ACI building code standards for concrete durability based on sulfate exposure levels and provides recommendations for improving concrete durability, such as using low water-cement ratio, testing materials, and avoiding aggregates known to cause issues.
Pudlo is a concrete admixture that modifies the microstructure of concrete to improve its durability. It reduces permeability, absorption, and diffusion by densifying the cement paste and reducing porosity and pore size. This makes concrete virtually water-tight and prevents ingress of chloride ions, carbon dioxide, water and other chemicals that can cause corrosion of steel reinforcement or chemical attacks on concrete. Pudlo also autogenously heals microcracks to further improve concrete's resistance to permeation and durability against various degradation mechanisms like corrosion, sulfate attack, and acid attack. Case studies and third party testing show that Pudlo modified concrete outperforms standard concrete in real world exposure conditions and infrastructure projects.
This document provides information on the key ingredients and composition of concrete. It discusses the main components of concrete including cement, aggregates, water, and admixtures. It describes the function of each component and how they contribute to the properties of hardened concrete. It also summarizes the manufacturing process of cement and discusses Bogue's compounds which form due to chemical reactions during cement production.
IRJET- Effect of Sea Water and Strength of ConcreteIRJET Journal
This document describes an experimental study on the effect of sea water and fresh water on the strength of concrete. 27 concrete specimens (cubes, cylinders, beams) were cast and cured using sea water, and another 27 specimens were cast and cured using fresh water. The specimens were tested for compressive strength, split tensile strength, and flexural strength at 7, 14, and 28 days. The study aims to investigate using sea water for mixing and curing concrete as an alternative to fresh water, which is scarce in some coastal areas. The results of the experiment will be presented to analyze how sea water affects the different strengths of concrete compared to using fresh water.
Oil and gas pipelines are critical infrastructure that require effective corrosion protection to ensure long-term operational effectiveness. Internally coating pipelines with epoxy provides benefits like increased gas flow capacity, faster drying times, and reduced operational costs from decreased pumping needs. Externally, fusion-bonded epoxy coatings form an electrical barrier against corrosion and have proven effective for onshore and offshore pipelines. Pipeline coating technologies continue to evolve to meet industry needs for transporting oil and gas from more challenging environments.
Flatline the alkali-silica reaction (ASR) in concrete using pumice-blended cement…at a cost of just pennies per yard. Quantifiable performance backed by ASTM-standard research.
This presentation will take you through a research study of five(5) different kinds of building
materials available on the Botswana market.
The objective of this assignment was to generate interest and facilitate student understanding of
different building materials available and their applications in the building construction environment.
The materials I personally researched about are as follows:
• Wood
• Tile
• Steel
• Glass
• Stone
This document provides an overview of the basic systems of operation for firearms: gas operation, blowback operation, and recoil operation. It describes the key components and cycling processes for each system. Gas operation uses propellant gases tapped from the barrel to operate the action. Blowback operation relies on the energy of the spent casing to cycle the action. Recoil operation uses Newton's Third Law - the equal and opposite reaction of firing a bullet down the barrel causes the bolt and barrel to recoil.
Silica fume is a finely-divided mineral admixture that fills voids between cement particles, resulting in very dense concrete with high compressive strength and low permeability. It works by filling voids created by water in the concrete matrix through particle packing. Advantages include lower permeability, higher strength, improved durability, reduced alkali-silica reactivity, and improved resistance to attack. It is used to produce high strength, corrosion resistant, and abrasion resistant concrete, as well as products like sewer pipes.
This document discusses the use of nano materials in concrete. It describes that nano materials, which are less than 100 nanometers in size, can significantly change the mechanical, thermal, electrical, and chemical properties of concrete. Common nano materials used include nano silica, carbon nano tubes, and titanium oxide. The document outlines the advantages these materials provide such as increased strength and durability. It also summarizes the results of a laboratory study that found nano silica concrete produced the most uniform microstructure and lowest surface roughness.
The document summarizes Tarun Kumar Matriaya's summer training internship with North Central Railways in Allahabad from June 30 to July 30, 2009. It provides an overview of optical fiber communication and its uses in Indian Railways. Optical fibers have advantages over other communication methods like being thinner, less expensive, and having high bandwidth. Indian Railways uses optical fiber communication to optimize train scheduling, measure speeds, distribute signals, and monitor traffic lights.
Tracking of Maximum Power from Wind Using Fuzzy Logic Controller Based On PMSGIJMER
Wind energy has gained a growing worldwide interest due to the nonstop rise in fuel cost. The main aim of the wind-energy system is to extract the maximum power present in the wind stream. In order to extract the highest power, the maximum power point tracking (MPPT) algorithm is used. This paper proposes the fuzzy logic MPPT controller to track the maximum power from the wind generation
system. The maximum power is achieved based on the rotor speed of the wind system which consists of
wind turbine and PMSG. The error and change in error is given as input to the fuzzy logic and its output
is connected to the boost converter. The voltage from the dc link is controlled by the Voltage Source
Inverter (VSI), and it is placed in grid side converter control. The proposed system is designed and evaluated in MATLAB/SIMULINK. Simulation results show the good dynamic performance of the proposed system.
Zigbee Based Wireless Sensor Networks for Smart CampusIJMER
The document discusses simulations of Zigbee-based wireless sensor networks using different topologies with static and dynamic positioning of the Zigbee coordinator node. The simulations analyzed the effect on throughput and end-to-end delay. Results showed that a tree topology with a mobile coordinator had the highest throughput. A mesh topology, whether with static or dynamic coordinator, produced the lowest end-to-end delay. The document concludes that making the coordinator node mobile generally provides better network performance than a static coordinator configuration.
The document discusses von Neumann entropy in quantum computation. It provides definitions of key terms like von Neumann entropy, density matrix, and computational complexity theory. Von Neumann entropy extends concepts of classical entropy to quantum mechanics and characterizes the classical and quantum information capacities of an ensemble. It quantifies the degree of mixing of a quantum state and how much a state departs from a pure state. The von Neumann entropy of a system is computed using the density matrix and eigendecomposition of the system's quantum state.
Scope of Improving Energy Utilization in Coal Based Co-Generation on Thermal ...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
This document summarizes a research paper on designing a secure cloud-assisted mobile health monitoring system. The system aims to address privacy and security issues while lowering healthcare costs. It incorporates techniques like multi-dimensional range queries, outsourcing decryption to the cloud, and proxy re-encryption to shift computational tasks to the cloud without compromising privacy. The system architecture allows a mobile health service provider to store encrypted data and programs in the cloud and deliver them securely. It enables clients to query the cloud for monitoring programs using privacy-preserving tokens. The cloud assists with computationally intensive tasks without learning private query inputs or outputs. The system aims to achieve effective privacy preservation while reducing the workload on clients and the service provider.
In this paper, we introduce the concepts of πgθ-closed map, πgθ-open map, πgθ-
homeomorphisms and πgθc-homeomorphisms and study their properties. Also, we discuss its relationship
with other types of functions.
Mathematics Subject Classification: 54E55
MK-Prototypes: A Novel Algorithm for Clustering Mixed Type Data IJMER
Clustering mixed type data is one of the major research topics in the area of data mining. In
this paper, a new algorithm for clustering mixed type data is proposed where the concept of distribution
centroid is used to represent the prototype of categorical variables in a cluster which is then combined
with the mean to represent the prototype of clusters with mixed type variables. In the method, data is
observed from different views and the variables are grouped into different views. Those instances that
can be viewed differently from different viewpoints can be defined as multiview data. During clustering
process the differences among views are ignored in usual cases. Here, both views and variables weights
are computed simultaneously. The view weight is used to determine the closeness or density of view and
variable weight is used to identify the significance of each variable. With the intention of determining
the cluster of objects both these weights are used in the distance function. In the proposed method,
enhancement to the k-prototypes is done so that it automatically computes both view and variable
weights. The proposed algorithm MK-Prototypes algorithm is compared with two other clustering
algorithms.
Effect of V Notch Shape on Fatigue Life in Steel Beam Made of High Carbon St...IJMER
The present work includes study effect of V notch shape with various angle orientation and
depths on fatigue life behavior in steel beam made of High Carbon Steel alloy AISI 1078 which has a wide
application in industry. Fatigue life of notched specimens is calculated using the fatigue life obtained from
the experiments for smooth specimens (reference) and by use Numerical method (FEA).The fatigue
experiments were carried out at room temperature, applying a fully reversed cyclic load with the
frequency of 50 Hz and mean stress equal to zero (R= -1), on a cantilever rotating-bending fatigue testing
machine. The stress ratio was kept constant throughout the experiment. Different instruments have been
used in this investigation like Chemical composition analyzer , Tensile universal testing machine
,Hardness tester , Fatigue testing machine and Scanning Electron Microscope (SEM).The results show
that there is acceptable error between experimental and numerical works
This document presents models for problems that arise in Yang-Mills theory. It factors Yang-Mills theory and provides a model for the left-hand side and right-hand side of the Yang-Mills equations. The models consider parameters like symmetry breaking, mass acquisition, strong and electroweak interactions, gauge invariance, gauge fields, and non-commutative symmetry groups. Differential equations are provided for six modules analyzing these concepts. The goal is to lay a foundation for further factorizations and solutions to problems at the Planck scale.
The Effect of insertion of different geometries on heat transfer performance ...IJMER
Under turbulent flow conditions, the increase in heat transfer rate is more significant than
that under laminar flow conditions. The turbulent effects become a dominant factor over secondary flow
at higher Reynolds number. The turbulent flow can be produced by inserting different geometries in the
circular pipe. This study focuses on the various methods or geometries used to produce turbulent
geometries and its effect on the heat transfer. The turbulent generators with different geometrical
configurations have been used as one of the passive heat transfer enhancement techniques and are the
most widely used in tubes in several heat transfer applications. Insertion of such geometries may lead to
increase the friction factor and pressure drop which directly enhances the heat transfer characteristics.
The document discusses Kosovo's energy strategy and its focus on increasing energy security, diversifying energy sources, and protecting the environment. It aims to stimulate efficient energy use and increase use of renewable resources. Currently, Kosovo's energy system relies heavily on thermal power generation from lignite, producing high emissions. The strategy proposes developing a new lignite power plant called "New Kosovo" to gradually replace aging facilities and meet future demand under two economic growth scenarios. It also discusses integrating Kosovo's energy sector with regional and European energy policies and markets.
This document summarizes research into improving the mechanical properties of neodymium-iron-boron bonded magnets through the addition of molybdenum disulfide (MoS2). Samples containing 0%, 0.5%, 1%, 1.5%, and 2% MoS2 by weight were produced and tested. Magnetic testing found that saturation magnetization and remanence increased with up to 1% MoS2 due to reduced friction, but decreased at higher amounts. Mechanical testing found density and compression strength increased with MoS2 due to reduced porosity, while hardness decreased slightly. Up to 1% MoS2 improved properties without harming magnetism, showing potential for stronger rare-earth magnets.
REVIEW ON THE IMPACT OF AIR ENTRAINTMENT ON THE PROPERTIES OF CONCRETE STRUCT...IRJET Journal
This document summarizes a review on the impact of air entrainment on the properties of concrete structures. It discusses how adding an air entraining agent creates tiny air bubbles in concrete that improve its durability. The document outlines the history of air entrainment and different air entraining agents used. It also reviews several research papers on how air entrainment affects properties like compressive strength, water absorption, chloride diffusion. The mechanism of how air entraining agents stabilize bubbles is explained. Advantages of air entrainment include increased workability and resistance to freezing and thawing. While air entrainment improves durability, it can slightly reduce compressive strength.
Critical review on Mix Proportioning stipulations for High Volume Fly ash con...IRJET Journal
This document provides a critical review of mix proportioning specifications for High Volume Fly Ash Concrete (HVFAC). It discusses how HVFAC can be more eco-friendly and cost-efficient than traditional Portland cement concrete. Less water-to-binder ratio, finer fly ash particles, and increased curing time all contribute to higher compressive strength in HVFAC. The document reviews previous research on mix proportioning of HVFAC and the effects of variables like water-to-binder ratio, fly ash content, and curing age. It also summarizes typical mix designs used in previous studies involving 50-65% fly ash replacement of cement by mass.
IRJET- Behaviour of Mineral Admixture on Strength and Durability of ConcreteIRJET Journal
This document discusses the effects of mineral admixtures on the strength and durability of high performance concrete (HPC). Two HPC mixes were designed - a control mix without admixtures and a mix replacing 15% cement with fly ash and 10% with silica fume. Testing found the admixture mix achieved higher 7-day and 28-day compressive strengths than the control. Durability testing also indicated the admixture mix had better resistance to chloride and sulfate attack over 180 days. The improved performance is attributed to the pozzolanic reactions of fly ash and silica fume creating a denser microstructure in the concrete.
Strength and durability studies on silica fume modified high volume fly ash c...IAEME Publication
This document discusses a study on the strength and durability of silica fume modified high-volume fly ash concrete. Five concrete mixes were tested: a control mix and four mixes where 50% of cement was replaced with fly ash and additional replacement of cement with 5%, 10%, and 15% silica fume. Testing included compressive strength at various ages, rapid chloride permeability, chloride ion diffusion, and carbonation resistance. The addition of silica fume to high-volume fly ash concrete was found to improve mechanical properties and durability compared to fly ash concrete without silica fume.
STUDY ON DURABILITY OF CONCRETE WHEN BLENDED WITH MICRO SILICA AND FLYASHIjripublishers Ijri
The environment in some concrete structures can become very acidic due to formation of sulphuric acid converted
from hydrogen sulphide by bacterial action. Significant deteriation of concrete in such harsh environments has
been reported world wide. Deteriotation of sewer system may result in serious problem such as the loss of ability to
transport sewerage, contamaniation of ground and ground water, excessive ground settelements.
Influence of silicone-based hydrophobic admixture on structural and mechanica...IRJET Journal
This document discusses a study that investigated the influence of silicone-based hydrophobic admixtures on the structural and mechanical properties of concrete mortar. Specifically, it examined how adding different percentages of an organosilicone admixture affected the hydration, water repellency, workability, and compressive strength of concrete mixtures. The study found that adding 0.3% admixture increased compressive strength by 11% compared to a reference concrete without admixture. It also significantly reduced water absorption through the concrete by over 80%. The admixture was found to extend the hydration period of the concrete mixtures and maintain workability with less water.
This study examined the effects of different proportions of light weight expanded clay aggregates on the compressive and flexural strength of concrete. Concrete mixtures were prepared with 0%, 25%, 50%, 75%, and 100% replacement of coarse aggregates with expanded clay aggregates. The mixtures also included 10% silica fume and 1.6% polyvinyl alcohol to replace cement and water. Test results found that compressive and flexural strength decreased as the expanded clay aggregate content increased. However, the densities of the concretes were significantly lower than conventional concrete, indicating light weight concrete is suitable when self-weight needs to be reduced.
This study investigated the effects of using different percentages of expanded clay aggregates (ECA) as a replacement for normal coarse aggregates in concrete. Concrete mixtures were prepared with 0%, 25%, 50%, 75%, and 100% replacement of ECA and tested for compressive strength and flexural strength after 28 days of curing. The results showed that as the percentage of ECA increased, the density and strengths of the concrete decreased. Concretes with higher ECA content achieved lower compressive strengths but still met the requirements for structural lightweight concrete. The study concluded that this lightweight concrete can be used in places where external forces are minimal as its strength is only sufficient to support its own weight.
AN EXPERIMENTAL INVESTIGATION ON EFFECT OF MECHANICAL PROPERTIES OF M50 GRADE...IRJET Journal
This document summarizes an experimental investigation on the effect of mechanical properties of M50 grade concrete with partial replacement of sand with copper slag. The study aims to determine the optimal percentage of polyethylene glycol (PEG-4000) to be added to self-curing concrete and examines how replacing sand with copper slag in various percentages affects the compressive strength, tensile strength, and flexural strength of the concrete mixes. Experimental results from previous studies on self-curing concrete and use of copper slag in concrete are discussed. The experimental procedure and materials used including cement, fine aggregate, coarse aggregate, water, PEG-4000, and copper slag are described.
Effect of Silica Fume on High Strength High Volume Fly Ash ConcreteIRJET Journal
The document presents research on the effect of adding silica fume to high-volume fly ash concrete. Fly ash is a byproduct of coal combustion that can replace up to 30% of cement, reducing pollution. High-volume fly ash concrete uses over 50% fly ash replacement. The study produced concrete mixtures with 50-60% fly ash and varying percentages of silica fume, an ultrafine pozzolan. Specimens were tested for compression, splitting tension, and flexural strength at various ages. The optimum silica fume addition was found to be 10%, improving strength and durability over plain high-volume fly ash concrete.
IRJET- Utilization of Various Industrial Waste Materials as Filler in Aerated...IRJET Journal
This document reviews the utilization of various industrial waste materials as fillers in aerated concrete. Aerated concrete, or foam concrete, is a lightweight concrete made by mixing cement, sand, and an aerating agent that creates air pockets. Using industrial wastes as partial replacements for fine aggregates can further reduce the density of aerated concrete while providing strength benefits and reducing non-recyclable waste. The document discusses the production of aerated concrete and examines literature on using waste materials like quarry dust, rubber crumbs, and plastic granules in aerated concrete mixes. Strength testing shows these materials can improve compressive strength when used as partial substitutes for fine aggregates.
This document summarizes a research study on the effect of using electrically precipitated fly ash (EPFA) as a partial replacement for cement in self-compacting concrete (SCC). The study tested SCC mixes with 0-30% EPFA replacement at 5% intervals. Tests were conducted on fresh properties, mechanical properties like compressive strength, and durability properties like rapid chloride permeability and water sorptivity. Results showed that 20% EPFA replacement provided better results than the control SCC mix, improving properties while also providing economic and environmental benefits through reduced cement usage.
IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of mechanical and civil engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in mechanical and civil engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Experimental evaluation of the durability properties of high performanceIAEME Publication
The document discusses the use of admixtures to improve the durability properties of high performance concrete (HPC). It describes how supplementary cementing materials (SCMs) like fly ash, silica fume, and metakaoline can improve the strength and durability of HPC when used to partially replace cement. The document also examines the acid resistance and sulfate resistance of HPC specimens containing these admixtures through immersion testing in acid and sulfate solutions. Test results showed that HPC with SCMs exhibited greater resistance to chemical attacks compared to plain cement concrete.
Experimental evaluation of the durability properties of high performanceIAEME Publication
The document discusses the use of admixtures to improve the durability properties of high performance concrete (HPC). It describes how supplementary cementing materials (SCMs) like fly ash, silica fume, and metakaoline can improve the strength and durability of HPC when used to partially replace cement. The document also examines the acid resistance and sulfate resistance of HPC mixtures containing various SCMs through experimental testing of specimens exposed to acids and sulfate solutions.
The influence of superabsorbent polymer beads used as internal curing agent o...IRJET Journal
The document discusses using superabsorbent polymer beads as an internal curing agent to improve the compressive strength of mortar. Internal curing provides additional internal water to continue cement hydration and reduce shrinkage cracking. Superabsorbent polymers are effective internal curing agents as they can absorb large amounts of water during mixing and release it later. The study aims to assess the impact of superabsorbent polymer beads on the compressive strength of mortar cured under different conditions (sealed, unsealed, pond, mist). Prior research on using superabsorbent polymers in concrete has shown mixed results, with some studies finding reduced compressive strength and others finding similar or improved strength compared to mixes without polymers.
Synergistic Effect on Ternary Blended Cementitious Systemijtsrd
This paper presents a detailed experimental investigation on the synergestic effects on ternary blended cementitious system containing fly ash and silica fume. The experimental programme consisted of three parts, the first part was to obtain the super plasticizer demand for each mix so as to obtain a workability of 110±5 , the second part was to determine the strength and durability properties of the mortar samples having different fly ash and silica fume contents and the third part was to determine the synergy existing in the ternary blends both in terms of durability and strength. Test results have shown that the ternary blended mixtures improved the mortar performance by improving the workability, strength and durability, therefore are applicable. Ternary mixtures performed in accordance with their ingredients however the degree of improvement that they contribute varies based on the selected dosage and type of SCMs. Synergy between the fly ash and silica fume is the main reason for the outstanding performance of ternary mixtures. The results obtained thus are encouraging for partial replacement. Jasir Thachaparambil "Synergistic Effect on Ternary Blended Cementitious System" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-7 , December 2022, URL: https://www.ijtsrd.com/papers/ijtsrd52289.pdf Paper URL: https://www.ijtsrd.com/engineering/civil-engineering/52289/synergistic-effect-on-ternary-blended-cementitious-system/jasir-thachaparambil
EFFECT OF PRE-SLASH SOAKED LIGHTWEIGHT AGGREGATES AND SUPER ABSORBENT POLYMER...IRJET Journal
The document discusses the use of internal curing agents like pre-soaked lightweight aggregates and super absorbent polymers to improve the properties of concrete. M25 concrete mixes were prepared by replacing sand with 6%, 12%, 18% vermiculite and cement with 0.245%, 0.345%, 0.445% super absorbent polymer. Cubes, beams and cylinders were cast and tested at 7, 14, 28 days to determine compressive strength, flexural strength and split tensile strength. The results showed that internal curing improved the strength properties of concrete compared to conventionally cured concrete. Prior studies also found maximum improvement in strength at around 5% vermiculite replacement and 0.35% super absorbent
IRJET- Experimental Study on the Behaviour of Self Healing Concrete using Sil...IRJET Journal
This document presents an experimental study on the behavior of self-healing concrete using silica gel in microcapsules as a healing agent. Concrete specimens were made with 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% dosages of silica gel by weight of cement. The specimens were initially cracked and then retested after 7 days of curing. Test results showed that specimens with 0.3% silica gel achieved the highest regain in compressive strength and split tensile strength after healing, reaching 55.34% of the original strength. The study aims to evaluate the influence of silica gel dosage on the strength properties of self-healing concrete.
Physio microstructural properties of aerated cement slurry for lightweight st...TalalSalem5
Cementitious composites, including ferrocement and continuous fiber reinforced cement,
are increasingly considered for building construction and repair. One alternative in processing
of these composites is to infiltrate the reinforcement (continuous fibers or chicken mesh) with a
flowable cementitious slurry. The relatively high density of cementitious binders, when compared
with polymeric binders, are a setback in efforts to introduce cementitious composites as lower-cost,
fire-resistant, and durable alternatives to polymer composites. Aeration of the slurry is an effective
means of reducing the density of cementitious composites. This approach, however, compromises
the mechanical properties of cementitious binders. An experimental program was undertaken in
order to assess the potential for production of aerated slurry with a desired balance of density,
mechanical performance, and barrier qualities. The potential for nondestructive monitoring of
strength development in aerated cementitious slurry was also investigated. This research produced
aerated slurries with densities as low as 0.9 g/cm3 with viable mechanical and barrier qualities for
production of composites. The microstructure of these composites was also investigated.
Similar to Analysis of Admixtures and Their Effects of Silica Fumes, Metakaolin and PFA on the Air Content (20)
A Study on Translucent Concrete Product and Its Properties by Using Optical F...IJMER
- Translucent concrete is a concrete based material with light-transferring properties,
obtained due to embedded light optical elements like Optical fibers used in concrete. Light is conducted
through the concrete from one end to the other. This results into a certain light pattern on the other
surface, depending on the fiber structure. Optical fibers transmit light so effectively that there is
virtually no loss of light conducted through the fibers. This paper deals with the modeling of such
translucent or transparent concrete blocks and panel and their usage and also the advantages it brings
in the field. The main purpose is to use sunlight as a light source to reduce the power consumption of
illumination and to use the optical fiber to sense the stress of structures and also use this concrete as an
architectural purpose of the building
Developing Cost Effective Automation for Cotton Seed DelintingIJMER
A low cost automation system for removal of lint from cottonseed is to be designed and
developed. The setup consists of stainless steel drum with stirrer in which cottonseeds having lint is mixed
with concentrated sulphuric acid. So lint will get burn. This lint free cottonseed treated with lime water to
neutralize acidic nature. After water washing this cottonseeds are used for agriculter purpose
Study & Testing Of Bio-Composite Material Based On Munja FibreIJMER
The incorporation of natural fibres such as munja fiber composites has gained
increasing applications both in many areas of Engineering and Technology. The aim of this study is to
evaluate mechanical properties such as flexural and tensile properties of reinforced epoxy composites.
This is mainly due to their applicable benefits as they are light weight and offer low cost compared to
synthetic fibre composites. Munja fibres recently have been a substitute material in many weight-critical
applications in areas such as aerospace, automotive and other high demanding industrial sectors. In
this study, natural munja fibre composites and munja/fibreglass hybrid composites were fabricated by a
combination of hand lay-up and cold-press methods. A new variety in munja fibre is the present work
the main aim of the work is to extract the neat fibre and is characterized for its flexural characteristics.
The composites are fabricated by reinforcing untreated and treated fibre and are tested for their
mechanical, properties strictly as per ASTM procedures.
Hybrid Engine (Stirling Engine + IC Engine + Electric Motor)IJMER
Hybrid engine is a combination of Stirling engine, IC engine and Electric motor. All these 3 are
connected together to a single shaft. The power source of the Stirling engine will be a Solar Panel. The aim of
this is to run the automobile using a Hybrid engine
Fabrication & Characterization of Bio Composite Materials Based On Sunnhemp F...IJMER
This document summarizes research on the fabrication and characterization of bio-composite materials using sunnhemp fibre. The document discusses how sunnhemp fibre was used to reinforce an epoxy matrix through hand lay-up methods. Various mechanical properties of the bio-composites were tested, including tensile, flexural, and impact properties. The results of the mechanical tests on the bio-composite specimens are presented. Potential applications of the sunnhemp fibre bio-composites are also suggested, such as in fall ceilings, partitions, packaging, automotive interiors, and toys.
Geochemistry and Genesis of Kammatturu Iron Ores of Devagiri Formation, Sandu...IJMER
The Greenstone belts of Karnataka are enriched in BIFs in Dharwar craton, where Iron
formations are confined to the basin shelf, clearly separated from the deeper-water iron formation that
accumulated at the basin margin and flanking the marine basin. Geochemical data procured in terms of
major, trace and REE are plotted in various diagrams to interpret the genesis of BIFs. Al2O3, Fe2O3 (T),
TiO2, CaO, and SiO2 abundances and ratios show a wide variation. Ni, Co, Zr, Sc, V, Rb, Sr, U, Th,
ΣREE, La, Ce and Eu anomalies and their binary relationships indicate that wherever the terrigenous
component has increased, the concentration of elements of felsic such as Zr and Hf has gone up. Elevated
concentrations of Ni, Co and Sc are contributed by chlorite and other components characteristic of basic
volcanic debris. The data suggest that these formations were generated by chemical and clastic
sedimentary processes on a shallow shelf. During transgression, chemical precipitation took place at the
sediment-water interface, whereas at the time of regression. Iron ore formed with sedimentary structures
and textures in Kammatturu area, in a setting where the water column was oxygenated.
Experimental Investigation on Characteristic Study of the Carbon Steel C45 in...IJMER
In this paper, the mechanical characteristics of C45 medium carbon steel are investigated
under various working conditions. The main characteristic to be studied on this paper is impact toughness
of the material with different configurations and the experiment were carried out on charpy impact testing
equipment. This study reveals the ability of the material to absorb energy up to failure for various
specimen configurations under different heat treated conditions and the corresponding results were
compared with the analysis outcome
Non linear analysis of Robot Gun Support Structure using Equivalent Dynamic A...IJMER
Robot guns are being increasingly employed in automotive manufacturing to replace
risky jobs and also to increase productivity. Using a single robot for a single operation proves to be
expensive. Hence for cost optimization, multiple guns are mounted on a single robot and multiple
operations are performed. Robot Gun structure is an efficient way in which multiple welds can be done
simultaneously. However mounting several weld guns on a single structure induces a variety of
dynamic loads, especially during movement of the robot arm as it maneuvers to reach the weld
locations. The primary idea employed in this paper, is to model those dynamic loads as equivalent G
force loads in FEA. This approach will be on the conservative side, and will be saving time and
subsequently cost efficient. The approach of the paper is towards creating a standard operating
procedure when it comes to analysis of such structures, with emphasis on deploying various technical
aspects of FEA such as Non Linear Geometry, Multipoint Constraint Contact Algorithm, Multizone
meshing .
Static Analysis of Go-Kart Chassis by Analytical and Solid Works SimulationIJMER
This paper aims to do modelling, simulation and performing the static analysis of a go
kart chassis consisting of Circular beams. Modelling, simulations and analysis are performed using 3-D
modelling software i.e. Solid Works and ANSYS according to the rulebook provided by Indian Society of
New Era Engineers (ISNEE) for National Go Kart Championship (NGKC-14).The maximum deflection is
determined by performing static analysis. Computed results are then compared to analytical calculation,
where it is found that the location of maximum deflection agrees well with theoretical approximation but
varies on magnitude aspect.
In récent year various vehicle introduced in market but due to limitation in
carbon émission and BS Séries limitd speed availability vehicle in the market and causing of
environnent pollution over few year There is need to decrease dependancy on fuel vehicle.
bicycle is to be modified for optional in the future To implement new technique using change in
pedal assembly and variable speed gearbox such as planetary gear optimise speed of vehicle
with variable speed ratio.To increase the efficiency of bicycle for confortable drive and to
reduce torque appli éd on bicycle. we introduced epicyclic gear box in which transmission done
throgh Chain Drive (i.e. Sprocket )to rear wheel with help of Epicyclical gear Box to give
number of différent Speed during driving.To reduce torque requirent in the cycle with change in
the pedal mechanism
Integration of Struts & Spring & Hibernate for Enterprise ApplicationsIJMER
This document discusses integrating the Spring, Struts, and Hibernate frameworks to develop enterprise applications. It provides an overview of each framework and their features. The Spring Framework is a lightweight, modular framework that allows for inversion of control and aspect-oriented programming. It can be used to develop any or all tiers of an application. The document proposes an architecture for an e-commerce website that integrates these three frameworks, with Spring handling the business layer, Struts the presentation layer, and Hibernate the data access layer. This modular approach allows for clear separation of concerns and reduces complexity in application development.
Microcontroller Based Automatic Sprinkler Irrigation SystemIJMER
Microcontroller based Automatic Sprinkler System is a new concept of using
intelligence power of embedded technology in the sprinkler irrigation work. Designed system replaces
the conventional manual work involved in sprinkler irrigation to automatic process. Using this system a
farmer is protected against adverse inhuman weather conditions, tedious work of changing over of
sprinkler water pipe lines & risk of accident due to high pressure in the water pipe line. Overall
sprinkler irrigation work is transformed in to a comfortableautomatic work. This system provides
flexibility & accuracy in respect of time set for the operation of a sprinkler water pipe lines. In present
work the author has designed and developed an automatic sprinkler irrigation system which is
controlled and monitored by a microcontroller interfaced with solenoid valves.
On some locally closed sets and spaces in Ideal Topological SpacesIJMER
This document introduces and studies the concept of δˆ s-locally closed sets in ideal topological spaces. Some key points:
- A subset A is δˆ s-locally closed if A can be written as the intersection of a δˆ s-open set and a δˆ s-closed set.
- Various properties of δˆ s-locally closed sets are introduced and characterized, including relationships to other concepts like generalized locally closed sets.
- It is shown that a subset A is δˆ s-locally closed if and only if A can be written as the intersection of a δˆ s-open set and the δˆ s-closure of A.
- Theore
Intrusion Detection and Forensics based on decision tree and Association rule...IJMER
This paper present an approach based on the combination of, two techniques using
decision tree and Association rule mining for Probe attack detection. This approach proves to be
better than the traditional approach of generating rules for fuzzy expert system by clustering methods.
Association rule mining for selecting the best attributes together and decision tree for identifying the
best parameters together to create the rules for fuzzy expert system. After that rules for fuzzy expert
system are generated using association rule mining and decision trees. Decision trees is generated for
dataset and to find the basic parameters for creating the membership functions of fuzzy inference
system. Membership functions are generated for the probe attack. Based on these rules we have
created the fuzzy inference system that is used as an input to neuro-fuzzy system. Fuzzy inference
system is loaded to neuro-fuzzy toolbox as an input and the final ANFIS structure is generated for
outcome of neuro-fuzzy approach. The experiments and evaluations of the proposed method were
done with NSL-KDD intrusion detection dataset. As the experimental results, the proposed approach
based on the combination of, two techniques using decision tree and Association rule mining
efficiently detected probe attacks. Experimental results shows better results for detecting intrusions as
compared to others existing methods
Natural Language Ambiguity and its Effect on Machine LearningIJMER
This document discusses natural language ambiguity and its effect on machine learning. It begins by introducing different types of ambiguity that exist in natural languages, including lexical, syntactic, semantic, discourse, and pragmatic ambiguities. It then examines how these ambiguities present challenges for computational linguistics and machine translation systems. Specifically, it notes that ambiguity is a major problem for computers in processing human language as they lack the world knowledge and context that humans use to resolve ambiguities. The document concludes by outlining the typical process of machine translation and how ambiguities can interfere with tasks like analysis, transfer, and generation of text in the target language.
Today in era of software industry there is no perfect software framework available for
analysis and software development. Currently there are enormous number of software development
process exists which can be implemented to stabilize the process of developing a software system. But no
perfect system is recognized till yet which can help software developers for opting of best software
development process. This paper present the framework of skillful system combined with Likert scale. With
the help of Likert scale we define a rule based model and delegate some mass score to every process and
develop one tool name as MuxSet which will help the software developers to select an appropriate
development process that may enhance the probability of system success.
Material Parameter and Effect of Thermal Load on Functionally Graded CylindersIJMER
The present study investigates the creep in a thick-walled composite cylinders made
up of aluminum/aluminum alloy matrix and reinforced with silicon carbide particles. The distribution
of SiCp is assumed to be either uniform or decreasing linearly from the inner to the outer radius of
the cylinder. The creep behavior of the cylinder has been described by threshold stress based creep
law with a stress exponent of 5. The composite cylinders are subjected to internal pressure which is
applied gradually and steady state condition of stress is assumed. The creep parameters required to
be used in creep law, are extracted by conducting regression analysis on the available experimental
results. The mathematical models have been developed to describe steady state creep in the composite
cylinder by using von-Mises criterion. Regression analysis is used to obtain the creep parameters
required in the study. The basic equilibrium equation of the cylinder and other constitutive equations
have been solved to obtain creep stresses in the cylinder. The effect of varying particle size, particle
content and temperature on the stresses in the composite cylinder has been analyzed. The study
revealed that the stress distributions in the cylinder do not vary significantly for various combinations
of particle size, particle content and operating temperature except for slight variation observed for
varying particle content. Functionally Graded Materials (FGMs) emerged and led to the development
of superior heat resistant materials.
Energy Audit is the systematic process for finding out the energy conservation
opportunities in industrial processes. The project carried out studies on various energy conservation
measures application in areas like lighting, motors, compressors, transformer, ventilation system etc.
In this investigation, studied the technical aspects of the various measures along with its cost benefit
analysis.
Investigation found that major areas of energy conservation are-
1. Energy efficient lighting schemes.
2. Use of electronic ballast instead of copper ballast.
3. Use of wind ventilators for ventilation.
4. Use of VFD for compressor.
5. Transparent roofing sheets to reduce energy consumption.
So Energy Audit is the only perfect & analyzed way of meeting the Industrial Energy Conservation.
An Implementation of I2C Slave Interface using Verilog HDLIJMER
This document describes the implementation of an I2C slave interface using Verilog HDL. It introduces the I2C protocol which uses only two bidirectional lines (SDA and SCL) for communication. The document discusses the I2C protocol specifications including start/stop conditions, addressing, read/write operations, and acknowledgements. It then provides details on designing an I2C slave module in Verilog that responds to commands from an I2C master and allows synchronization through clock stretching. The module is simulated in ModelSim and synthesized in Xilinx. Simulation waveforms demonstrate successful read and write operations to the slave device.
Discrete Model of Two Predators competing for One PreyIJMER
This paper investigates the dynamical behavior of a discrete model of one prey two
predator systems. The equilibrium points and their stability are analyzed. Time series plots are obtained
for different sets of parameter values. Also bifurcation diagrams are plotted to show dynamical behavior
of the system in selected range of growth parameter
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
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Analysis of Admixtures and Their Effects of Silica Fumes, Metakaolin and PFA on the Air Content
1. International
OPEN ACCESS Journal
Of Modern Engineering Research (IJMER)
| IJMER | ISSN: 2249–6645 | www.ijmer.com | Vol. 4 | Iss. 6| June. 2014 | 28|
Analysis of Admixtures and Their Effects of Silica Fumes,
Metakaolin and PFA on the Air Content
T. Subramani1
, T. Senthilkumar2
, J. Jayalakshmi3
1
Professor & Dean, Department of Civil Engineering, VMKV Engineering College, Vinayaka Missions
University, Salem, India.
2,3
PG Students of Structural Engineering, Department of Civil Engineering, VMKV Engineering College,
Vinayaka Missions University, Salem,
1. Introduction
The raw materials needed for the manufacture of Portland cement (PC) are available in most parts of
the world, and the energy requirements for its production may be considered to be relatively modest.
Nevertheless the use of alternative binders or cement replacement materials, has become a necessity for the
construction industry because of the economic, environmental and technological benefits derived from
their use. Furthermore recent years have seen increased concerns regarding the depletion of raw
materials, energy demands and the consequent environmental damage. These concerns have led to
wider utilization of existing cement replacement materials and further search for other less energy intensive
materials. Many of these mineral admixtures are industrial by-products, and are considered as waste. When
used as a partial cement replacement material, typically in the range of 20 to 60% by mass, the energy and
cost savings are substantial. From an environmental point of view mineral admixtures are playing an undisputed
role. They are responsible for substantial “environmental unloading” because their disposal can be hazardous
to the environment and higher utilisation of them can result in reduction of greenhouse gas emissions
attributed to the cement industry. Two of the revolutionary developments in concrete technology in the last
century have been produced by air entraining agents (AEAs) and superplasticizers. Superplasticizers or
high range water reducing admixtures (HRWRAs) are concrete admixtures which can be mainly used either to
increase the workability of fresh concrete at a given mix composition or to reduce the amount of mixing
water and water/cement (w/c) ratio for a given workability in order to increase strength and durability. For
instance to compensate for the loss of workability in mixes like those containing pozzolanic materials such as
condensed silica fume (CSF) and metakaolin (MK) or even increase the water reduction effect of pulverized
fuel ash (PFA) and ground granulated blast furnace slag (GGBS) we normally use superplasticizers. Due to
addition of superplasticizers the slump increase at a given mix composition can be 150-200 mm and the
reduction of mixing water at a given slump can be up to 30%, both depending on the method of addition, dosage
and type of admixture used. Presently the most important HRWRAs available are based on condensed
melamine sulfonated formaldehyde (MSF) or naphtalene sulfonated formaldehyde (NSF) in the form of 40%
aqueous solution to facilitate an accurate, reliable and automatic dispensing at the batching plant. The optimum
dosage of commercial superplasticizers is in general in the range 1- 2% by mass of cement. The main action
of the molecules of such superpalsticizers is to wrap themselves around the cement particles and give them a
Abstract: This paper presents a review of the properties of fresh concrete including workability, heat
of hydration, setting time, bleeding, and reactivity by using mineral admixtures fly ash (FA), silica
fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA).
Comparison of normal and high strength concrete in which cement has been partially supplemented
by mineral admixture has been considered. It has been concluded that mineral admixtures may be
categorized into two groups: chemically active mineral admixtures and microfiller mineral
admixtures. Chemically active mineral admixtures decrease workability and setting time of concrete
but increase the heat of hydration and reactivity. On the other hand, micro filler mineral admixtures
increase workability and setting time of concrete but decrease the heat of hydration and reactivity. In
general, small particle size and higher specific surface area of mineral admixture are favourable to
produce highly dense and impermeable concrete; however, they cause low workability and demand
more water which may be offset by adding effective super plasticizer.
Keywords: Silica Fume (SF), Metakaolin (MK), Fly Ash (FA), Ground Granulated Blast Furnace Slag
(GGBS),
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| IJMER | ISSN: 2249–6645 | www.ijmer.com | Vol. 4 | Iss. 6| June. 2014 | 29|
highly negative charge so that they repel each other. This results in deflocculation and dispersion of cement
particles with the resulting improvement in workability.
Air entraining agents are admixtures which are capable of forming air bubbles dispersed
throughout the cement matrix that binds the aggregates. After compaction, normal concrete is likely to
contain about 1-2% air by volume, this accidentally entrapped air being unevenly distributed and
consisting of bubbles of irregular size and shape. Air entraining agents introduce a controlled amount of air
in the form of millions of bubbles of uniform size and uniformly distributed throughout the concrete
mix. There is another distinctive difference between air voids accidentally entrapped in concrete and the
deliberately entrained air bubbles. The latter are very much smaller, typically 50 m in diameter whereas
the former can be as large as the familiar, albeit undesirable, pockmarks on the formed surface of
concrete. Numerous types of air entraining agents are commercially available with the vinsol resin based
products being the most common ones. The optimum dosage for AEAs is usually below 1% by mass of
cement.
The presence of entrained air in fresh concrete has a pronounced effect on its properties. One of
these is workability, which is improved. For adequate workability, the aggregate particles must be spaced in
a way that they can move past one another with relative ease during mixing and placing. In this
respect, the entrained air voids are often thought of as millions of tiny ball bearings in the concrete,
making the mix more workable. Entrained air also eliminates or minimises segregation and subsequent
bleeding. Although there are also other advantages to be realised, the principal reason behind the use of
air entrainment agents is the improvement that they impart to the concrete’s resistance to frost action and
to its deterioration due to repeated freezing and thawing. A given volume of air and an appropriate
spacing factor are required to produce an adequate air bubbles system to protect concrete from freezing
and thawing. Because the damaging action of freezing and thawing involves expansion of water on
freezing and associated osmotic processes, it is logical to expect that, if excess water can readily escape
into adjacent air-filled voids, damage to the concrete will not occur. This is the underlying principle of
improved frost resistance by air entrainment.
II. Admixture
2.1 CHEMICAL ADMIXTURES FOR CONCRETE
Definition: what are chemical admixtures?
The definition of RILEM (International Union of Testing and Research Laboratories for Materials and
Structures) is:
Admixtures for concrete, mortar or paste are inorganic or organic materials
These are added to the normal components of a mix not normally exceeding 5% by mass of cement or
cementitious materials
Why admixtures? The need.
If we are pouring a low grade concrete, say M20, If we are not unduly concerned about its water
content nor its water-cement ratio,
If the cost of materials and labour are paid entirely by the owner (or some one else) at whatever rates
we have quoted, then, Admixtures will make the concrete more expensive. But then our concrete will be an
indifferent one,
How do they act?
The chemical, physical or physio-chemical actions of admixtures in cement concrete are quite complex.
In fact, cement itself is an extremely complex compound with major compounds such as calcium
silicates, calcium aluminates, gypsum.
Besides it contains many alkali and other calcium salts.
The action of admixtures can, however, be simplified for the sake of Understanding, as:
(i) adsorption
(ii) De-flocculation or dispersion
(iii)Chemical absorption or interaction
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Often, all the three take place. We should know a little about these so that we can choose admixtures for our job
more correctly
2.2 PHYSICO-CHEMICAL ACTIONS OF ADMIXTURES
The most important compounds of cement that react very early when water is added are:
Tricalcium silicate (C3S), and
Tricalcium Aluminate (C3A)
III. Silica fume, Metakaolin,
PULVERISED FUEL ASH (PFA)
3.1 SILICA FUME
Silica fume (SF) is a byproduct of the smelting process in the silicon and ferrosilicon industry. The
reduction of high-purity quartz to silicon at temperatures up to 2,000_C produces SiO2 vapours, which oxidizes
and condense in the low temperature zone to tiny particles consisting of non-crystalline silica. (Fig.3.1)
Fig. 3.1 Silica fume
Properties of Silica Fume
Physical Properties
Silica fume particles are extremely small, with more than 95% of the particles finer than 1 lm. Its
typical physical properties are given in Table.3.1 & Fig.3.2. Silica fume colour is either premium white or grey.
Chemical Composition
Silica fume is composed primarily of pure silica in non-crystalline form. X-ray diffraction analysis of
different silica fumes reveals that material is essentially vitreous silica, mainly of cristobalite form. Silica fume
has a very high content of amorphous silicon dioxide and consists of very fine spherical particles.
Fig. 3.2 Schematic diagram of silica fume production
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Table 3.1 Typical physical properties of silica fume
3.2 METAKAOLIN
What is metakaolin?
Metakaolin is refined kaolin clay that is fired (calcined) under carefully controlled conditions to create
an amorphous aluminosilicate that is reactive in concrete. Like other pozzolans (fly ash and silica fume are two
common pozzolans), metakaolin reacts with the calcium hydroxide (lime) byproducts produced during cement
hydration.(Fig.3.3)
3.3 PULVERISED FUEL ASH (PFA)
The Lands and Works Branch Practice Note on Concrete Technology No. 4, The Use of Pulverised
Fuel Ash in Structural Concrete, was issued in 1983. It was stated therein that the Note would be reviewed when
more information on the local use of PFA was available. There is more information available now, but there is
nothing which requires the Note to be amended. There are, however, other factors which make the issue of this
Addendum desirable.(Fig.3.4)
IV. Result and Discussion
Fig 4.1 comparison of the effect of CSF and MK on the dosage of air entraining agent to obtain
7±1 % air content in the fresh concrete
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Fig 4.1 indicates comparison of the effect of CSF and MK on the dosage of air entraining agent
needed to attain 7.5 0.6 % air content of the fresh mix is shown in Figure 1. A constant amount of
superplastisizer of 0.35% by mass of the binder was adopted for both CSF and MK mixes. The dosage of
air entraining admixture required to produce a given volume of air in concrete containing more than 5% CSF
or MK, as partial mass replacement for PC, increases markedly with increasing amounts of CSF or MK. The
admixture requirement rises very sharply for increase in CSF or MK content from 15 to 20%, indicating even
higher air entraining admixture demand for higher amounts of the two pozzolanic materials. The trend of
this increase is identical for both CSF and MK concretes. However the CSF concrete is more
demanding in air entraining agent than MK concrete. This is primarily due to the higher specific surface
of CSF which leads to more air entraining agent being adsorbed and fewer molecules of the agent available
to be adsorbed at the air-water interfaces. The carbon content of CSF (Table 1) will also contribute to this
additional adsorption. The measured slumps for these mixtures were in the ranges 45-210 mm and 50-210
mm for the CSF and MK concretes respectively. Figure 2 shows the variations in the slump with the level of
pozzolanic replacements. The results demonstrate the higher water demand of CSF as compared to MK, as the
replacement level increases. The inconsistency in the results obtained for the 20% replacements is attributed to
specimen variability.
Fig 4.2 comparison of the effect of CSF and MF on the slumps obtained for concretes
Figure 4.2 indicates a constant dosage of air entraining agent (0.06%) and the target air content
was achieved even at the higher cement replacement levels. This suggests that the presence of super
plasticizer enhances the ability of the air entraining agent to entrain air in concrete containing these two
pozzolanic materials possibly by competing with the latter for surface adsorption sites.
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Fig 4.3 comparison of the effect of CSF and MK on the dosage of super plasticizer required to obtain 6
±1 % air content and 100±20 mm slump in the fresh concrete
Figure 4.3 gives the variations in the measured air contents in the control and CSF concrete with
increasing dosage of air entraining agent. The results clearly demonstrate the efficiency of the admixture in
entraining air in all the concretes investigated. It is seen that sharp rises in the air contents are obtained for
dosages up to 0.12%. Dosages greater than 0.12% have less influence on air content in the case of 20% CSF
whereas the air content of the control and 10% CSF concretes show continuous increase. A similar
behavior was encountered by Carette and Malhotra who found it difficult to entrain more than 6% air in
concretes with 20% CSF.
Fig 4.4 Effect of air entraining agent on air content of control and MK concrete with 0.3 and
0.5% super plasticizer respectively
Figure 4. 4 gives the variations in the measured air contents of MK concrete with increasing air
entraining agent. Again as with CSF concrete, the results show the efficiency of the admixture in entraining
air in such concretes. It is seen that steady increases in the air contents are obtained for dosages up to 0.24%.
This optimum limit is significantly greater than the limit of 0.12% dosage exhibited by CSF concrete.
7. Analysis of Admixtures and Their Effects of Silica Fumes, Metakaolin and Pfa on the Air Content
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Fig 4.5 Effect of air entraining agent on air content of control and PFA concrete
Fig 4.5 also indicate that it would be difficult to entrain air in excess of about 6%, (though normally
not desirable) in 20% MK concrete even with high dosages of air entraining agent. In the case of 10%
MK, air contents in excess of 10% may be entrained. Similar results were encountered in the case of the
CSF concretes. This behaviour is attributed to the dispersal effects when high dosages of air entraining
agent are used in conjunction with high pozzolan levels, leading to greater adsorption rates
entraining agent on air content of control and PFA
Fig 4.6 comparison of the effect of air entraining agent on air content of control and
20% CSF, MK and PFA concrete
Figure 4 . 6 shows the large the air content caused by the incorporation of PFA, irrespective of
the dosage of the air entraining agent. This reduction increases as the PFA level increases for all dosages
of the admixture. Although moderate increases in air content are obtained for the 20% PFA concrete,
albeit at the cost of high dosages of the
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Fig 4.7 percentage strength reduction versus percentage air content increase for concretes under
investigation at different curing ages
Figure4.7 gives a plot of the percentage reductions in strength with percentage increases in the
air content of concretes incorporating CSF, MK or PFA. It can be seen that the relationship between
the percentage reductions in strength and the percentage increases in strength is almost linear with the
exception of those reductions corresponding to small increases in the air content of the fresh concrete.
Table 4.1 summarises the results for the compressive strength reductions at each of the ages
of 7, 14, 28 and 90 days corresponding to increases in the air contents for concretes incorporating CSF,
MK or PFA & Effect of increase in air content on reduction in compressive strength.
Table 4.1 Results for the compressive strength reductions
For example when the air content in 10% CSF concrete increases by 304% i.e. from 2.6 to 10.5%
there is a reduction in the 28-day compressive strength of 41%. The reduction in the 28-day strength of
the 10% MK concrete corresponding to an increase in the air content of 300%, i.e. from 2.5 to 10% is
33%. Similar effects are produced in the PFA concretes. For example an increase in air content of 150%,
i.e. from 2.6 to 6.5% in 20% PFA concrete gives a reduction in the 28 day strength of 24%. The results show
that irrespective of the curing time, the percentage reductions in strength due the increase in air content are
more or less the same for all concretes considered in the present study.
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V. Conclusions
The following conclusions may be drawn from the work reported in this paper:
For a given slump and air content CSF has more demand for superplasticiser and air entraining admixtures than
MK. The superplasticiser enhances the performance of the air entraining admixture and/or itself plays a
secondary role in entraining air to the fresh concrete. A three fold increase in slump is produced in control
and 10% CSF concretes by adding 0.12% of air entraining admixture.
Although further additions of the admixture lead to increased slump in the control, little
benefit in workability is exhibited by the CSF concrete. This is attributed to the greater diffusion of the air
entrain inggent and consequent adsorption of the admixture by the very fine CSF particles. Up to 0.12% air
entraining admixture results in steep rises in the air content of superplasticised CSF concrete.
The benefits of higher levels of the admixture diminish, particularly in the concretes with
high CSF contents (20%). The superplasticiser plays an important role in increasing the air content of
low level CSF concrete. Up to 0.24% air entraining admixture results in a steady increase in the air content
of MK concrete. This is compared to a limit of 0.12% for CSF concrete. Non-air entrained control, CSF and
MK concretes all have the same volume of naturally entrapped air (approximately 2%).
This is attributed to the role played by the additional superplasticiser used in the CSF and MK
concretes. PFA causes large reductions in the air content of fresh concrete, irrespective of the dosage of the
air entraining admixture. The compressive strength of all concretes show systematic and more or less linear
reductions with increasing air contents (2 to 10%) of the fresh concrete. Further analysis is done with software
for extra accuracy in result.
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