Workability refers to the ease with which fresh concrete can be mixed, placed, compacted and finished. It is affected by factors like water content, mix proportions, aggregate size and shape, grading and surface texture. Increasing water content or using admixtures improves workability by acting as a lubricant between particles. Larger, rounded aggregates require less water than smaller, angular ones. Well-graded aggregates with minimal voids also increase workability. Workability can be measured using slump, compacting factor, flow, or Vee Bee tests.
The document provides information on aggregates used in concrete, including their definition, classification, properties, grading, and tests. It defines aggregates as materials such as sand and gravel used to make concrete and mortar. Aggregates are classified by their geological origin, size, and shape. Their properties including strength, absorption, and density are described. The importance of proper grading of aggregates for density and strength of concrete is discussed. Common tests on aggregates like crushing value, impact value, and abrasion value are outlined.
This document provides an overview of concrete, including its composition, properties, production process, and testing. Some key points:
- Concrete is a composite material made of cement, fine and coarse aggregates, and water. It can be classified based on its cementing material, mix proportions, performance specifications, grade, density, and place of casting.
- The production of concrete involves batching, mixing, transporting, placing, compacting, curing, and finishing. Proper batching and mixing are important to ensure uniform strength. Compaction removes entrapped air for maximum strength. Curing maintains moisture for proper hardening.
- Concrete properties depend on water-cement ratio, with maximum theoretical
The document describes 7 different tests conducted on cement:
1. Field testing examines the cement's appearance, texture, and behavior when mixed with water.
2. The standard consistency test determines the percentage of water needed to achieve a standardized consistency for cement paste.
3. The fineness test evaluates the particle size distribution of cement, with finer particles offering a greater surface area for hydration.
4. The soundness test ensures cement does not expand after setting, which could indicate excess lime causing unsoundness.
5. The strength test measures the compressive strength of cement mortar mixtures at various ages (3, 7, 28 days).
6. The heat of hydration test examines the heat released
This document discusses the classification and properties of aggregates used in concrete. It describes three main classifications of aggregates: 1) based on unit weight as normal, heavyweight, or lightweight, 2) based on size as fine or coarse aggregate, and 3) based on shape as rounded, irregular, angular, or flaky. It then discusses various physical and engineering properties of aggregates including size, shape, strength, surface texture, specific gravity, bulk density, water absorption, and soundness. The purpose is to provide information on aggregates for use in concrete mixtures in civil engineering applications.
Admixtures are materials added to concrete mixes to modify properties. There are two main types - chemical and mineral. Chemical admixtures include plasticizers, superplasticizers, retarders, accelerators, and air-entraining agents. Mineral admixtures include fly ash, slag, and silica fume. Admixtures are used to increase workability, strength, and durability while decreasing water demand and permeability. Common admixtures like plasticizers and superplasticizers work by dispersing cement particles and lubricating the mix to increase flowability.
This document discusses concrete construction in extreme hot and cold weather conditions in India. It addresses the challenges of hot weather concreting such as increased water demand, accelerated slump loss, and increased risk of plastic shrinkage cracking. Recommendations for hot weather concreting include cooling the concrete, reducing placement time, and prompt curing. Cold weather concreting risks include reduced strength if water freezes within concrete. Recommendations include protecting concrete from freezing, using accelerants, and maintaining minimum curing temperatures. Proper planning, materials, and protection methods can help produce quality concrete despite temperature extremes.
This document discusses several special concreting techniques:
- Pumped concrete is concrete that can be pushed through a pipeline and must have a design that prevents blockages.
- Shortcrete or gunite is a mortar or fine concrete pneumatically projected at high velocity, used for thin sections with less formwork.
- Underwater concrete requires special mixes placed via bagging, buckets, tremie pipes, or grouted aggregates to prevent water intrusion.
- Other techniques include pre-packed concrete placed underwater and special considerations for hot/cold weather concreting. Proper mix design and placement methods are essential for successful implementation of special concreting applications.
This document discusses the components, classification, properties, workability, and strength testing of concrete. Concrete is made up of cement, coarse aggregate, fine aggregate, air, and water. It can be classified as hardened or fresh concrete. The properties of fresh concrete include workability, segregation, and bleeding, while hardened concrete properties include strength, impermeability, durability, and dimensional variations. Workability is tested using slump, compaction factor, and Vebe tests. Compressive strength of hardened concrete is tested using cube or cylinder tests.
The document provides information on aggregates used in concrete, including their definition, classification, properties, grading, and tests. It defines aggregates as materials such as sand and gravel used to make concrete and mortar. Aggregates are classified by their geological origin, size, and shape. Their properties including strength, absorption, and density are described. The importance of proper grading of aggregates for density and strength of concrete is discussed. Common tests on aggregates like crushing value, impact value, and abrasion value are outlined.
This document provides an overview of concrete, including its composition, properties, production process, and testing. Some key points:
- Concrete is a composite material made of cement, fine and coarse aggregates, and water. It can be classified based on its cementing material, mix proportions, performance specifications, grade, density, and place of casting.
- The production of concrete involves batching, mixing, transporting, placing, compacting, curing, and finishing. Proper batching and mixing are important to ensure uniform strength. Compaction removes entrapped air for maximum strength. Curing maintains moisture for proper hardening.
- Concrete properties depend on water-cement ratio, with maximum theoretical
The document describes 7 different tests conducted on cement:
1. Field testing examines the cement's appearance, texture, and behavior when mixed with water.
2. The standard consistency test determines the percentage of water needed to achieve a standardized consistency for cement paste.
3. The fineness test evaluates the particle size distribution of cement, with finer particles offering a greater surface area for hydration.
4. The soundness test ensures cement does not expand after setting, which could indicate excess lime causing unsoundness.
5. The strength test measures the compressive strength of cement mortar mixtures at various ages (3, 7, 28 days).
6. The heat of hydration test examines the heat released
This document discusses the classification and properties of aggregates used in concrete. It describes three main classifications of aggregates: 1) based on unit weight as normal, heavyweight, or lightweight, 2) based on size as fine or coarse aggregate, and 3) based on shape as rounded, irregular, angular, or flaky. It then discusses various physical and engineering properties of aggregates including size, shape, strength, surface texture, specific gravity, bulk density, water absorption, and soundness. The purpose is to provide information on aggregates for use in concrete mixtures in civil engineering applications.
Admixtures are materials added to concrete mixes to modify properties. There are two main types - chemical and mineral. Chemical admixtures include plasticizers, superplasticizers, retarders, accelerators, and air-entraining agents. Mineral admixtures include fly ash, slag, and silica fume. Admixtures are used to increase workability, strength, and durability while decreasing water demand and permeability. Common admixtures like plasticizers and superplasticizers work by dispersing cement particles and lubricating the mix to increase flowability.
This document discusses concrete construction in extreme hot and cold weather conditions in India. It addresses the challenges of hot weather concreting such as increased water demand, accelerated slump loss, and increased risk of plastic shrinkage cracking. Recommendations for hot weather concreting include cooling the concrete, reducing placement time, and prompt curing. Cold weather concreting risks include reduced strength if water freezes within concrete. Recommendations include protecting concrete from freezing, using accelerants, and maintaining minimum curing temperatures. Proper planning, materials, and protection methods can help produce quality concrete despite temperature extremes.
This document discusses several special concreting techniques:
- Pumped concrete is concrete that can be pushed through a pipeline and must have a design that prevents blockages.
- Shortcrete or gunite is a mortar or fine concrete pneumatically projected at high velocity, used for thin sections with less formwork.
- Underwater concrete requires special mixes placed via bagging, buckets, tremie pipes, or grouted aggregates to prevent water intrusion.
- Other techniques include pre-packed concrete placed underwater and special considerations for hot/cold weather concreting. Proper mix design and placement methods are essential for successful implementation of special concreting applications.
This document discusses the components, classification, properties, workability, and strength testing of concrete. Concrete is made up of cement, coarse aggregate, fine aggregate, air, and water. It can be classified as hardened or fresh concrete. The properties of fresh concrete include workability, segregation, and bleeding, while hardened concrete properties include strength, impermeability, durability, and dimensional variations. Workability is tested using slump, compaction factor, and Vebe tests. Compressive strength of hardened concrete is tested using cube or cylinder tests.
MEANING OF MIX DESIGN
GRADE OF CONCRETE.
FACTORS INFLUCING THE CHOICE OF MIX DESIGN.
MATHODS OF CONCRETE MIX DESIGN
MIX DESIGN BY INDIAN STANDARD METHOD.
This document discusses underwater concrete, including its production, placement methods, and quality control. It notes that underwater concrete must have proper mix design and flowability to consolidate under its own weight without vibration. The main placement methods described are tremie, pump, toggle bags, and bagwork. Quality control includes monitoring placement rate and volume. Common issues with underwater concrete include cement washout, laitance, and segregation, which mix design and proper placement seek to prevent.
The document outlines the key stages in the production of concrete: batching, mixing, transporting, placing, compacting, curing, and finishing. It describes the various methods used at each stage, including volume and weight batching, hand mixing and stationary mixers, transport using trucks and conveyors, placement using different techniques, compaction through hand tools and vibration, curing methods like immersion and membrane curing, and finishing concrete surfaces.
Properties of fresh and Hardened ConcreteVijay RAWAT
The document discusses various properties of fresh and hardened concrete. It describes workability, consistency, segregation, bleeding, mixing, placing, consolidating, and curing of fresh concrete. It also discusses compressive strength, tensile strength, modulus of elasticity, permeability, and durability of hardened concrete. The key properties of fresh concrete include workability, consistency, segregation, bleeding, setting time, and uniformity. Compressive strength is identified as the most important property of hardened concrete.
Curing concrete is important to allow the cement hydration process to continue and develop strength over time. Proper curing ensures concrete reaches its designed strength and durability by controlling moisture loss. Common curing methods include water curing through ponding, sprinkling or wet coverings; membrane curing using plastic sheeting or curing compounds; and steam curing to accelerate strength gain. Curing should continue for at least 7 days for normal concrete and 14 days if blended cements are used. Inadequate curing can lead to reduced strength, increased permeability and poor durability.
Permeability is the property that governs the rate of flow of a fluid into a porous solid like concrete. The main factors affecting permeability in concrete are the water-cement ratio, cement properties, aggregate size and grading, curing methods, and age of the concrete. A higher water-cement ratio results in more capillary pores in the concrete, increasing permeability. Proper curing and the ongoing hydration process over time causes the permeability of concrete to decrease as capillary pores reduce in size and number. High permeability in concrete can lead to issues like corrosion of reinforcement and damage from frost.
NDT techniques can evaluate concrete structures in a non-destructive manner by assessing strength, quality, and durability without damaging the concrete. Some key NDT tests described in the document include rebound hammer testing to estimate concrete strength, UPV testing to evaluate homogeneity and detect cracks or voids, half-cell potential testing to assess corrosion risk, and cover meter testing to determine reinforcement location and concrete cover thickness. NDT allows for more extensive evaluation than destructive testing methods at a lower cost. Test results are influenced by factors like moisture, temperature, reinforcement properties, and concrete composition.
This document discusses quality control and durability factors in concrete. It defines quality as conformance to requirements and durability as a concrete's ability to resist deterioration when exposed to the environment. Several factors influence concrete durability, including the materials used, water-cement ratio, compaction, curing and the physical and chemical conditions of the service environment. Common durability issues include corrosion, cracking from sulfate attack or alkali-silica reaction, and carbonation reducing alkalinity. Proper quality control of materials and construction processes is needed to produce durable concrete.
This document discusses the durability and permeability of concrete. It defines durability as the ability to last a long time without significant deterioration. Permeability is defined as the property that governs the rate of flow of a fluid into a porous solid. The document discusses factors that affect the durability and permeability of concrete such as water-cement ratio, cement properties, aggregate type and quality, curing methods, and use of admixtures. Maintaining a low water-cement ratio and limiting chloride and sulfate levels in concrete are important for ensuring durability.
The document discusses the gel/space ratio in concrete and its relationship to concrete strength. It states that the gel/space ratio governs the porosity of concrete, with a higher ratio resulting in lower porosity and higher strength. The gel/space ratio is affected by the water/cement ratio, as a higher water/cement ratio decreases the gel/space ratio by increasing porosity. Power's experiment showed the strength of concrete has a specific relationship to the gel/space ratio that can be calculated.
Concrete is the most widely used construction material in India with annual consumption exceeding 100 million cubic meters.
High performance concrete is a concrete in which certain characteristics are developed for a particular application and environment, so that it will give excellent performance in the structure in which it will be placed.
A high-strength concrete is always a high performance concrete, but a high-performance concrete is not always a high-strength concrete.
Vacuum dewatering is a process that removes excess water from freshly poured concrete to achieve an ideal water-cement ratio and improved properties. Concrete is poured and a vacuum pump then removes 15-25% of the water through a suction mat and filter pads. This results in higher strength, less cracking and shrinkage, improved abrasion resistance, and a smooth, level surface. Vacuum dewatering is commonly used for industrial and commercial floors that require high durability.
This document discusses fresh concrete and factors that affect its workability. It describes workability as the ease with which concrete can be mixed, placed, and compacted. Key factors that influence workability include water content, aggregate size and shape, admixtures, aggregate surface texture, and aggregate grading. Common tests to measure workability are the slump test, compacting factor test, and VeeBee consistometer test. The document also covers segregation and bleeding of concrete, their causes, and methods to prevent them.
This document discusses different methods for soil stabilization, including mechanical, physical, chemical, and bituminous stabilization. Mechanical stabilization involves compacting soil to increase density and strength. Physical stabilization involves blending soils or adding admixtures to improve properties. Chemical stabilization uses lime, cement, or other chemicals like calcium chloride to react with soils and modify their characteristics. Bituminous stabilization involves adding bitumen or asphalt to seal soil pores and increase cohesion between particles. The document provides details on appropriate soil types, required quantities, and construction methods for each stabilization technique.
The document discusses concrete mix design, including:
- Concrete is made from cement, aggregates, water, and sometimes admixtures.
- ACI and BIS methods are described for determining mix proportions based on factors like strength, workability, durability, and materials.
- A step-by-step example is provided to design a mix using the ACI method for a specified 30MPa strength, including determining water-cement ratio, volumes, and final proportions.
Workability of concrete is defined as the ease and homogeneity with which a freshly mixed concrete or mortar can be mixed, placed, compacted and finished. Strictly, it is the amount of useful internal work necessary to produce 100% compaction.
This document discusses different types of special concretes, including light weight concrete, aerated concrete, and no fines concrete. It provides details on the properties and production methods of these concretes. Light weight concrete has lower density than normal concrete, which provides benefits like reduced structural weight. Aerated concrete is made by introducing air bubbles into cement mortar, creating a lightweight cellular structure. No fines concrete omits fine aggregates, consisting of only cement, coarse aggregates, and water. These special concretes are used for applications requiring specific properties like lower density or higher insulation.
This document provides information on grouting and guniting processes. It defines grouting as placing a cementitious material into cavities to improve load capacity or repair structures. Grouting mixtures are described along with categories, properties, specifications and applications. Guniting is introduced as a technique using pneumatic application of cementitious mortar to rehabilitate structures like bridges and buildings. The document outlines equipment, procedures and processes for mixing, pumping and applying grouts and shotcrete.
This presentation gives a brief introduction on FRC's history, definition and why is it used. Types of FRC's and it's applications is explained in detail in later stages.Also, it covers various properties that affects FRC and a Case study in end.
This document discusses the compressive strength of concrete. It defines compressive strength as the ability of a material to withstand pushing forces. Concrete is strong in compression but weak in tension. The document describes how to test the compressive strength of concrete cube and cylinder specimens. It provides details on specimen size, curing, loading rate, and calculating compressive strength based on applied load divided by cross-sectional area.
The document discusses workability of fresh concrete. It defines workability as the ability of concrete to fill forms properly under vibration without reducing quality. Workability depends on water content, mix proportions, aggregate size and shape, and use of admixtures. The ideal workability allows for proper compaction and finishing with minimal bleeding or segregation. Common tests to measure workability include slump test, compacting factor test, flow test, and Vee Bee consistometer test. Factors like water-cement ratio, aggregate size and shape, grading, and admixtures affect workability.
The document discusses the properties of fresh concrete. Fresh concrete is a freshly mixed material that can be molded into any shape. Workability refers to how easily the concrete can be placed and compacted. Factors that affect the workability of concrete include the water content, mix proportions, size and shape of aggregates, aggregate surface texture, aggregate grading, and use of admixtures. Common tests used to measure the workability of fresh concrete include the slump test, compacting factor test, flow test, and consistometer tests. These tests help evaluate how easily the concrete can be mixed, transported, placed, and compacted.
MEANING OF MIX DESIGN
GRADE OF CONCRETE.
FACTORS INFLUCING THE CHOICE OF MIX DESIGN.
MATHODS OF CONCRETE MIX DESIGN
MIX DESIGN BY INDIAN STANDARD METHOD.
This document discusses underwater concrete, including its production, placement methods, and quality control. It notes that underwater concrete must have proper mix design and flowability to consolidate under its own weight without vibration. The main placement methods described are tremie, pump, toggle bags, and bagwork. Quality control includes monitoring placement rate and volume. Common issues with underwater concrete include cement washout, laitance, and segregation, which mix design and proper placement seek to prevent.
The document outlines the key stages in the production of concrete: batching, mixing, transporting, placing, compacting, curing, and finishing. It describes the various methods used at each stage, including volume and weight batching, hand mixing and stationary mixers, transport using trucks and conveyors, placement using different techniques, compaction through hand tools and vibration, curing methods like immersion and membrane curing, and finishing concrete surfaces.
Properties of fresh and Hardened ConcreteVijay RAWAT
The document discusses various properties of fresh and hardened concrete. It describes workability, consistency, segregation, bleeding, mixing, placing, consolidating, and curing of fresh concrete. It also discusses compressive strength, tensile strength, modulus of elasticity, permeability, and durability of hardened concrete. The key properties of fresh concrete include workability, consistency, segregation, bleeding, setting time, and uniformity. Compressive strength is identified as the most important property of hardened concrete.
Curing concrete is important to allow the cement hydration process to continue and develop strength over time. Proper curing ensures concrete reaches its designed strength and durability by controlling moisture loss. Common curing methods include water curing through ponding, sprinkling or wet coverings; membrane curing using plastic sheeting or curing compounds; and steam curing to accelerate strength gain. Curing should continue for at least 7 days for normal concrete and 14 days if blended cements are used. Inadequate curing can lead to reduced strength, increased permeability and poor durability.
Permeability is the property that governs the rate of flow of a fluid into a porous solid like concrete. The main factors affecting permeability in concrete are the water-cement ratio, cement properties, aggregate size and grading, curing methods, and age of the concrete. A higher water-cement ratio results in more capillary pores in the concrete, increasing permeability. Proper curing and the ongoing hydration process over time causes the permeability of concrete to decrease as capillary pores reduce in size and number. High permeability in concrete can lead to issues like corrosion of reinforcement and damage from frost.
NDT techniques can evaluate concrete structures in a non-destructive manner by assessing strength, quality, and durability without damaging the concrete. Some key NDT tests described in the document include rebound hammer testing to estimate concrete strength, UPV testing to evaluate homogeneity and detect cracks or voids, half-cell potential testing to assess corrosion risk, and cover meter testing to determine reinforcement location and concrete cover thickness. NDT allows for more extensive evaluation than destructive testing methods at a lower cost. Test results are influenced by factors like moisture, temperature, reinforcement properties, and concrete composition.
This document discusses quality control and durability factors in concrete. It defines quality as conformance to requirements and durability as a concrete's ability to resist deterioration when exposed to the environment. Several factors influence concrete durability, including the materials used, water-cement ratio, compaction, curing and the physical and chemical conditions of the service environment. Common durability issues include corrosion, cracking from sulfate attack or alkali-silica reaction, and carbonation reducing alkalinity. Proper quality control of materials and construction processes is needed to produce durable concrete.
This document discusses the durability and permeability of concrete. It defines durability as the ability to last a long time without significant deterioration. Permeability is defined as the property that governs the rate of flow of a fluid into a porous solid. The document discusses factors that affect the durability and permeability of concrete such as water-cement ratio, cement properties, aggregate type and quality, curing methods, and use of admixtures. Maintaining a low water-cement ratio and limiting chloride and sulfate levels in concrete are important for ensuring durability.
The document discusses the gel/space ratio in concrete and its relationship to concrete strength. It states that the gel/space ratio governs the porosity of concrete, with a higher ratio resulting in lower porosity and higher strength. The gel/space ratio is affected by the water/cement ratio, as a higher water/cement ratio decreases the gel/space ratio by increasing porosity. Power's experiment showed the strength of concrete has a specific relationship to the gel/space ratio that can be calculated.
Concrete is the most widely used construction material in India with annual consumption exceeding 100 million cubic meters.
High performance concrete is a concrete in which certain characteristics are developed for a particular application and environment, so that it will give excellent performance in the structure in which it will be placed.
A high-strength concrete is always a high performance concrete, but a high-performance concrete is not always a high-strength concrete.
Vacuum dewatering is a process that removes excess water from freshly poured concrete to achieve an ideal water-cement ratio and improved properties. Concrete is poured and a vacuum pump then removes 15-25% of the water through a suction mat and filter pads. This results in higher strength, less cracking and shrinkage, improved abrasion resistance, and a smooth, level surface. Vacuum dewatering is commonly used for industrial and commercial floors that require high durability.
This document discusses fresh concrete and factors that affect its workability. It describes workability as the ease with which concrete can be mixed, placed, and compacted. Key factors that influence workability include water content, aggregate size and shape, admixtures, aggregate surface texture, and aggregate grading. Common tests to measure workability are the slump test, compacting factor test, and VeeBee consistometer test. The document also covers segregation and bleeding of concrete, their causes, and methods to prevent them.
This document discusses different methods for soil stabilization, including mechanical, physical, chemical, and bituminous stabilization. Mechanical stabilization involves compacting soil to increase density and strength. Physical stabilization involves blending soils or adding admixtures to improve properties. Chemical stabilization uses lime, cement, or other chemicals like calcium chloride to react with soils and modify their characteristics. Bituminous stabilization involves adding bitumen or asphalt to seal soil pores and increase cohesion between particles. The document provides details on appropriate soil types, required quantities, and construction methods for each stabilization technique.
The document discusses concrete mix design, including:
- Concrete is made from cement, aggregates, water, and sometimes admixtures.
- ACI and BIS methods are described for determining mix proportions based on factors like strength, workability, durability, and materials.
- A step-by-step example is provided to design a mix using the ACI method for a specified 30MPa strength, including determining water-cement ratio, volumes, and final proportions.
Workability of concrete is defined as the ease and homogeneity with which a freshly mixed concrete or mortar can be mixed, placed, compacted and finished. Strictly, it is the amount of useful internal work necessary to produce 100% compaction.
This document discusses different types of special concretes, including light weight concrete, aerated concrete, and no fines concrete. It provides details on the properties and production methods of these concretes. Light weight concrete has lower density than normal concrete, which provides benefits like reduced structural weight. Aerated concrete is made by introducing air bubbles into cement mortar, creating a lightweight cellular structure. No fines concrete omits fine aggregates, consisting of only cement, coarse aggregates, and water. These special concretes are used for applications requiring specific properties like lower density or higher insulation.
This document provides information on grouting and guniting processes. It defines grouting as placing a cementitious material into cavities to improve load capacity or repair structures. Grouting mixtures are described along with categories, properties, specifications and applications. Guniting is introduced as a technique using pneumatic application of cementitious mortar to rehabilitate structures like bridges and buildings. The document outlines equipment, procedures and processes for mixing, pumping and applying grouts and shotcrete.
This presentation gives a brief introduction on FRC's history, definition and why is it used. Types of FRC's and it's applications is explained in detail in later stages.Also, it covers various properties that affects FRC and a Case study in end.
This document discusses the compressive strength of concrete. It defines compressive strength as the ability of a material to withstand pushing forces. Concrete is strong in compression but weak in tension. The document describes how to test the compressive strength of concrete cube and cylinder specimens. It provides details on specimen size, curing, loading rate, and calculating compressive strength based on applied load divided by cross-sectional area.
The document discusses workability of fresh concrete. It defines workability as the ability of concrete to fill forms properly under vibration without reducing quality. Workability depends on water content, mix proportions, aggregate size and shape, and use of admixtures. The ideal workability allows for proper compaction and finishing with minimal bleeding or segregation. Common tests to measure workability include slump test, compacting factor test, flow test, and Vee Bee consistometer test. Factors like water-cement ratio, aggregate size and shape, grading, and admixtures affect workability.
The document discusses the properties of fresh concrete. Fresh concrete is a freshly mixed material that can be molded into any shape. Workability refers to how easily the concrete can be placed and compacted. Factors that affect the workability of concrete include the water content, mix proportions, size and shape of aggregates, aggregate surface texture, aggregate grading, and use of admixtures. Common tests used to measure the workability of fresh concrete include the slump test, compacting factor test, flow test, and consistometer tests. These tests help evaluate how easily the concrete can be mixed, transported, placed, and compacted.
This document discusses the stages of concrete, including fresh concrete and hardened concrete. It describes the ingredients that make up fresh concrete, including cement, aggregates, admixtures, and water. It explains the roles of each ingredient and discusses factors like aggregate size, grading, and surface texture that affect workability. The document outlines the process of manufacturing concrete, including batching, mixing, transporting, placing, compacting, and curing. It also discusses concepts like bleeding, segregation, workability tests, and factors that affect bleeding of concrete such as water-cement ratio, cement content, and aggregate type.
The document discusses performance of concrete blended with steel fibers. It aims to increase the compressive strength, tensile strength and ductility of concrete. It describes factors affecting the workability of concrete such as water content, mix proportions, size and shape of aggregates, grading of aggregates, and use of admixtures. It also discusses tests to measure workability including slump test and compaction factor test. Compressive strength testing of hardened concrete is also covered.
This document provides information on various types of admixtures that are added to concrete mixtures. It discusses chemical admixtures including accelerators, retarders, water reducers, super plasticizers, and air entraining agents. It also discusses mineral admixtures such as fly ash, blast furnace slag, silica fume, and rice husk ash. It provides details on plasticizers and their mechanisms of action in dispersing cement particles. It describes different types of super plasticizers and discusses the purposes and examples of retarders and accelerators. The document concludes with sections on air entraining admixtures and their effects, as well as details on various mineral admixtures including their sources and functions in concrete.
During filtration, the clear water passes through filters that have different pore sizes and are made of different materials (such as sand, gravel, and charcoal). These filters remove dissolved particles and germs, such as dust, chemicals, parasites, bacteria, and viruses.
Influence of Water Cement Ratio and The Size of Aggregate on The Properties O...IRJESJOURNAL
Abstract: Pervious concrete is a tailored-property concrete with high water permeability which allow the passage of water to flow easily through the existing interconnected large pore structure which is obtained by eliminating the sand from the normal concrete mix. This study investigates the effect of water cement ratio and size of aggregate on the property of pervious concrete. Concrete mixes with five different water cement ratio (0.28, 0.30, 0.32, 0.33, 0.34) and two different single sized aggregate (10mm and 12.5mm) were prepared to find an optimum mix yielding the highest strength but the strength of no-fine concrete is lower that of normal concrete. It was found that the compressive strength increases with increase in water/cement ratio where the permeability decreases. Both the permeability and compressive strength increases as the size of aggregate increases.
Concrete is a mixture of aggregates, water, and a paste made from portland cement and water. The aggregates make up 60-70% of the volume and include coarse and fine materials. Water is needed for the cement's chemical reaction and workability, though excess water reduces strength. Admixtures such as retarders, accelerators, and air entrainers can modify properties. Slump tests measure workability, with higher slumps indicating better flow. Factors like water-cement ratio, temperature, aggregate size and properties affect slump. Curing protects the concrete as it hardens and influences long-term strength and durability.
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This document provides information on the properties of fresh and hardened concrete. It discusses workability of fresh concrete, including factors that affect workability such as water-cement ratio, aggregate size and shape, and admixtures. It also describes tests used to measure workability, including slump, compaction factor, and vee-bee tests. The document then covers topics related to hardened concrete such as compressive strength, shrinkage, and permeability. It analyzes factors that influence the strength of concrete like water-cement ratio, gel-space ratio, aggregate size, curing temperature, and concrete age. The functions of admixtures in concrete are also briefly mentioned.
Water plays a crucial role in concrete as it is required for the chemical process of hydration where water reacts with cement to gain strength over time. The water-cement ratio affects properties like strength and durability, with lower ratios producing higher strengths and more durable concrete. Proper curing with water is also important to ensure continued hydration and development of strength and durability.
This document provides information about concrete, its ingredients, properties, types of cement, and methods of placing and curing concrete. It discusses that concrete is composed of cement, fine aggregates (sand), coarse aggregates, and water. The main ingredients are cement (usually Portland cement), water, fine aggregates, and coarse aggregates. It also outlines some key properties of good concrete including being strong, durable, water tight, workable, and able to resist wear and tear. The document then discusses reinforced concrete and factors affecting the workability and durability of concrete. It concludes with descriptions of different cement types and methods for placing and curing concrete.
SPRAYCRETE is supplied in powder form, specially developed and designed to meet the demand for efficient and multifold properties desired at guniting job sites. It is suitable admixture for guniting and shotcreting operations. Accelerates the rate of hardening gives perfect water proofing. It have excellent bonding properties which reduces the wastage during operation of guniting, shotcreting or sprayed job, can be do a thick layer in single operation.
By guniting with adding the admixture, it accelerats the hardening process by the reactive components rapidly combine with cement particles to setting and hardening process thereby making the mortar or concrete rock hard in minutes after jetting. It reduces the loss of material caused by rebound, thus reducing the cost. It can be used with all types of cement.
This document discusses different types of admixtures used in concrete, including their uses and effects. It covers mineral admixtures like fly ash and silica fume that can reduce costs and improve properties. It also discusses chemical admixtures, specifically highlighting water reducers, superplasticizers, accelerators, and retarders. Water reducers and superplasticizers can lower the water-cement ratio while maintaining workability, leading to increased strength. Accelerators can reduce setting time while retarders have the opposite effect of delaying setting.
The document discusses various types of chemical admixtures used for concrete, including plasticizers, superplasticizers, retarders, accelerators, and air-entraining admixtures. It explains that admixtures can modify the properties of fresh and hardened concrete by altering workability, strength development, permeability, and durability. Superplasticizers in particular are highlighted as they can significantly reduce water content and increase workability and strength. The document concludes that superplasticizers and air-entraining admixtures are most commonly used, and that superplasticizers allow for reduced cement and increased construction of large structures.
Water plays a key role in cement concrete as it acts as a reactant in the chemical process of hydration that provides concrete its strength over time. The water-cement ratio is an important factor, with lower ratios producing higher strength concrete. Water used for mixing must meet requirements for quality and impurities. Admixtures can be used to improve workability or reduce the water content. Proper curing is also important for achieving design strength and durability of the concrete. Sprayed concrete has advantages over poured concrete such as lower permeability and faster strength gain.
concrete, presentation includes ingredients of concrete , how we can achieve high strength of concrete in less days of curing, practically shown in the presentation according to the standards of ACI.
Concrete admixtures are added ingredients beyond cement, water, and aggregates that are used to modify the properties of fresh and hardened concrete. The main types of admixtures are air entrainers, water reducers, set retarders, set accelerators, and plasticizers. Air entrainers add microscopic air bubbles that increase durability in freezing environments. Water reducers allow a reduction in water while maintaining workability, increasing strength. Set retarders delay setting for hot weather, while set accelerators increase early strength for cold weather. Plasticizers make low-slump concrete flowable. Admixtures are selected and dosed to achieve specific concrete properties for construction needs.
CON 121 Session 5 - Special Considerations and Lightweightalpenaccedu
The document discusses special considerations for concrete mixes using lightweight aggregates, including factors that influence workability, bleeding, segregation, and strength. It describes properties of structural lightweight aggregates and notes that structural lightweight concrete requires attention to workability, placeability, finishability, and adequate air entrainment for durability. Mix designs should account for the lower density and higher absorption of lightweight aggregates.
An In-Depth Exploration of Natural Language Processing: Evolution, Applicatio...DharmaBanothu
Natural language processing (NLP) has
recently garnered significant interest for the
computational representation and analysis of human
language. Its applications span multiple domains such
as machine translation, email spam detection,
information extraction, summarization, healthcare,
and question answering. This paper first delineates
four phases by examining various levels of NLP and
components of Natural Language Generation,
followed by a review of the history and progression of
NLP. Subsequently, we delve into the current state of
the art by presenting diverse NLP applications,
contemporary trends, and challenges. Finally, we
discuss some available datasets, models, and
evaluation metrics in NLP.
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2. Workability
The ease with which concrete mixes can be compacted as
completely as possible while using the lowest possible
water/cement ratio.
OR
Workability is the ability of a fresh (plastic) concrete
mix to fill the form/mold properly with the desired
work (vibration) and without reducing the concrete's
quality
3. Water for Lubrication
The function of water is also to lubricate the
concrete so that the concrete can be compacted with
specified effort forthcoming at the site of work.
The lubrication required for handling concrete
without segregation, for placing without loss of
homogeneity, for compacting with the amount of
efforts forth-coming and to finish it sufficiently easily,
the presence of a certain quantity of water is of vital
importance.
4. Factors Affecting Workability
Water Content
Mix Proportions
Size of Aggregates
Shape of Aggregates
Surface Texture of Aggregate
Grading of Aggregate
Use of Admixtures.
5. Water content or Water Cement Ratio
More the water cement ratio more will be workability of
concrete. Since by simply adding water the inter particle
lubrication is increased.
High water content results in a higher fluidity and greater
workability. Increased water content also results in
bleeding. another effect of increased water content can
also be that cement slurry will escape through joints of
formwork.
More water can be added, provided a correspondingly
higher quantity of cement is also added to keep the
water/cement ratio constant, so that the strength
remains the same.
6. Mix Proportions
The higher the aggregate/cement ratio,
less quantity of paste is available for
providing lubrication, per unit surface area
of aggregate and hence the mobility of
aggregate is restrained.
On the other hand, in case of rich concrete
with lower aggregate/cement ratio, more
paste is available to make the mix cohesive
and fatty to give better workability.
7. Size of Aggregate & Surface Texture
The bigger the size of the aggregate, the less is the
surface area and hence less amount of water is required
for wetting the surface and less matrix or paste is
required for lubricating the surface to reduce internal
friction.
Greater size of Aggregate- less water is required to
lubricate it, the extra water is available for workability
Porous aggregates require more water compared to non
absorbent aggregates for achieving same degree of
workability.
8. Shape of Aggregates
Angular, elongated or flaky aggregate makes the concrete
very harsh when compared to rounded aggregates or
cubical shaped aggregates.
Contribution to better workability of rounded aggregate
will come from the fact that for the given volume or
weight it will have less surface area and less voids than
angular or flaky aggregate.
Not only that, being round in shape, the frictional
resistance is also greatly reduced. This explains the
reason why river sand and gravel provide greater
workability to concrete than crushed sand and aggregate.
9. Grading of Aggregates
A well graded aggregate is the one which has least amount of voids in a given
volume and higher the workability.
Other factors being constant, when the total voids are less, excess paste is
available to give better lubricating effect.
With excess amount of paste, the mixture becomes cohesive and fatty which
prevents segregation of particles.
10. Use of Admixtures
Chemical admixtures can be used to increase
workability.
Use of air entraining agent produces air bubbles
which acts as a sort of ball bearing between
particles and increases mobility, workability and
decreases bleeding, segregation.
The use of fine pozzolanic materials also have
better lubricating effect and more workability.
11. Weather Conditions
If temperature is high, evaporation
increases, thus workability decreases.
If wind is moving with greater velocity,
the rate of evaporation also increase
reduces the amount of water and
ultimately reducing workability.
12. Measurement of Workability
It is discussed earlier that workability of concrete is a complex property which
can be measured by
Slump Test
Compacting Factor Test
Flow Test
Vee Bee Consistometer Test.
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