Introduction to use of aggregates in concrete. Various Properties of aggregates and their effect on fresh and hardened concrete. Flakiness and Elongation Index of Concrete have also been discussed. Various tests performed for suitable usage of concrete in Civil engineering projects have also been discussed.
Cement is tested through laboratory and field tests to evaluate its properties and suitability. Key laboratory tests described in the document include:
- Fineness tests which measure particle size and surface area to determine reactivity.
- Setting time tests which ensure cement sets within specified time limits.
- Compressive strength tests where cement mortar cubes are crushed to determine strength over time.
- Soundness and loss of ignition tests which evaluate volume stability and carbon/moisture content.
Results of laboratory tests help ensure cement meets standards before use in construction projects.
The document discusses factors that affect the strength of concrete, including water-cement ratio, aggregate-cement ratio, maximum aggregate size, and degree of compaction. It states that concrete strength is inversely proportional to water-cement ratio according to Abrams' law. A lower water-cement ratio and higher degree of compaction produce stronger concrete by reducing porosity. A leaner aggregate-cement ratio also increases strength by absorbing water and reducing shrinkage. Larger aggregate size can reduce water needs but may decrease strength by lowering surface area for bond development.
Strength of concrete (for civil engineering) laxman singh
i have made all the slide for civil engineering and poly diploma civil.
these are 100% correct but in case of some error comment down or contact me on (laxmans227@gmail.com)
follow me for all updates
if u have any doubt fell free to ask on comment section
i upload new slides every sunday,
so keep calm and follow me(now).
software - power point presentation 2015
High-Volume Fly Ash Concrete: According to some researchers, more than 30% fly ash by mass (equivalent as 50% by volume) of the cementitious material may be considered enough to classify the mixtures as High-Volume Fly Ash (HVFA) concrete. It is possible to produce sustainable, high performance concrete mixtures with 50% or more cement replacement by fly ash.
Aggregates make up 60-75% of the total volume of concrete and include materials like gravel, sand, and crushed stone. The physical properties of aggregates that are important for concrete include unit weight, void content, specific gravity, particle shape and surface texture, shrinkage, absorption, and resistance to freezing and thawing. Proper aggregate selection and testing physical properties helps ensure high-quality concrete with good strength and durability.
Cement is tested through laboratory and field tests to evaluate its properties and suitability. Key laboratory tests described in the document include:
- Fineness tests which measure particle size and surface area to determine reactivity.
- Setting time tests which ensure cement sets within specified time limits.
- Compressive strength tests where cement mortar cubes are crushed to determine strength over time.
- Soundness and loss of ignition tests which evaluate volume stability and carbon/moisture content.
Results of laboratory tests help ensure cement meets standards before use in construction projects.
The document discusses factors that affect the strength of concrete, including water-cement ratio, aggregate-cement ratio, maximum aggregate size, and degree of compaction. It states that concrete strength is inversely proportional to water-cement ratio according to Abrams' law. A lower water-cement ratio and higher degree of compaction produce stronger concrete by reducing porosity. A leaner aggregate-cement ratio also increases strength by absorbing water and reducing shrinkage. Larger aggregate size can reduce water needs but may decrease strength by lowering surface area for bond development.
Strength of concrete (for civil engineering) laxman singh
i have made all the slide for civil engineering and poly diploma civil.
these are 100% correct but in case of some error comment down or contact me on (laxmans227@gmail.com)
follow me for all updates
if u have any doubt fell free to ask on comment section
i upload new slides every sunday,
so keep calm and follow me(now).
software - power point presentation 2015
High-Volume Fly Ash Concrete: According to some researchers, more than 30% fly ash by mass (equivalent as 50% by volume) of the cementitious material may be considered enough to classify the mixtures as High-Volume Fly Ash (HVFA) concrete. It is possible to produce sustainable, high performance concrete mixtures with 50% or more cement replacement by fly ash.
Aggregates make up 60-75% of the total volume of concrete and include materials like gravel, sand, and crushed stone. The physical properties of aggregates that are important for concrete include unit weight, void content, specific gravity, particle shape and surface texture, shrinkage, absorption, and resistance to freezing and thawing. Proper aggregate selection and testing physical properties helps ensure high-quality concrete with good strength and durability.
This document discusses high-strength concrete (HSC). It defines HSC as concrete with a 28-day compressive strength of over 40 MPa. HSC uses a low water-cement ratio, smaller aggregate sizes, and admixtures like silica fume and superplasticizers. Compared to normal-strength concrete, HSC has higher resistance to pressure, modulus of elasticity, and strength gained at an earlier age. Some applications of HSC mentioned include bridges, high-rise buildings, power plants, and skyscrapers. The document concludes that interest in HSC is growing rapidly due to its advantages like reduced material needs and increased construction speeds.
Self-compacting concrete (SCC) was developed in Japan in the 1980s to achieve complete compaction without vibration. SCC flows under its own weight, fills formwork and passes through reinforced areas without segregation of ingredients. It consists of cement, fine and coarse aggregates, chemical and mineral admixtures. Superplasticizers and viscosity modifying agents provide workability and stability. Tests like slump flow, V-funnel, and J-ring evaluate filling ability, passing ability and resistance to segregation. SCC offers benefits of reduced labor, better compaction and surface finish compared to conventional concrete but requires more precise material proportions and quality control.
This document provides information on concrete mix design and testing concrete cubes. It discusses determining the target mean strength of concrete, properties and types of aggregates, and how to calculate the aggregate to cement ratio and water to cement ratio. It also outlines the process for sampling concrete, filling and compacting concrete cubes, curing the cubes, and testing them to determine compressive strength. The compressive strength tests help evaluate the quality of the concrete mix and its constituents. Maintaining proper procedures at each stage of mixing, placing, and curing the concrete is important for achieving the desired compressive strength.
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 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 various types and causes of cracks in buildings. It classifies cracks as either structural or non-structural and further categorizes them based on their width. Common causes of cracks include moisture movement, thermal variation, excessive loading, and foundation settlement. Plastic shrinkage, bleeding, delayed curing, and use of poor quality materials can lead to cracks in concrete before it hardens. Thermal expansion and contraction from temperature changes is another major cause of cracks. Various remedial measures are proposed to prevent or reduce cracking in structures.
Concrete permeability is a key factor in its durability. Permeability is affected by water-cement ratio, with lower ratios producing less permeable concrete. Curing also impacts permeability. Proper curing, including moist curing, produces less permeable concrete. Permeability testing involves measuring water flow through a sample over time under pressure. Sulfate attack can occur when sulfates penetrate permeable concrete and form expansive compounds that crack the material. Resistance to sulfates is improved with lower permeability concrete.
High temperatures can lead to issues with concrete like loss of workability, increased risk of cracking, and thermal cracking. To address this, the temperature of concrete ingredients should be lowered by cooling the water, shading aggregates, and using set-retarding admixtures. In large pours, lower cement content mixtures and measures to control temperature differentials within the concrete mass are important. For cold weather, air-entrained concrete and protecting plastic concrete from freezing are crucial.
1. Vacuum concrete involves mixing concrete with high water content to improve workability, then extracting extra water using vacuum dewatering to reduce the water-cement ratio and improve strength and durability.
2. A series of experiments investigated the effects of various factors on the volume of water extracted and the compressive strength distribution within vacuum concrete slabs. Higher slump, lower strength, thicker slabs, and earlier vacuum treatment resulted in more water extracted.
3. Vacuum treatment improved compressive strengths throughout the slab thickness but particularly at upper layers, reducing the strength gradient. Strengths were highest with later vacuum treatment and lower water-cement ratios.
Hydration is the chemical reaction between cement and water that forms bonds and results in a solid mass. The main compounds in cement - C3S, C2S, C3A, and C4AF - hydrate to form calcium silicate hydrates (C-S-H gel), calcium hydroxide, and calcium aluminate hydrates. Hydration is affected by factors like composition, fineness, water-cement ratio, and curing temperature. Special cements include acid-resistant, blast furnace, expanding, colored, high alumina, hydrophobic, low heat, and oil well cements used for their properties.
Utilisation of Fly Ash in Cement ConcretePramey Zode
This document discusses the use of fly ash as a partial replacement for cement in concrete. Fly ash is a byproduct of coal combustion in thermal power plants. Using fly ash in concrete can reduce costs, improve workability and durability, and provide environmental benefits by reducing the amount of cement needed. The document examines the chemical properties of fly ash and how it reacts with cement. It recommends using fly ash to replace up to 50% of cement in high-volume fly ash concrete, which can further improve sustainability and concrete performance.
Sulphate attack occurs when sulphates react with hardened cement paste, causing expansion and cracking of concrete. Soil sulphates do not severely damage concrete, but water sulphates can enter porous concrete and react with hydration products. This forms ettringite which increases in volume, disintegrating the concrete. Sulphate attack can be external from sulphates in groundwater penetrating concrete, or internal from sulphates in the original mix. Delayed ettringite formation is a type of internal sulphate attack where ettringite decomposes during curing then reforms, expanding and damaging the 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.
This document discusses using a scientific approach to determine the workability of concrete by measuring its rheological properties. It outlines that workability is traditionally determined through empirical tests like slump tests, which have limitations. Rheology allows measurement of yield stress and plastic viscosity, parameters that better describe concrete flow. Various rheometers are described that can measure these properties, like coaxial cylinder and parallel plate devices. Factors influencing concrete rheology are also discussed. The document concludes workability should be evaluated based on rheological measurements to address limitations of empirical tests.
This document discusses polymer modified concrete (PMC). It begins by providing background on the early patents for polymer modification of cement and concrete in the 1920s. Styrene-butadiene rubber (SBR) latex is commonly used to produce PMC and improves its flexural and compressive strength as well as durability. The document examines the tensile and compressive strengths of PMC made with varying proportions of polymers like PVA emulsion. PMC has applications in pavements, tunnel linings, bridges and more due to its high performance, low cost, durability and improved strength properties over ordinary concrete.
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 provides information on aggregates used in traditional building materials. It defines aggregates as fillers used with binding materials that are derived from rocks. Aggregates make up 70-80% of concrete's volume and influence its properties. Aggregates are broadly classified into fine aggregates smaller than 4.75mm and coarse aggregates larger than 4.75mm. The document discusses various types of coarse aggregates based on geological origin, size, shape, and unit weight. It also covers properties of aggregates like strength, shape, specific gravity, moisture content and tests conducted on aggregates. Alkali aggregate reaction and measures to prevent it are summarized.
The document discusses various tests used to evaluate the properties of fresh and hardened concrete, including slump tests, compaction factor tests, Vee-Bee consistometer tests, flow tests, and Kelly ball tests for fresh concrete workability. Hardened concrete is evaluated using rebound hammer tests to estimate compressive strength and ultrasonic pulse velocity tests to assess quality. A case study describes a reinforced concrete structure collapse due to design flaws in accounting for beam-column joint forces, inadequate reinforcement detailing, and omitted column links.
This document discusses water and admixtures used in concrete. It describes how the quality of water can impact concrete strength, durability and corrosion. It outlines acceptable limits for impurities in water and discusses the effects of seawater. It also categorizes and explains the purpose and effects of different types of admixtures (A-F) including water reducers, retarders, accelerators and superplasticizers. Specialty admixtures like air-entraining and waterproofing are also briefly covered.
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 discusses high-strength concrete (HSC). It defines HSC as concrete with a 28-day compressive strength of over 40 MPa. HSC uses a low water-cement ratio, smaller aggregate sizes, and admixtures like silica fume and superplasticizers. Compared to normal-strength concrete, HSC has higher resistance to pressure, modulus of elasticity, and strength gained at an earlier age. Some applications of HSC mentioned include bridges, high-rise buildings, power plants, and skyscrapers. The document concludes that interest in HSC is growing rapidly due to its advantages like reduced material needs and increased construction speeds.
Self-compacting concrete (SCC) was developed in Japan in the 1980s to achieve complete compaction without vibration. SCC flows under its own weight, fills formwork and passes through reinforced areas without segregation of ingredients. It consists of cement, fine and coarse aggregates, chemical and mineral admixtures. Superplasticizers and viscosity modifying agents provide workability and stability. Tests like slump flow, V-funnel, and J-ring evaluate filling ability, passing ability and resistance to segregation. SCC offers benefits of reduced labor, better compaction and surface finish compared to conventional concrete but requires more precise material proportions and quality control.
This document provides information on concrete mix design and testing concrete cubes. It discusses determining the target mean strength of concrete, properties and types of aggregates, and how to calculate the aggregate to cement ratio and water to cement ratio. It also outlines the process for sampling concrete, filling and compacting concrete cubes, curing the cubes, and testing them to determine compressive strength. The compressive strength tests help evaluate the quality of the concrete mix and its constituents. Maintaining proper procedures at each stage of mixing, placing, and curing the concrete is important for achieving the desired compressive strength.
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 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 various types and causes of cracks in buildings. It classifies cracks as either structural or non-structural and further categorizes them based on their width. Common causes of cracks include moisture movement, thermal variation, excessive loading, and foundation settlement. Plastic shrinkage, bleeding, delayed curing, and use of poor quality materials can lead to cracks in concrete before it hardens. Thermal expansion and contraction from temperature changes is another major cause of cracks. Various remedial measures are proposed to prevent or reduce cracking in structures.
Concrete permeability is a key factor in its durability. Permeability is affected by water-cement ratio, with lower ratios producing less permeable concrete. Curing also impacts permeability. Proper curing, including moist curing, produces less permeable concrete. Permeability testing involves measuring water flow through a sample over time under pressure. Sulfate attack can occur when sulfates penetrate permeable concrete and form expansive compounds that crack the material. Resistance to sulfates is improved with lower permeability concrete.
High temperatures can lead to issues with concrete like loss of workability, increased risk of cracking, and thermal cracking. To address this, the temperature of concrete ingredients should be lowered by cooling the water, shading aggregates, and using set-retarding admixtures. In large pours, lower cement content mixtures and measures to control temperature differentials within the concrete mass are important. For cold weather, air-entrained concrete and protecting plastic concrete from freezing are crucial.
1. Vacuum concrete involves mixing concrete with high water content to improve workability, then extracting extra water using vacuum dewatering to reduce the water-cement ratio and improve strength and durability.
2. A series of experiments investigated the effects of various factors on the volume of water extracted and the compressive strength distribution within vacuum concrete slabs. Higher slump, lower strength, thicker slabs, and earlier vacuum treatment resulted in more water extracted.
3. Vacuum treatment improved compressive strengths throughout the slab thickness but particularly at upper layers, reducing the strength gradient. Strengths were highest with later vacuum treatment and lower water-cement ratios.
Hydration is the chemical reaction between cement and water that forms bonds and results in a solid mass. The main compounds in cement - C3S, C2S, C3A, and C4AF - hydrate to form calcium silicate hydrates (C-S-H gel), calcium hydroxide, and calcium aluminate hydrates. Hydration is affected by factors like composition, fineness, water-cement ratio, and curing temperature. Special cements include acid-resistant, blast furnace, expanding, colored, high alumina, hydrophobic, low heat, and oil well cements used for their properties.
Utilisation of Fly Ash in Cement ConcretePramey Zode
This document discusses the use of fly ash as a partial replacement for cement in concrete. Fly ash is a byproduct of coal combustion in thermal power plants. Using fly ash in concrete can reduce costs, improve workability and durability, and provide environmental benefits by reducing the amount of cement needed. The document examines the chemical properties of fly ash and how it reacts with cement. It recommends using fly ash to replace up to 50% of cement in high-volume fly ash concrete, which can further improve sustainability and concrete performance.
Sulphate attack occurs when sulphates react with hardened cement paste, causing expansion and cracking of concrete. Soil sulphates do not severely damage concrete, but water sulphates can enter porous concrete and react with hydration products. This forms ettringite which increases in volume, disintegrating the concrete. Sulphate attack can be external from sulphates in groundwater penetrating concrete, or internal from sulphates in the original mix. Delayed ettringite formation is a type of internal sulphate attack where ettringite decomposes during curing then reforms, expanding and damaging the 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.
This document discusses using a scientific approach to determine the workability of concrete by measuring its rheological properties. It outlines that workability is traditionally determined through empirical tests like slump tests, which have limitations. Rheology allows measurement of yield stress and plastic viscosity, parameters that better describe concrete flow. Various rheometers are described that can measure these properties, like coaxial cylinder and parallel plate devices. Factors influencing concrete rheology are also discussed. The document concludes workability should be evaluated based on rheological measurements to address limitations of empirical tests.
This document discusses polymer modified concrete (PMC). It begins by providing background on the early patents for polymer modification of cement and concrete in the 1920s. Styrene-butadiene rubber (SBR) latex is commonly used to produce PMC and improves its flexural and compressive strength as well as durability. The document examines the tensile and compressive strengths of PMC made with varying proportions of polymers like PVA emulsion. PMC has applications in pavements, tunnel linings, bridges and more due to its high performance, low cost, durability and improved strength properties over ordinary concrete.
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 provides information on aggregates used in traditional building materials. It defines aggregates as fillers used with binding materials that are derived from rocks. Aggregates make up 70-80% of concrete's volume and influence its properties. Aggregates are broadly classified into fine aggregates smaller than 4.75mm and coarse aggregates larger than 4.75mm. The document discusses various types of coarse aggregates based on geological origin, size, shape, and unit weight. It also covers properties of aggregates like strength, shape, specific gravity, moisture content and tests conducted on aggregates. Alkali aggregate reaction and measures to prevent it are summarized.
The document discusses various tests used to evaluate the properties of fresh and hardened concrete, including slump tests, compaction factor tests, Vee-Bee consistometer tests, flow tests, and Kelly ball tests for fresh concrete workability. Hardened concrete is evaluated using rebound hammer tests to estimate compressive strength and ultrasonic pulse velocity tests to assess quality. A case study describes a reinforced concrete structure collapse due to design flaws in accounting for beam-column joint forces, inadequate reinforcement detailing, and omitted column links.
This document discusses water and admixtures used in concrete. It describes how the quality of water can impact concrete strength, durability and corrosion. It outlines acceptable limits for impurities in water and discusses the effects of seawater. It also categorizes and explains the purpose and effects of different types of admixtures (A-F) including water reducers, retarders, accelerators and superplasticizers. Specialty admixtures like air-entraining and waterproofing are also briefly covered.
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.
1) The document discusses different types of aggregates used in construction including their classification, physical properties, and testing methods.
2) Aggregates are classified based on size, source, and density. Common physical properties examined include shape, texture, strength, specific gravity, porosity, and moisture content.
3) Key tests described are for crushing strength, impact value, abrasion resistance, specific gravity, absorption, and moisture content. Proper testing ensures aggregates meet requirements for uses like concrete.
This document discusses the properties and classification of aggregates used in concrete. It describes how aggregates can be classified based on size, weight, and composition. The key properties discussed include shape, texture, strength, density, moisture content, cleanliness, soundness, and thermal properties. Testing methods are provided for sieve analysis, grading, crushing strength, abrasion resistance, impact value, and soundness. The document also covers the workability of concrete and factors that influence it such as water-cement ratio, aggregate type and amount, cement type and amount, and use of admixtures.
Aggregates make up 70-80% of concrete by volume and can be classified by source, size, shape, and other properties. Their properties affect the workability, strength, and economics of concrete. Igneous, sedimentary, and metamorphic rocks are common sources. Aggregate size, shape, texture, strength, and durability all impact the performance of concrete. Tests are used to evaluate aggregate crushing strength, impact resistance, and abrasion characteristics important for different concreting applications. Proper aggregate selection and testing are essential for producing high quality concrete.
This document discusses the key materials used in concrete - cement, water, aggregates, and admixtures. It describes what concrete is, its types and uses. The main ingredients are described in detail, including their properties and how they affect the strength and performance of concrete. Aggregates make up the largest portion by volume and come in various sizes and grades. Proper mix design and material selection are important to produce durable concrete.
The document summarizes the key properties and classifications of aggregates used to make concrete. It discusses that aggregates provide bulk and strength to concrete. It classifies aggregates based on their geological origin, size, shape, grading, and unit weight. The summary properties of fine and coarse aggregates are also provided, including requirements for good aggregates.
Briefly describe about Construction Aggregates. How to manufractured how sampling its uses application all thing are described here. To understand about aggregate read this slide.
Aggregates are granular materials like sand, gravel, or crushed stone used with water and cement to make concrete. They come in two sizes: fine aggregates smaller than 5 mm and coarse aggregates larger than 5 mm. Aggregates provide strength, reduce cracking, and lower the cost of concrete. They are selected based on being hard, durable, and free of organic materials or other substances that could weaken the concrete. Aggregates are classified by size, manufacturing method, and density. Physical tests are conducted to determine properties like strength, hardness, porosity, and grading.
This document contains information about aggregates used in concrete provided by Deblina Dutta, a third year civil engineering student. It discusses the classification, properties, and uses of aggregates. Aggregates make up 70-80% of concrete by volume and include natural materials like sand, gravel, and crushed stone. They are classified based on their geological origin, size, shape, and unit weight. The properties of aggregates like composition, size, surface texture, specific gravity, bulk density, voids, porosity, absorption, and fineness modulus affect the properties of concrete. Aggregates are an important part of concrete as they give it body, make it economical, and contribute to its mechanical strength.
Aggregates are a combination of different sized stones used in construction. They are classified based on size, source, and density. Fine aggregates are less than 5mm while coarse aggregates are greater than 5mm. Natural aggregates come from sources like rivers while manufactured aggregates are crushed. Normal weight aggregates have densities from 1520-1680kg/m3 while lightweight aggregates are less than 1120kg/m3. Tests are conducted to determine properties like strength, hardness, durability and water absorption. Sieve analysis tests the grading and ensures a range of aggregate sizes are present.
Concrete is a mixture of paste and aggregates. Aggregates make up 60-75% of concrete and include sand, gravel, or crushed stone. Aggregates are classified as fine or coarse based on their size, and can be natural or manufactured. Tests are performed on aggregates to determine properties like grading, shape, density, moisture content, and durability which influence the properties of fresh and hardened concrete. Proper aggregate selection and testing is important for producing high quality, high strength concrete.
The aggregate is a relatively inert material and it imparts volume stability.
The aggregate provide about 75% of the body of the concrete and hence its influence is extremely important (70 to 80 %)
An aggregate should be of proper shape and size, clean, hard and well graded.
It must possess chemical stability and it must exhibit abrasion resistance.
Classification of Aggregate
I. Classification Based on Size
a. Fine aggregates:
b. Coarse aggregates:
II. Classification Based on Shape
a. Rounded aggregate:
b. Irregular aggregates
c. Angular aggregates
d. Flaky and elongated aggregates
III. Classification based on unit weight
a. Normal weight aggregates
b. Heavy weight aggregates
c. Light weight aggregates
The physical properties of aggregates are;
1. Shape
2. Size
3. Color
4. Texture
5. Gradation
6. Fineness modulus
Effect of aggregate properties on concrete
a. Particle Size, Grading and Dust Content
b. Particle Shape
c. Particle Surface Texture
d. Water Absorption
fineness modulus - According to IS 2386-1963, the sieves that are to be used for the sieve analysis of the aggregate for concrete are 80mm, 40mm, 20mm, 10mm, 4.75mm, 2.36mm, 1.18mm, 600m, 300m and 150m.
Gradation of aggregates
Gradation refers to the particle size distribution of aggregates.
The gradation of coarse aggregate plays an important role in workability and paste requirements.
The gradation of fine aggregate affects the workability and finishing ability of concrete.
Types of gradation:
a. Well graded
b. Poor / Uniform graded
c. Gap graded
Mechanical Properties
The following are the properties to be analyzed for aggregates, they are
a. Toughness
b. Hardness
c. Specific gravity
d. Bulk Density
e. Porosity and absorption of aggregates
f. Moisture content of aggregate
Mechanical Strength Test
a. Crushing strength Test
b. Impact strength Test
c. Abrasion Test (Los Angeles Test)
Water (for concrete)
Water is the most important material for construction, especially for making concrete.
The purpose of water in concrete are
a. It distributes the cement evenly.
b. It reacts with cement chemically and produces calcium silicate hydrate (C-S-H) gel which gives the strength to concrete.
c. It provides for workability, i.e., it lubricates the mix.
d. Hence, for construction, quantity and quality of water is as important as cement.
As water quantity goes up in a mix (ill effect), the following are the effects:
a. Strength decreases
b. Durability decreases
c. Workability increases
d. Cohesion decreases
e. Economy may increase at the expense of quality and reliability.
Quality of water for concrete (IS10500:2012)
a. Chlorides: They can cause corrosion of steel reinforcement, can accelerate setting.
b. Sulphates: They reduce long-term strength levels.
c. Organic matter: If an alga is present, water should not be used. It will affect the setting and strength development.
d. Sugar: It will retard setting time.
e. Wastewater: It should never be used in construction.
Aggregates Physical Properties and Mechanical Properties.pptxADCET, Ashta
Aggregates make up 65-80% of concrete by volume and come in two sizes: fine aggregates smaller than 4.75mm (such as sand) and coarse aggregates larger than 4.75mm (such as gravel). The physical properties of aggregates like shape, texture and grading impact the performance of fresh and hardened concrete. Aggregates are classified based on size, specific gravity, availability and other physical properties. Proper aggregate selection and testing of properties like flakiness index, elongation index and bulk density are important to achieve high quality concrete.
Aggregates are granular materials such as sand, gravel, crushed stone and recycled concrete used with cementing materials like cement or asphalt to produce concrete or asphalt. They make up 75% of concrete and over 90% of asphalt. Aggregates must be strong, durable and meet certain shape and size requirements. Common tests evaluate properties like strength, hardness, absorption and abrasion resistance. Sources of aggregates in Pakistan include limestone from Margalla Hills and Salt Range as well as dolomite deposits in Hazara and Kashmir regions.
1. Concrete is a composite material consisting of cement, water, fine aggregate (sand), and coarse aggregate (gravel). It constitutes 30-40% paste and 60-70% aggregates by volume.
2. The selection of concrete proportions involves balancing economy, workability, consistency, density, strength, and durability. Key factors are water-cement ratio, which controls strength, and durability to withstand weather conditions.
3. Aggregates are relatively inexpensive fillers that provide volume stability, abrasion resistance, and reduce volume changes in concrete. Their properties like density, grading, shape, and texture influence the properties of fresh and hardened concrete.
This document discusses the physical and chemical properties of aggregates that are important for their use in highway construction. It describes key properties like absorption, porosity, permeability, surface texture, strength, density, specific gravity, hardness, particle shape, and coatings. It also discusses undesirable components and how the chemical composition, reactions with asphalt and cement, and surface charge of aggregates are important. Finally, it provides an overview of the general uses of aggregates in compacted bases and mixes, hot mix asphalt, Portland cement concrete, and other applications.
Aggregate are important constituents in concrete, making up 70-80% of its volume. Aggregates can be classified in several ways: by size (coarse or fine), source (natural or manufactured), unit weight (lightweight, normal weight, or heavyweight), shape (rounded, angular, flaky), and surface texture (smooth, granular, crystalline). Ideal aggregates are hard, strong, durable, dense, clean, and free of materials that could compromise the concrete. Tests are conducted on aggregates to determine properties like particle size, impact value, crushing value, and abrasion value to ensure good quality for use in concrete.
Concrete is made up of ingredients like Cement, Fine Aggregate (Sand), Coarse Aggregate, Water and admixtures. Concrete mix design is done to Optimize the requirements of Cement, Sand, Aggregate and Water in order to ensure that concrete parameters in both Plastic Stage (like workability) and in Hardened Stage (like Compressive Strength and durability) are achieved. The Concrete mix design is as per Indian Standards (IS 10262) and might vary from country to country. The nominal mix design ratios available for concrete less than M30 in strength are only thumb rules and are generally over designed. As the actual site conditions vary and the mix design should be adjusted as per the location and other factors.
Similar to Introduction To Aggregates Its Properties And Effectson Concrete (20)
Sri Guru Hargobind Ji - Bandi Chor Guru.pdfBalvir Singh
Sri Guru Hargobind Ji (19 June 1595 - 3 March 1644) is revered as the Sixth Nanak.
• On 25 May 1606 Guru Arjan nominated his son Sri Hargobind Ji as his successor. Shortly
afterwards, Guru Arjan was arrested, tortured and killed by order of the Mogul Emperor
Jahangir.
• Guru Hargobind's succession ceremony took place on 24 June 1606. He was barely
eleven years old when he became 6th Guru.
• As ordered by Guru Arjan Dev Ji, he put on two swords, one indicated his spiritual
authority (PIRI) and the other, his temporal authority (MIRI). He thus for the first time
initiated military tradition in the Sikh faith to resist religious persecution, protect
people’s freedom and independence to practice religion by choice. He transformed
Sikhs to be Saints and Soldier.
• He had a long tenure as Guru, lasting 37 years, 9 months and 3 days
Sachpazis_Consolidation Settlement Calculation Program-The Python Code and th...Dr.Costas Sachpazis
Consolidation Settlement Calculation Program-The Python Code
By Professor Dr. Costas Sachpazis, Civil Engineer & Geologist
This program calculates the consolidation settlement for a foundation based on soil layer properties and foundation data. It allows users to input multiple soil layers and foundation characteristics to determine the total settlement.
Better Builder Magazine brings together premium product manufactures and leading builders to create better differentiated homes and buildings that use less energy, save water and reduce our impact on the environment. The magazine is published four times a year.
Introduction To Aggregates Its Properties And Effectson Concrete
1.
2. MILITARY COLLEGE OF ENGINEERING
RISALPUR
CE 308 – PRC I - LECTURE 3
AGGREGATES
3. AGGREGATE
According to ASTM 25 and D8: Aggregate is the granular
material, such as sand, gravel, crushed stone, crushed blast-furnace
slag, or construction and demolition waste that is used with a
cementing medium to produce either concrete or mortar.
Coarse aggregate - particles larger than 4.75 mm (No. 4 sieve)
Fine aggregate - particles smaller than 4.75 mm but larger than
75 μm (No. 200 sieve)
4. Aggregates may be divided into two categories depending on the
source :
Natural aggregate
Artificial aggregate
Natural aggregates are usually derived from natural sources and
may have been naturally reduced to size (e.g. gravel or shingle) or
may have to be reduced by crushing.
The most widely used artificial aggregates are clean broken bricks
and air-cooled fresh blast-furnace-slag.
DEPENDING ON SOURCE
11. Aggregates
Since approximately three quarters of the volume of concrete is
occupied by aggregate, its quality is of considerable importance
The aggregate properties greatly affect the durability and
structural performance of concrete
Aggregate was originally viewed as inert, inexpensive material
disperse throughout the cement paste so as to produce large
volume of concrete
In fact aggregates are not truly inert, because its physical,
thermal and sometimes chemical properties influence the
properties of concrete
From eco point of view it is advantageous to have as many
aggregates and less cement, but the cost benefit has to be
balanced against the desired properties of its fresh and hardened
state
12. Aggregates
Natural aggregates are formed by the process of weathering or
artificial cutting of a larger parent mass
Thus, many properties of the aggregate depends upon the
parent rock, e.g. chemical and mineral composition,
petrographic classification (Petrography is a branch of
petrology that focuses on detailed descriptions of rocks. ),
specific gravity, hardness, strength, pore structure, color etc.
In addition, there are other properties of aggregates which are
absent in the parent rock, particle shape and size, surface texture
and absorption. All these properties may have a considerable
impact on the quality of fresh and hardened concrete
13. Size classification
Concrete is made with aggregate particles covering a range of
size up to a maximum which usually lies between 10 mm and 50
mm (20 mm as typical).
The particle size distribution is called grading
Low grade concrete may be made with aggregates from
deposits containing a whole range of sizes, ranging from the
largest to the smallest, known as all-in or pit-run aggregates
The alternative, very much more common is to obtain the
aggregate in two separate lots, the main division being at a size
of 5 mm or no. 4 ASTM sieve. This divides fine aggregates from
coarse aggregate
It should be noted that the term aggregate is sometime used to
mean coarse aggregate, a practice which is not correct
14. Petrographic classification
Petrology is the branch of geology that studies the origin,
composition, distribution and structure of rocks.
From petrographic standpoint aggregates can be divided into
several groups of rocks having common characteristics as
classified by BS 812 , part 1, 1975.
The group classification does not imply the suitability of any
aggregate for making of concrete, unsuitable materials may be
found in any group, although some groups tend to have better
record than others.
Silica minerals, carbonate minerals, sulphate minerals etc.
15. Particle shape and texture
In addition to petrological character of aggregate, its
external characteristics are of importance, in particular the
particle shape and texture
The shape of three-dimensional objects is rather difficult
to describe, therefore, it is convenient to define certain
geometric characteristics of such bodies
16.
17.
18. Particle shape and texture
In case of crushed aggregates the particle shape depends on
the nature of parent material and on the type of crusher
Roundness measures the relative sharpness of the edges and
corners of a particle
Roundness is controlled largely by the strength and abrasion
(the process of scarping and wearing) resistance of the parent
rock
Since the degree of packing of particles of one size depends
on their shape, the angularity of aggregates can be estimated
from the proportion of voids in a sample compacted in a simple
way
BS 812: part 1: 1975 defines the Angularity number
20. Particle shape and texture
Angularity number can be taken as 67 minus the percentage
of solid volume in the vessel filled with aggregate in a
standard manner
The number 67 in the expression for angularity represents
the solid volume of the most rounded gravel, so that the
angularity number measures the percentage of voids in excess
of that of the round gravel (i.e. 33 %). The higher the number
the more angular the aggregates, the range for practical
aggregates being 0 to 11.
A particle is said to be flaky if its thickness (least
dimension) is less than 0.6 times the mean sieve size of the
size fraction to which it belongs.
The mean size is defined as the arithmetic mean of the sieve
size on which the particle is just retained and the sieve size
through which it passes
21. Particle shape and texture
The mass of the flaky particles, expressed as the
percentage of the mass of the sample, is called the flakiness
index. Elongation index is similarly defined.
Some particles are both flaky and elongated and are ,
therefore, counted in both categories.
Sea aggregates may contain shells whose content needs to
be controlled because they are brittle and they also reduce
the workability of the mix. The shell content is determined
by weighing hand-picked shells and shell fragments from a
sample of aggregates greater than 5mm.
The classification of surface texture is based on the degree
to which the particle surfaces are polished or dull, smooth or
rough. Surface textures are glassy, smooth, granular (more
or less round), rough, crystalline and honeycomb (with
visible voids).
22. Mechanical properties
Bond
Both the shape and surface texture of aggregates influence
considerably the strength of concrete, especially for high
strength concrete; flexural strength is more affected than the
compressive strength.
A rougher texture results in a greater adhesion or bond
between the particles and the cement matrix.
Likewise the larger surface area of a more angular
aggregate provides a greater bond.
Softer and heterogeneous particles result in a better bond.
The determination of quality of bond is rather difficult and
no accepted test exists.
Generally, a crushed concrete specimen should contain
some aggregate particles broken right through, in addition to
the more numerous ones separated from the paste matrix.
23. Mechanical properties
Strength
It is not easy to determine the crushing strength of
aggregate itself.
A few weak particles can be tolerated; after all, voids can
be viewed as aggregate particles of zero strength.
The required information about the aggregate particles has
to be obtained from indirect tests; crushing strength of
prepared rock samples, crushing value of aggregate, and
performance of aggregate in concrete.
The latter simply means either previous experience with
the given aggregate or a trial use of aggregate in a mix
known to have a certain strength with previously proven
aggregates.
24. Mechanical properties
The material to be tested should pass a 14 mm sieve and
be retained on a 10 mm sieve.
When, however, this size is not available, particles of other
sizes may be used, but those larger than the standard will in
general give a higher crushing value, and the smaller ones a
lower value than would be obtained with the same rock of
standard size.
The sample should be dried in oven at 100 to 110 degree
Centigrade for four hours and then placed in a cylindrical
mould and tamped in a prescribed manner.
25. Mechanical properties
Toughness
Toughness can be defined as the resistance of the
aggregate to failure by impact, and it is usual to determine
the aggregate impact value of bulk aggregate.
The details of the test are available in BS 812: part
112:1990
It can be used as a replacement test for strength of
aggregate.
27. STRENGTH
The strength of concrete cannot exceed the strength of the
aggregate.
In practice, concrete strength is likely to be much less than
the strength of the aggregate, because stress concentrations
are generated at the aggregate- cement paste interface
(Interfacial Transition Zone, ITZ) when stress is applied on
concrete.
Weak aggregates may break down during mixing, handling
and compaction.
29. POROSITY AND PERMEABILITY
The internal pore characteristics are very important properties of
aggregates. The size, the number, and the continuity of the pores
through an aggregate particle may affect the strength of the
aggregate, abrasion resistance, surface texture, specific gravity,
bonding capabilities, and resistance to freezing and thawing action.
Porosity is a ratio of the volume of the pores to the total volume
of the particle.
Permeability refers to the particle's ability to allow liquids to pass
through. If the rock pores are not connected, a rock may have high
porosity and low permeability. An aggregate can be very porous
but very less permeable.
30. ABSORPTION AND MOISTURE
CONTENT
Absorption relates to the particle's ability to take in a liquid.
Moisture Content is defined as the water in excess of the
saturated and surface-dry conditions.
Thus, the total water content of a moist aggregate is equal to the
sum of absorption and moisture content.
Aggregate exposed to rain collects a considerable amount of
moisture on the surface of the particles, and, except at the surface
of the stockpile, keeps this moisture over long periods.
This is particularly true of fine aggregate, and the moisture
content must be allowed for in the calculation of batch quantities
and of the total water requirement of the mix during mix design.
33. BULKING OF SAND
In the case of sand, there is another effect of the presence of
moisture i.e. bulking, which is an increase in the volume of a given
mass of sand caused by the films of water pushing the sand
particles apart.
Bulking of sand affects the proportioning of materials by
volume.
In volume batching, bulking results in a smaller mass of sand
occupying the fixed volume of the measuring box.
34. SOUNDNESS
A sound aggregate is able to resist stresses induced by
environmental or climatic conditions.
Some aggregates degrade or disintegrate under the action of
cycles of freezing and thawing or salt weathering.
Susceptible aggregates are usually micro porous, that is, they
have high absorption arising from a large proportion of fine
pores.
Freezing or salt crystallization can induce considerable
stresses in fine pores that may lead to degradation.
35. SOUNDNESS TEST
The Soundness Test determines
the resistance of aggregates to
disintegrate when exposed to
solutions of Sodium Sulphate and
Magnesium Sulphate.
36. IMPURITIES
Impurity Effect on fresh concrete Effect on hardened concrete
Chlorides Accelerate the set Damp patches and efflorescence
Sulfates Interference with hydration Cracking and spalling
Shells Reduce workability Damage to surface finish
Acid soluble
material in sand
None
Reduced skid resistance of
pavement
quality concrete
Alkali reactive
silica
None Risk of alkali–silica reaction
Swelling clays Increased water demand Reduced strength
Reactive iron
pyrites
Possible reduced yield Surface staining
Mica Increased water demand Reduced strength
Organic matter Possible retardation Possible reduced strength
Coal and lignite Possible retardation Surface staining, pop-outs
Soluble lead or
zinc
Possible retardation Possible reduced strength