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.
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.
Aggregates make up 65-80% of concrete's volume and are inert fillers that float in the cement paste. Their characteristics impact the performance of fresh and hardened concrete. Aggregates are classified based on size, specific gravity, availability, shape, and texture. Proper aggregate grading leads to a dense, strong concrete mixture. The fineness modulus is a number that indicates an aggregate's grading, and the flakiness index measures elongated particles. Well-graded aggregates with low elongation produce high quality concrete.
The document discusses the different types of shrinkage that can occur in concrete, including plastic shrinkage, drying shrinkage, autogenous shrinkage, and carbonation shrinkage. Plastic shrinkage causes cracks on the surface of fresh concrete due to evaporation before setting. Drying shrinkage is defined as the contraction of hardened concrete from the loss of capillary water, which can lead to cracking, warping, and deflection without any external loading. In summary, the document outlines the main types of volume changes and shrinkage that concrete undergoes both during the plastic and hardened states.
This document discusses quality control of concrete through various tests on fresh and hardened concrete. It begins with an introduction to concrete and quality, then discusses where quality control begins in the production of materials and continues through handling, batching, mixing, transporting and placing concrete. Key tests on fresh concrete include slump and compacting factor tests, while tests on hardened concrete include compression, tensile strength, and flexural strength tests to evaluate the quality and strength of the concrete. The document also reviews materials used in concrete such as cement, water, aggregates, and admixtures.
This document discusses quality control in concrete construction. It explains that concrete is made by mixing cement, fine aggregate, coarse aggregate, water, and admixtures. Quality control is important to ensure the concrete has strength, durability, and aesthetics. Quality control involves testing the materials used, the fresh concrete mix, and the hardened concrete. Tests on fresh concrete include slump and compacting factor tests, while tests on hardened concrete include compression, tensile, and flexural strength tests. The document outlines the quality control process from the production of materials to placement and curing of the concrete.
This document discusses the process of concrete mix design. The goal of mix design is to produce concrete with the required strength, durability and workability at the lowest cost. It describes the factors that must be considered such as minimum strength, workability, water-cement ratio and aggregate size and grading. The different types of mixes are described as nominal, standard or design mixes. The key steps of mix design are outlined, including selecting the target strength, water-cement ratio, water content, cement content and aggregate volumes. Durability, aggregate properties and mix calculations are also summarized.
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.
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.
Aggregates make up 65-80% of concrete's volume and are inert fillers that float in the cement paste. Their characteristics impact the performance of fresh and hardened concrete. Aggregates are classified based on size, specific gravity, availability, shape, and texture. Proper aggregate grading leads to a dense, strong concrete mixture. The fineness modulus is a number that indicates an aggregate's grading, and the flakiness index measures elongated particles. Well-graded aggregates with low elongation produce high quality concrete.
The document discusses the different types of shrinkage that can occur in concrete, including plastic shrinkage, drying shrinkage, autogenous shrinkage, and carbonation shrinkage. Plastic shrinkage causes cracks on the surface of fresh concrete due to evaporation before setting. Drying shrinkage is defined as the contraction of hardened concrete from the loss of capillary water, which can lead to cracking, warping, and deflection without any external loading. In summary, the document outlines the main types of volume changes and shrinkage that concrete undergoes both during the plastic and hardened states.
This document discusses quality control of concrete through various tests on fresh and hardened concrete. It begins with an introduction to concrete and quality, then discusses where quality control begins in the production of materials and continues through handling, batching, mixing, transporting and placing concrete. Key tests on fresh concrete include slump and compacting factor tests, while tests on hardened concrete include compression, tensile strength, and flexural strength tests to evaluate the quality and strength of the concrete. The document also reviews materials used in concrete such as cement, water, aggregates, and admixtures.
This document discusses quality control in concrete construction. It explains that concrete is made by mixing cement, fine aggregate, coarse aggregate, water, and admixtures. Quality control is important to ensure the concrete has strength, durability, and aesthetics. Quality control involves testing the materials used, the fresh concrete mix, and the hardened concrete. Tests on fresh concrete include slump and compacting factor tests, while tests on hardened concrete include compression, tensile, and flexural strength tests. The document outlines the quality control process from the production of materials to placement and curing of the concrete.
This document discusses the process of concrete mix design. The goal of mix design is to produce concrete with the required strength, durability and workability at the lowest cost. It describes the factors that must be considered such as minimum strength, workability, water-cement ratio and aggregate size and grading. The different types of mixes are described as nominal, standard or design mixes. The key steps of mix design are outlined, including selecting the target strength, water-cement ratio, water content, cement content and aggregate volumes. Durability, aggregate properties and mix calculations are also summarized.
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.
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.
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.
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.
A presentation on concrete-Concrete TechnologyAbdul Majid
Concrete is a composite material made from cement, sand, gravel and water. It is one of the most commonly used building materials due to its advantages like durability, fire resistance and ability to be easily formed. Fresh concrete must be properly mixed, placed, consolidated and cured. Mixing ensures uniform distribution of ingredients while consolidation removes air pockets. Curing keeps concrete saturated to allow continued hydration and improve strength over time. Proper mixing, placing and curing are necessary to achieve the desired properties of hardened concrete.
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.
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.
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.
The document discusses the hydration of cement compounds. The four main compounds (Bogue's compounds) are tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), and tetracalcium aluminoferrite (C4AF). C3S hydrates rapidly and provides early strength, while C2S hydrates slowly and provides later strength. C3A hydrates very fast unless gypsum is added, in which case it forms ettringite. C4AF hydrates similarly to C3A but more slowly. The hydration processes of the individual compounds involve formation of calcium silicate hydrate, calcium hydroxide
Concrete is a widely used construction material consisting of cement, water, and aggregates. The strength of concrete is specified using its 28-day cube strength in N/sq.mm. Formwork is used to mold wet concrete into desired shapes and allow it to cure. Formwork design involves choosing traditional or systematic approaches using wood or steel components like props, beams, sheathing to form columns, walls, and beams until the concrete gains sufficient strength. Proper formwork is important for quality concrete finish and structural integrity.
Here, I attach a PowerPoint presentation created by me for a competition held by UltraTech. Have a look at this and feel free to share your views with me.
Self-compacting concrete (SCC) was developed in Japan in the 1980s to solve issues with inadequate concrete compaction. SCC is highly flowable under its own weight and fills formwork without vibration. It was pioneered by Professor Hajime Okamura and has seen increasing use globally since 2000. The document discusses the constituents, properties, testing, and advantages of SCC compared to traditional vibrated concrete.
Special concrete is used when special properties are more important than normal concrete properties. It is produced using chemical and mineral admixtures added to conventional concrete mixes. There are several types of special concrete including lightweight concrete, high strength concrete, fibre reinforced concrete, ferrocement, ready mix concrete, and others. Each type has specific properties and uses in construction where standard concrete is not suitable.
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.
This document provides information on various tests conducted on aggregates that are used in construction. It describes the aggregate abrasion value test, which determines the abrasion resistance and hardness of aggregates. It also summarizes the aggregate impact value test, which evaluates the resistance of aggregates to shocks and impacts, and the aggregate crushing value test, which determines the resistance of aggregates to crushing under gradually applied compressive loads. Finally, it outlines the procedure to determine the specific gravity and water absorption of aggregates.
This document provides information on concrete, including:
- Concrete is a mixture of cement, water, and aggregates that hardens over time into a strong building material.
- Proper mixing, placing, and curing of the concrete allows it to gain strength through a process called hydration as it ages.
- Factors like the water-cement ratio, type of aggregates, compaction, and curing affect the properties and strength of hardened concrete.
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 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.
How to determine Initial and Final Setting Time of Cement?Civil Insider
Get PPT here
https://civilinsider.com/initial-and-final-setting-time-of-cement/
During Construction using concrete, cement paste, mortar certain time is required for mixing, transportation, placing, compacting and finishing. During this time concrete, mortar, cement paste should be in plastic condition and should not harden and it is mandatory that one should use the concrete before it starts to loose its plasticity. So How should someone know how long is concrete workable? and How much travel time is permitted for concrete?
Well its Setting time that tells us how long concrete is going to be workable. Now the question is What is Setting Time of Cement?
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.
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.
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.
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.
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.
A presentation on concrete-Concrete TechnologyAbdul Majid
Concrete is a composite material made from cement, sand, gravel and water. It is one of the most commonly used building materials due to its advantages like durability, fire resistance and ability to be easily formed. Fresh concrete must be properly mixed, placed, consolidated and cured. Mixing ensures uniform distribution of ingredients while consolidation removes air pockets. Curing keeps concrete saturated to allow continued hydration and improve strength over time. Proper mixing, placing and curing are necessary to achieve the desired properties of hardened concrete.
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.
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.
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.
The document discusses the hydration of cement compounds. The four main compounds (Bogue's compounds) are tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), and tetracalcium aluminoferrite (C4AF). C3S hydrates rapidly and provides early strength, while C2S hydrates slowly and provides later strength. C3A hydrates very fast unless gypsum is added, in which case it forms ettringite. C4AF hydrates similarly to C3A but more slowly. The hydration processes of the individual compounds involve formation of calcium silicate hydrate, calcium hydroxide
Concrete is a widely used construction material consisting of cement, water, and aggregates. The strength of concrete is specified using its 28-day cube strength in N/sq.mm. Formwork is used to mold wet concrete into desired shapes and allow it to cure. Formwork design involves choosing traditional or systematic approaches using wood or steel components like props, beams, sheathing to form columns, walls, and beams until the concrete gains sufficient strength. Proper formwork is important for quality concrete finish and structural integrity.
Here, I attach a PowerPoint presentation created by me for a competition held by UltraTech. Have a look at this and feel free to share your views with me.
Self-compacting concrete (SCC) was developed in Japan in the 1980s to solve issues with inadequate concrete compaction. SCC is highly flowable under its own weight and fills formwork without vibration. It was pioneered by Professor Hajime Okamura and has seen increasing use globally since 2000. The document discusses the constituents, properties, testing, and advantages of SCC compared to traditional vibrated concrete.
Special concrete is used when special properties are more important than normal concrete properties. It is produced using chemical and mineral admixtures added to conventional concrete mixes. There are several types of special concrete including lightweight concrete, high strength concrete, fibre reinforced concrete, ferrocement, ready mix concrete, and others. Each type has specific properties and uses in construction where standard concrete is not suitable.
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.
This document provides information on various tests conducted on aggregates that are used in construction. It describes the aggregate abrasion value test, which determines the abrasion resistance and hardness of aggregates. It also summarizes the aggregate impact value test, which evaluates the resistance of aggregates to shocks and impacts, and the aggregate crushing value test, which determines the resistance of aggregates to crushing under gradually applied compressive loads. Finally, it outlines the procedure to determine the specific gravity and water absorption of aggregates.
This document provides information on concrete, including:
- Concrete is a mixture of cement, water, and aggregates that hardens over time into a strong building material.
- Proper mixing, placing, and curing of the concrete allows it to gain strength through a process called hydration as it ages.
- Factors like the water-cement ratio, type of aggregates, compaction, and curing affect the properties and strength of hardened concrete.
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 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.
How to determine Initial and Final Setting Time of Cement?Civil Insider
Get PPT here
https://civilinsider.com/initial-and-final-setting-time-of-cement/
During Construction using concrete, cement paste, mortar certain time is required for mixing, transportation, placing, compacting and finishing. During this time concrete, mortar, cement paste should be in plastic condition and should not harden and it is mandatory that one should use the concrete before it starts to loose its plasticity. So How should someone know how long is concrete workable? and How much travel time is permitted for concrete?
Well its Setting time that tells us how long concrete is going to be workable. Now the question is What is Setting Time of Cement?
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.
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.
IRJET - An Experimental Study on Effects of Grainite Powder in Paver BlocksIRJET Journal
The document presents the results of an experimental study that investigated the effects of partially replacing cement with granite powder in paver blocks. Various percentages of granite powder (25%, 50%, and 75%) were used to replace cement by weight in the production of paver blocks. The study found that replacing cement with up to 50% granite powder improved the compression strength of the paver blocks while also providing environmental and cost benefits through the reuse of the granite powder waste.
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.
The document discusses the types, properties, and classifications of aggregates used to make concrete. It describes how aggregates provide bulk and strength to concrete while reducing shrinkage. Various tests are used to evaluate the size, shape, strength, density and other physical properties of aggregates to ensure they will perform well when used to manufacture durable concrete.
Strength Characteristics of Concrete Produced by Replacing Fine Aggregates wi...IRJET Journal
This document presents the results of a study investigating the strength properties of concrete with partial replacement of fine aggregate by marble powder and the addition of 2% basalt fiber. Concrete cubes, beams, and cylinders were cast with 0%, 25%, 50%, and 75% replacement of fine aggregate by marble powder. The specimens were water cured for 7 and 28 days and then tested for compressive strength, split tensile strength, and flexural strength. The results showed that partial replacement of fine aggregate with marble powder, along with the addition of basalt fiber, can increase the strength of concrete at an economical cost while also providing an environmentally friendly way to dispose of industrial waste like marble powder.
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.
This document provides a summary of a project on green structures using non-conventional materials. The project will study bricks and concrete made with fly ash as a partial replacement for conventional materials like clay. Tests will be conducted to evaluate the dimensional tolerance, water absorption, compressive strength, and efflorescence of fly ash bricks. Additional tests will examine the bulk density, specific gravity, water absorption, aggregate crushing value, aggregate impact value, and aggregate abrasion value of fly ash concrete. The project aims to determine if green materials can provide comparable or improved strength parameters over conventional materials while reducing costs and environmental impacts.
This document evaluates the strength parameters of self-compacting concrete incorporated with carbon and glass fibres. It discusses how the concrete was made with various percentages of micro silica and fibres as a replacement for cement. The compressive, tensile, and flexural strength of the concrete mixtures were tested at 7 and 28 days. The results showed that the concrete achieved the highest strength at 0.6% addition of carbon or glass fibres, with carbon fibres performing slightly better. In conclusion, the compressive strength increased by 12% for carbon fibre and 8% for glass fibre mixtures at the 0.6% fibre level.
Analysis the Effect of Steel Fibre and Marble Dust with Strength of Pavement ...ijtsrd
The thrust nowadays is to produce thinner and green pavement sections of better quality, which can carry the heavy loads. The high strength steel fibre reinforced concrete is a concrete having compressive strength greater than 40MPa, made of hydraulic cements and containing fine and coarse aggregates; and discontinuous, unconnected, randomly distributed steel fibres. The present study aims at, developing pavement quality concrete mixtures incorporating marble dust as partial replacement of cement as well as steel fibres. The aim is to the design of slab thickness of PQC pavement using the achieved flexural strength of the concrete mixtures. In this study, the flexural, compressive and split tensile strength for pavement quality concrete mixtures for different percentage of steel fibres and replacement of cement with marble dust are reported. It is found out the maximum increase in flexure strength, compressive strength and split tensile strength is for 0% Marble Dust and 1% Steel fibre. Also it has been possible to achieve savings in cement by replacing it with marble dust and adding fibres. This study also shows that in view of the high flexural strength, high values of compressive strength and high values of split tensile strength, higher load carrying capacity and higher life expectancy, the combination of 10 to 20% marble dust replacement along with addition of 0.5 to 1% steel fibres is ideal for design of Pavement Quality Concrete (PQC). Krishan Kumar | Sumesh Jain"Analysis the Effect of Steel Fibre and Marble Dust with Strength of Pavement Quality Concrete" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-4 , June 2017, URL: http://www.ijtsrd.com/papers/ijtsrd152.pdf http://www.ijtsrd.com/engineering/civil-engineering/152/analysis-the-effect-of-steel-fibre-and-marble-dust-with-strength-of-pavement-quality-concrete/krishan-kumar
Building Materials and Concrete Technology Unit 2DineshGunturu1
Aggregates: Classification of aggregate, Bond, Strength and other mechanical properties of aggregate, Physical properties of aggregate, bulking of sand, Deleterious substance in aggregate, Soundness of aggregate, Alkali-Aggregate reaction – Thermal properties, Sieve analysis – Fineness modulus – Grading curves – Grading of fine and coarse aggregates as per relevant IS code, Maximum aggregate size
Portland Cement: Chemical composition, Hydration, Structure of hydrated cement – Setting of cement, Fineness of cement, Tests for physical properties – Different grades of cements-Supplementary cementitious materials: Fly ash, GGBS, Silica fume, Rice husk ash, Calcinated ash (Basic properties and their contribution to concrete strength). Admixtures: Mineral and Chemical admixtures
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.
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Test on Aggregates.ppt
1. Mr. S. Vinoth
Assistant Professor in Department of civil Engineering at KPR Institute of Engineering and
Technology
Education
U.G : B.E Civil Engineering
KPR Institute of Engineering and Technology
P.G : M.E Structural Engineering
Sri Shakthi Institute of Engineering and Technology
Experience
1.Technical Assistant in Town Planning Section at Singanallur Corporation office, Coimbatore
Areas of Interest
- Structural Engineering
- Infrastructure Engineering and Management
- Earth System Science and Engineering
3. Aggregate
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.
4. Classification of Aggregate
I. Classification Based on Size
a. Fine aggregates:
It is the aggregate, which is passes through a 4.75mm IS sieve and retained
on 0.7 mm. The fine aggregate may be natural sand, crushed stone sand or crushed gravel sand. According to IS
383-1970, there are four grading zones of the fine sand, Zone I, Zone II, Zone III and Zone IV.
b. Coarse aggregates:
The aggregates, most of which are retained on 4.75mm IS sieve are termed as coarse aggregates. The coarse
aggregates may be Crushed stone, Uncrushed gravel and Partially crushed stone or gravel.
[*Sometimes combined aggregates are available in nature consisting of different fractions of fine and coarse
aggregates, which are known as all in aggregate.]
5. Classification of Aggregate
II. Classification Based on Shape
a. Rounded aggregate:
The aggregate with rounded particles (river or sea
shore gravel) has
minimum voids ranging from 32 to 33%.
It gives minimum ratio of surface area to
the volume, thus requiring minimum cement paste to make
good concrete.
The only disadvantage is that the interlocking between its particles is less, and
hence the development of the bond is poor, making it unsuitable for high
strength concrete and pavement.
6. Classification of Aggregate
b. Irregular aggregates:
The aggregate having partly round particles (pit sand and gravel) has
higher percentage of voids ranging from 35 to 38 %.
It requires more paste for a given workability.
The interlocking between particles, though better than that obtained
with the rounded aggregate, is inadequate for high strength concrete.
7. Classification of Aggregate
c. Angular aggregates:
The aggregate with sharp angular and rough particles (crushed
rock) has a maximum percentage of voids ranging from 38 to 40%.
The interlocking between particles is good, providing a good
bond.
The aggregate requires more paste to make workable concrete of
high strength.
The angular aggregate is suitable for high strength concrete and
pavements subjected to tension.
8. Classification of Aggregate
d. Flaky and elongated aggregates:
An aggregate is termed flaky when the ratio of least dimension
(thickness)
to the mean dimension is less than three-fifth (0.6).
The particle is said to be elongated when the ratio of greatest
dimension (length) to the mean dimension is more than nine-fifth
(1.8 times).
9. Classification of Aggregate
III. Classification based on unit weight
a. Normal weight aggregates:
The commonly used aggregates i.e. sand, gravel, crushed rocks such as granite, basalt, sandstone
(sedimentary) and limestone.
It has specific gravities between 2.5 and 2.7 produce concrete with
unit weight ranging from 23 to 26 kN/m3
The compressive strength at 28 days between 15 to 40
MPa are termed Normal weight aggregate.
b. Heavy weight aggregates:
Heavy weight concrete is produced from heavy weight aggregate, which is more effective as a radiation
shield.
The unit weight of concrete varies from 30 to 57 kN /m3.
The specific gravity is varies from 4 – 6.8
Example: Baryte (Gs = 4 to 4.6), Ferrophosphorus (Gs = 5.8 to 6.8), Haematite (Gs = 4.9 to 5.3) and
Magnetite (Gs= 4.2 to 5.2)
10. Classification of Aggregate
c. Light weight aggregates:
The light weight aggregates have unit weight up to 12 kN /m3.
These aggregates are obtained from pumice, volcanic cinder, Diatomite, blast furnace slag, fly ash etc,.
The weight of concrete (structure) is reduced to a great extent
and it provides better thermal insulation and improved fire resistance.
11. Physical Properties of Aggregates
The physical properties of aggregates are;
1. Shape
2. Size
3. Color
4. Texture
5. Gradation
6. Fineness modulus
12. Effect of aggregate properties on
concrete
i. Particle Size, Grading and Dust Content
Well-graded sands tend to have lower water requirements than single-sized sands and increasing dust contents
tend to increase the water requirement of sands.
ii.Particle Shape
It is fact that sands with well-rounded particles will be less water and make more workable concrete than
sands with flaky, elongated particles. However, the strength is undesirable. Aggregate with angular shape,
will give moderate water and high strength to concrete by good interlocking characteristics.
13. Effect of aggregate properties
on concrete
iii. Particle Surface Texture
In general, aggregate with a rough surface texture will have a higher water requirement than aggregate with
smooth particle surfaces.
iv. Water Absorption
All aggregates absorb water to a greater or lesser degree. The higher the water absorption the higher the
water requirement will be, but the water absorbed into the aggregate will not affect the effective water:
binder ratio or the strength. It will however lead to rapid slump loss if absorption is excessive, say >1%
by mass. In general it is preferable to avoid concrete aggregate properties with water absorptions of
more than 1 or 1.5% by mass
14. FINENESS MODULUS (FM)
The fineness modulus (FM) is a numerical index of fineness, giving some idea of the mean
size of the particles present in the entire body of the aggregate.
The 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.
15. FINENESS MODULUS
For example, a fineness modulus of 6 can be interpreted to mean that the sixth sieve, i.e. 4.75 mm is
the average size.
The value of fineness modulus is higher for coarser aggregate and lower for
fine aggregate.
Limitations:
The FM for fine sand = 2 - 3.5
The FM for coarse aggregate = 5.5 - 8
[Note: higher FM, the mix will be harsh and if on the other hand gives a lower FM, it produces an
uneconomical mix]
17. FINENESS MODULUS
Therefore, fineness modulus of coarse aggregates = sum (cumulative % retained) / 100
= (717/100) = 7.17
Fineness modulus of 7.17 means, the average size of particle of given coarse aggregate sample is
in between 7th and 8th sieves, that is between 10mm to 20mm.
18. 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:
1. Well graded
2. Poor / Uniform graded
3. Gap graded
19. Gradation of aggregates
1. Well graded
Incorporates a combination of particles of many sizes. Hence, it has Low void content, Low permeability
and High stability but increases the particle surface area. This is the preferred gradation for making a
good concrete.
20. Gradation of aggregates
2. Poor / Uniform graded
All particles are of same size. It produces a large volume of voids irrespective of particle size. Hence the
paste requirement for this concrete is high.
21. Gradation of aggregates
3. Gap graded
This involves grading in which one or more sizes are omitted. It has low stability, moderate voids content
and permeability than well graded aggregate. This type of concrete is generally used for architectural or
aesthetic purposes.
22. Mechanical Properties
The following are the properties to be analyzed for aggregates, they are
1. Toughness
2. Hardness
3. Specific gravity
4. Bulk Density
5. Porosity and absorption of aggregates
6. Moisture content of aggregate
23. 1. Toughness
Toughness of the aggregate is the resistance to the failure by load (impact or crushing)
The impact and crushing load value should not exceed 45% for the aggregate in concrete and 30% for
the concrete for wearing surfaces such as runways, roads and pavements. (IS: 2386 (part – 4) - 1963)
2. Hardness
Wear and tear property of aggregate is checked (concrete used in roads and in floor surfaces subjected to
heavy traffic).
For determining the hardness or resistance to wear property - abrasion test is carried out. (IS: 2386 (part
– 4) - 1963)
24. Deval machine and Los Angeles machine are used to perform the abrasion test.
For a good stone the aggregate abrasion value shall not exceed 16%.
3. Specific gravity
The specific gravity is defined as the ratio of weight of the solid(aggregate), referred to vacuum, to the
weight of an equal volume of gas-free distilled water, both taken at standard temperature.
The quantity of aggregate required for given volume of concrete is calculated using specific gravity.
(IS: 2386 (part – 3) - 1963)
The majority of aggregates have specific gravity value between 2.6 – 2.7
25. 4. Bulk density
The bulk density is the weight of the material in a given volume and expressed in terms of kg/lit or
cubic cm.
It is affected by several factors including the Fineness modulus, shape of particles and the amount of
moisture present in the material.
When aggregate is to be actually batched by volume it is essential to know the weight of the aggregate
that would the fill the container unit volume is known as bulk density of aggregate.
The bulk density of the aggregate is depends on how densely is packed.
(IS: 2386 (part – 3) - 1963) used for bulk density test.
26. 5. Porosity and Absorption
The bond between aggregate and cement paste is get affected by the permeability and water absorption.
(thus causes strength decrease)
Even the smallest aggregate pores are generally larger than the gel pores in the cement paste.
But there is no theoretical relation between the concrete strength and aggregate water absorption.
(IS: 2386 (part – 3) - 1963) describes the test for finding the water absorption.
27. 6. Moisture content of aggregate
The surface moisture is expressed as a percentage of weight saturated an surface dry aggregate (termed
as moisture content).
The moisture content of aggregate changes with weather condition, if aggregate exposed to rain, then
they will absorb some water (especially for fine aggregate) and also from one stockpile to another.
(IS: 2386 (part – 3) - 1963) describes the test to determine the moisture content.
28. 1. Crushing strength Test
Ascertained by aggregate crushing value
It gives a relative measure of the resistance of an aggregate to crushing under a gradually applied
compressive load
For this test, 12.5 mm passed and 10 mm retained aggregates are used
Surface dry condition aggregates are filled into the standard cylinder with three layer of 25 blows
Compressive force is gradually applied up to 40 tons in 10 minutes time
The crushed aggregates are sieved in 2.36 mm sieve
Then aggregate crushing value = B/A x 100
where, A- Weight of sample and B- weight of retained aggregate in 2.36mm sieve.
[Crushing value should not higher than 45%]
30. 2. Impact strength Test
Ascertained by aggregate impact value
It gives a relative measure of the resistance of an aggregate to sudden shock or
impact. For this test, 12.5 mm passed and 10 mm retained aggregates are used
Surface dry condition aggregates are filled into the test cylinder with three layer of 25 blows
Filled cylinder is placed in impact testing machine
Then, 15 blows are given to the cylinder using 14 kg weight hammer.
The crushed aggregates are sieved in 2.36 mm sieve
Then aggregate impact value = B/A x 100
where, A- Weight of sample and B- weight of retained aggregate in
2.36 mm sieve. [Crushing value should not higher than 45%]
32. 3. Abrasion Test (Los Angeles Test)
Select the grading to be used in the test such that it conforms to the grading to be used in construction
Choose the abrasive charge balls depending on grading of aggregates.
Place the aggregates and abrasive charge on the cylinder and fix the cover.
Rotate the machine at a speed of 30 to 33 revolutions per minute with uniform speed.
The machine is stopped after the desired number of revolutions and material is discharged to a tray.
The entire stone dust is sieved on 1.70 mm IS sieve.
The material coarser than 1.7mm size is weighed correct to one gram.
33. Abrasion Test (Los Angeles Test)
Abrasion Value = (W1 – W2 ) / W1 X 100
Where,
Original weight of aggregate sample = W1 g
Weight of aggregate sample retained = W2 g
Weight passing 1.7mm IS sieve = W1 – W2 g
[Note: Abrasion value should not more than 16%]
34. Water (for concrete)
Water is the most important material for construction, especially
for making concrete.
The purpose of water in concrete are
It distributes the cement evenly.
It reacts with cement chemically and produces calcium silicate hydrate (C-S-H) gel which gives the
strength to concrete.
It provides for workability, i.e., it lubricates the mix.
Hence, for construction, quantity and quality of water is as important as cement.
35. As water quantity goes up in a mix (ill effect), the following are the effects:
Strength decreases
Durability decreases
Workability increases
Cohesion decreases
Economy may increase at the expense of quality and reliability.
36. Quality of water for concrete (IS10500:2012)
Water used for mixing and curing should be free from oil, acid and alkali, salts and organic material.
It should be potable and concreting generally requires a value purer than that of drinking
Whenever there is uncertainty in quality, water should be tested before use.
Even chlorine added for city water supply will affect concrete if used carelessly without proper testing
and treatment.
If well water is used for construction, it must be tested for
impurities.
37. Chlorides: They can cause corrosion of steel reinforcement, can accelerate setting. The water used
may be contaminated with chlorides because of seawater, some admixtures, salts or deliberate
chlorination for disinfections.
Sulphates: They reduce long-term strength levels.
Organic matter: Their effects on concrete are variable. If an alga is present, water should not be used.
It will affect the setting and strength development.
Sugar: It will retard setting time. Too much may ‘kill' the concrete (the concrete will never set).
Wastewater: It should never be used in construction. Water for curing should be as pure as water for
mixing concrete.
Quality of water for concrete (IS10500:2012)