Concrete and its types and properties and admixtures used in concrete

Concrete

ConcretePresented To: Sir Sohail Mustafa

Presented By: Zeeshan Afzal

Outline1. Introduction.2. Ingredients.3.Manufacturing.4. Classification On Installation Bases. 5.Terminologies.

Outline6.Admixtures And Their Types.7.Types Of Concrete.8.Properties Of Concrete.9.Uses Of Concrete.

ObjectiveTo know more about concrete.How you can prevent corrosion?How you can give strength to your structure using concrete?What kind of admixtures you can use to get the required result?What are the terminologies that are associated with concrete?What are the tests that can be performed to check the quality?

1. INTRODUCTION

Who Invented The Concrete ?

Concrete is derived from a Latin word concretus which means compact.To create this structure, between 1756 and 1759, British engineer John Smeaton pioneered the use of hydraulic lime cement was patented byJoseph Aspdinon 1824. Reinforced concrete was invented in 1849 byJoseph Moniere in concrete, using pebbles and powdered brick as aggregate. A method for producing Portland.

Concrete

A composite material that consists essentially of a binding medium, such as a mixture of Portland cement and water, within which are embedded particles or fragments of aggregate, usually a combination of fine and coarse aggregate.Concrete is by far the most versatile and most widely used construction material worldwide.

Composite Material Acomposite materialis amaterialmade from two or more constituentmaterialswith significantly different physical or chemical properties, that when combined, produce amaterialwith characteristics different from the individual components.

Why Concrete Is A Composite Material?

Concreteis made from small stones and gravel called aggregate, sharp sand, cement and water. The small stone and gravel (aggregate) is the reinforcement and the cement is the matrix that binds it together.

Material In ConcreteThere are three main materials that combine together to form concrete.1.1 Cement.1.2 Aggregate.1.3 Sand.

1.1 CementIn concrete, the most commonly used is Portland cement, a hydraulic cement which sets and hardens by chemical reaction with water and is capable of doing so under water. Cement is the glue that binds the concrete ingredients together & instrumental for the strength of the composite

1.2 AggregateThe Aggregate is a granular material, such as sand, gravel, crushed stone, or in iron-blast furnace slag. The aggregate constitutes typically 75% of the concrete volume, or more, and therefore its properties largely determine the properties of the concrete.

1.3 Sand

To make theconcrete stronger, add more cement or less sand.The closer you bring the ratio to an even one-to-one of sand to cement, the stronger the rating becomes. This principles works in the opposite direction as well.

(2) INGREDIENTS

Ingredients of concreteConcrete is made up of three basic components:2.1 Water.2.2 Aggregate(rock,sand, or gravel).2.3 Portland cement.Cement, usually in powder form, acts as a binding agent when mixed withwaterandaggregates.

Proportion of ingredientsA mix is about 10 to 15 percent cement, 60 to 75 percent aggregate and 15 to 20 percent water. Entrained air in many concrete mixes may also take up another 5 to 8 percent.

(3)How concrete is made ?

(4) Classification of concrete on basis of installation method

(4) Types4.1 Ready-Mix Concrete.4.2 Reinforced Concrete.4.3 Fresh Concrete.4.4 Pre-cast Concrete.4.5 Shrink-Mix Concrete.

(4.1) Ready/Pre Mix ConcreteConcrete that is batched and mixed in a plant and than transported by truck in its fresh, or plastic, state to the construction site for final placement is called ready/pre mix concrete.

Ready Mix Concrete Plant

Institute of Geology24

(4.2) Reinforced ConcreteConcrete reinforced with steel or high strength material is known as reinforced concrete.

(4.3) Fresh Concrete

The material obtained immediately upon mixing of various concrete ingredients is called fresh concrete.

Fresh Concrete

(4.4) Pre-cast ConcretePre-cast concrete refer to any structure or component that is produced at one site, typically in a pre-casting plant, and then transported in its hardened state to its final destination is known as pre-cast concrete.

(4.5) Shrink-Mix Concrete.Concretethat is partiallymixedin a plant mixer and then discharged into the drum of the truck mixer for completion of the mixing is calledshrink mixed concrete.

(5) TERMINOLOGIES

Terminologies Associated With Concrete5.1 Portland Cement.5.2 Corrosion.5.3 Pigments.5.4 Cement Paste5.5 Mortar.


Cont5.6 Creep.5.7 Shrinkage.5.8 Hydration.

(5.1) Portland CementCement manufactured from chalk and clay which hardens under water and when hard resembles Portland stone in colour.

(5.2) CorrosionIt is the gradual destruction of materials (usually metals) by chemical reaction with their environment.


(5.3) PigmentsThe natural colouring matter of animal or plant tissue.Titanium WhiteUltra White.Cool Grey.Warm Grey.Curry.Sesame.Redwood.

(5.4) Cement PasteA mixture of cement and water is called cement paste.

(5.5) Mortar

Cement paste + Fine aggregate is called mortar or concrete matrix.

(5.6) Creep

Creep is the tendency of a solid material to move slowly or deform permanently under the influence of mechanical stresses.

(5.7) Shrinkage Contracting of harden concrete mixture due to the lose of capillary water and it causes an increase of tensile stress which may lead to cracking, internal wrapping and external deflection.

(5.8) HydrationAddition of water.

(6) ADMIXTURES

(6.1) AdmixturesThe action of adding an ingredient to Something else.

(6.1.1) Chemical Admixtures6.1.1.1 Air Entraining Admixtures.6.1.1.2 Water Reducing Admixtures.6.1.1.3 Retarding Admixtures.6.1.1.4 Accelerating Admixtures.6.1.1.5 Colour Pigments.

6.1.1.1 Air Entraining AdmixturesAir entraining agents are chemicals that are added to concrete to improve freeze and thaw resistance.

6.1.1.2 Water Reducing AdmixturesWater Reducing Admixtures, is also known as super-per-plasticizers, are chemicals that lower the viscosity of concrete in liquid state.

Cont..

6.1.1.3 Retarding AdmixturesIt delay the setting time, which may be necessary in situation where delay is the placement of concrete can be expected.

6.1.1.4 Accelerating AdmixturesAccelerating admixtures can be used to increase the rate of stiffening or setting of the concrete.

6.1.1.5 Colour PigmentsIt is powder or in liquid form may be added to the concrete mix to produce colour concrete.

6.1.2 Mineral Admixtures6.1.2.1 Pozzollanic.6.1.2.2 Ground Granulated Blast Furnace Slag (GGBFS).6.1.2.3 Silica Fume.

6.1.2.1 PozzolanA pozzolan is a material which, when combined with lime, exhibits cementations properties. Pozzolans are commonly used as an addition (the technical term is "cement extender") to Portland cement concrete mixtures to increase the long-term strength and other material properties of Portland cement concrete and in some cases reduce the material cost of concrete.

6.1.2.2 Ground Granulated Blast-furnance Slag

Ground granulated blast-furnace slag is thegranular materialformed when molten iron blast furnace slag (a by-product of iron and steel making) is rapidly chilled (quenched) by immersion in (Blast-Furnace Slag:A by-product of steel manufacture which is sometimes used as a substitute for Portland cement. In steel industry when iron ore is molted, then in the molted state all the impurities come at its surface which are removed called slag. It consists mainly of the silicates and alumino silicates of calcium, which are formed in the blast furnace in molten form simultaneously with the metallic iron. Blast furnace slag is blended with Portland cement clinker to form PORTLAND BLASTFURNACE SLAG CEMENT). GGBFS is used to make durable

6.1.2.2 Ground Granulated Blast-furnance Slag

ContStrengthConcrete containing GGBFS cement has a higher ultimate strength than concrete made with Portland cement. it has higher proportion of calcium silicate hydrate than concrete made with portland cement

cold jointsOften to mistakes in structural ,cracking in building.

6.1.2.3 Silica FumeBy-product of semiconductor industry.The terms condensed silica fume, micro silica, silica fume and volatilized silica are often used to describe the by-products extracted from the exhaust gases of silicon, ferrosilicon and other metal alloy furnaces. However, the terms micro silica and silica fume are used to describe those condensed silica fumes that are of high quality, for use in the cement and concrete industry.

6.1.2.3 Silica FumeSilica Fume consists of very fine particles with a surface area ranging from 60,000 to 150,000 ft/lb or 13,000 to 30,000 m/kg, with particles approximately 100 times smaller than the average cement particle. Because of its extreme fineness and high silica content, Silica Fume is a highly effective pozzolanic . Silica Fume is used in concrete to improve its properties. It has been found that Silica Fume improves compressive strength, bond strength, and abrasion resistance; reduces permeability of concrete to chloride ions; and therefore helps in protecting reinforcing steel from corrosion.

6.1.2.3 Silica Fume

(7) TYPES OF CONCRETE

Types Of ConcreteConcrete is an engineered material, with a variety of specialty product design for specific application.7.1 Light-Weight Concrete.7.2 Heavy-Weight Concrete.7.3 Architectural Concrete.7.4 Fiber-Reinforced Concrete.7.5 Polymer-Modified Concrete.

Cont.

7.6 Roller-Compacted Concrete.7.7 Ultra-High Strength Concrete.7.8 Self-Leveling Concrete.7.9 Green Concrete.

(7.1) Light-weight ConcreteLightweight aggregate concrete can be produced using a variety of lightweight aggregates.two types of light weight concrete(a)Including expanding agent(b)Having low density and thermal conductivityConstruction material Manufacture from industrial by-products such as fly ash, i.e. Lytag.

Light-weight Concrete

(7.2) Heavy-weight ConcreteHeavyweight concreteuses heavy natural aggregates such as barites or magnetite or manufactured aggregates such as iron or lead shot.

(7.3) Architectural ConcreteArchitectural concreterefers toconcretethat while providing an aesthetic finish to the building also serves a structural function. Decorativeconcretetypically refers toconcreteflatwork or building elements such as panels, that while enhanced with texture or color, are not structural building members.

(7.4) Fiber-reinforced ConcreteFiber reinforced concrete(FRC) isconcretecontaining fibrous material which increases its structural integrity. It contains short discretefibersthat are uniformly distributed and randomly oriented.Fibersinclude steel fibers, glassfibers, syntheticfibersand naturalfibers.

(7.5) Polymer-modified ConcreteWhen certain types of admixtures are blended into Portland cementconcrete, the resulting mixes may be calledpolymer-modifiedconcretes.

(7.6) Roller-compacted ConcreteRoller-compacted concrete(RCC) or rolledconcreteis a special blend ofconcretethat has essentially the same ingredients as conventionalconcretebut in different ratios, and increasingly with partial substitution of fly ash for Portland cement.

(7.7) Ultra-high Strength ConcreteConcrete with compressive strength of 40-85 MPa.

(7.8) Self-leveling ConcreteSelf-levelingconcreteis polymer-modifiedcementthat has highflow characteristicsand, in contrast to traditional concrete, does not require the addition of excessive amounts of water for placement.

(7.9) Green ConcreteConcretewhich is made fromconcretewastes that are eco-friendly are called as Green concrete. The other name forgreen concreteis resource saving structures with reduced environmental impact for e.g. Energy saving ,co2 emissions, waste water.

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(8) Properties

(8.1) Properties of fresh concreteProperties of concrete in its fresh state are very important because the influence the quality of the hardened concrete. The fresh concrete has the following procedure.8.1.1 Consistency8.1.2 Workability8.1.3 Settlement & Bleeding8.1.4 Plastic shrinkage8.1.5 Loss of consistency


(8.2) Properties of harden concreteHardened concrete has a number of properties, including:8.2.1 Mechanical Strength.8.2.2 Durability.8.2.3 Fire resistance.8.2.4 Thermal and Acoustic Insulation Properties.8.2.5 Impact Resistance.

(8.3) Durability Durability of concrete may be defined as the ability of concrete to resist weathering action, chemical attack, and abrasion while maintaining its desired engineering properties.8.3.1 Physical Durability

(8.3.1) Physical Durability Physical durability is against the following actions:8.3.1.1 Freezing and thawing action:

Cont8.3.1.2 Percolation / Permeability of water:

Cont8.3.1.3 Ultraviolet Resistance:

Cont8.3.1.4 Abrasion: Examples of severe abrasion and erosion are particles in rapidly moving water, floating ice, or areas where steel studs are allowed on tires.

(8.4) Thermal And Other PropertiesThe influence of factors such as age, water/cement ratio, temperature and moisture content on specific heat, thermal expansion and diffusivity of cement paste fall in this category.

(9) USES

Uses

UsesBeing one of the most versatile building materials, concrete is used in many forms of construction.9.1 Reinforced concrete is used to make building columns and decks in high rises9.2 Concrete is often used in residential driveways, house foundations, walls, paving, curb & gutter applications.9.3 Precast concrete used to produce a variety of items such as drainage piping. Large warehouses with a large flat floor and wall sections use what is called Tilt-up concrete construction.

Education

Concrete and its types and properties and admixtures used in concrete