Download ppt - Concrete By John Templeton. What is concrete used for? SidewalksDrivewaysFoundations

ConcreteConcrete

By John TempletonBy John Templeton

What is concrete used for?What is concrete used for?

SidewalksSidewalks

DrivewaysDriveways

FoundationsFoundations

Advantages of Using Concrete:Advantages of Using Concrete:

Fire ProofFire Proof

Low MaintenanceLow Maintenance

Durable Durable

Termite and Rodent Termite and Rodent

PermanentPermanent

WatertightWatertight

SanitarySanitary

EconomicalEconomical

Storm ResistantStorm Resistant

Agricultural Uses of Concrete:Agricultural Uses of Concrete:

DrivewaysDriveways

PorchesPorches

Walls and Walls and FoundationsFoundations

StepsSteps

Small BridgesSmall Bridges

Setting PostsSetting Posts

WalksWalks

Water TroughsWater Troughs

Quality ConcreteQuality Concrete

Hardened Concrete should have the following Hardened Concrete should have the following qualities:qualities:– Durability:Durability: refers to resistance to chemical actions, refers to resistance to chemical actions,

freezing, and thawing.freezing, and thawing.

– Strength:Strength: measured as compressive and tensile. measured as compressive and tensile.

– Water tightness:Water tightness: the ability to prevent water passage the ability to prevent water passage through the mass.through the mass.

– Wear resistance:Wear resistance: the ability of hardened concrete to the ability of hardened concrete to resist abrasive action of vehicles, feet, and flowing resist abrasive action of vehicles, feet, and flowing water.water.

Quality ConcreteQuality Concrete

Fresh concrete should have the following Fresh concrete should have the following qualities:qualities:

– Consistency:Consistency: refers to the “wetness” and “dryness” of refers to the “wetness” and “dryness” of the mix.the mix.

– Uniformity:Uniformity: refers to the thorough mixing of all refers to the thorough mixing of all ingredientsingredients

– Workability:Workability: refers to the ease with which concrete refers to the ease with which concrete can be placed and shaped.can be placed and shaped.

Concrete IngredientsConcrete Ingredients

PORTLAND CEMENTPORTLAND CEMENT – Most cement used today is portland cement.Most cement used today is portland cement.

– This is a carefully proportioned and specially This is a carefully proportioned and specially

processed combination of lime, silica, iron oxide, and processed combination of lime, silica, iron oxide, and alumina. alumina.

– It is usually manufactured from limestone mixed with It is usually manufactured from limestone mixed with shale, clay, or marl. shale, clay, or marl.


PORTLAND CEMENTPORTLAND CEMENT

– Properly proportioned raw materials are pulverized Properly proportioned raw materials are pulverized and fed into kilns where they are heated to a and fed into kilns where they are heated to a temperature of 2,700°F and maintained at that temperature of 2,700°F and maintained at that temperature for a specific time. temperature for a specific time.

– There are five types of Portland cement covered There are five types of Portland cement covered under “Standard Specifications for Portland under “Standard Specifications for Portland

Cement.” Cement.”


AGGREGATESAGGREGATES – The material combined The material combined

with cement and water with cement and water to make concrete is called to make concrete is called aggregate. Aggregate aggregate. Aggregate makes up 60 to 80 percent makes up 60 to 80 percent of concrete volume. of concrete volume.

– It increases the strength It increases the strength of concrete of concrete

reduces the shrinking reduces the shrinking tendencies of the tendencies of the cementand is used as cementand is used as an economical filler. an economical filler.


AGGREGATESAGGREGATES– Aggregates are divided Aggregates are divided

into fine (usually into fine (usually consisting of sand) and consisting of sand) and coarse categories. coarse categories.

– For most building concrete, For most building concrete, the coarse aggregate the coarse aggregate

consists of gravel consists of gravel

or crushed stone up or crushed stone up

to 1 1/2 inches in to 1 1/2 inches in

size. size.


AGGREGATES (SAND)AGGREGATES (SAND)– Finer aggregates such as sand fill-in between Finer aggregates such as sand fill-in between

the larger partials (gravel).the larger partials (gravel).

– They give strength between the larger They give strength between the larger partials.partials.

Mixing RatioMixing Ratio

1 part Cement1 part Cement

2 parts Fine Aggregate2 parts Fine Aggregate

3 Parts Coarse Aggregate3 Parts Coarse Aggregate

Pouring MixturePouring Mixture

PreparationPreparation

Concrete may be mixed Concrete may be mixed – In a wheelbarrow using a shovel or In a wheelbarrow using a shovel or – Shoveled into a small electric or gasoline Shoveled into a small electric or gasoline

powered mixerpowered mixer

Most people purchase ready-mixed Most people purchase ready-mixed concrete from a local supplier.concrete from a local supplier.

Digging Digging

In many cases the area where concrete is In many cases the area where concrete is to be poured or placed must be dug out. to be poured or placed must be dug out. – Example: Driveways and sidewalks are Example: Driveways and sidewalks are

generally one inch above the ground level generally one inch above the ground level when finished.when finished.

Small areas: A shovel may be usedSmall areas: A shovel may be used

FormsForms

Concrete form: Frame or mold that Concrete form: Frame or mold that holds new concrete in shape until it has holds new concrete in shape until it has set or hardened. set or hardened.

The forms must be strong and rigid to The forms must be strong and rigid to prevent sagging, bulging, and prevent sagging, bulging, and spreadingspreading

Reinforcing Bars and WireReinforcing Bars and Wire

If heavy equipment will drive over concrete If heavy equipment will drive over concrete or freezing and thawing will be a problem, or freezing and thawing will be a problem, concrete should be reinforcedconcrete should be reinforced

Reinforcing bars: Steel bars with ridges Reinforcing bars: Steel bars with ridges that bond with the concretethat bond with the concrete– Commonly seen in the construction of Commonly seen in the construction of

highways and bridge deckshighways and bridge decks

Moving and Spreading ConcreteMoving and Spreading Concrete

Common tools used to move and spread Common tools used to move and spread material:material:– Shovels, Shovels, – Spades,Spades,– Rakes, and Rakes, and – Concrete drags Concrete drags

FloatingFloatingPushing the rocks down and bringing sand-Pushing the rocks down and bringing sand-cement paste to the surface and beginning cement paste to the surface and beginning the smoothing processthe smoothing process

Magnesium or wooden hand float: Used to Magnesium or wooden hand float: Used to smooth the area near the edge of the work smooth the area near the edge of the work areaarea

( Picture Courtesy, Interstate Publishers, Inc.)

FloatingFloating

Darby: Two handed float usually 18” long Darby: Two handed float usually 18” long that is also used near the edgethat is also used near the edge

Bull float: 36 or 42 inch float with long Bull float: 36 or 42 inch float with long round handle used to reach areas away round handle used to reach areas away from the edgefrom the edge

Calculating Material NeededCalculating Material Needed

Example:Example:– You are going to pour a concrete slab for a You are going to pour a concrete slab for a

small pump house the slab will need to be:small pump house the slab will need to be:8’X6’X4”8’X6’X4”

– 8 feet wide8 feet wide– 6 feet long6 feet long– 4 inches thick4 inches thick

How much concrete will be needed?How much concrete will be needed?

CalculationsCalculations