Concrete By John Templeton. What is concrete used for? SidewalksDrivewaysFoundations.
-
Upload
august-glenn -
Category
Documents
-
view
220 -
download
1
Transcript of 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.
Concrete IngredientsConcrete Ingredients
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.”
Concrete IngredientsConcrete Ingredients
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.
Concrete IngredientsConcrete Ingredients
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.
Concrete IngredientsConcrete Ingredients
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