Curing Concrete Concrete S tart to Finish 1. Batch 2. Mix 3. - - PowerPoint PPT Presentation

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Curing Concrete Concrete S tart to Finish 1. Batch 2. Mix 3. - - PowerPoint PPT Presentation

May 29, 2023 175 likes •787 views

Mixing, Placing and Curing Concrete Concrete S tart to Finish 1. Batch 2. Mix 3. Transport 4. Place 5. Consolidate 6. Finish 7. Cure CIVL 3137 2 Concrete S tart to Finish 1. Batch Ready 2. Mix Mixed 3. Transport 4. Place 5.

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SLIDE 1

Mixing, Placing and

Curing Concrete

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SLIDE 2

CIVL 3137 2

Concrete S tart to Finish

  • 1. Batch
  • 2. Mix
  • 3. Transport
  • 4. Place
  • 5. Consolidate
  • 6. Finish
  • 7. Cure
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SLIDE 3

CIVL 3137 3

Concrete S tart to Finish

  • 1. Batch
  • 2. Mix
  • 3. Transport
  • 4. Place
  • 5. Consolidate
  • 6. Finish
  • 7. Cure

Ready Mixed

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SLIDE 4

CIVL 3137 4

Ready-Mixed Concrete

Ready-Mixed Concrete Central Mixing Transit Mixing Shrink Mixing

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CIVL 3137 5

Central Mixing

  • Approximately 20% of all plants in US
  • Concrete is completely mixed using a

stationary mixer (drum, paddle, pan)

  • High production volumes (4000 yd3/day)
  • Rapid mixing (30 to 120 seconds)
  • Improved quality control
  • Can use ordinary dump trucks for transit
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SLIDE 6

CIVL 3137 7

Concrete Wet Mix Plant

https://www.easymixconcrete.com/news/the-ready-mix-concrete-process/

Cement and Fly Ash Silos Aggregate Bins Mixer Control Room

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CIVL 3137 8

Concrete Wet Mix Plant

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SLIDE 8

Concrete S lipform Paving

CIVL 3137 11

https://www.gomaco.com/Resources/gp2400.html

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SLIDE 9

Concrete S lipform Paving

CIVL 3137 12

https://www.gomaco.com/Resources/gp2400.html

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SLIDE 10

CIVL 3137 19

S hrink Mixing

  • Concrete is partially mixed using a

stationary plant mixer to reduce volume

  • 1 yd3 of fully mixed concrete requires

1½ yd3 of ingredients

  • Concrete finishes mixing in a transit mix

truck on the way to the job site

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SLIDE 11

CIVL 3137 21

Transit Mix Truck

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SLIDE 12

Transit Mix Truck

CIVL 3137 22

https://concretetruckmixer.net/volumetric-concrete-mixer-truck/

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Transit Mix Trucks

  • 9-12 yd3 mixing drums are typical
  • Low speed rotation (2 rpm) agitates
  • High speed rotation (12-15 rpm) mixes
  • Drum rotates one direction to mix
  • Drum rotates the other to discharge
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SLIDE 14

Transit Mix Truck

CIVL 3137 25

https://en.wikipedia.org/wiki/Concrete_mixer

OPERATION

OF A TRUCK MIXER

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SLIDE 15

CIVL 3137 27

Transit Mixing

  • Concrete is batched dry at a central

plant and placed in a transit mix truck

  • Water is either added at the plant or

from a tank on the truck itself

  • Concrete is mixed entirely in the truck
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Dry Batch Concrete Plant

CIVL 3137 28

https://www.cmi-roadbuilding.com/concrete

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SLIDE 17

Dry Batch Concrete Plant

CIVL 3137 29

https://www.ceienterprises.com/literature/52-products/concrete-equipment/

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CIVL 3137 30

Transit Mixing Options

  • 1. Mixing at the batch plant

a) Mix for 50 revs at 12-15 rpm at batch plant b) Agitate at 2 rpm while in transit

  • 2. Mixing in transit

a) Mix for 70 revs at 8 rpm while in transit b) Agitate at 2 rpm until ready to discharge

  • 3. Mixing at the job site

a) Agitate at 2 rpm while in transit b) Mix 50-100 revs at 12-15 rpm at job site

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SLIDE 19

CIVL 3137 31

Concrete S tart to Finish

  • 1. Batch
  • 2. Mix
  • 3. Transport
  • 4. Place
  • 5. Consolidate
  • 6. Finish
  • 7. Cure
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SLIDE 20

CIVL 3137 32

Placement Methods

Wheelbarrow Conveyor Belt Chute Bucket Pump Tuckerbilt

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CIVL 3137 33

Chute Delivery

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CIVL 3137 34

Bucket Delivery

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CIVL 3137 35

Concrete Pumping

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SLIDE 24

CIVL 3137 36

Concrete Pumping

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CIVL 3137 38

Tuckerbilt

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CIVL 3137 39

Concrete S tart to Finish

  • 1. Batch
  • 2. Mix
  • 3. Transport
  • 4. Place
  • 5. Consolidate
  • 6. Finish
  • 7. Cure
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SLIDE 27

Consolidation

Consolidation is the process of reducing the volume of voids, air pockets, and entrapped air in fresh concrete, usually through the input of mechanical energy (e.g., vibrating, tamping, or rodding).

CIVL 3137 40

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SLIDE 28

Consolidation

Consolidation is needed because freshly placed concrete is usually honeycombed with entrapped air voids that are larger than the intentionally entrained air voids. Without consolidation, the concrete will be weak, porous, and poorly bonded to the reinforcement (and unsightly).

CIVL 3137 41

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SLIDE 29

CIVL 3137 42

Poor Vibration

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CIVL 3137 43

Poor Vibration

https://www.construct-ed.com/concrete-vibration/

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SLIDE 31

Tamping

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https://www.concretenetwork.com/concrete/concrete_tools/tampers.htm

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SLIDE 32

Internal Vibrators

CIVL 3137 45

https://civilsnapshot.com/concrete-vibrators-and-its-type/

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SLIDE 33

External Vibrators

CIVL 3137 47

https://www.mooser.net/en/construction-references/industry-construction/bv-augustin-riederau-e.html

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SLIDE 34

CIVL 3137 49

Concrete S tart to Finish

  • 1. Batch
  • 2. Mix
  • 3. Transport
  • 4. Place
  • 5. Consolidate
  • 6. Finish
  • 7. Cure
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SLIDE 35

CIVL 3137 50

Flatwork Finishing Methods

Screeding

bringing concrete to correct height

Floating

pushing coarse aggregate below surface

Troweling

bringing bleed water to surface and sealing

Brooming

providing nonskid texture

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Flatwork

Flatwork is any poured concrete whose surface is horizontal. This includes floor slabs, patios, sidewalks, driveways, and pavements. In tilt-up construction, walls are poured flat on the ground then tilted into place, so that is also a form of flatwork.

CIVL 3137 51

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SLIDE 37

S creeding

Screeding removes excess concrete and brings the surface to the proper grade. Screeding takes place immediately after the concrete is placed and must be completed before excess bleedwater appears on the surface.

CIVL 3137 52

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CIVL 3137 53

S creeding

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SLIDE 39

Floating

Floating fills voids left by screeding and pushes the coarse aggregate particles slightly below the surface. Floating leaves a thin layer of mortar at the surface to aid in finishing.

CIVL 3137 54

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SLIDE 40

CIVL 3137 55

Floating

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SLIDE 41

Troweling

Troweling brings a small amount of bleed water to the surface to produce a hard, dense finish.

CIVL 3137 56

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CIVL 3137 57

Troweling

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SLIDE 43

Brooming / Dragging

Brooming and dragging impart a rough texture to the surface of pavement slabs to provide good traction in wet weather.

CIVL 3137 58

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SLIDE 44

CIVL 3137 60

Brooming

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CIVL 3137 61

Burlap Dragging

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CIVL 3137 62

Concrete S tart to Finish

  • 1. Batch
  • 2. Mix
  • 3. Transport
  • 4. Place
  • 5. Consolidate
  • 6. Finish
  • 7. Cure
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SLIDE 47

Concrete Curing

Curing is essential to developing proper strength and durability by

  • 1. Maintaining adequate moisture in the

concrete to hydrate the cement

  • 2. Maintaining a minimum temperature

in the concrete so hydration proceeds at an adequate rate

CIVL 3137 63

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SLIDE 48

CIVL 3137 64

Poor Curing

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SLIDE 49

CIVL 3137 65

Concrete Curing

Replacement Methods ponding fogging wet burlap wet straw wet sawdust Barrier Methods plastic sheets curing compounds insulating blankets

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CIVL 3137 66

Ponding

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CIVL 3137 68

Ponding

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SLIDE 52

CIVL 3137 69

Fogging

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CIVL 3137 70

Fogging

http://www.concretebridgeviews.com/i80/Article3.php

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CIVL 3137 71

Wet Burlap / S traw

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CIVL 3137 73

Wet Burlap and Plastic S heeting

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SLIDE 56

CIVL 3137 74

Plastic S heeting

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CIVL 3137 75

Insulating Blankets

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SLIDE 58

CIVL 3137 76

Curing Compounds

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SLIDE 59

CIVL 3137 77

Curing Compounds