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The following information is offered for reference purposes only.  Consult a construction professional prior to performing any work.  D & K Concrete assumes no responsibility for events resulting from the use of this information.

Concrete Info

Site Prep


The sub-grade (location where concrete is being poured) should be smooth and have uniform depth.  The depth will vary with application.  It should also be uniformly compacted and dampened.  Soil containing alkali should be covered with plastic, the plastic should have sand over it.  Never pour concrete on muddy soil or in standing water.


Be sure slabs have proper slope/fall for water runoff.






















Be sure you are using the appropriate mix for your application.  Concrete is measured by compressive strength.  Adding excessive water to concrete weakens is substantially.


Effects of Water on Concrete:


• Adding one gallon of water to one yard of 3000 psi concrete will increase slump by about one inch.


• Adding one gallon of water to one yard of 3000 psi concrete will reduce compressive strength by as much as 250 psi.


• Adding one gallon of water to one yard of 3000 psi concrete will waste the effect of about 25 lb of cement per yard.


• Adding one gallon of water to one yard of 3000 psi concrete you increase the possibility of passage of moisture through the concrete by up to 50%


• Adding one gallon of water to one yard of 3000 psi concrete will increase the shrinkage potential about 10-15%.


• Adding one gallon of water to one yard of 3000 psi concrete you lower the quality of concrete in other ways:


- Less wear resistance


- Dusting


- Cracking


- Reduced durability


Finishing


All concrete cracks.  Expansion joints/control joints control where the cracks occur, making for a more appealing slab.  If done properly, saw cuts will also control cracking.

















Set Time


The setting-up of concrete is a chemical reaction.  The ambient temperature effects the timeframe in which the chemical reaction occurs.


 

















 

Curing


• Improper curing can reduce the designed strength by as much as 50%

• Properly cured concrete will crack less, dust less, be stronger, more durable, and have better wear resistance.

• Properly cured concrete will have fewer pores where water can enter and freeze causing damage to the concrete.

• Methods of curing

- Membrane curing compounds

- Water spray (keep slab continuously damp)

- Waterproof curing paper

- Damp burlap

- Plastic sheets

- Damp earth, straw, sand and hay

- Ponding for seven days

One Yard of Concrete will Cover:

Thickness in Inches:

Area in Square Feet

3.5"

93 ft2

4"

81 ft2

4.5"

72 ft2

5"

64.75 ft2

5.5"

59 ft2

6"

54 ft2

6.5"

50 ft2

7"

46 ft2

7.5"

43.33 ft2

The effects of temperature on set times.

Temperature, ˚F

Approximate setting time, Hours

100

1-2/3

90

2-2/3

80

4

70

6

60

8

50

11

40

14

30

19+

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