Concrete
Tips
Even though concrete
is a versatile substance it does have its limitations that you should
consider. Concrete is affected by temperature, too hot and it dries with
cracks, too cold and it takes forever to set-up. There are chemicals available
that will allow experts to pour concrete in even the worst conditions,
but trailered ready mix is not intended for these specialized applications.
But if you make proper plans in advance you should be able to pour concrete
anytime.
Most small concrete
pours should be planned when temperatures are between 60 and 90 degrees
Fahrenheit. This means that the concrete will begin to set-up in a reasonable
time but won't set-up before you have a chance to touch it up.
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Hot Weather Tips
- Plan ahead. If
you can make arrangements to pour in the cooler time of the day, this
will minimize the effects of trying to finish the concrete in the heat.
- Wet down all the
forms and ground just before you pour in the concrete. This will reduce
the rate of evaporation of the moisture in the concrete mix.
- Avoid adding water
to the mixture because it will lower the strength, increase cracking
and reduce the durability.
- Limit the time
between placing the concrete and final finishing.
- Use a fog type
spray nozzle to maintain surface moisture and to prevent evaporating
away the "bleed" water out of the concrete mix before it can
be troweled smooth.
- Provide sunshades
to control the surface temperature on the exposed surfaces.
- Erect windbreaks
to reduce the chances of a dry wind that will cause the surface to cure
too fast and crack.
- As soon as the
concrete is finished, begin a moist cure by keeping the finished surfaces
and pour area damp for the next few days.
- On extremely hot
or windy days, it may be best to reschedule the pour for a day with
more favorable conditions.
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Cold
Weather Tips
- Do not plan to
pour concrete when the temperatures will not get above 60 degrees Fahrenheit.
- If you can wait
until the sun is shining on the pour site, then wait.
- Use a concrete
mix with a low water volume so that it will have less moisture to reduce
the cure time.
- Provide a curing
membrane that can be as simple as a plastic tarp or as sophisticated
as a concrete curing blanket.
- It will take long
to cure so you will want to take precautions to keep unwanted travelers
from making an impression on your hard work.
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Concrete Facts
Too
much water weakens
the Concrete causing sandy surfaces, peeling and chipping.
Too little
water Causes the Concrete to cure too fast and will result in
wind check and cracking.
Concrete will reach
half its strength in 10 days and its full strength in 27 days hot
days or windy days can affect the finish of your job.
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