Thursday, September 5, 2019

Surface Voids in Concrete | Bug Holes in Concrete



Surface Voids in Concrete | Bug Holes in Concrete

Surface Voids
These are the little holes that appear on the concrete surface. These voids may produce unacceptable appearance on the surface of the finished casting.


Voids on Concrete Surface, holes on concrete
Air Voids/Surface Voids/Bug Holes

Causes of Surface Voids / Bug Holes in Concrete
It is generally due to the following three factors:
1. Release Agent
2. Release Water
3. Release Air


mixing concrete time, concrete mixing time limit
Mixing Concrete/Mixing Time
Helpful Hints 

Fill voids under concrete 

Hint No. 1
Extend the mix time to help break up any residual air or water bubbles. This will promote a more uniform and workable consistency.



Shuttering oil, lubricant oil
Shuttering Oil
Hint No. 2
Make sure to that release agents are applied in thin films. This will eliminated any pooling or puddling in the lower portions of your mold.





Hint No. 3
Cement, Cement Fineness
Cement
Lower the viscosity of cement by adding sand or fly ash.
This allows large aggregate to move more freely and reduces
the amount of air entrapment.




Hint No. 4
Aggregate, Aggregate Size
Aggregate
Use aggregate that is more uniform in shape. Irregular shaped pieces of aggregate tend to make the concrete less fluid.






Vibrator, vibrating in concrete
Vibrator
Hint No. 5
Techniques used during vibration can eliminate most surface voids.
Vibrating both the outside and inside of you mold will draw most air
and water bubbles away from the surface of the concrete. Hammering
the mold can eliminate any residual voids.

hammer, wooden hammer
Wooden Hammer



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