Ok, so that definitely didn’t go like I planned.
The reason it’s important to vibrate concrete is to bring all the air bubbles and voids to the surface.
Concrete with air bubbles and voids is not nearly as dense or strong as concrete that has been vibrated.
This is especially important for structural things like walls or support columns.
We built this form to represent a column and put a piece of clear plexi-glass on the front so we could see what happens when the concrete is vibrated.
I tried to mix this concrete fairly dry, you can see how hard it was to get out of the bucket- it was coming out in clumps.
I used this backpack style vibrator, and it was totally overkill for this small job.
Because it’s so powerful, I barely revved it up so the form wouldn’t blow apart.
It was cool to see how much air started coming out of the concrete right away, and it settled a good 2 or 3 inches from the top.
Finally, one of the form boards did split in half.
If you’re planning on vibrating concrete, I recommend making sure your form is reinforced. It puts a lot more stress on them.
Let me know in the comments if you have a concrete horror story. @hausplans
#build #howto #vibrate #concrete #construction #diy #contractor
