0:00
Hi, I'm Tim Carter from AskTheBuilder.com. We're here at a job site where they're
0:09
pouring a concrete slab. And I want to show you something that a lot of people don't get to see
0:13
and it's really, really important to know because this is where a lot of concrete fails. It's called
0:19
concrete bleed water. Concrete bleed water. Look at this. So, you can see that shine on the concrete right here, right there
0:39
What you're seeing is that's a really thin sheen of water up on top of the concrete
0:47
Now what's that all about? Okay, think about it for a second
0:51
What's concrete made out of? What are the four ingredients? Gravel, sand, Portland cement, and what? Water
0:59
Water is the lightest ingredient because if you pour all those other things into a bucket
1:02
of water, they all sink to the bottom. So concrete, what happens is right after you've full floated it or screated it, the water
1:10
kind of comes to the top. But you've got to make sure that you don't float that into the concrete
1:16
It'll go away on its own in just a little bit. But if you float it in, it will dissolve the cement paste at the top of the slab, and it'll
1:23
make the concrete, the upper part of the concrete, very weak. And that's one of the causes of spalling
1:29
So don't trowel bleed water into the concrete. I'm Tim Carter for AskTheBuilder.com
1:36
If you want to discover more home improvement tips, go to AskTheBuilder.com
