Making precast concrete panel - GIF

[Altair]

Making precast concrete panel.




Previously:

Aerated concrete block shaping and cutting machine - GIF
Industrial concrete block production - GIF
Pouring a concrete roof - GIF
Crane collapses due to bad rigging - GIF
Crane overturns while erecting tilt-up wall - GIF

[Frank S]

Is there still any concrete left in that soup? First time I believe I've concrete so wet it was full slump self leveling like paint.

[piper184]

Agreed.

Unfortunately I have seen housing contractors pour basements and driveways with stuff that was nearly that bad. Filled an entire basement wall from one corner of the forms.

The mix arrived on site with the correct slump, but the foreman had them keep adding water until it would flow without much effort from his men. They also "vibrated" the set by sending a guy inside the forms with a rubber mallet to smack each one twice as he made one trip about the house.

Sad, but true...

[Frank S]

Agreed.

Unfortunately I have seen housing contractors pour basements and driveways with stuff that was nearly that bad. Filled an entire basement wall from one corner of the forms.

The mix arrived on site with the correct slump, but the foreman had them keep adding water until it would flow without much effort from his men. They also "vibrated" the set by sending a guy inside the forms with a rubber mallet to smack each one twice as he made one trip about the house.

Sad, but true...

A full slump in a basement floor is one thing, all that slab is going to do is lay there. but those precast panels will have to be moved and stood vertically. The only way i can see them haveing any nstrength would be if they are made of some kind of epoxy or resin mix possibly would even have fiber in it.

[piper184]

The big problem is as the mix is running through the forms to get to the far side of the basement wall, gravity is pulling the aggregate to the bottom and the water is floating the cement out of the mix. The walls at the far corner from the pour are most likely just sand and what is left of the cement.

The same applies to the floors and driveways. Aggregate goes to the bottom and the cement floats to the top with the sand somewhere in between. Then after a couple of winter's of freeze/thaw cycles the top of the driveway starts to flake off. But by then it is the home owners problem and the contractor gets away with it.

I watched those clowns pour a driveway that was fairly steep with thinned out mix. Before they could get it all screeded down, it was running over the forms at the bottom end. They had to quick grab some guys with shovels and start tossing it back up to the top. Eventually enough of the excess water ran out the bottom and the mix stiffened up enough to stay in place. Two years later that driveway looked like it was 80 years old.

By the time our house in that neighborhood was 5 year old the garage floor had cracks that were an inch wide. You could look down inside and see the fiberglass fuzz sticking out into the crack. It hadn't added anything to the strength of the pad.