Dry Tamp?

[stewchi]

Does anyone have any opinions on pouring concrete dry. It seems the basic idea is put the concrete in place dry and wet after it is in the appropriate forms. Supposedly this makes a stronger concrete. Is this true, what are the drawbacks?

[Rich]

Dry concrete is cement. It's not concrete until you add water and some type of aggregrate material. Then it goes through a pozzolanic action to become concrete... anyway.. enough with the concrete lesson :)
It really depends in what capacity you will be using the cement for.. not recommended for a driveway, sidewalk, or foundation.

[mfinley919]

I've done that method for split rail fence posts, but I would shy away from it for anything else.

As far as it being the strongest method, I would have my doubts about that.

[Rich]

Yep.. works excellent for that. I've also used cement and sand mixture for doing dry non-mortared patios. The mixture works as an excellent binder... works by sweeping it in. Then it settles some.. sweep some more. About 3 days later it's pretty much bomb proof.

[mfinley919]

Good example Rich, I forgot about that one also.

[mjpliv]

I have used something close to that which we refer to as a dry pack. After we place the metal pan for a custom shower our tile trades use a cement mix with just enough moisture in it to allow it to pack. This is packed down and shaped with a trowell to give a positive slope to the drain. It sets up just fine but if you felt the mix before packing, it would feel dry to the touch.