usefullness of old cement.

Not to me.

Large paperweight? It will have very little strength.

Yes, it'll still make weak concrete.

John

Throw it away. It's no good.

You could mix it up, but it won't have any strength when it sets. You see, cement cures by a chemical reaction with the water that's added to it. In your bag of old cement, that reaction has already taken place, with humidity in the air. You can't make concrete with that stuff. It will set, but it will crumble the first time any stress is applied to it.

Sure - if your soil is too acidic, you can mix some of that cement into the soil to make it more alkaline.

In the winter, if your walk or driveway is covered with ice, you could spread some of it around to provide traction, and possibly help melt the ice.

If you have any plants you want to kill, you could dump it on top of them.

Not for making concrete. Just buy some more. It's cheap.

It will deteriorate quickly so it is worthless.

If you have a gravel driveway, just spread it into the gravel with a rake and let it add to the pavement filler.

If you are setting posts us it at the bottom where it doesn't need strength, it can act as filler there.

I use this sort of thing to fill woodchuck holes.

You could add more strength to it by mixing it with cement in a ratio of perhaps 1 part cement to 8 part ready mix concrete. Make sure you break up the ready mix really well first.

If you had kept it indoors then it might be OK after a year, but I wouldn't push cement in a bag in a house much further than that.

I used some old cement with new to make a mix of 9:1 sharp sand/cement for bedding flags on. No strenght required there

Just mix it up and make small bricks with it, using cut off milk jugs or whatever. Should work spectacular when hit with a bullet! ;)

LOL!