i've been doing quite a bit of this lately.
you can maybe break it up with a hammer, but i wouldn't try it unless you
have
a large prybar to get under one end of the slab to lift slightly. without a
bit of
air gap under the slab, it could be very tough going.
if no big prybar, rent an electric breaker hammer.
btw, the electric hammers are kind of fun.

bill

"RB" wrote in message
...
We have a massive concrete step that I'm going to replace. The question
is
whether or not I can bust it up with a sledge, in place.

The piece is 3'W x 4'L x 8"Thick.

Will whacking on it with a sledge finally break through that 8" thickness
and start shattering pieces off?

The reason I'm asking before trying is because, if I can bust it up, it
will
have to stay in place and maintain function and appearance for a short
interval until I can figure out how to rig it out there in one piece.

I'm hoping sledge blows will put fault lines though the mass and start it
breaking up.