I use a leaf blower to clean out the shop and the concrete pad in front of it all of the time. I usually sweep the big chunks up and then blow the rest out the door. You need to keep in mind which way the wind is blowing. LOL If it is away from or even across your garage door it works well. If the wind is blowing toward the door at all it is a no go. It will just makes a big mess.
Also the vac side of a leaf blower/vac is not worth a darn for what you want to use it for. The vac part will work but the bag is not like your house sweeper that filters all of the dust out. You get a fair amount of dust through the bag which makes it use inside a problem. It is made to vac out eve troughs and that type of thing out side.