Well, I've never heard of that!! Makes sense, though - the stuff swells up nicely. BTW, it's available at farm stores - I bought some at the local farmers co-op to fix a pond leak.
About the SDS drill/rotary hammer - I bought a Bosch about 25 years ago and don't know what I'd do without it. Drilling a 1" holes in concrete is nothing. Switch it to the chisel mode and carve out concrete like it is wood. Remodeling a basement bathroom I drilled the edges then chiseled out a channel big enough to run a shower drain maybe 4' in length. The hardest thing about the job was getting these old bones back up off the floor when done.
As for the concrete rounds in this thread, I started thinking - they could be very handy around the farm as is.
JKJ