Tell us about yourself!
Really? The cement I found was cheaper than the quickcrete ready mix we have here. I guess it depends on where you are
Quick note about CO poisoning, its doesn't bind to the O2, it binds to the oxygen receptor site on the alpha/beta-hemoglobin in your red blood cells, and doesn't detach as easily as O2 and CO2, which is what prevents your tissues from getting oxygen. Great 'ible :)
I'd suggest using Portland cement instead of concrete containing larger aggregate bits, it would look a little cleaner on the end