Bob F.,
The amount of weight needed to keep the wheels on your CC100 (that's what you have, correct?) from spinning on concrete will depend on how much snow you're trying to push with your blade, the weight of the operator, the width & diameter of your tires, the condition that your engine is in (amount of HP being produced), the amount of traction on the surface (is the concrete driveway 'dry' & only covered with powdery snow -or- is there a layer of packed snow/ice on the concrete to produce a slick layer to try to get traction on), the number of cross-chains on your tire chain set (I've seen some sets with only four cross-chains and other sets with upwards of 20+ cross-chains).... all those factors and more will play a part in whether or not your wheels will spin when snow plowing. It all depends; you may need to experiment some for your situation. Realize too that your 100 isn't the heaviest nor highest HP CC built, so when comparing notes, make it "apples to apples".
I would recommend that you do some research in the archives to determine if you're willing to 'load' your tires with either a brine or RV antifreeze solution (if you do, I'd suggest using inner tubes for loading) and/or locate and secure some wheel weights to mount on the inside and outside of the rims for starters.
As you have probably seen from other examples on these pages, most folks feel that 'the more weight, the better' so adding 200-lbs to your tractor would be a good beginning effort.
In the meantime, if you simply plow less snow at one time, such as only push a 1/2 blade width, this reduces the amount of snow being pushed, thus will reduce the likelihood of spinning your tires and causing the chains to scratch your concrete drive.
Good Luck!
Ryan W.