Has anyone used these pellets for heating prime water? What do pumpers use these pellets for 

OOps got that one wrong. It is not a retarder.

They use calcium chloride powder to accelerate concrete curing in the cold. Last week i pumped a job with 2 % chloride (one bag) in 7 degree F weather they also used hot water and plastersiser. 1 1/2 hour job and they were burning last round with the power trowel when i left!

In Louisiana the temperature will rise 20- 30 degrees in a matter of hours. It's really fun when the batch man "forgets" to take out the Calcium when Temps get up to the 40s n 50s. I keep a close eye on my tickets whenever they're using it when I know Temps will be rising that day.