CaCl is usually stored in moisture proof bags until needed. Otherwise its ability to draw moisture can cause it to cake and form into large chunks. A mixture of calcium chloride and salt can be very effective. Even a small amount of calcium chloride will start melting at low temperatures. The resulting brine and heat allow the salt to start working.
Wetting provides moisture to make brine.
Faster melting action may be expected. In addition, the wet salt has less tendency to bounce or be blown off the road by traffic. Applications of 6-10 gallons per cubic yard of salt are recommended. Calcium chloride has the added advantage of producing extra melting due to its effectiveness. Using salt brine to pre-wet is becoming more common because of its lower cost.