Rapid moisture loss may cause the concrete to crack. Curing compound puts a 'cap' or 'membrane' on the concrete, slowing down the rate of moisture loss. Other methods of curing concrete include water-ponding, blankets, and hessian.
Finish Aid - also know as Anti-Vap - is applied whilst placing and finishing concrete. It helps the concrete cure the bottom up, giving you more working time in hot and windy conditions. Simply spray on when screeding, after bull-floating, and after first pass with power trowel. It's suitable for all types of concrete, slabs, paving, coloured concrete etc.