the set retarding concrete admixtures are often used to inhibit the chemical reaction which occurs when the concrete starts the setting process. The main use of these this type of concrete admixture is often to bring down the effects of high temperatures which may bring about a speedier setting of concrete. This type of admixtures is most commonly used in making pavements. They are used in pavement construction to give more time to finish concrete pavements. This reduces any more costs that would have been incurred to put up a new concrete batch plant on the construction site; it also eliminates cold joints in concrete.
Retarders also can be used to help resist cracking caused by form deflection which occurs when horizontal slaps are put in sections. Retarders can also be used as water reducers; they also help to entrain some air in the concrete.