Accelerating admixtures can be used either to increase the rate of stiffening / setting of the concrete or to increase the rate of hardening and early strength gain to allow earlier demoulding and handling. Most accelerators primarily achieve one rather than both of these functions.

 Accelerators can be used in conjunction with superplasticisers where very early age strength is required, especially at lower temperatures as they are more effective at low temperatures.

Accelerating admixtures increase the rate of hydration of tricalcium silicate (C3S) and tricalcium aluminate (C3A) phases of the cement, thereby providing earlier heat evolution and strength development. Unless combined with a water reducer, accelerating admixtures give only a small increase in workability.