Dispersants are used as plasticizers or superplasticizers in concrete formulations to lower the use of water while retaining the needed slump (flow) property. A lower water content makes the concrete stronger and more impervious to water penetration.
Similarly, dispersants are used as plasticizers in the gypsum slurry during wallboard manufacture, to reduce the amount of water used. The lower water usage allows lower energy use to dry the wallboard.