Admixture

Any substance other than cement, water, or aggregate, added to a concrete or mortar mix to alter its properties or those of the hardened product. Also called Additive.

Air-entraining Agent

An admixture that disperses entrained air In a concrete or mortar mix toIncrease workability, Improveresistance of the cured product to the cracking Induced by free-thaw cycles or the scaling caused by deicing chemicals. And In larger amount. To produce lightweight Insulating concrete.

Accelerator

An admixture that hastens the settingand strength development of aconcrete. mortar, or plaster mix.

Retarder

An admixture that slows the setting ofa concrete, mortar. or plaster mix inorder to allow more time for placing andworking the mix.

Surface-Active Agent

An admixture for reducing the surfacetension of the mixing water to in a concrete mix. Thereby facilitating thewetting and penetrating acting of thewater. or aiding-In the emulsifying anddispersion of other additives in the mix. Also called surfactant.

Water-Reducing Agent

An admixture for reducing the amountof mixing water required for the desired workability of a concrete or mortar mix. lowering the water-cement ration in this manner generally results in increased strength. Also calledSuper plasticizer.

Coloring Agent

A pigment or dye added to a concretemix to alter or control its color.