Документы

ASTM International

Standard Specification for Chemical Admixtures for Concrete
 N C494/C494M

Annotation

This specification covers materials for use as chemical admixtures to be added to hydraulic-cement concrete mixtures in the field for the purpose or purposes indicated for the eight types as follows:

Type A—Water-reducing admixtures,

Type B—Retarding admixtures,

Type C—Accelerating admixtures,

Type D—Water-reducing and retarding admixtures,

Type E—Water-reducing and accelerating admixtures,

Type F—Water-reducing, high range admixtures,

Type G—Water-reducing, high range, and retarding admixtures, and

Type S—Specific performance admixtures.

This specification stipulates tests of an admixture with suitable concreting materials as described in 11.1 – 11.3 or with cement, pozzolan, aggregates, and an air-entraining admixture proposed for specific work (11.4). Unless specified otherwise by the purchaser, the tests shall be made using concreting materials as described in 11.1 – 11.3.

NOTE 1—It is recommended that, whenever practicable, tests be made using the cement, pozzolan, aggregates, air-entraining admixture, and the mixture proportions, batching sequence, and other physical conditions proposed for the specific work (11.4) because the specific effects produced by chemical admixtures may vary with the properties and proportions of the other ingredients of the concrete. For instance, Types F and G admixtures may exhibit much higher water reduction in concrete mixtures having higher cement factors than that listed in 12.1.1.