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Normas ASTM – AENOR
ASTM C494/C494M-10a

ASTM C494/C494M-10a

Standard Specification for Chemical Admixtures for Concrete

Fecha:
2011-08-10 /Historical
Superseeded by:
Abstract:

This specification covers the materials and the test methods for use in chemical admixtures to be added to hydraulic-cement concrete mixtures in the field. The seven types of admixtures are indicated as follows: Type Awater reducing; Type Bretarding; Type Caccelerating; Type Dwater reducing and retarding; Type Ewater reducing and accelerating; Type Fwater reducing, high range; and Type Gwater reducing, high range, and retarding. The materials used in the concrete mixtures shall include Type I or Type II cement, pozzolan, fine and coarse aggregates, and air-entraining admixture. Samples of freshly mixed concrete from at least three separate batches for each condition of concrete shall be tested in accordance with the slump, air content, time of setting, and water content tests. Physical properties retesting shall consist of uniformity and equivalence tests using infrared analysis which is intended to compare qualitatively the composition of different samples, residue by oven drying which shall be either a forced circulation type or one with provision for free access of air, and specific gravity determination using hydrometers. Test specimens of the hardened concrete shall be prepared in accordance to compressive strength, flexural strength, resistance to freezing and thawing, and length change.

Scope:

1.1 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:

1.1.1 Type AWater-reducing admixtures,

1.1.2 Type BRetarding admixtures,

1.1.3 Type CAccelerating admixtures,

1.1.4 Type DWater-reducing and retarding admixtures,

1.1.5 Type EWater-reducing and accelerating admixtures,

1.1.6 Type FWater-reducing, high range admixtures,

1.1.7 Type GWater-reducing, high range, and retarding admixtures, and

1.1.8 Type SSpecific performance admixtures.

1.2 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.

Keywords:
accelerating; chemical admixtures; concrete; physical requirements; retarding; specific performance; testing; water reducing; Accelerating admixtures (for concrete); Concrete admixtures--specifications; Moisture analysis--concrete; Water-reducing admixtures (for concrete)
50,8
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