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ASTM C494/C494M-15a
Standard Specification for Chemical Admixtures for Concrete (Includes all amendments And changes 8/10/2016).
Automaticky přeložený název:
Standardní Specifikace pro chemické příměsi do betonu
NORMA vydána dne 1.10.2015
Informace o normě:
Označení normy: ASTM C494/C494M-15a
Poznámka: NEPLATNÁ
Datum vydání normy: 1.10.2015
Kód zboží: NS-622409
Počet stran: 10
Přibližná hmotnost: 30 g (0.07 liber)
Země: Americká technická norma
Kategorie: Technické normy ASTM
Kategorie - podobné normy:
Anotace textu normy ASTM C494/C494M-15a :
Keywords:
accelerating, chemical admixtures, concrete, physical requirements, retarding, specific performance, testing, water reducing,, ICS Number Code 91.100.30 (Concrete and concrete products)
Doplňující informace
| 1. Scope | ||||||||||||||||||||||||||||||||||||||||||||
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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 A—Water-reducing admixtures, 1.1.2 Type B—Retarding admixtures, 1.1.3 Type C—Accelerating admixtures, 1.1.4 Type D—Water-reducing and retarding admixtures, 1.1.5 Type E—Water-reducing and accelerating admixtures, 1.1.6 Type F—Water-reducing, high range admixtures, 1.1.7 Type G—Water-reducing, high range, and retarding admixtures, and 1.1.8 Type S—Specific 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.
Mixtures having a high range water reduction generally display a higher rate of slump loss. When high-range admixtures are used to impart increased workability (6 to 8-in. slump [150 to 200–mm]), the effect may be of limited duration, reverting to the original slump in 30 to 60 min depending on factors normally affecting rate of slump loss. The use of chemical admixtures to produce high-slump (flowing) concrete is covered by Specification C1017/C1017M. Note 2: The purchaser should ensure that the admixture
supplied for use in the work is equivalent in composition to the
admixture subjected to test under this specification (see Section
6, Uniformity and
Equivalence).
Note 3: Admixtures that contain relatively large amounts of
chloride may accelerate corrosion of prestressing steel. Compliance
with the requirements of this specification does not constitute
assurance of acceptability of the admixture for use in prestressed
concrete.
1.3 This specification provides for three levels of testing. 1.3.1 Level 1—During the initial approval stage, proof of compliance with the performance requirements defined in Table 1 demonstrates that the admixture meets the requirements of this specification. Admixtures (except for Types B, C, E, and S) shall qualify for provisional compliance when the physical requirements and any of the alternative compressive strength requirements in Table 1 are met. If subsequent test results at six months or one year fail to meet the standard requirement of 100 % of reference strength, the compliance of the admixture to this standard is withdrawn and all users of the admixture shall be notified immediately. Uniformity and equivalence tests of Section 6 shall be carried out to provide results against which later comparisons can be made (see Note 4). Note 4: Allowing for provisional compliance while retaining
longer term compressive strength requirements promotes more rapid
qualification of new materials, but also provides assurance that
new admixture technologies will not exhibit unexpected longer term
performance. The alternative compressive strength requirements in
Table 1 are based on
statistical analysis of 103 Specification C494/C494M evaluation tests. The
alternative requirements correspond to a 99 % probability of
passing subsequent test age requirements.2
1.3.2 Level 2—Limited retesting is described in 5.2 – 5.2.2. Proof of compliance with the requirements of Table 1 demonstrates continued conformity of the admixture with the requirements of the specification. 1.3.3 Level 3—For acceptance of a lot or for measuring uniformity within or between lots, when specified by the purchaser, the uniformity and equivalence tests of Section 6 shall be used. 1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.5 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard. 1.6 The following precautionary caveat pertains only
to the test method sections, Sections 11 – 18 of this Specification:
Standard Specification for Portland
Cement Standard Test Method for Slump of
Hydraulic-Cement Concrete Standard Test Method for Density (Unit
Weight), Yield, and Air Content (Gravimetric) of Concrete Standard Test Method for Sieve Analysis
of Fine and Coarse Aggregates Standard Test Method for Flexural
Strength of Concrete (Using Simple Beam with Third-Point
Loading) Standard Specification for Concrete
Aggregates Standard Test Method for Compressive
Strength of Cylindrical Concrete Specimens Standard Practice for Sampling and the
Amount of Testing of Hydraulic Cement Standard Practice for Making and Curing
Concrete Test Specimens in the Laboratory Standard Test Method for Air Content of
Freshly Mixed Concrete by the Pressure Method Standard Test Method for Length Change of
Hardened Hydraulic-Cement Mortar and Concrete Standard Specification for Air-Entraining
Admixtures for Concrete ACI 211.1–91 Standard Practice for Selecting
Proportions for Normal, Heavyweight, and Mass Concrete Available
from American Concrete Institute (ACI), P.O. Box 9094, Farmington
Hills, MI 48333-9094, http://www.aci-int.org. Manual of Aggregate and Concrete Testing Standard Practice for General Techniques
for Obtaining Infrared Spectra for Qualitative Analysis Standard Specification for ASTM
Hydrometers Standard Specification for Reagent
Water Standard Test Methods for Specific
Gravity, Apparent, of Liquid Industrial Chemicals Standard Practice for Sampling
Aggregates Standard Specification for Chemical
Admixtures for Use in Producing Flowing Concrete Standard Test Method for Resistance of
Concrete to Rapid Freezing and Thawing (Withdrawn 2024) Standard Test Method for Time of Setting
of Concrete Mixtures by Penetration Resistance |
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