1、Designation:C494/C494M11 Designation: C494/C494M 12Standard Specification forChemical Admixtures for Concrete1This standard is issued under the fixed designation C494/C494M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This specification covers materia
3、ls for use as chemical admixtures to be added to hydraulic-cement concrete mixtures in thefield 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 a
4、nd 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, and1.1.8 Type SSpecific performance admixtures.1.2 This specification stipulates tests of an admixture wi
5、th suitable concreting materials as described in 11.1-11.3 or withcement, pozzolan, aggregates, and an air-entraining admixture proposed for specific work (11.4). Unless specified otherwise by thepurchaser, the tests shall be made using concreting materials as described in 11.1-11.3.NOTE 1It is reco
6、mmended that, whenever practicable, tests be made using the cement, pozzolan, aggregates, air-entraining admixture, and themixture proportions, batching sequence, and other physical conditions proposed for the specific work (11.4) because the specific effects produced bychemical admixtures may vary
7、with the properties and proportions of the other ingredients of the concrete. For instance, Types F and G admixtures mayexhibit 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 hi
8、gher rate of slump loss. When high-range admixtures are used to impart increasedworkability (6 to 8-in. slump 150 to 200mm), the effect may be of limited duration, reverting to the original slump in 30 to 60 min depending on factorsnormally affecting rate of slump loss. The use of chemical admixture
9、s to produce high-slump (flowing) concrete is covered by SpecificationC1017/C1017M.NOTE 2The purchaser should ensure that the admixture supplied for use in the work is equivalent in composition to the admixture subjected to testunder this specification (see Section 6, Uniformity and Equivalence).NOT
10、E 3Admixtures that contain relatively large amounts of chloride may accelerate corrosion of prestressing steel. Compliance with the requirementsof this specification does not constitute assurance of acceptability of the admixture for use in prestressed concrete.1.3 This specification provides for th
11、ree levels of testing.1.3.1 Level 1During the initial approval stage, proof of compliance with the performance requirements defined in Table 1demonstrates that the admixture meets the requirements of this specification. Admixtures (except for Types B, C, E, and S) shallqualify for provisional compli
12、ance when the physical requirements and any of the alternative compressive strength requirementsin Table 1 are met. If subsequent test results at 6 months or one year fail to meet the standard requirement of 100 % of referencestrength, the compliance of the admixture to this standard is withdrawn an
13、d 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 4Allowing for provisional compliance while retaining longer term compressive strength requirem
14、ents promotes more rapid qualification ofnew materials, but also provides assurance that new admixture technologies will not exhibit unexpected longer term performance. The alternativecompressive strength requirements in Table 1 are based on statistical analysis of 103 Specification C494/C494M evalu
15、ation tests. The alternativerequirements correspond to a 99 % probability of passing subsequent test age requirements.21.3.2 Level 2Limited retesting is described in 5.2, 5.2.1 and 5.2.2. Proof of compliance with the requirements of Table 1demonstrates continued conformity of the admixture with the
16、requirements of the specification.1This specification is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.23 onChemical Admixtures.Current edition approved July 1, 2011.2012. Published August 2011.September 2012. Or
17、iginally approved in 1962. Last previous edition approved in 2010 asC494/C494M10a.C494/C494M11. DOI: 10.1520/C0494_C0494M-112.2Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:C09-1030.1This document is not an ASTM standard and i
18、s intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the
19、 current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.1.3.3 Level 3For acceptan
20、ce of a lot or for measuring uniformity within or between lots, when specified by the purchaser, theuniformity 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 eachsystem may
21、not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo 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(e
22、xcluding 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: Thisstandard does not purport to address all of the safety concerns, if any, associate
23、d with its use. It is the responsibility of the userof this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations priorto use.2. Referenced Documents2.1 ASTM Standards:3C33 Specification for Concrete AggregatesC39/C39M Test Method for
24、 Compressive Strength of Cylindrical Concrete SpecimensC78 Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)C136 Test Method for Sieve Analysis of Fine and Coarse AggregatesC138/C138M Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric)
25、 of ConcreteC143/C143M Test Method for Slump of Hydraulic-Cement ConcreteC150 Specification for Portland CementC157/C157M Test Method for Length Change of Hardened Hydraulic-Cement Mortar and ConcreteC183 Practice for Sampling and the Amount of Testing of Hydraulic CementC192/C192M Practice for Maki
26、ng and Curing Concrete Test Specimens in the LaboratoryC231 Test Method for Air Content of Freshly Mixed Concrete by the Pressure MethodC260 Specification for Air-Entraining Admixtures for ConcreteC403/C403M Test Method for Time of Setting of Concrete Mixtures by Penetration ResistanceC666/C666M Tes
27、t Method for Resistance of Concrete to Rapid Freezing and ThawingC1017/C1017M Specification for Chemical Admixtures for Use in Producing Flowing ConcreteD75 Practice for Sampling AggregatesD891 Test Methods for Specific Gravity, Apparent, of Liquid Industrial ChemicalsD1193 Specification for Reagent
28、 WaterE100 Specification for ASTM HydrometersManual of Aggregate and Concrete Testing2.2 American Concrete Institute Standard:ACI 211.191 Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete43. Terminology3.1 Definitions:3.1.1 accelerating admixturean admixture that
29、 accelerates the setting and early strength development of concrete.3.1.2 retarding admixturean admixture that retards the setting of concrete.3.1.3 water-reducing admixturean admixture that reduces the quantity of mixing water required to produce concrete of agiven consistency.3.1.4 water-reducing
30、admixture, high rangean admixture that reduces the quantity of mixing water required to produceconcrete of a given consistency by 12 % or greater.3.1.5 water-reducing and accelerating admixture an admixture that reduces the quantity of mixing water required to produceconcrete of a given consistency
31、and accelerates the setting and early strength development of concrete.3.1.6 water-reducing and retarding admixture an admixture that reduces the quantity of mixing water required to produceconcrete of a given consistency and retards the setting of concrete.3.1.7 water-reducing, high range, and reta
32、rding admixturean admixture that reduces the quantity of mixing water requiredto produce concrete of a given consistency by 12 % or greater and retards the setting of concrete.3.1.8 specific performance admixturean admixture that provides a desired performance characteristic(s) other than reducingwa
33、ter content, or changing the time of setting of concrete, or both, without any adverse effects on fresh, hardened and durabilityproperties of concrete as specified herein, excluding admixtures that are used primarily in the manufacture of dry-cast concreteproducts (See Note 5).3For referencedASTM st
34、andards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills,
35、MI 48333-9094, http:/www.aci-int.org.C494/C494M 122NOTE 5Other specific performance characteristics include, but are not limited to, shrinkage reduction, mitigation of alkali-silica reaction, andviscosity modification. Admixtures used for the purposes of reducing water content or changing the time o
36、f setting of concrete are classified within theType A through Type G grouping. Plasticizing, water-repellent, and efflorescence-controlling admixtures are examples of admixtures that are used in themanufacture of dry-cast concrete products.4. Ordering Information4.1 The purchaser shall specify the t
37、ype of chemical admixture desired, and in the case of a Type S admixture the specificperformance characteristic(s) required.5. General Requirements5.1 For initial compliance with this specification, test concrete in which each type of admixture shown in 1.1 is used shallconform to the respective req
38、uirements prescribed in Table 1.5.2 The purchaser is allowed to require a limited retesting to confirm current compliance of the admixture to specificationrequirements. The limited retesting will cover physical properties and performance of the admixture.5.2.1 The physical properties retesting shall
39、 consist of uniformity and equivalence tests for infrared analysis, residue by ovendrying and specific gravity.5.2.2 The performance property retesting shall consist of water content of fresh concrete, setting time and compressive strengthat 3, 7 and 28 days. Purchasers having special requirements a
40、re allowed to require additional tests currently in this standard.5.3 At the request of the purchaser, when the admixture is to be used in prestressed concrete, the manufacturer shall state inwriting the chloride content of the admixture and whether or not chloride has been added during its manufact
41、ure.5.4 At the request of the purchaser, the manufacturer shall provide data to substantiate the specific performance characteristic(s)stated by the manufacturer for a Type S admixture.5.5 Tests for uniformity and equivalence, as indicated in Section 6, shall be made on the initial sample and the re
42、sults retainedfor reference and comparison with the results of tests of samples taken from elsewhere within the lot or subsequent lots ofadmixture supplied for use in the work.5.6 At the request of the purchaser, the manufacturer shall state in writing that the infrared analysis spectrum, residue by
43、 ovendrying, and specific gravity of the admixture supplied for use in the work are within the limits in Section 6 when compared withthe initial sample tested under Level 1 of this specification.6. Uniformity and Equivalence6.1 When specified by the purchaser, the uniformity of a lot, or the equival
44、ence of different lots from the same source shall beestablished by the use of the following requirements:6.1.1 Infrared AnalysisThe absorption spectra of the initial sample and the test sample, obtained as specified in 18.1, shallbe essentially similar.6.1.2 Residue by Oven Drying (Liquid Admixtures
45、)When dried as specified in 18.2, the oven-dried residues of the initialsample and of subsequent samples shall be within 6 12 % of the mid-point of the manufacturers stated range, but not exceedingthe manufacturers stated limits (See Note 6).NOTE 6As an example, for an admixture produced with a resi
46、due range from 27 to 35 %, the manufacturer would provide maximum acceptable limitsof 27.3 to 34.7 %, representing 6 12 % of the mid-point of the limits, where the mid-point is 31.0 %.6.1.3 Residue by Oven Drying (Nonliquid Admixtures)When dried as specified in 18.3, the oven-dried residues of the i
47、nitialsample and of the subsequent samples shall be within a range of variation not greater than 6 4 percentage points.6.1.4 Specific Gravity (Liquid Admixtures)When tested as specified in 18.4, the specific gravity of subsequent test samplesshall not differ from the specific gravity of the initial
48、sample by more than 10 % of the difference between the specific gravity ofthe initial sample and that of reagent water at the same temperature. If 10 % of the difference between the specific gravity of theinitial sample and water is less than 0.01, use the value 0.01 as the maximum allowable differe
49、nce. Reagent water conforming toSpecification D1193, Types III or IV, and prepared by distillation ion exchange, reverse osmosis, electrodialysis, or a combinationof these procedures is adequate.6.2 When the nature of the admixture or the analytical capability of the purchaser make some or all of these proceduresunsuitable, other requirements for uniformity and equivalence from lot to lot or within a lot shall be established by agreementbetween the purchaser and the manufacturer.7. Packaging and Marking7.1 When the admixture is delivered in packa
