1、Designation: C 494/C 494M 08aStandard Specification forChemical Admixtures for Concrete1This standard is issued under the fixed designation C 494/C 494M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of last revision. A
2、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 materials for use as chemic
3、aladmixtures to be added to hydraulic-cement concrete mixturesin the field for the purpose or purposes indicated for the eighttypes 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 admixture
4、s,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 retardingadmixtures, and1.1.8 Type SSpecific performance admixtures.1.2 This specification stipulates tests of an admixture withsuitable concreting m
5、aterials as described in 11.1-11.3 or withcement, pozzolan, aggregates, and an air-entraining admixtureproposed for specific work (11.4). Unless specified otherwiseby the purchaser, the tests shall be made using concretingmaterials as described in 11.1-11.3.NOTE 1It is recommended that, whenever pra
6、cticable, tests be madeusing the cement, pozzolan, aggregates, air-entraining admixture, and themixture proportions, batching sequence, and other physical conditionsproposed for the specific work (11.4) because the specific effects producedby chemical admixtures may vary with the properties and prop
7、ortions ofthe other ingredients of the concrete. For instance, Types F and Gadmixtures may exhibit much higher water reduction in concrete mixtureshaving higher cement factors than that listed in 12.1.1.Mixtures having a high range water reduction generally display a higherrate of slump loss. When h
8、igh-range admixtures are used to impartincreased workability (6 to 8-in. slump 150 to 200mm), the effect maybe of limited duration, reverting to the original slump in 30 to 60 mindepending on factors normally affecting rate of slump loss. The use ofchemical admixtures to produce high-slump (flowing)
9、 concrete is coveredby Specification C 1017.NOTE 2The purchaser should ensure that the admixture supplied foruse in the work is equivalent in composition to the admixture subjected totest under this specification (see Section 6, Uniformity and Equivalence).NOTE 3Admixtures that contain relatively la
10、rge amounts of chloridemay accelerate corrosion of prestressing steel. Compliance with therequirements of this specification does not constitute assurance of accept-ability of the admixture for use in prestressed concrete.1.3 This specification provides for three levels of testing.1.3.1 Level 1Durin
11、g the initial approval stage, proof ofcompliance with the performance requirements defined inTable 1 demonstrates that the admixture meets the require-ments of this specification.Admixtures (except for Types B, C,E, and S) shall qualify for provisional compliance when thephysical requirements and an
12、y of the alternative compressivestrength requirements in Table 1 are met. If subsequent testresults at 6 months or one year fail to meet the standardrequirement of 100 % of reference strength, the compliance ofthe admixture to this standard is withdrawn and all users of theadmixture shall be notifie
13、d immediately. Uniformity andequivalence tests of Section 6 shall be carried out to provideresults against which later comparisons can be made (See Note4).NOTE 4Allowing for provisional compliance while retaining longerterm compressive strength requirements promotes more rapid qualificationof new ma
14、terials, but also provides assurance that new admixturetechnologies will not exhibit unexpected longer term performance. Thealternative compressive strength requirements in Table 1 are based onstatistical analysis of 103 Specification C 494/C 494M evaluation tests.The alternative requirements corres
15、pond to a 99 % probability of passingsubsequent test age requirements.21.3.2 Level 2Limited retesting is described in 5.2, 5.2.1and 5.2.2. Proof of compliance with the requirements of Table1 demonstrates continued conformity of the admixture with therequirements of the specification.1.3.3 Level 3For
16、 acceptance of a lot or for measuringuniformity within or between lots, when specified by thepurchaser, the uniformity and equivalence tests of Section 6shall be used.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach syste
17、m may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1This specification is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct
18、 responsibility of SubcommitteeC09.23 on Chemical Admixtures.Current edition approved Sept. 1, 2008. Published September 2008. Originallyapproved in 1962. Last previous edition approved in 2008 as C 494/C 494M 08.2Supporting data have been filed at ASTM International Headquarters and maybe obtained
19、by requesting Research Report RR: C09-1030.1*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.1.5 The text of this standard references notes and footnoteswhich provide ex
20、planatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of the standard.1.6 The following precautionary caveat pertains only to thetest method sections, Sections 11-18 of this Specification: Thisstandard does not purport to address
21、all of the safety concerns,if any, associated with its use. It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:3C33 Specification fo
22、r Concrete AggregatesC 39/C 39M Test Method for Compressive Strength of Cy-lindrical Concrete SpecimensC78 Test Method for Flexural Strength of Concrete (UsingSimple Beam with Third-Point Loading)C 136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC 138/C 138M Test Method for Density (U
23、nit Weight),Yield, and Air Content (Gravimetric) of ConcreteC 143/C 143M Test Method for Slump of Hydraulic-Cement ConcreteC 150 Specification for Portland CementC 157/C 157M Test Method for Length Change of Hard-ened Hydraulic-Cement Mortar and ConcreteC 183 Practice for Sampling and the Amount of
24、Testing ofHydraulic CementC 192/C 192M Practice for Making and Curing ConcreteTest Specimens in the LaboratoryC 231 Test Method for Air Content of Freshly MixedConcrete by the Pressure MethodC 260 Specification forAir-EntrainingAdmixtures for Con-creteC 403/C 403M Test Method for Time of Setting of
25、ConcreteMixtures by Penetration ResistanceC 666/C 666M Test Method for Resistance of Concrete toRapid Freezing and ThawingC 1017/C 1017M Specification for Chemical Admixturesfor Use in Producing Flowing ConcreteD75 Practice for Sampling AggregatesD 1193 Specification for Reagent WaterE 100 Specifica
26、tion for ASTM HydrometersManual of Aggregate and Concrete Testing2.2 American Concrete Institute Standard:ACI 211.191 Standard Practice for Selecting Proportionsfor Normal, Heavyweight, and Mass Concrete43. Terminology3.1 Definitions:3.1.1 accelerating admixturean admixture that acceler-ates the set
27、ting and early strength development of concrete.3.1.2 retarding admixturean admixture that retards thesetting of concrete.3.1.3 water-reducing admixturean admixture that reducesthe quantity of mixing water required to produce concrete of agiven consistency.3.1.4 water-reducing admixture, high rangea
28、n admixturethat reduces the quantity of mixing water required to produceconcrete of a given consistency by 12 % or greater.3.1.5 water-reducing and accelerating admixtureanad-mixture that reduces the quantity of mixing water required toproduce concrete of a given consistency and accelerates thesetti
29、ng and early strength development of concrete.3.1.6 water-reducing and retarding admixture an admix-ture that reduces the quantity of mixing water required toproduce concrete of a given consistency and retards the settingof concrete.3.1.7 water-reducing, high range, and retardingadmixturean admixtur
30、e that reduces the quantity of mixingwater required to produce concrete of a given consistency by12 % or greater and retards the setting of concrete.3.1.8 specific performance admixturean admixture thatprovides a desired performance characteristic(s) other thanreducing water content, or changing the
31、 time of setting ofconcrete, or both, without any adverse effects on fresh,hardened and durability properties of concrete as specifiedherein, excluding admixtures that are used primarily in themanufacture of dry-cast concrete products (See Note 5).NOTE 5Other specific performance characteristics inc
32、lude, but are notlimited to, shrinkage reduction, mitigation of alkali-silica reaction, andviscosity modification. Admixtures used for the purposes of reducingwater content or changing the time of setting of concrete are classifiedwithin the Type A through Type G grouping. Plasticizing, water-repell
33、ent,and efflorescence-controlling admixtures are examples of admixtures thatare used in the manufacture of dry-cast concrete products.4. Ordering Information4.1 The purchaser shall specify the type of chemical admix-ture desired, and in the case of a Type S admixture the specificperformance characte
34、ristic(s) required.5. General Requirements5.1 For initial compliance with this specification, test con-crete in which each type of admixture shown in 1.1 is usedshall conform to the respective requirements prescribed inTable 1.5.2 The purchaser is allowed to require a limited retesting toconfirm cur
35、rent compliance of the admixture to specificationrequirements. The limited retesting will cover physical prop-erties and performance of the admixture.5.2.1 The physical properties retesting shall consist ofuniformity and equivalence tests for infrared analysis, residueby oven drying and specific gra
36、vity.5.2.2 The performance property retesting shall consist ofwater content of fresh concrete, setting time and compressivestrength at 3, 7 and 28 days. Purchasers having specialrequirements are allowed to require additional tests currently inthis standard.3For referenced ASTM standards, visit the A
37、STM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available fromAmerican Concrete Institute (ACI), P.O. Box 9094, FarmingtonHills, MI 48333-9094, http:/w
38、ww.aci-int.org.C 494/C 494M 08a25.3 At the request of the purchaser, the manufacturer shallstate in writing that the admixture supplied for use in the workis identical in all essential respects, including concentration, tothe admixture tested under this specification.5.4 At the request of the purcha
39、ser, when the admixture is tobe used in prestressed concrete, the manufacturer shall state inwriting the chloride content of the admixture and whether ornot chloride has been added during its manufacture.5.5 At the request of the purchaser, the manufacturer shallprovide data to substantiate the spec
40、ific performance charac-teristic(s) stated by the manufacturer for a Type S admixture.5.6 Tests for uniformity and equivalence, as indicated inSection 6, shall be made on the initial sample and the resultsretained for reference and comparison with the results of testsof samples taken from elsewhere
41、within the lot or subsequentlots of admixture supplied for use in the work.6. Uniformity and Equivalence6.1 When specified by the purchaser, the uniformity of a lot,or the equivalence of different lots from the same source shallbe established by the use of the following requirements:6.1.1 Infrared A
42、nalysisThe absorption spectra of the ini-tial sample and the test sample, obtained as specified in 18.1,shall be essentially similar.6.1.2 Residue by Oven Drying (Liquid Admixtures)Whendried as specified in 18.2, the oven-dried residues of the initialsample and of subsequent samples shall be within
43、6 12 % ofthe mid-point of the manufacturers stated range, but notexceeding the manufacturers stated limits (See Note 6).NOTE 6As an example, for an admixture produced with a residuerange from 27 to 35 %, the manufacturer would provide maximumacceptable limits of 27.3 to 34.7 %, representing 6 12 % o
44、f the mid-pointof 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 theinitial sample and of the subsequent samples shall be within arange of variation not greater than 6 4 percentage points.6.1.4
45、Specific Gravity (Liquid Admixtures)When tested asspecified in 18.4, the specific gravity of subsequent testsamples shall not differ from the specific gravity of the initialsample by more than 10 % of the difference between thespecific gravity of the initial sample and that of reagent waterat the sa
46、me temperature. If 10 % of the difference between thespecific gravity of the initial sample and water is less than 0.01,use the value 0.01 as the maximum allowable difference.Reagent water conforming to Specification D 1193, Types IIIor IV, and prepared by distillation ion exchange, reverseosmosis,
47、electrodialysis, or a combination of these proceduresis adequate.6.2 When the nature of the admixture or the analyticalcapability of the purchaser make some or all of these proce-dures unsuitable, other requirements for uniformity andequivalence from lot to lot or within a lot shall be establishedby
48、 agreement between the purchaser and the manufacturer.7. Packaging and Marking7.1 When the admixture is delivered in packages or con-tainers, the proprietary name of the admixture, the type underthis specification, and the net weight or volume shall be plainlymarked thereon. Similar information shal
49、l be provided in theshipping advices accompanying packaged or bulk shipments ofadmixtures.8. Storage8.1 The admixture shall be stored in such a manner as topermit easy access for proper inspection and identification ofeach shipment, and in a suitable weathertight building that willprotect the admixture from dampness and freezing.9. Sampling and Inspection9.1 Every facility shall be provided the purchaser for carefulsampling and inspection, either at the point of manufacture orat the site of the work, as specified by the purchaser.9.2 Samples shall
