1、Designation: C494/C494M 15aStandard 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 of last revision. A numb
2、er 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 U.S. Department of Defense.1. Scope*1.1 This specification covers materials for use as chemi
3、caladmixtures 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 admixtur
4、es,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
5、materials 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 pr
6、acticable, 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 pro
7、portions 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 ahigher rate of slump loss. When
8、high-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 C1017/C1017M.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 relati
10、vely large 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
11、 1During 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
12、 and any of the alternative compressivestrength requirements in Table 1 are met. If subsequent testresults at six 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 b
13、e notified 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 qualification
14、of new materials, 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 C494/C494M evaluation tests. Thealternative requirements
15、 correspond to a 99 % probability of passingsubsequent test age requirements.21.3.2 Level 2Limited retesting is described in 5.2 5.2.2.Proof of compliance with the requirements of Table 1 demon-strates continued conformity of the admixture with the require-ments 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 Oct. 1, 2015. Published December 2015. Originallyapproved in 1962. Last previous edition approved in 2015 as C494/C494M 15.DOI: 10.1520/C0494_C0494M-15A.2Supporting data have been filed at ASTM International Headqu
19、arters and maybe obtained by requesting Research Report RR:C09-1030.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.5 The text of this standard references notes and fo
20、otnoteswhich provide explanatory 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 1118of this Specification:This standard does no
21、t purport to address all of the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3C
22、33 Specification for Concrete AggregatesC39/C39M Test Method for Compressive Strength of Cylin-drical Concrete SpecimensC78 Test Method for Flexural Strength of Concrete (UsingSimple Beam with Third-Point Loading)C136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC138/C138M Test Method
23、for Density (Unit Weight), Yield,and Air Content (Gravimetric) of ConcreteC143/C143M Test Method for Slump of Hydraulic-CementConcreteC150 Specification for Portland CementC157/C157M Test Method for Length Change of HardenedHydraulic-Cement Mortar and ConcreteC183 Practice for Sampling and the Amoun
24、t of Testing ofHydraulic CementC192/C192M Practice for Making and Curing Concrete TestSpecimens in the LaboratoryC231 Test Method for Air Content of Freshly Mixed Con-crete by the Pressure MethodC260 Specification for Air-Entraining Admixtures for Con-creteC403/C403M Test Method for Time of Setting
25、of ConcreteMixtures by Penetration ResistanceC666/C666M Test Method for Resistance of Concrete toRapid Freezing and ThawingC1017/C1017M Specification for Chemical Admixtures forUse in Producing Flowing ConcreteD75 Practice for Sampling AggregatesD891 Test Methods for Specific Gravity,Apparent, of Li
26、quidIndustrial ChemicalsD1193 Specification for Reagent WaterE100 Specification for ASTM HydrometersE1252 Practice for General Techniques for Obtaining Infra-red Spectra for Qualitative AnalysisManual of Aggregate and Concrete Testing2.2 American Concrete Institute Standard:ACI 211.191 Standard Prac
27、tice for Selecting Proportionsfor Normal, Heavyweight, and Mass Concrete43. Terminology3.1 Definitions:3.1.1 accelerating admixture, nan admixture that acceler-ates the setting and early strength development of concrete.3.1.2 retarding admixture, nan admixture that retards thesetting of concrete.3.1
28、.3 water-reducing admixture, nan admixture that re-duces the quantity of mixing water required to produceconcrete of a given consistency.3.1.4 water-reducing admixture, high range, nan admix-ture that reduces the quantity of mixing water required toproduce concrete of a given consistency by 12 % or
29、greater.3.1.5 water-reducing and accelerating admixture, nanadmixture that reduces the quantity of mixing water required toproduce concrete of a given consistency and accelerates thesetting and early strength development of concrete.3.1.6 water-reducing and retarding admixture, nan ad-mixture that r
30、educes 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 retarding admixture,nan admixture that reduces the quantity of mixing waterrequired to produce concrete of a given consistency by 12 % orgre
31、ater and retards the setting of concrete.3.1.8 specific performance admixture, nan admixture thatprovides a desired performance characteristic(s) other thanreducing water content, or changing the time of setting ofconcrete, or both, without any adverse effects on fresh,hardened and durability proper
32、ties 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 include, but are notlimited to, shrinkage reduction, mitigation of alkali-silica reaction, andviscosity modi
33、fication. 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-repellent,and efflorescence-controlling admixtures are examples of admixtures thatare used in the manufacture o
34、f 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 characteristic(s) required.5. General Requirements5.1 For initial compliance with this specification, test con-cr
35、ete in which each type of admixture shown in 1.1 is usedshall conform to the respective requirements prescribed inTable 1.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, ref
36、er to the standards Document Summary page onthe ASTM website.4Available fromAmerican Concrete Institute (ACI), P.O. Box 9094, FarmingtonHills, MI 48333-9094, http:/www.aci-int.org.C494/C494M 15a25.2 The purchaser is allowed to require a limited retesting toconfirm current compliance of the admixture
37、 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 gravity.5.2.2 The performance prope
38、rty 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.5.3 At the request of the purchaser, when the admixture is tobe used in pre
39、stressed concrete, the manufacturer shall state inwriting the chloride content of the admixture and whether ornot chloride has been added during its manufacture.5.4 At the request of the purchaser, the manufacturer shallprovide data to substantiate the specific performance charac-teristic(s) stated
40、by the manufacturer for a Type S admixture.5.5 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 within the lot or subsequentlots of admixtu
41、re supplied for use in the work.5.6 At the request of the purchaser, the manufacturer shallstate in writing that the infrared analysis spectrum, residue byoven drying, and specific gravity of the admixture supplied foruse in the work are within the limits in Section 6 whencompared with the initial s
42、ample tested under Level 1 of thisspecification.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 AnalysisThe absorption spect
43、ra 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 612 % ofthe mid-point of th
44、e 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 612 % of the mid-pointof the limits,
45、 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 64 percentage points.6.1.4 Specific Gravity (LiquidAdmixt
46、ures)When tested asspecified in 18.4, the specific gravity of the initial sample andsubsequent test samples shall not differ from the mid-point ofthe manufacturers stated range by more than 10 % of thedifference between the mid-point of the manufacturers statedrange and that of reagent water. If 10
47、% of the differencebetween the specific gravity of the initial sample and water isless than 0.01, use the value 0.01 as the maximum allowabledifference. Reagent water conforming to Specification D1193,Types III or IV, and prepared by distillation ion exchange,reverse osmosis, electrodialysis, or a c
48、ombination of theseprocedures is 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 agreement between the
49、purchaser and the manufacturer.7. Packaging and Marking7.1 When the admixture is delivered in packages orcontainers, the proprietary name of the admixture, the typeunder this specification, and the net weight or volume shall beplainly marked thereon. Similar information shall be providedin the shipping advices accompanying packaged or bulkshipments of admixtures.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 build
