1、Designation: C494/C494M 16C494/C494M 17Standard 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 revi
2、sion. 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 U.S. Department of Defense.1. Scope*1.1 This specification covers materials for
3、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 and reta
4、rding 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 with suit
5、able 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 recommended
6、 that, whenever practicable, tests be made using the cement, pozzolan, aggregates, air-entraining admixture, and the mixtureproportions, batching sequence, and other physical conditions proposed for the specific work (11.4) because the specific effects produced by chemicaladmixtures may vary with th
7、e properties and proportions of the other ingredients of the concrete. For instance, Types F and G admixtures may exhibitmuch 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 ra
8、te 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 admixtures to pr
9、oduce 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).NOTE 3Admi
10、xtures 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 three lev
11、els 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 compliance wh
12、en the physical requirements and any of the alternative compressive strength requirementsin Table 1 are met. If subsequent test results at six months or one year fail to meet the standard requirement of 100 % of referencestrength, the compliance of the admixture to this standard is withdrawn and all
13、 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 requirements
14、promotes more rapid qualification of newmaterials, but also provides assurance that new admixture technologies will not exhibit unexpected longer term performance. The alternative compressivestrength requirements in Table 1 are based on statistical analysis of 103 Specification C494/C494M evaluation
15、 tests. The alternative requirementscorrespond to a 99 % probability of passing subsequent test age requirements.21 This 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.Cur
16、rent edition approved July 1, 2016June 15, 2017. Published August 2016July 2017. Originally approved in 1962. Last previous edition approved in 20152016 asC494/C494M 15a.C494/C494M 16. DOI: 10.1520/C0494_C0494M-16.10.1520/C0494_C0494M-17.2 Supporting data have been filed at ASTM International Headqu
17、arters and may be obtained by requesting Research Report RR:C09-1030.This document is not an ASTM standard and is 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
18、 all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the 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 standardCopyright ASTM International
19、, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.3.2 Level 2Limited retesting is described in 5.2 5.2.2. Proof of compliance with the requirements of Table 1 demonstratescontinued conformity of the admixture with the requirements of the specification.1.3.3 Leve
20、l 3For acceptance 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
21、eachsystem may 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
22、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:Thisstandard does not purport to address all of the safety concerns, if
23、any, associated 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.1.7 This international standard was developed in accordance with internationally recognized pr
24、inciples on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3C33C33/C33M Specification for C
25、oncrete AggregatesC39/C39M Test Method for Compressive Strength of Cylindrical Concrete SpecimensC78C78/C78M Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)C136C136/C136M Test Method for Sieve Analysis of Fine and Coarse AggregatesC138/C138M Test Method for
26、 Density (Unit Weight), Yield, and Air Content (Gravimetric) of ConcreteC143/C143M Test Method for Slump of Hydraulic-Cement ConcreteC150C150/C150M Specification for Portland CementC157/C157M Test Method for Length Change of Hardened Hydraulic-Cement Mortar and ConcreteC183C183/C183M Practice for Sa
27、mpling and the Amount of Testing of Hydraulic CementC192/C192M Practice for Making and Curing Concrete Test Specimens in the LaboratoryC231C231/C231M Test Method for Air Content of Freshly Mixed Concrete by the Pressure MethodC260C260/C260M Specification for Air-Entraining Admixtures for ConcreteC40
28、3/C403M Test Method for Time of Setting of Concrete Mixtures by Penetration ResistanceC666/C666M Test Method for Resistance of Concrete to Rapid Freezing and ThawingC1017/C1017M Specification for Chemical Admixtures for Use in Producing Flowing ConcreteD75D75/D75M Practice for Sampling AggregatesD89
29、1 Test Methods for Specific Gravity, Apparent, of Liquid Industrial ChemicalsD1193 Specification for Reagent WaterE100 Specification for ASTM HydrometersE1252 Practice for General Techniques for Obtaining Infrared Spectra for Qualitative AnalysisManual of Aggregate and Concrete Testing2.2 American C
30、oncrete Institute Standard:ACI 211.191 Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete43. Terminology3.1 Definitions:3.1.1 accelerating admixture, nan admixture that accelerates the setting and early strength development of concrete.3.1.2 retarding admixture, n
31、an admixture that retards the setting of concrete.3.1.3 water-reducing admixture, nan admixture that reduces the quantity of mixing water required to produce concrete of agiven consistency.3.1.4 water-reducing admixture, high range, nan admixture that reduces the quantity of mixing water required to
32、 produceconcrete of a given consistency by 12 % or greater.3.1.5 water-reducing and accelerating admixture, nan admixture that reduces the quantity of mixing water required toproduce concrete of a given consistency and accelerates the setting and early strength development of concrete.3 For referenc
33、edASTM standards, 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.4 Available from American Concrete Institute (ACI), P.O. Box 9094, Farmingt
34、on Hills, MI 48333-9094, http:/www.aci-int.org.C494/C494M 1723.1.6 water-reducing and retarding admixture, nan 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 retarding ad
35、mixture, nan 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 admixture, nan admixture that provides a desired performance characteristic(s) other than reducingwate
36、r 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).NOTE 5Other specific per
37、formance 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 of setting of concrete are classified within theType A through Type G groupi
38、ng. 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 type of chemical admixture desired, and in the case of a Type S admixture th
39、e 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 requirements prescribed in Table 1.5.2 The purchaser is allowed to require a l
40、imited 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 consist of uniformity and equivalence tests for infrared analysis, residue
41、 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 are allowed to require additional tests currently in this standard.5.3 At th
42、e 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 manufacture.5.4 At the request of the purchaser, the manufacturer shall provide dat
43、a 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 results retainedfor reference and comparison with the results of tests of sam
44、ples 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 ovendrying, and specific gravity of the admixture supplied for use in the
45、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 equivalence of different lots from the same source shall beestablished by the use
46、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, shall beessentially similar.6.1.2 Residue by Oven Drying (Liquid Admixtures)When dried as specified in 18.2, the oven-dried residues of the initialsam
47、ple and of subsequent samples shall be within 612 % 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 residue range from 27 to 35 %, the manufacturer would provide maximum acceptable
48、 limitsof 27.3 to 34.7 %, representing 612 % 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 initialsample and of the subsequent samples shall be within a range of variati
49、on not greater than 64 percentage points.6.1.4 Specific Gravity (Liquid Admixtures)When tested as specified in 18.4, the specific gravity of the initial sample andsubsequent test samples shall not differ from the mid-point of the manufacturers stated range by more than 10 % of the differencebetween the mid-point of the manufacturers stated range and that of reagent water. If 10 % of the difference between the specificgravity of the initial sample and water is less than 0.01, use the value 0.01 as the maximum allowable difference. Rea
