1、Designation: C494/C494M 12C494/C494M 13Standard 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 Department of Defense.1. Scope*1.1 This specification covers materials for use a
3、s 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 retarding
4、 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 suitable
5、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 that
6、, 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 the pro
7、perties 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 rate of
8、 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 produce
9、 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 3Admixture
10、s 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 levels o
11、f 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 when th
12、e 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 and all users
13、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 promote
14、s 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 tests.
15、 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.Current ed
16、ition approved July 1, 2012April 1, 2013. Published September 2012April 2013. Originally approved in 1962. Last previous edition approved in 20102012 asC494/C494M11.12. DOI: 10.1520/C0494_C0494M-12.10.1520/C0494_C0494M-13.2 Supporting data have been filed at ASTM International Headquarters and may b
17、e 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 all changes acc
18、urately, 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, 100 Barr Harbo
19、r Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.3.2 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 requirements of the specification.1.3.3 Level 3Fo
20、r 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 eachs
21、ystem 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 and f
22、ootnotes(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 any,
23、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.2. Referenced Documents2.1 ASTM Standards:3C33 Specification for Concrete AggregatesC39/C39M Test M
24、ethod for 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 (Gra
25、vimetric) 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
26、 for Making 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/
27、C666M Test 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 fo
28、r Reagent 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 admix
29、ture that 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 a givenconsistency.3.1.4 water-
30、reducing 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 admixturean admixture that reduces the quantity of mixing water required to produceconcrete of a given cons
31、istency and accelerates the setting and early strength development of concrete.3.1.6 water-reducing and retarding admixturean admixture that reduces the quantity of mixing water required to produceconcrete of a given consistency and retards the setting of concrete.3 For referencedASTM standards, vis
32、it 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, Farmington Hills, MI 48333-90
33、94, http:/www.aci-int.org.C494/C494M 1323.1.7 water-reducing, high range, and retarding 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 adm
34、ixture that provides a desired performance characteristic(s) other than reducingwater 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 i
35、n the manufacture of dry-cast concreteproducts (See Note 5).NOTE 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 t
36、he time of 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 spec
37、ify the type 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 respe
38、ctive requirements 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 retest
39、ing shall 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 requi
40、rements are 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
41、 manufacture.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 a
42、nd the results 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, r
43、esidue by 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 th
44、e equivalence 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, shall beessentially similar.6.1.2 Residue by Oven Drying (Liquid A
45、dmixtures)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 wi
46、th a residue 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
47、 of the initialsample 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
48、 initial 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 allowabl
49、e difference. 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.C494/C494M 1337. Packaging and Marking7.1 When the admix
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1