ASTM C359-2018 Standard Test Method for Early Stiffening of Hydraulic Cement (Mortar Method).pdf

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1、Designation: C359 18Standard Test Method forEarly Stiffening of Hydraulic Cement (Mortar Method)1This standard is issued under the fixed designation C359; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A

2、 number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of earlystiffening in hydraulic-cement mortar.1.2 The values stated in SI units are to be r

3、egarded asstandard. The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibilit

4、y of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.Warning: Fresh hydraulic cementitious mixtures are causticand may cause chemical burns to skin and tissue uponprolonged exposure.21.4 The text

5、of this standard references notes and footnoteswhich provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of the standard.1.5 This international standard was developed in accor-dance with internationally recognized prin

6、ciples on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3C183/C183M Practice for Samplin

7、g and the Amount ofTesting of Hydraulic CementC185 Test Method for Air Content of Hydraulic CementMortarC187 Test Method for Amount of Water Required for Nor-mal Consistency of Hydraulic Cement PasteC305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC670

8、Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC778 Specification for Standard SandC1005 Specification for Reference Masses and Devices forDetermining Mass and Volume for Use in the PhysicalTesting of Hydraulic CementsD1193 Specification for Reagent Wa

9、terE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision Liquids3. Terminology3.1 Definitions:3.1.1 early stiffening, nthe early development of stiffnessin the working characteristics of a hydraulic-cement paste,mortar, or concrete; varieties include false set and flas

10、h set.3.1.2 false set, nthe early development of stiffness in theworking characteristics of a hydraulic-cement paste, mortar, orconcrete without the evolution of much heat, which stiffnesscan be dispelled and plasticity regained by further mixingwithout addition of water; also known as “grab set,” “

11、prema-ture stiffening,” “hesitation set,” and “rubber set.”3.1.3 flash set, nthe early development of stiffness in theworking characteristics of a hydraulic-cement paste, mortar, orconcrete, usually with the evolution of considerable heat,which stiffness cannot be dispelled nor can the plasticity be

12、regained by further mixing without addition of water; alsoknown as “quick set.”4. Summary of Test Method4.1 A mortar is prepared with the cement to be tested, usingspecified quantities of cement, standard sand, and an amount ofwater that will produce a mortar with an initial penetration of46 6 3 mm,

13、 using the modified Vicat apparatus. Measurementsof penetration are made at stipulated intervals after the begin-ning of the mixing procedure. Upon completion of the firstseries of penetration measurements, the mortar is returned tothe mixer to be remixed. Following the remix procedure, anadditional

14、 penetration, termed the remix penetration, is deter-mined. The report is a tabulation of the penetration measure-ments and the amount of mixing water used.1This test method is under the jurisdiction of ASTM Committee C01 on Cementand is the direct responsibility of Subcommittee C01.30 on Time of Se

15、t.Current edition approved Oct. 15, 2018. Published November 2018. Originallyapproved in 1955. Last previous edition approved in 2013 as C359 13. DOI:10.1520/C0359-18 .2Section on Safety, Manual of Cement Testing, Annual Book of ASTMStandards, Vol 04.01.3For referenced ASTM standards, visit the ASTM

16、 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Har

17、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendat

18、ions issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15. Significance and Use5.1 The purpose of this test method is to determine thedegree to which a cement mortar develops early stiffening. It isintended for use by those interested in methods for determiningthe po

19、tential early stiffening of hydraulic cement.5.2 When used for estimating the relative tendency of acement to manifest early stiffening, a judgment may be madeby comparing the behavior in the penetration series (see 10.4.1and 10.4.2) and the remix procedure (see 10.4.3) to differen-tiate a relativel

20、y less serious and less persistent tendency toearly stiffening (false set) from one that is more persistent and,consequently, more serious (flash set).5.3 Severe false setting in a cement may cause difficultyfrom a placing and handling standpoint, but it is not likely tocause difficulties where conc

21、rete is mixed for a longer timethan usual, as usually occurs in transit mixing, or where it isremixed prior to placing or transporting, in concrete pumpingoperations. It is most likely noticed where concrete is mixedfor a short period of time in stationary mixers and transportedto the forms in non-a

22、gitating equipment, as on some pavingjobs, and when concrete is made in an on-site batch plant.5.4 Cements with severe false setting usually requireslightly more mixing water to produce the same consistency,which may result in slightly lower strengths and increaseddrying shrinkage.5.5 Early stiffeni

23、ng resulting from false set is not likely tocause a cement to fail the applicable time of setting require-ment.5.6 Early stiffening resulting from flash set, depending onseverity, can cause a cement to fail the applicable time ofsetting requirement.6. Apparatus6.1 Vicat Apparatus, conforming to the

24、requirements ofFig. 1 in Test Method C187, with the following modifications:6.1.1 The 1-mm needle shall be replaced by a mass, suchthat the total mass of the 10-mm plunger, indicator, and addedmass shall be 400 6 0.5 g.6.2 Spoon, conforming to the requirements of Test MethodC185.6.3 Mixer, Bowl, Pad

25、dle, and Scraper, conforming to therequirements of Practice C305.6.4 Glass Graduates, 200 or 250 mL capacity, conformingto the requirements of Specification C1005.6.5 Masses and Mass Determining Devices, conforming tothe requirements of Specification C1005. The devices fordetermining mass shall be e

26、valuated for continuing preciseperformance utilizing the procedure in Specification C1005,Appendix X1, using a verification check mass of approxi-mately 1000 g.6.6 Thermometer, ASTM No. S12C or S12F, conforming tothe requirements of Specification E2251.6.7 Flat Trowel, having a sharpened straight-ed

27、ged steelblade 100 to 150 mm in length. The edges when placed on aplane surface shall not depart from straightness by more than1 mm.6.8 Clock Timer, having a readability to the nearest second.6.9 Containers, approximately 50 by 50 by 150 mm (2 by 2by 6 in.) inside dimensions (Fig. 1). These containe

28、rs, whichmay be made of any suitable materials such as sheet metal orplastic, shall be rigid, watertight, and at least 50 mm (2 in.)deep.7. Reagents and Materials7.1 Standard Sand, 20-30 and Graded, conforming to therequirements of Specification C778.7.2 Mixing WaterPotable water is satisfactory for

29、 routinetests. For all referee and cooperative tests, reagent waterconforming to the requirements of Specification D1193 forType III or Type IV grades of reagent water shall be used.8. Sampling8.1 When the test is part of acceptance testing, sample thecement in accordance with Practice C183/C183M.9.

30、 Conditioning9.1 Maintain the temperature of the room, dry materials,paddle, bowl, and containers at 23.0 6 3.0C.9.2 The relative humidity of the mixing room shall not beless than 50 %.10. Procedure10.1 BatchMix at one time 600 g of cement, 300 g ofgraded standard sand, 300 g of 20-30 standard sand,

31、 and anamount of water that produces a mortar with an initialpenetration of 46 6 3 mm.10.2 Mixing of MortarMix in the mechanical mixer asfollows:10.2.1 Place the sand and cement in the dry bowl, and mixthe dry materials for a few seconds with the spoon.10.2.2 Place the bowl in the mixer, set the pad

32、dle in place,and mix the dry materials for 10 s at a slow speed (140 65 r min).FIG. 1 Container for Early Stiffening TestsC359 18210.2.3 With the mixer operating at a slow speed (140 65 r min), add the entire quantity of mixing water within 5 s.Stop the mixer, quickly change to a medium speed (285 6

33、10 r min), and continue the mixing for 1 min, timing from thefirst addition of water.10.2.4 Stop the mixer, scrape the sides of the mixing bowlwith the rubber scraper, and quickly place the thermometer inthe mortar. Allow it to stand undisturbed for the remainder ofa 45-s interval from the time of s

34、topping the mixer.10.2.5 Read the temperature, remove the thermometer, startthe mixer, and mix for 15 s at a medium speed (285 6 10r/min). If the mortar temperature is not in the range from 23 62.0C, discard the batch and adjust the temperature of the wateror sand, or both, to give the required temp

35、erature.10.3 Filling Container:10.3.1 Immediately after completion of the mixing, removethe bowl from the mixer and with a spoon, uniformly distributea portion of the mortar into the container until the container isheaping full. Quickly and gently place each spoonful of mortarin the container. When

36、removing the mortar from the bowl, donot remove the material pushed up on the side of the bowl bythe paddle. After the container has been filled, reassemble themixer, cover the bowl with a lid, and retain the remainingmortar for a remix test to be performed later. To compact themortar in the contain

37、er, lift the container approximately 80 mm(3 in.) from the table with both hands and rap it twice againstthe surface of the table.10.3.2 With the leading edge slightly raised, strike off themortar with one stroke of the trowel along the length of thecontainer. Then remove the excess mortar by means

38、of asawing motion with the straightedge of the trowel along thelength of the container in a direction opposite to that used instriking off. Then, smooth the surface of the mortar with asingle stroke of the trowel.10.4 Penetration Tests:10.4.1 After filling the container, immediately place the10-mm p

39、lunger of the modified Vicat apparatus in contact withthe surface of the mortar at the midpoint of the container on thelongitudinal center line. Set the movable indicator at zero.Release the plunger 3 min after the beginning of the wetmixing and record, as the initial penetration, the depth inmillim

40、etres to which the plunger has settled below the surface10 s after being released. If the plunger does not settle to adepth of 46 6 3 mm, discard the batch and adjust the quantityof water to produce the required consistency.10.4.2 Immediately withdraw and clean the plunger. In asimilar manner, deter

41、mine, after moving the Vicat apparatus tothe desired location, the penetrations at intervals of 5, 8, and11 min after the beginning of mixing. Do not move the filledcontainer until these measurements are completed. Make allpenetrations along the longitudinal center line of the container.Obtain 5 and

42、 8-min penetrations at a distance of approximately40 mm (112 in.) from each end of the container, respectively,and determine the 11-min penetration at a point approximatelymidway between the points at which the initial and 5-minpenetrations were determined.10.4.3 At the completion of the measurement

43、 of the 11-minpenetration, immediately return the mortar in the container tothe bowl. Start the mixer, raise the bowl into mixing position,and remix the contents of the bowl at medium speed (285 610 r min) for 1 min. Fill a clean container as outlined in 10.3.1and 10.3.2, and determine the penetrati

44、on 45 s after completionof mixing.11. Calculation11.1 Early Stiffening AmountThe change in penetrationfrom the initial penetration to the 11 min penetration.11.1.1 Calculate as follows: A D, where:A = Initial PenetrationB = Penetration at 5 minC = Penetration at 8 minD = Penetration at 11 minE = Pen

45、etration after REMIX11.1.2 Report to the nearest mm.11.2 Average Early Stiffening RateAn average of the rateof penetration change between each set of measurements.11.2.1 Calculate as follows:A 2 B21B 2 C31C 2 D33where A,B,C,D are as defined in 11.1.1.11.2.2 Report to the nearest 0.1 mm/min.11.3 Earl

46、y Stiffening RecoveryThe percent penetrationrecovery accomplished with the REMIX procedure.11.3.1 Calculate as follows:100*EAwhere E and A are as defined in 11.1.1. (See Note 2.)11.3.2 Report to the nearest percent.12. Report12.1 Report the measured and calculated values as shownbelow:Mixing Water _

47、mLInitial penetration _mm5-min penetration _mm8-min penetration _mm11-min penetration _mmRemix penetration _mmEarly Stiffening Amount _mmAverage Early Stiffening Rate _mm/minEarly Stiffening Recovery _%13. Precision and Bias413.1 Early Stiffening Amount13.1.1 The single-operator standard deviation h

48、as beenfound to be 1.8 mm over a range from 35 to 49 mm. Therefore,results of two properly conducted tests by the same operator onthe same material are not expected to differ by more than5 mm. (See Note 3.)13.1.2 The multilaboratory standard deviation has beenfound to be 2.5 mm over a range from 35

49、to 49 mm. Therefore,results of two properly conducted tests from two different4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:C01-1008.C359 183laboratories on samples of the same cement are not expected todiffer by more than 7 mm. (See Note 3.)13.2 Average Early Stiffening Rate13.2.1 The single-operator standard deviation has beenfound to be 0.50 mm/min over a range from 4.0 to 8.0 mm/min.Therefore, results of two properly conducted tests by the sameoperator on the same mate