1、Designation: C 359 08Standard Test Method forEarly Stiffening of Hydraulic Cement (Mortar Method)1This standard is issued under the fixed designation C 359; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 A 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
3、 regarded 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 theresponsibil
4、ity 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. (WarningFreshhydraulic cementitious mixtures are caustic and may causechemical burns to skin and tissue upon prolonged exposure.The use of g
5、loves, protective clothing, and eye protection isrecommended. Wash contact area with copious amounts ofwater after contact. Wash eyes for a minimum of 15 min.Avoidexposure of the body to clothing saturated with the liquid phaseof the unhardened material. Remove contaminated clothingimmediately after
6、 exposure.2)1.4 The text 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.2. Referenced Documents2.1 ASTM Standards:3C 183 Practice for Sampling a
7、nd the Amount of Testing ofHydraulic CementC 185 Test Method for Air Content of Hydraulic CementMortarC 187 Test Method for Normal Consistency of HydraulicCementC 305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC 670 Practice for Preparing Precision and
8、 Bias Statementsfor Test Methods for Construction MaterialsC 778 Specification for Standard SandC 1005 Specification for Reference Masses and Devices forDetermining Mass and Volume for Use in the PhysicalTesting of Hydraulic CementsD 1193 Specification for Reagent WaterE 2251 Specification for Liqui
9、d-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 flash set.3.1.2 false set, nthe earl
10、y 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,” “premature stiffening,” “hesitati
11、on 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 beregained by further mixing withou
12、t 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, using the modified Vicat apparat
13、us. 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, an1This test method is under the jurisdiction
14、 of ASTM Committee C01 on Cementand is the direct responsibility of Subcommittee C01.30 on Time of Set.Current edition approved June 1, 2008. Published June 2008. Originallyapproved in 1955. Last previous edition approved in 2007 as C 359 07.2Section on Safety, Manual of Cement Testing, Annual Book
15、of ASTMStandards, Vol 04.01.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section ap
16、pears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.additional penetration, termed the remix penetration, is deter-mined. The report is a tabulation of the penetration measure-ments and the amount of mixi
17、ng water used.5. 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 potential early stiffening of hydraulic cement.5.2 When used for estimating t
18、he 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 relatively less serious and less persistent tendency toearly stiffening (false set)
19、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 concrete is mixed for a longer timethan usual, as usually occurs in transit mix
20、ing, 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-agitating equipment, as on some pavingjobs, and when concrete is made in an
21、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 stiffening resulting from false set is not likely tocause a cement to fail the appl
22、icable 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 requirements ofFig. 1 in Test Method C 187, with the following modification
23、s: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 MethodC 185.6.3 Mixer, Bowl, Paddle, and Scraper, conforming to therequirements of Practice C 305.6.4 Gla
24、ss Graduates, 200 or 250 mL capacity, conformingto the requirements of Specification C 1005.6.5 Masses and Mass Determining Devices, conforming tothe requirements of Specification C 1005. The devices fordetermining mass shall be evaluated for precision and accuracyat a total load of 1000 g.6.6 Therm
25、ometer, ASTM No. S12C or S12F, conforming tothe requirements of Specification E 2251.6.7 Flat Trowel, having a sharpened straight-edged steelblade 100 to 150 mm in length. The edges when placed on aplane surface shall not depart from straightness by more than 1mm.6.8 Clock Timer, having a readabilit
26、y to the nearest second.6.9 Containers, approximately 50 by 50 by 150 mm (2 by 2by 6 in.) inside dimensions (Fig. 1). These containers, 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 St
27、andard Sand, 20-30 and Graded, conforming to therequirements of Specification C 778.7.2 Mixing WaterPotable water is satisfactory for routinetests. For all referee and cooperative tests, reagent waterconforming to the requirements of Specification D 1193 forType III or Type IV grades of reagent wate
28、r shall be used.8. Sampling8.1 When the test is part of acceptance testing, sample thecement in accordance with Practice C 183.9. Conditioning9.1 Maintain the temperature of the room, dry materials,paddle, bowl, and containers at 23.0 6 3.0 C.9.2 The relative humidity of the mixing room shall not be
29、less 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, 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
30、 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 paddle in place,and mix the dry materials for 10 s at a slow speed (140 6 5r/min).10.2.3 With the mixer operating at a slow speed (140 6 5r/min), add the entire quantity of
31、mixing water within 5 s. Stopthe mixer, quickly change to a medium speed (285 6 10r/min), and continue the mixing for 1 min, timing from the firstaddition 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
32、 it to stand undisturbed for the remainder ofa 45-s interval from the time of stopping the mixer.FIG. 1 Container for Early Stiffening TestsC35908210.2.5 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
33、 in the range from 23 62.0 C, discard the batch and adjust the temperature of thewater or sand, or both, to give the required temperature.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 mor
34、tar into the container until the container isheaping full. Quickly and gently place each spoonful of mortarin the container. When 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, cov
35、er the bowl with a lid, and retain the remainingmortar for a remix test to be performed later. To compact themortar in the container, 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 ra
36、ised, strike off themortar with one stroke of the trowel along the length of thecontainer. Then remove the excess mortar by means 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 th
37、e mortar with asingle stroke of the trowel.10.4 Penetration Tests:10.4.1 After filling the container, immediately place the10-mm plunger 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
38、 at zero.Release the plunger 3 min after the beginning of the wetmixing and record, as the initial penetration, the depth inmillimetres 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
39、 quantityof water to produce the required consistency.10.4.2 Immediately withdraw and clean the plunger. In asimilar manner, determine, after moving the Vicat apparatus tothe desired location, the penetrations at intervals of 5, 8, and 11min after the beginning of mixing. Do not move the filledconta
40、iner until these measurements are completed. Make allpenetrations along the longitudinal center line of the container.Obtain 5 and 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 approximate
41、lymidway between the points at which the initial and 5-minpenetrations were determined.10.4.3 At the completion of the measurement 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 b
42、owl at medium speed (285 6 10r/min) for 1 min. Fill a clean container as outlined in 10.3.1 and10.3.2, and determine the penetration 45 s after completion ofmixing.11. Calculation11.1 Early Stiffening AmountThe change in penetrationfrom the initial penetration to the 11 min penetration.11.1.1 Calcul
43、ate as follows: A D, where:A = Initial PenetrationB = Penetration at 5 minC = Penetration at 8 minD = Penetration at 11 minE = Penetration 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
44、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 Early 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
45、 Note 2)11.3.2 Report to the nearest percent.12. Report12.1 Report the measured and calculated values as shownbelow:Mixing Water _mLInitial penetration _mm5-min penetration _mm8-min penetration _mm11-min penetration _mmRemix penetration _mmEarly Stiffening Amount _mmAverage Early Stiffening Rate _mm
46、/minEarly Stiffening Recovery _%13. Precision and Bias413.1 Early Stiffening Amount13.1.1 The single-operator standard deviation has 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 di
47、ffer by more than 5mm. (See Note 3)13.1.2 The multilaboratory standard deviation has beenfound to be 2.5 mm over a range from 35 to 49 mm. Therefore,results of two properly conducted tests from two differentlaboratories on samples of the same cement are not expected todiffer by more than 7 mm. (See
48、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 material are not expected to differ bymore than 1.4 mm/min. (S
49、ee Note 3)13.2.2 The multilaboratory standard deviation has beenfound to be 0.86 mm/min over a range from 4.0 to 8.0 mm/min.Therefore, results of two properly conducted tests from two4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: C01-1008.C359083different laboratories on samples of the same cement are notexpected to differ by more than 2.4 mm/min. (See Note 3)13.3 Early Stiffening Recovery13.3.1 The single-operator standard deviation has beenfound to be 6.6 % over a range from
