1、Designation: C191 18 American Association StateHighway and Transportation Officials StandardAASHTO No.: T131Standard Test Methods forTime of Setting of Hydraulic Cement by Vicat Needle1This standard is issued under the fixed designation C191; the number immediately following the designation indicate
2、s the year oforiginal adoption or, in the case of revision, the year of last revision. 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 These test methods determine the time of sett
3、ing ofhydraulic cement by means of the Vicat needle. Two testmethods are given; Method A is the Reference Test Methodusing the manually operated standard Vicat apparatus, whileMethod B permits the use of an automatic Vicat machine thathas, in accordance with the qualification requirements of thismet
4、hod, demonstrated acceptable performance.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of th
5、e 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 caus-tic and may cause chemical burns to skin and tissue uponprolonged exposure.21.4 The text of th
6、is 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.NOTE 1For the method for determining the time of setting byGillmore needles, see Test Method C266.1.5
7、This international standard was developed in accor-dance with internationally recognized principles 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 Tra
8、de (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3C150/C150M Specification for Portland CementC151/C151M Test Method for Autoclave Expansion of Hy-draulic CementC183/C183M Practice for Sampling and the Amount ofTesting of Hydraulic CementC187 Test Method for Amount of Water Required for
9、Nor-mal Consistency of Hydraulic Cement PasteC219 Terminology Relating to Hydraulic CementC266 Test Method for Time of Setting of Hydraulic-CementPaste by Gillmore NeedlesC305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC511 Specification for Mixing Roo
10、ms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC595/C595M Specification for Blended Hydraulic CementsC1005 Specification for Reference Masses and Devices forDetermining Mass and Volume for Use in the PhysicalTesting of Hydraulic CementsC1
11、157/C1157M Performance Specification for HydraulicCementD1193 Specification for Reagent Water3. Terminology3.1 DefinitionsThe terms used in this test method aredefined in accordance with Terminology C219.4. Summary of Test Method4.1 A paste that is proportioned and mixed to normalconsistency, as des
12、cribed in the Test Method C187, is moldedand placed in a moist cabinet and allowed to start setting.Periodic penetration tests are performed on this paste byallowing a 1-mm Vicat needle to settle into this paste. TheVicat initial time of setting is the time elapsed between theinitial contact of ceme
13、nt and water and the time when the1These test methods are under the jurisdiction of ASTM Committee C01 onCement and is the direct responsibility of Subcommittee C01.30 on Time of Set.Current edition approved June 15, 2018. Published June 2018. Originallyapproved in 1944. Last previous edition approv
14、ed in 2013 as C191 13. DOI:10.1520/C0191-18.2Section on Safety, Manual of Cement Testing, Annual Book 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 informat
15、ion, 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 Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordan
16、ce with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1penetration is measured or calculat
17、ed to be 25 mm. The Vicatfinal time of setting is the time elapsed between initial contactof cement and water and the time when the needle does notleave a complete circular impression in the paste surface.5. Significance and Use5.1 This test method provides a means of determiningcompliance with a sp
18、ecification limit for Vicat time of setting.Refer to the appropriate specification for the cement todetermine if this test method is used for specification compli-ance.5.2 Time of setting measured by this method will notnecessarily provide the same results as the time of setting ofhydraulic cement p
19、aste measured by other methods, or the timeof setting of mortar or concrete.6. Apparatus6.1 Vicat ApparatusSee Annex A1.1 and Fig. A1.1. TheVicat apparatus for this test method shall have a movable rod,B, of mass 300 6 0.5 g.6.1.1 The end of the rod used for measuring penetrationshall have a straigh
20、t steel removable needle with a diameter of1.00 6 0.05 mm and length no less than 50 mm.6.1.2 The needle end that contacts the specimen shall be flat,plane, and at right angles to the axis of the rod.6.2 Reference Masses and Devices for Determining Mass,conforming to the requirements of Specificatio
21、n C1005. Thedevices for determining mass shall be evaluated for continuingprecise performance utilizing the procedure in SpecificationC1005, Appendix X1 using a verification check mass ofapproximately 1000 g.6.3 Glass Graduates, 200 or 250-mLcapacity, and conform-ing to the requirements of Specifica
22、tion C1005.6.4 Plane non-adsorptive plate, 100 6 5 mm square ofsimilar planeness, corrosivity, and absorptivity to that of glass(see Annex A1.1, Fig. A1.1, H).6.5 Flat trowel, having a sharpened straight-edged steelblade 100 to 150 mm in length. The edges when placed on aplane surface shall not depa
23、rt from straightness by more than1 mm.6.6 Conical ring, made of a rigid, non-corroding, non-absorbent material and having a height of 40 6 1 mm, aninside diameter at the bottom of 70 6 3 mm, and an insidediameter at the top of 60 6 3 mm (see Annex A1.1, Fig. A1.1,G).6.7 Mixer, bowl, and paddle, conf
24、orming to Practice C305.6.8 Automatic Vicat Needle Apparatus for Method BTheapparatus shall be equipped with a Vicat needle as described in6.1.1 and 6.1.2. The total mass supported by the needle tip atthe time of measurement shall be 300 6 0.5 g. The instrumentshall be capable of automatically compl
25、eting and recordingpenetration measurements of a test specimen at predeterminedtime intervals not exceeding 10 min and make each penetrationtest at least 5 mm away from any previous penetration and atleast 10 mm away from the inner side of the mold.6.9 Specimen Mold for Method BThe cement paste is h
26、eldin a conical ring with the height of 40 6 1 mm and a removablebase plate. The test surface shall have a minimum diameter of60 6 3 mm.6.10 Inspect and document Section 6 apparatus for confor-mance to the requirements of this test method at least every 212years (see Note 2).NOTE 2Specification C100
27、5 requires annual compliance checks forthe reference masses and for the devices for determining mass.7. Reagents and Materials7.1 Mixing WaterPotable water is satisfactory for routinetests. Use water conforming to the requirements of Specifica-tion D1193 for Type III or Type IV grade reagent water f
28、or allreferee and cooperative tests.8. Sampling8.1 When the test is required for acceptance testing, samplecement in accordance with Practice C183/C183M.9. Conditioning9.1 Maintain the temperature of the air in the vicinity of themixing slab, the dry cement, molds, and base plates at 23.0 63.0C.9.2
29、Maintain the temperature of the mixing water at 23.0 62.0C.9.3 The relative humidity of the mixing room shall be notless than 50 %.9.4 The moist cabinet or moist room shall be in accordancewith Specification C511.10. Preparation of Cement Paste410.1 The cement paste used for the determination of the
30、time of setting is obtained from one of the following methods:10.1.1 Prepare a new batch of paste by mixing 650 g ofcement with the percentage of mixing water required fornormal consistency (Test Method C187), following the proce-dure described in Practice C305.10.1.2 For method A, at the option of
31、the tester, use the testspecimen used for determining normal consistency (see Note3).10.1.3 At the option of the tester, use the paste remainingfrom the batch used for the autoclave specimen (Test MethodC151/C151M) or from the normal consistency determination(Test Method C187).NOTE 3The specimen use
32、d for the determination of the normalconsistency will have an irregular surface, making it unsuitable formethod B.11. Calculation11.1 Calculate the Vicat time of setting to the nearest 1 minas follows:SSH 2 E!C 2 D!D3 C 2 25!D1E (1)4See Test Method C187.C191 182where:E = time in minutes of last pene
33、tration greater than 25 mm,H = time in minutes of first penetration less than 25 mm,C = penetration reading at time E, andD = penetration reading at time H.11.2 Calculate the Vicat final time of setting by determiningthe elapsed time between the time of the initial contact betweencement and water an
34、d the time when the needle does not sinkvisibly into the paste, rounded to the nearest 5 min.12. Report12.1 Report the time of setting and the method used asfollows:Vicat time of setting (A or B) _ minVicat final time of setting (A or B) _ minMethod AManual Vicat Needle Apparatus13. Manual Vicat App
35、aratus13.1 Refer to theApparatus section, paragraphs 6.1, 6.4, and6.6, and Annex A1 for a description of the Vicat apparatus.14. Procedure A14.1 Molding Test SpecimenQuickly form the cementpaste, prepared as described in the section on preparation ofcement paste, into a ball with gloved hands and to
36、ss six timesfrom one hand to the other, maintaining the hands about150 mm (6 in.) apart. Press the ball, resting in the palm of thehand, into the larger end of the conical ring, G, Fig. A1.1, heldin the other hand, completely filling the ring with paste.Remove the excess at the larger end by a singl
37、e movement ofthe palm of the hand. Place the ring on its larger end onto thenon-absorptive plate, H, and slice off the excess paste at thesmaller end at the top of the ring by a single oblique stroke ofthe trowel held at a slight angle with the top of the ring.Smooth the top of the specimen, if nece
38、ssary, with one or twolight touches of the pointed end of the trowel. During theoperation of cutting and smoothing, take care not to compressthe paste. Immediately after molding, place the test specimenin the moist cabinet or moist room and allow it to remain thereexcept when penetration measurement
39、s are being made. Thespecimen shall remain in the conical mold, supported by thenon-absorptive plate throughout the test period.14.2 Time of Setting DeterminationAllow the time ofsetting specimen to remain in the moist cabinet or moist roomfor 30 min after molding without being disturbed. Determinet
40、he penetration of the 1-mm needle at this time and every15 min thereafter (every 10 min for Type III cements) until apenetration of 25 mm or less is obtained. Perform the penetra-tion test by lowering the needle D of the rod B until it rests onthe surface of the cement paste. Tighten the setscrew, E
41、, and setthe indicator, F, at the upper end of the scale, or take an initialreading. Release the rod quickly by releasing the set screw, E,and allow the needle to settle for 30 s; then take the reading todetermine the penetration. At the option of the tester, if thepaste is obviously quite soft on t
42、he early readings, retard thefall of the rod to avoid bending the 1-mm needle, but whenactual penetration measurements to determine the time ofsetting are made, release the rod only by the setscrew. Makeeach penetration test at least 5 mm away from any previouspenetration and at least 10 mm away fro
43、m the inner side of themold. Record the results of all penetration tests and, byinterpolation, determine the time when a penetration of 25 mmis obtained. The elapsed time between the initial contact ofcement and water and the penetration of 25 mm is the Vicattime of setting or Vicat initial time of
44、setting.14.3 Determine the Vicat final time of setting end point tobe the first penetration measurement that does not mark thespecimen surface with a complete circular impression. Verifyfinal set by performing two additional penetration measure-ments on different areas of the specimen surface. Obtai
45、nverification measurements within 90 s of the first “final set”measurement. The elapsed time between the initial contact ofcement and water and the end point determination above is theVicat final time of setting.14.4 PrecautionsKeep all the apparatus free from vibra-tion during the penetration test.
46、 Keep the 1-mm needle straightand clean. The needle must be kept clean to prevent cementfrom adhering to the sides of the needle and decreasingpenetration, and to prevent cement from adhering to the pointand increasing penetration.15. Precision and Bias15.1 Precision:15.1.1 The single-operator (with
47、in-laboratory) standard de-viation has been found to be 12 min for the initial time ofsetting, throughout the range of 49 to 202 min, and 20 min forthe final time of settings throughout the range of 185 to312 min. Therefore, results of two properly conducted tests bythe same operator on Vicat initia
48、l time of setting of similarpaste should not differ from each other by more than 34 minand on Vicat final time of setting of similar pastes should notdiffer from each other by more than 56 min.15.1.2 The multilaboratory (between-laboratory) standarddeviation has been found to be 16 min for the initi
49、al time ofsetting throughout the range of 49 to 207 min, and 43 min forthe final time of setting throughout the range of 185 to 312 min.Therefore, results of two properly conducted tests from twodifferent laboratories on Vicat initial time of setting of similarpastes should not differ from each other by more than 45 min,and on Vicat final time of setting of similar pastes should notdiffer from each other by more than 122 min.15.2 BiasSince there are no accepted reference materialssuitable for determining the bias for the procedure in this testmethod, no
