1、Designation: C 191 08American 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 C 191; the number immediately following the designation indicat
2、es 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 set
3、ting 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 thisme
4、thod, 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 t
5、he user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. See 1.4 for aspecific warning statement.1.4 WarningFresh hydraulic cementitious mixtures arecaustic and may cause chemical burns to skin and tissue
6、uponprolonged exposure. The use of gloves, protective clothing,and eye protection is recommended. Wash contact area withcopious amounts of water after contact. Wash eyes for aminimum of 15 min. Avoid exposure of the body to clothingsaturated with the liquid phase of the unhardened material.Remove co
7、ntaminated clothing immediately after exposure.21.5 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.NOTE 1For the method for determining
8、 the time of setting byGillmore needles, see Test Method C 266.2. Referenced Documents2.1 ASTM Standards:3C 150 Specification for Portland CementC 151 Test Method for Autoclave Expansion of HydraulicCementC 183 Practice for Sampling and the Amount of Testing ofHydraulic CementC 187 Test Method for N
9、ormal Consistency of HydraulicCementC 219 Terminology Relating to Hydraulic CementC 266 Test Method for Time of Setting of Hydraulic-Cement Paste by Gillmore NeedlesC 305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC511 Specification for Mixing Rooms, M
10、oist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC 595 Specification for Blended Hydraulic CementsC 1005 Specification for Reference Masses and Devices forDetermining Mass and Volume for Use in the PhysicalTesting of Hydraulic CementsC 1157 Perf
11、ormance Specification for Hydraulic CementD 1193 Specification for Reagent Water3. Terminology3.1 DefinitionsThe terms used in this test method aredefined in accordance with Terminology C 219.4. Summary of Test Method4.1 A paste that is proportioned and mixed to normalconsistency, as described in th
12、e Test Method C 187, 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 cement and wate
13、r and the time when thepenetration is measured or calculated 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
14、method provides a means of determiningcompliance with a specification 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.1These test methods are under the jurisdiction of ASTM Committee C01 onCem
15、ent and is the direct responsibility of Subcommittee C01.30 on Time of Set.Current edition approved June 1, 2008. Published July 2008. Originally approvedin 1944. Last previous edition approved in 2007 as C 191 07.2Section on Safety, Manual of Cement Testing, Annual Book of ASTMStandards, Vol 04.01.
16、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 appears at the end of this sta
17、ndard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Time of setting measured by this method will notnecessarily provide the same results as the time of setting ofhydraulic cement paste measured by other methods, or the timeof se
18、tting 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 0.5g.6.1.1 The end of the rod used for measuring penetrationshall have a straight steel removable needle with a diameter of1.00 6
19、 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 Specification C 1005. Thedevices for determining mass shall b
20、e evaluated for precisionand accuracy at a total load of 1000 g.6.3 Glass Graduates, 200 or 250-mLcapacity, and conform-ing to the requirements of Specification C 1005.6.4 Plane non-adsorptive plate, 100 6 5 mm square ofsimilar planeness, corrosivity, and absorptivity to that of glass(see Annex A1.1
21、, 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 depart from straightness by more than 1mm.6.6 Conical ring, made of a rigid, non-corroding, non-absorbent material and having a height of 40 6 1 mm
22、, 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, conforming to Practice C 305.6.8 Automatic Vicat Needle Apparatus for Method BTheapparatus shall be equipped with a Vicat needle as described in6.1
23、.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 completing and recordingpenetration measurements of a test specimen at predeterminedtime intervals not exceeding 10 min and make each penetrationte
24、st 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 heldin 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 I
25、nspect and document Section 6 apparatus for con-formance to the requirements of this test method at least every212 years.7. Reagents and Materials7.1 Mixing WaterPotable water is satisfactory for routinetests. Use water conforming to the requirements of Specifica-tion D 1193 for Type III or Type IV
26、grade reagent water for allreferee and cooperative tests.8. Sampling8.1 When the test is required for acceptance testing, samplecement in accordance with Practice C 183.9. Conditioning9.1 Maintain the temperature of the air in the vicinity of themixing slab, the dry cement, molds, and base plates at
27、 23.0 63.0 C.9.2 Maintain the temperature of the mixing water at 23.0 62.0 C.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 de
28、termination of thetime 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 C 187), following the proce-dure described in Practice C 305.10.1.2 For method
29、A, at the option of the tester, use the testspecimen used for determining normal consistency (see Note2).10.1.3 At the option of the tester, use the paste remainingfrom the batch used for the autoclave specimen (Test MethodC 151) or from the normal consistency determination (TestMethod C 187).NOTE 2
30、The specimen used 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 E!C D!D3 C 25!D1 E (1)where:E = time in minutes of last penetration greater tha
31、n 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 and the time when the
32、 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 Apparatus13.1 Refer to
33、 theApparatus section, paragraphs 6.1, 6.4, and6.6, and Annex A1 for a description of the Vicat apparatus.4See Test Method C 187.C19108214. Procedure A14.1 Molding Test SpecimenQuickly form the cementpaste, prepared as described in the section on preparation ofcement paste, into a ball with gloved h
34、ands and toss six timesfrom one hand to the other, maintaining the hands about 150mm (6 in.) apart. Press the ball, resting in the palm of the hand,into the larger end of the conical ring, G, Fig. A1.1, held in theother hand, completely filling the ring with paste. Remove theexcess at the larger end
35、 by a single movement of the palm ofthe hand. Place the ring on its larger end onto the non-absorptive plate, H, and slice off the excess paste at the smallerend at the top of the ring by a single oblique stroke of thetrowel held at a slight angle with the top of the ring. Smooththe top of the speci
36、men, if necessary, with one or two lighttouches of the pointed end of the trowel. During the operationof cutting and smoothing, take care not to compress the paste.Immediately after molding, place the test specimen in the moistcabinet or moist room and allow it to remain there except whenpenetration
37、 measurements are being made. The specimen shallremain in the conical mold, supported by the non-absorptiveplate 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
38、. Determinethe penetration of the 1-mm needle at this time and every 15min 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
39、 setscrew, E, 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 qui
40、te soft on the 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
41、 mm away from 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 init
42、ial time of 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 su
43、rface. Obtainverification 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 penet
44、ration test. 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-op
45、erator (within-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 to 312min. Therefore, results of two properly conducted tests by thesame operator on
46、Vicat initial time of setting of similar pasteshould not differ from each other by more than 34 min and onVicat final time of setting of similar pastes should not differfrom each other by more than 56 min.15.1.2 The multilaboratory (between-laboratory) standarddeviation has been found to be 16 min f
47、or the initial 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 fr
48、om 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 statement on bias is present
49、ed.Method BAutomatic Vicat16. Automatic Vicat Apparatus16.1 Automatic Vicat Needle ApparatusRefer to the Ap-paratus section, paragraphs 6.8 and 6.9, for a description of theAutomatic Vicat needle apparatus.17. Procedure17.1 Molding the SpecimenQuickly form the cementpaste, prepared as described in the section on preparation ofcement paste, into a ball with gloved hands and toss six timesfrom one hand to the other, maintaining the hands about 150mm apart. Press the ball, resting in the palm of the hand, intothe larger end of the conical ring, held
