1、Designation: C191 18C191 18a 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
2、indicates 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
3、 of setting of hydraulic cement by means of the Vicat needle. Two test methods aregiven; MethodAis the Reference Test Method using the manually operated standard Vicat apparatus, while Method B permits theuse of an automatic Vicat machine that has, in accordance with the qualification requirements o
4、f this method, demonstratedacceptable performance.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the respons
5、ibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.Warning: Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolongedexposure.21.4 The te
6、xt of this standard references notes and footnotes which provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be considered as requirements of the standard.NOTE 1For the method for determining the time of setting by Gillmore needles, see Test Metho
7、d C266.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barrier
8、s to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3C150/C150M Specification for Portland CementC151/C151M Test Method for Autoclave Expansion of Hydraulic CementC183/C183M Practice for Sampling and the Amount of Testing of Hydraulic CementC187 Test Method for Amount of Water Requi
9、red for Normal Consistency of Hydraulic Cement PasteC219 Terminology Relating to Hydraulic CementC266 Test Method for Time of Setting of Hydraulic-Cement Paste by Gillmore NeedlesC305 Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic ConsistencyC511 Specification for M
10、ixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of HydraulicCements and ConcretesC595/C595M Specification for Blended Hydraulic CementsC1005 Specification for Reference Masses and Devices for Determining Mass and Volume for Use in the Physical Testing ofHydrauli
11、c CementsC1157/C1157M Performance Specification for Hydraulic CementD1193 Specification for Reagent Water3. Terminology3.1 DefinitionsThe terms used in this test method are defined in accordance with Terminology C219.1 These test methods are under the jurisdiction of ASTM Committee C01 on Cement and
12、 is the direct responsibility of Subcommittee C01.30 on Time of Set.Current edition approved June 15, 2018Oct. 1, 2018. Published June 2018October 2018. Originally approved in 1944. Last previous edition approved in 20132018 asC191 13.C191 18. DOI: 10.1520/C0191-18.10.1520/C0191-18A.2 Section on Saf
13、ety, Manual of Cement Testing, Annual Book of ASTM Standards, Vol 04.01.3 For referencedASTM standards, visit 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 AS
14、TM website.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 accurately, ASTM recommends that users consul
15、t 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 Harbor Drive, PO Box C700, West Conshohocken, P
16、A 19428-2959. United States14. Summary of Test Method4.1 A paste that is proportioned and mixed to normal consistency, as described in the Test Method C187, is molded and placedin a moist cabinet and allowed to start setting. Periodic penetration tests are performed on this paste by allowing a 1-mm
17、Vicatneedle to settle into this paste. The Vicat initial time of setting is the time elapsed between the initial contact of cement and waterand the time when the penetration is measured or calculated to be 25 mm.TheVicat final time of setting is the time elapsed betweeninitial contact of cement and
18、water and the time when the needle does not leave a complete circular impression in the paste surface.5. Significance and Use5.1 This test method provides a means of determining compliance with a specification limit for Vicat time of setting. Refer tothe appropriate specification for the cement to d
19、etermine if this test method is used for specification compliance.5.2 Time of setting measured by this method will not necessarily provide the same results as the time of setting of hydrauliccement paste measured by other methods, or the time of setting of mortar or concrete.6. Apparatus6.1 Vicat Ap
20、paratusSee Annex A1.1 and Fig. A1.1. The Vicat apparatus for this test method shall have a movable rod, B, ofmass 300 6 0.5 g.6.1.1 The end of the rod used for measuring penetration shall have a straight steel removable needle with a diameter of 1.006 0.05 mm and length no less than 50 mm.6.1.2 The
21、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 C1005. The devicesfor determining mass shall be evaluated for continuing precise performance u
22、tilizing the procedure in Specification C1005,Appendix X1 using a verification check mass of approximately 1000 g.6.3 Glass Graduates, 200 or 250-mL capacity, and conforming to the requirements of Specification C1005.6.4 Plane non-adsorptive plate, 100 6 5 mm square of similar planeness, corrosivity
23、, and absorptivity to that of glass (seeAnnex A1.1, Fig. A1.1, H).6.5 Flat trowel, having a sharpened straight-edged steel blade 100 to 150 mm in length. The edges when placed on a planesurface shall not depart from straightness by more than 1 mm.6.6 Conical ring, made of a rigid, non-corroding, non
24、-absorbent material and having a height of 40 6 1 mm, an inside diameterat the bottom of 70 6 3 mm, and an inside diameter 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 C305.6.8 Automatic Vicat Needle Apparatus for Method BThe apparatus sh
25、all be equipped with a Vicat needle as described in 6.1.1and 6.1.2. The total mass supported by the needle tip at the time of measurement shall be 300 6 0.5 g. The instrument shall becapable of automatically completing and recording penetration measurements of a test specimen at predetermined time i
26、ntervalsnot exceeding 10 min and make each penetration test at least 5 mm away from any previous penetration and at least 10 mm awayfrom the inner side of the mold.6.9 Specimen Mold for Method BThe cement paste is held in a conical ring with the height of 40 6 1 mm and a removablebase plate. The tes
27、t surface shall have a minimum diameter of 60 6 3 mm.6.10 Inspect and document Section 6 apparatus for conformance to the requirements of this test method at least every 212 years(see Note 2).NOTE 2Specification C1005 requires annual compliance checks for the reference masses and for the devices for
28、 determining mass.7. Reagents and Materials7.1 Mixing WaterPotable water is satisfactory for routine tests. Use water conforming to the requirements of SpecificationD1193 for Type III or Type IV grade reagent water for all referee and cooperative tests.8. Sampling8.1 When the test is required for ac
29、ceptance testing, sample cement in accordance with Practice C183/C183M.9. Conditioning9.1 Maintain the temperature of the air in the vicinity of the mixing slab, the dry cement, molds, and base plates at 23.063.0C.9.2 Maintain the temperature of the mixing water at 23.0 6 2.0C.9.3 The relative humid
30、ity of the mixing room shall be not less than 50 %.9.4 The moist cabinet or moist room shall be in accordance with Specification C511.C191 18a210. Preparation of Cement Paste410.1 The cement paste used for the determination of the time of setting is obtained from one of the following methods:10.1.1
31、Prepare a new batch of paste by mixing 650 g of cement with the percentage of mixing water required for normalconsistency (Test Method C187), following the procedure described in Practice C305.10.1.2 For method A, at the option of the tester, use the test specimen used for determining normal consist
32、ency (see Note 3).10.1.3 At the option of the tester, use the paste remaining from the batch used for the autoclave specimen (Test MethodC151/C151M) or from the normal consistency determination (Test Method C187).NOTE 3The specimen used for the determination of the normal consistency will have an ir
33、regular surface, making it unsuitable for method B.11. Calculation11.1 Calculate the Vicat time of setting to the nearest 1 min as follows:SSH 2E!C2D!D 3C 225!D1E (1)where:E = time in minutes of last penetration greater than 25 mm,H = time in minutes of first penetration less than 25 mm,C = penetrat
34、ion reading at time E, andD = penetration reading at time H.11.2 Calculate the Vicat final time of setting by determining the elapsed time between the time of the initial contact betweencement and water and the time when the needle does not sink visibly into the paste,Vicat final time of setting end
35、-point describedin 14.3 is determined, rounded to the nearest 5 min.12. Report12.1 Report the time of setting and the method used as follows: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 the
36、Apparatus section, paragraphs 6.1, 6.4, and 6.6, and Annex A1 for a description of the Vicat apparatus.14. Procedure A14.1 Molding Test SpecimenQuickly form the cement paste, prepared as described in the section on preparation of cementpaste, into a ball with gloved hands and toss six times from one
37、 hand to the other, maintaining the hands about 150 mm (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 the other hand,completely filling the ring with paste. Remove the excess at the larger end by a single movement of the p
38、alm of the hand. Placethe ring on its larger end onto the non-absorptive plate, H, and slice off the excess paste at the smaller end at the top of the ringby a single oblique stroke of the trowel held at a slight angle with the top of the ring. Smooth the top of the specimen, if necessary,with one o
39、r two light touches of the pointed end of the trowel. During the operation of cutting and smoothing, take care not tocompress the paste. Immediately after molding, place the test specimen in the moist cabinet or moist room and allow it to remainthere except when penetration measurements are being ma
40、de. The specimen shall remain in the conical mold, supported by thenon-absorptive plate throughout the test period.14.2 Time of Setting DeterminationAllow the time of setting specimen to remain in the moist cabinet or moist room for 30min after molding without being disturbed. Determine the penetrat
41、ion of the 1-mm needle at this time and every 15 min thereafter(every 10 min for Type III cements) until a penetration of 25 mm or less is obtained. Perform the penetration test by lowering theneedle D of the rod B until it rests on the surface of the cement paste. Tighten the setscrew, E, and set t
42、he indicator, F, at the upperend of the scale, or take an initial reading. Release the rod quickly by releasing the set screw, E, and allow the needle to settle for30 s; then take the reading to determine the penetration. At the option of the tester, if the paste is obviously quite soft on the early
43、readings, retard the fall of the rod to avoid bending the 1-mm needle, but when actual penetration measurements to determine thetime of setting are made, release the rod only by the setscrew. Make each penetration test at least 5 mm away from any previouspenetration and at least 10 mm away from the
44、inner side of the mold. Record the results of all penetration tests and, by4 See Test Method C187.C191 18a3interpolation, determine the time when a penetration of 25 mm is obtained. The elapsed time between the initial contact of cementand water and the penetration of 25 mm is the Vicat time of sett
45、ing or Vicat initial time of setting.14.3 Determine the Vicat final time of setting end point to be the first penetration measurement that does not mark the specimensurface with a complete circular impression. Verify final set by performing two additional penetration measurements on differentareas o
46、f the specimen surface. Obtain verification measurements within 90 s of the first “final set” measurement. The elapsed timebetween the initial contact of cement and water and the end point determination above is the Vicat final time of setting.14.4 PrecautionsKeep all the apparatus free from vibrati
47、on during the penetration test. Keep the 1-mm needle straight andclean. The needle must be kept clean to prevent cement from adhering to the sides of the needle and decreasing penetration, andto prevent cement from adhering to the point and increasing penetration.15. Precision and Bias15.1 Precision
48、:15.1.1 The single-operator (within-laboratory) standard deviation has been found to be 12 min for the initial time of setting,throughout the range of 49 to 202 min, and 20 min for the final time of settings throughout the range of 185 to 312 min. Therefore,results of two properly conducted tests by
49、 the same operator on Vicat initial time of setting of similar paste should not differ fromeach other by more than 34 min and on Vicat final time of setting of similar pastes should not differ from each other by more than56 min.15.1.2 The multilaboratory (between-laboratory) standard deviation has been found to be 16 min for the initial time of settingthroughout the range of 49 to 207 min, and 43 min for the final time of setting throughout the range of 185 to 312 min. Therefore,results of two properly conducted tests from two different laboratories
