AASHTO T 131-2015 Standard Method of Test for Time of Setting of Hydraulic Cement by Vicat Needle.pdf

1、Standard Method of Test for Time of Setting of Hydraulic Cement by Vicat Needle AASHTO Designation: T 131-15 ASTM Designation: C191-13 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3a T 131-1 AASHTO Standard Meth

2、od of Test for Time of Setting of Hydraulic Cement by Vicat Needle AASHTO Designation: T 131-15 ASTM Designation: C191-13 1. SCOPE 1.1. These test methods determine the time of setting of hydraulic cement by means of the Vicat needle. Two test methods are given: Method A is the Reference Test Method

3、 using the manually operated standard Vicat apparatus, while Method B permits the use of an automatic Vicat machine that has, in accordance with the qualification requirements of this method, demonstrated acceptable performance. 1.2. The values stated in SI units are to be regarded as the standard.

4、The values given in parentheses are for information only. 1.3. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicabi

5、lity of regulatory limitations prior to use. WarningFresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure. 1.4. The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (e

6、xcluding 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 T 154. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 85, Portland Cement M 201, Mixing Rooms, Moist Cabinets, Moist Room

7、s, and Water Storage Tanks Used in the Testing of Hydraulic Cements and Concretes M 240M/M 240, Blended Hydraulic Cement T 129, Amount of Water Required for Normal Consistency of Hydraulic Cement Paste T 154, Time of Setting of Hydraulic Cement Paste by Gillmore Needles T 162, Mechanical Mixing of H

8、ydraulic Cement Pastes and Mortars of Plastic Consistency 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 131-2 AASHTO 2.2. ASTM Standards: C151/C151M, Standard Test Method for Autoclave Expansio

9、n of Hydraulic Cement C183, Standard Practice for Sampling and the Amount of Testing of Hydraulic Cement C219, Standard Terminology Relating to Hydraulic Cement C1005, Standard Specification for Reference Masses and Devices for Determining Mass and Volume for Use in the Physical Testing of Hydraulic

10、 Cements C1157/C1157M, Standard Performance Specification for Hydraulic Cement D1193, Standard Specification for Reagent Water 3. TERMINOLOGY 3.1. DefinitionsThe terms used in this test method are defined in accordance with ASTM C219. 4. SUMMARY OF TEST METHOD 4.1. A paste that is proportioned and m

11、ixed to normal consistency, as described in the test method T 129, is molded and placed in a moist cabinet and allowed to start setting. Periodic penetration tests are performed on this paste by allowing a 1-mm Vicat needle to settle into this paste. The Vicat initial time of setting is calculated a

12、s the time elapsed between the initial contact of cement and water and the time when the penetration is at 25 mm. The Vicat final time of setting is calculated as the time when the needle does not sink visibly into the paste. 5. SIGNIFICANCE AND USE 5.1. This test method provides a means of determin

13、ing compliance with a specification limit for Vicat time of setting. Refer to the appropriate specification for the cement to determine if this test method is used for specification compliance. 5.2. The measured time of setting is affected by the percentage and temperature of the water used, amount

14、of kneading the paste received, and temperature and humidity of the mixing room air and the moist cabinet or moist room air. 5.3. The measured time of setting of hydraulic cement is test method specific. Time of setting as measured by this method will not necessarily be similar to other methods used

15、 for determining the time of setting of hydraulic cements. 6. APPARATUS 6.1. Vicat ApparatusSee Annex A, Figure A1.1. The Vicat apparatus for this test method shall have a movable rod, B, of mass 300 0.5 g. 6.1.1. The end of the rod used for measuring penetration shall have a removable needle, D, wi

16、th a diameter of 1.00 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. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violati

17、on of applicable law.TS-3a T 131-3 AASHTO 6.2. Reference Masses and Devices for Determining MassConforming to the requirements of ASTM C1005. The devices for determining mass shall be evaluated for precision and accuracy at a total load of 1 kg. 6.3. Glass Graduates200- or 250-mL capacity, and confo

18、rming to the requirements of ASTM C1005. 6.4. Plane Nonabsorptive Plate100 5 mm square of similar planeness, corrosivity, and absorptivity to that of glass (see Annex A, Figure A1.1, H). 6.5. Flat TrowelHaving a sharpened straight-edged steel blade 100 to 150 mm in length. The edges, when placed on

19、a plane surface, shall not depart from straightness by more than 1 mm. 6.6. Conical RingMade of a rigid noncorroding, nonabsorbent material that shall have a height of 40 1 mm, an inside diameter at the bottom of 70 3 mm, and an inside diameter at the top of 60 3 mm (see Annex A, Figure A1.1, G). 6.

20、7. Mixer, Bowl, and PaddleConforming to T 162. 6.8. Automatic Vicat Needle Apparatus for Method BThe apparatus shall be equipped with a Vicat needle as described in Sections 6.1.1 and 6.1.2. The total mass supported by the needle tip at the time of measurement shall be 300 0.5 g. The instrument shal

21、l be capable of automatically completing and recording penetration measurements of a test specimen at predetermined time intervals not exceeding 10 min and make each penetration test at least 5 mm away from any previous penetration and at least 10 mm away from the inner side of the mold. 6.9. Specim

22、en Mold for Method BThe cement paste is held in a conical ring with a height of 40 1 mm and a removable base plate. The test surface shall have a minimum diameter of 60 3 mm. 6.10. Inspect and document Section 6 apparatus for conformance to the requirements of this test method at least every 21/2yea

23、rs. 7. REAGENTS AND MATERIALS 7.1. Mixing WaterPotable water is satisfactory for routine tests. Use water conforming to the requirements of ASTM D1193 for Type III or Type IV grade reagent water for all referee and cooperative tests. 8. SAMPLING 8.1. When the test is required for acceptance testing,

24、 sample cement in accordance with ASTM C183. 9. CONDITIONING 9.1. Maintain the temperature of the air in the vicinity of the mixing slab, the dry cement, molds, and base plates at 23.0 3.0C. 9.2. Maintain the temperature of the mixing water at 23.0 2.0C. 9.3. The relative humidity of the mixing room

25、 shall not be less than 50 percent. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 131-4 AASHTO 9.4. The moist closet or moist room shall be in accordance with M 201. 10. PREPARATION OF CEMENT P

26、ASTE 10.1. The cement paste used for the determination of the time of setting is obtained from one of the following methods: 10.1.1. Prepare a new batch of paste by mixing 650 g of cement with the percentage of mixing water required for normal consistency (T 129), following the procedure described i

27、n T 162. 10.1.2. For Method A, at the option of the tester, use the test specimen used for determining normal consistency (see Note 2). Note 2The specimen used for the determination of the normal consistency will have an irregular surface, making it unsuitable for Method B. 10.1.3. At the option of

28、the tester, use the paste remaining from the batch used for the autoclave specimen (ASTM C151/C151M) or from the normal consistency determination (T 129). 11. METHOD AMANUAL VICAT NEEDLE 11.1. ApparatusRefer to Sections 6.1, 6.4, and 6.6, and Annex A for a description of the Vicat apparatus. 12. MET

29、HOD APROCEDURE 12.1. Molding Test Specimen: 12.1.1. With gloved hands, quickly form the cement paste, prepared as described in Section 10, into a ball and toss six times from one hand to the other, maintaining the hands about 150 mm (6 in.) apart. Press the ball, resting in the palm of the hand, int

30、o the larger end of the conical ring (G), held in the other hand, completely filling the ring with paste. (See Figure A1.1.) Remove the excess at the larger end by a single movement of the palm of the hand. Place the ring on its larger end onto a nonabsorptive plate (H), and slice off the excess pas

31、te at the smaller end at the top of the ring by 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 or two light touches of the pointed end of the trowel. During the operation of cutting and smoothing, take car

32、e not to compress the paste. 12.1.2. Immediately after molding, place the test specimen in the moist closet or moist room and allow it to remain there except when penetration measurements are being made. The specimen shall remain in the conical mold, supported by the nonabsorptive plate throughout t

33、he test period. 12.2. Time of Setting Determination: 12.2.1. Allow the time of setting specimen to remain in the moist cabinet for 30 min after molding without being disturbed. Determine the penetration of the 1-mm needle at this time and every 15 min thereafter (every 10 min for Type III cements) u

34、ntil a penetration of 25 mm or less is obtained. Perform the penetration test by lowering the needle (D) of the rod (B) until it rests on the surface of the cement paste. Tighten the set screw (E) and set the indicator (F) at the upper end of the scale or take an initial reading. Release the rod qui

35、ckly by releasing the set screw (E) and allow the needle to settle for 30 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 readings, retard the fall of the rod to 2016 by the American Association of State Highway an

36、d Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 131-5 AASHTO avoid bending the 1-mm needle, but when actual penetration measurements to determine the time of setting are made, release the rod only by the set screw. 12.2.2. Make each penetration te

37、st at least 5 mm away from any previous penetration and at least 10 mm away from the inner side of the mold. Record the results of all penetration tests and, by interpolation, determine the time when a penetration of 25 mm is obtained. The elapsed time between the initial contact of cement and water

38、 and the penetration of 25 mm is the Vicat time of setting or Vicat initial time of setting. 12.3. Determine the Vicat final time of setting end point to be the first penetration measure that does not mark the specimen surface with a complete circular impression. Verify final set by performing two a

39、dditional penetration measurements on different areas of the specimen surface. Obtain verification measurements within 90 s of the first “final set” measurement. The elapsed time between the initial contact of cement and water and the end point determination above is the Vicat final time of setting.

40、 12.4. PrecautionsKeep all the apparatus free from vibration during the penetration test. Keep the 1-mm needle straight and clean. The needle must be kept clean to prevent cement from adhering to the sides of the needle and decreasing penetration, and to prevent cement from adhering to the point and

41、 increasing penetration. 13. METHOD APRECISION AND BIAS 13.1. Precision: 13.1.1. 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 setting throughout the range

42、of 185 to 312 min. Therefore, results of two properly conducted tests by the same operator on the Vicat initial time of setting of similar pastes should not differ from each other by more than 34 min, and on the Vicat final time of setting of similar pastes should not differ from each other by more

43、than 56 min. 13.1.2. The multilaboratory (between-laboratory) standard deviation has been found to be 16 min for the initial time of setting throughout 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 cond

44、ucted tests from two different laboratories on the Vicat initial time of setting of similar pastes should not differ from each other by more than 45 min, and on the Vicat final time of setting of similar pastes should not differ from each other by more than 122 min. 13.2. BiasBecause there are no ac

45、cepted reference materials suitable for determining the bias for the procedure in this test method, no statement on bias is presented. 14. METHOD BAUTOMATIC VICAT APPARATUS 14.1.1. Automatic Vicat Needle ApparatusRefer to Sections 6.8 and 6.9 for a description of the Automatic Vicat needle apparatus

46、. 15. METHOD BPROCEDURE 15.1. Molding Test Specimen: 15.1.1. With gloved hands, quickly form the cement paste, prepared as described in Section 10, into a ball and toss six times from one hand to the other, maintaining the hands about 150 mm (6 in.) apart. 2016 by the American Association of State H

47、ighway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 131-6 AASHTO Press the ball, resting in the palm of the hand, into the larger end of the conical ring, held in the other hand, completely filling the ring with paste. Remove the excess at th

48、e larger end by a single movement of the palm of the hand. Place the ring on its larger end on to the base plate. Use a trowel to remove the excess paste at the top of the mold. Holding the trowel at about a 30-degree incline with the leading edge raised and starting near the center of the mold, lev

49、el the paste by drawing the trowel across the top of the mold using a sawing motion; repeat the procedure for the other half of the surface. Then smooth the surface level to the top of the mold making steady and complete strokes across the entire surface with the trailing edge of the trowel. 15.1.2. Repeat the cutting and smoothing steps, but at 90 degrees from the previous cut. Repeat the steps as required to produce a surface level with the top of the mold. Usually the paste is level within two cycles, but occas