AASHTO T 197M T 197-2011 Standard Method of Test for Time of Setting of Concrete Mixtures by Penetration Resistance.pdf

《AASHTO T 197M T 197-2011 Standard Method of Test for Time of Setting of Concrete Mixtures by Penetration Resistance.pdf》由会员分享，可在线阅读，更多相关《AASHTO T 197M T 197-2011 Standard Method of Test for Time of Setting of Concrete Mixtures by Penetration Resistance.pdf（12页珍藏版）》请在麦多课文档分享上搜索。

1、Standard Method of Test for Time of Setting of Concrete Mixtures by Penetration Resistance AASHTO Designation: T 197M/T 197-11 (2015) ASTM Designation: C403/C403M-08 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-

2、3b T 197M/T 197-1 AASHTO Standard Method of Test for Time of Setting of Concrete Mixtures by Penetration Resistance AASHTO Designation: T 197M/T 197-11 (2015) ASTM Designation: C403/C403M-08 1. SCOPE 1.1. This test method covers the determination of the time of setting of concrete, with slump greate

3、r than zero, by means of penetration resistance measurements on mortar sieved from the concrete mixture. 1.2. This test method is suitable for use only when tests of the mortar fraction will provide the information required. 1.3. This test method may also be applied to prepared mortars and grouts. 1

4、.4. This test method is applicable under controlled laboratory conditions, as well as under field conditions. 1.5. The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system

5、 shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.6. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to establish appro

6、priate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 92, Wire-Cloth Sieves for Testing Purposes R 39, Making and Curing Concrete Test Specimens in the Laboratory R 60, Sampling Freshly Mixed Concre

7、te T 119M/T 119, Slump of Hydraulic Cement Concrete T 152, Air Content of Freshly Mixed Concrete by the Pressure Method T 196M/T 196, Air Content of Freshly Mixed Concrete by the Volumetric Method 2.2. ASTM Standards: C125, Standard Terminology Relating to Concrete and Concrete Aggregates C143/C143M

8、, Standard Test Method for Slump of Hydraulic-Cement Concrete C172/C172M, Standard Practice for Sampling Freshly Mixed Concrete 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 197M/T 197-2 AASHTO

9、 C173/C173M, Standard Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method C192/C192M, Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory C231/C231M, Standard Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method C670, S

10、tandard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials D1558, Standard Test Method for Moisture Content Penetration Resistance Relationships of Fine-Grained Soils E11, Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves E2251, Stan

11、dard Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids 3. TERMINOLOGY 3.1. Definitions: 3.1.1. time of initial settingthe elapsed time, after initial contact of cement and water, required for the mortar sieved from the concrete to reach a penetration resistance of

12、 3.5 MPa (500 psi). 3.1.2. time of final settingthe elapsed time, after initial contact of cement and water, required for the mortar sieved from the concrete to reach a penetration resistance of 27.6 MPa (4000 psi). 4. SUMMARY OF TEST METHOD 4.1. A mortar sample is obtained by sieving a representati

13、ve sample of fresh concrete. The mortar is placed in a container and stored at a specified ambient temperature. At regular time intervals, the resistance of the mortar to penetration by standard needles is measured. From a plot of penetration resistance versus elapsed time, the times of initial and

14、final setting are determined. 5. SIGNIFICANCE AND USE 5.1. Because the setting of concrete is a gradual process, any definition of time of setting must necessarily be arbitrary. In this test method, the times required for the mortar to reach specified values of resistance to penetration are used to

15、define times of setting. 5.2. This test method can be used to determine the effects of variables, such as brand, type, and content of cementitious material; water content; and admixtures, upon the time of setting of concrete. This test method may also be used to determine compliance with specified t

16、ime of setting requirements. 5.3. This test method may also be applied to prepared mortars and grouts. However, when the setting time of concrete is desired, the test shall be performed on mortar sieved from the concrete mixture and not on a prepared mortar intended to simulate the mortar fraction o

17、f the concrete; it has been shown that the initial and final setting times may be increased when using the prepared mortar. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 197M/T 197-3 AASHTO 6.

18、APPARATUS 6.1. Containers for Mortar SpecimensThe containers shall be rigid, watertight, nonabsorptive, nonoiled, and either cylindrical or rectangular in cross section. Mortar surface area shall be provided for 10 undisturbed readings of penetration resistance in accordance with Section 9.2 for cle

19、ar distance requirements. The minimum lateral dimension shall be 150 mm (6 in.) and the height at least 150 mm (6 in.). 6.2. Penetration NeedlesNeedles shall be provided that can be attached to the loading apparatus and that have the following bearing areas: 645, 323, 161, 65, 32, and 16 mm2(1, 1/2,

20、 1/4, 1/10, 1/20, and 1/40in.2). Each needle shank shall be scribed circumferentially at a distance 25 mm (1 in.) from the bearing area. The length of the 16-mm2(1/40-in.2) needle shall not be more than 90 mm (31/2in.). 6.3. Loading ApparatusA device shall be provided to measure the force required t

21、o cause penetration of the needles. The device shall be capable of measuring the penetration force with an accuracy of 10 N (2 lbf) and shall have a capacity of at least 600 N (130 lbf). Note 1Suitable loading apparatus can be of the spring-reaction type as described in ASTM D1558, or of other types

22、 with a calibrated force measuring device, such as an electronic load cell or a hydraulic pressure gauge. 6.4. Tamping RodThe tamping rod shall be a round, straight, steel rod 16 mm (5/8in.) in diameter and approximately 600 mm (24 in.) in length, having the tamping end or both ends rounded to a hem

23、ispherical tip, the diameter of which is 16 mm (5/8in.). 6.5. PipetA pipet or other suitable instrument shall be used for drawing off bleeding water from the surface of the test specimen. 6.6. ThermometerThe thermometer shall be capable of measuring the temperature of the fresh mortar to 0.5C (1F).

24、ASTM liquid-in-glass thermometers having a temperature range from 18 to 49C (0 to 120F) and conforming to the requirements of Thermometer S59C (S59F), as prescribed in ASTM E2251, are satisfactory. Other thermometers of the required accuracy, including the metal immersion type, are acceptable. 7. SA

25、MPLING, TEST SPECIMENS, AND TEST UNITS 7.1. For tests under field conditions, three specimens shall be prepared from each sample of concrete. 7.2. For tests under laboratory conditions, the requirements depend upon the purpose of the tests. 7.2.1. For testing to prove compliance of a material with p

26、erformance requirements, make at least three separate concrete batches for each variable under investigation. One time of setting test shall be made on each batch. An equal number of batches for each condition shall be made on any given day. When it is impossible to make at least one test for each v

27、ariable on a given day, the mixing of the entire series of batches shall be completed in as few days as possible and one of the mixtures shall be repeated each day as a standard of comparison. 7.2.2. For other tests, three test specimens shall be prepared from one batch of concrete for each test con

28、dition. 7.3. Record the time at which initial contact was made between cement and mixing water. 7.4. For tests under field conditions, obtain a representative sample of the fresh concrete in accordance with R 60. Determine and record the slump (T 119M/T 119) and air content (T 196M/T 196 or T 152) o

29、f the fresh concrete. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 197M/T 197-4 AASHTO 7.5. From the concrete mixture not used in the slump and air content tests, select a representative porti

30、on of concrete of sufficient volume to provide enough mortar to fill the test container, or containers, to a depth of at least 140 mm (51/2in.). 7.6. Using the procedure in Section 6.4.1 of R 60, obtain a mortar sample by wet-sieving the selected portion of concrete through a 4.75-mm (No. 4) sieve1o

31、nto a nonabsorptive surface. 7.7. Thoroughly remix the mortar by hand methods on the nonabsorptive surface. Measure and record the temperature of the mortar. Place the mortar in the container, or containers, using a single layer. Consolidate the mortar to eliminate air pockets in the specimen and le

32、vel the top surface. This may be accomplished by rocking the container back and forth on a solid surface, by tapping the sides of the container with the tamping rod, by rodding the mortar, or by placing the container on a vibrating table. (See Note 2.) If rodding is used, rod the mortar with the rou

33、nd end of the tamping rod. Rod the mortar once for each 645 mm2(1 in.2) of top surface area of the specimen and distribute the strokes uniformly over the cross section of the specimen. After completion of the rodding, tap the sides of the containers lightly with the tamping rod to close voids left b

34、y the tamping rod and to further level the surface of the specimen. Upon completion of specimen preparation, the mortar surface shall be at least 13 mm (0.5 in.) below the top edge of the container to provide space for the collection and removal of bleeding water and to avoid contact between the mor

35、tar surface and the protective covering specified in Section 8. Note 2Sieved mortar is generally of fluid consistency and air pockets are readily removed by the listed consolidation methods. The user is called upon to exercise judgment in the selection of the consolidation method. Rocking the contai

36、ner or tapping of the sides should be sufficient for fluid mortars. Rodding or using a vibrating table may be desirable for stiffer mortars. When using a vibrating table, use low-amplitude vibration so that portions of the sample are not ejected from the container. 8. CONDITIONING 8.1. For tests und

37、er laboratory conditions, the storage temperature for specimens shall be within the range 20 to 25C (68 to 77F), or as specified by the user. 8.2. For tests under field conditions, store the specimens under ambient conditions, or as specified by the user. Shield the specimens from direct sunlight. 8

38、.3. Measure and record the ambient temperature at the start and finish of the test. To prevent excessive evaporation of moisture, keep the specimens covered with a suitable material such as damp burlap or a tight-fitting, water-impermeable cover for the duration of the test, except when bleeding wat

39、er is being removed or penetration tests are being made. 9. PROCEDURE 9.1. Just prior to making a penetration test, remove bleeding water from the surface of the mortar specimens by means of a pipet or suitable instrument. To facilitate collection of bleeding water, tilt the specimen carefully to an

40、 angle of about 10 degrees from the horizontal by placing a block under one side 2 min prior to removal of the bleeding water. 9.2. Insert a needle of appropriate size, depending upon the degree of setting of the mortar, in the penetration resistance apparatus and bring the bearing surface of the ne

41、edle into contact with the mortar surface. Gradually and uniformly apply a vertical force downward on the apparatus until the needle penetrates the mortar to a depth of 25 1.5 mm (1 0.0625 in.), as indicated by the scribe mark (Note 4). The time required to penetrate to the 25 mm (1 in.) depth shall

42、 be 10 2 s. Record the force required to produce the 25 mm (1 in.) penetration and the time of application, 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 197M/T 197-5 AASHTO measured as elapsed

43、 time after initial contact of cement and water. Calculate the penetration resistance by dividing the recorded force by the bearing area of the needle, and record the penetration resistance. In subsequent penetration tests, take care to avoid areas where the mortar has been disturbed by previous tes

44、ts. The clear distance between needle impressions shall be at least two diameters of the needle being used but not less than 13 mm (0.5 in.). The clear distance between any needle impression and the side of the container shall be at least 25 mm (1 in.) but no more than 2 in. 50 mm as depicted in Fig

45、ure 1. Note: Gray shaded areas define where needle penetrations are permitted. Figure 1Top View of Mortar Test Specimen Note 3For a cylindrical container with the smallest allowable outer diameter of 6 in., the operator can reasonably expect to achieve approximately eight penetrations before impingi

46、ng upon previous penetrations. This is based on using needles of the following surface areas: 1 at 1/2(13), 2 at 1/4(6), 2 at 1/10(2.5), 2 at 1/20(1.3), and 1 at 1/40(0.6) mm2(in.2). Note 4To facilitate determination of when the required penetration has been attained, a sliding marker may be attache

47、d to the needle shaft. For example, a paper clip or masking tape may be placed on the shaft so that it coincides with the scribe mark. The marker should not interfere with the penetration of the needle into the mortar. The position of the marker should be checked prior to making a penetration. 9.3.

48、For conventional concrete mixtures at laboratory temperatures 20 to 25C (68 to 77F), make the initial test after an elapsed time of 3 to 4 h after initial contact between cement and water. Subsequent tests should be made at 1/2- to 1-h intervals. For concrete mixtures containing accelerators, or at

49、temperatures higher than laboratory, it is advisable to make the initial test after an elapsed time of 1 to 2 h and subsequent tests at 1/2-h intervals. For concrete mixtures containing retarders, or at temperatures lower than laboratory, the initial test may be deferred until an elapsed time of 4 to 6 h. In all cases, time intervals between subsequent tests may be adjusted as necessary, depending upon the rate of setting, to obtain the required number of penetrations. 9.4. Make at least six penetrations for each time-of-