AASHTO T 158-2011 Standard Method of Test for Bleeding of Concrete.pdf

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1、Standard Method of Test for Bleeding of Concrete AASHTO Designation: T 158-11 (2015) ASTM Designation: C232/C232M-09 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3b T 158-1 AASHTO Standard Method of Test for Ble

2、eding of Concrete AASHTO Designation: T 158-11 (2015) ASTM Designation: C232/C232M-09 1. SCOPE 1.1. These test methods cover the determination of the relative quantity of mixing water that will bleed from a sample of freshly mixed concrete. Two test methods that differ primarily in the degree of vib

3、ration to which the concrete sample is subjected are included. 1.2. The two test methods are not expected to yield the same test results when samples of concrete from the same batch are tested by each method. When various concretes are to be compared, all the tests should be conducted using the same

4、 method, and the sample masses, if the batches are of similar unit weight, should not differ by more than 1 kg 2 lb. 1.3. 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

5、 system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.4. 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 t

6、o establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: R 39, Making and Curing Concrete Test Specimens in the Laboratory R 60, Sampling Freshly Mixed Concrete T 121M/T 121, Density (Un

7、it Weight), Yield, and Air Content (Gravimetric) of Concrete 2.2. ASTM Standard: C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials 3. SIGNIFICANCE AND USE 3.1. This test method provides procedures to be used for determining the effect of

8、variables of composition, treatment, environment, or other factors in the bleeding of concrete. It may also be used to determine the conformance of a product or treatment with a requirement relating to its effect on bleeding of concrete. 2016 by the American Association of State Highway and Transpor

9、tation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 158-2 AASHTO 3.2. Method AFor a sample consolidated by rodding only and tested without further disturbance, thus simulating conditions in which concrete, after placement, is not subjected to intermittent vibra

10、tion. 3.3. Method BFor a sample consolidated by vibration and tested with further intermittent periods of vibration, thus simulating conditions in which concrete, after being placed, is subjected to intermittent vibration. METHOD ASAMPLE CONSOLIDATED BY TAMPING 4. APPARATUS 4.1. ContainerA cylindric

11、al container of approximately 14-L approximately 1/2-ft3 capacity, having an inside diameter of 255 5 mm 10 1/4in. and an inside height of 280 5 mm 11 1/4in. The container shall be made of metal having a thickness of 2.67 to 3.40 mm 0.105 to 0.134 in. and shall be externally reinforced around the to

12、p with a 2.67- to 3.40-mm 0.105- to 0.134-in. metal band, 40 mm 11/2in. wide. The inside shall be smooth and free from corrosion, coatings, or lubricants. 4.2. ScaleOf sufficient capacity to determine the mass of the load required with an accuracy of 0.5 percent. Balances or scales shall be calibrat

13、ed at least annually or whenever there is a reason to question the accuracy of the equipment. Equipment not in operating condition or out of tolerance shall be marked as such and taken out of service until corrected. 4.3. PipetOr similar instrument for drawing off free water from the surface of the

14、test specimen. 4.4. Glass GraduateOf 100-mL capacity for collecting and measuring the quantity of water withdrawn. 4.5. Tamping RodA round, straight steel rod, with a 16 2-mm 58in. 116-in. diameter. The length of the tamping rod shall be at least 100 mm 4 in. greater than the depth of the measure in

15、 which rodding is being performed but not greater than 600 mm 24 in. in overall length. The length tolerance for the tamping rod shall be 4 mm 18in. The rod shall have the tamping end or both ends rounded to a hemispherical tip of the same diameter as the rod. 4.6. Metal Beaker (Optional)A 1000-mL m

16、etal beaker for collecting the decanted supernatant water and sludge (Note 1). 4.7. Balance (Optional)A balance sensitive to 1 g for determining the mass of the decanted water and sludge (Note 1). 4.8. Hot Plate (Optional)A small electric hot plate or other source of heat for evaporating decanted wa

17、ter (Note 1). Note 1The apparatus listed in Sections 4.6, 4.7, and 4.8 will be required if the procedure of measuring the amount of bleeding water recovered is one involving weighing, evaporation, and reweighing. 2016 by the American Association of State Highway and Transportation Officials.All righ

18、ts reserved. Duplication is a violation of applicable law.TS-3b T 158-3 AASHTO 5. TEST SPECIMEN 5.1. For concrete made in the laboratory, prepare the concrete as described in R 39. For concrete made in the field, sample the concrete as described in R 60. The apparatus described in this method may be

19、 used with samples of concrete containing any size of aggregate graded up to and including a nominal maximum size of 50 mm 2 in. Concrete containing aggregate larger than 50 mm 2 in. in nominal maximum size shall be wet-sieved over a 37.5-mm 11/2-in. sieve and the test performed on a portion of the

20、sample that passes through the sieve. 5.2. Fill the container with the concrete in accordance with T 121M/T 121, except that the container shall be filled to a height of 254 3 mm 10 1/8in. Level the top surface of the concrete to a reasonably smooth surface by a minimum amount of troweling. 6. PROCE

21、DURE 6.1. During the test, maintain the ambient temperature between 18 and 24C 65 and 75F. Immediately after troweling the surface of the specimen, record the time and determine the mass of the container and contents. 6.2. Place the specimen and container on a level platform or floor free from notic

22、eable vibration and cover the container to prevent evaporation of the bleed water. Keep the cover in place throughout the test, except when drawing off the water. 6.3. Draw off (with pipet or similar instrument) the water that has accumulated on the surface, at 10-min intervals during the first 40 m

23、in and at 30-min intervals thereafter, until cessation of bleeding. To facilitate the collection of bleeding water, tilt the specimen carefully by placing a block approximately 50-mm 2-in. thick under one side of the container 2 min prior to each time the water is withdrawn. After the water is remov

24、ed, return the container to a level position without jarring. 6.4. After each withdrawal, transfer the water to a 100-mL graduate. Record the accumulated quantity of water after each transfer. When only the total volume of bleeding is desired to be determined, the periodic removal procedure may be o

25、mitted and the entire amount removed in a single operation. If it is desired to determine the mass of the bleeding water and to exclude the material present other than the water, carefully decant the contents of the cylinder into a metal beaker. 6.5. Determine the mass and record the mass of the bea

26、ker and its contents. 6.6. Dry the beaker and its contents to constant mass and record the final mass. The difference between the two masses, D, is equal to the mass of the bleeding water. The mass of the sludge may also be obtained, if desired, by initially determining the tare mass of the beaker.

27、7. CALCULATIONS 7.1. Calculate the volume of bleeding water per unit area of surface, V, as follows: 1/VVA= (1) where: V1= volume of bleeding water during the selected time interval, mL; and A = area of exposed concrete, cm2. The comparative rate of bleeding can be determined as the test progresses

28、by comparing the volume of bleeding water for each equal time interval. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 158-4 AASHTO 7.2. Calculate the accumulated bleeding water, expressed as a

29、percentage of the net mixing water contained within the test specimen, as follows: C = (w/M) S (2) Bleeding, percent = D/C 100 (3) where: C = mass of water in the test specimen, g; M = total mass of batch, kg; w = net mixing water (the total amount of water minus the water absorbed by the aggregates

30、), kg; S = mass of sample, g; and D = mass of bleeding water, g, or total volume withdrawn from the test specimen in cubic centimeters multiplied by 1 g/mL3. METHOD BSAMPLE CONSOLIDATED BY VIBRATION 8. APPARATUS 8.1. Vibrating PlatformA platform shall be provided upon which the filled container shal

31、l be mounted. The platform shall be equipped with a suitable device so that intermittent periods of vibration of reproducible duration, frequency, and amplitudes will be imparted to the specimen container as prescribed by Section 8. (See Figure 1.) Suitable vibration will be provided if there is bol

32、ted to the platform a 93-W 1/8-hp electric motor, to the shaft of which a small eccentric whose mass is approximately 110 g is attached by means of a setscrew. The eccentric should be fabricated from cold-rolled stock in accordance with the details and dimensions shown in Figure 2. The hole through

33、the eccentric is 13.5 mm 17/32in. or an appropriate size to accommodate the motor shaft. The platform should be supported on rubber supports resting on a concrete slab. The concrete slab should be separated from the floor by a layer of cork as shown in Figure 2. 8.2. TimerA timing device, by means o

34、f which the periods of vibration provided to the platform and specimen in accordance with the provisions of Section 8 may be regulated. 8.3. ContainerA steel container 290 mm 111/2in. in diameter at the top, 279 mm 11 in. in diameter at the bottom, and 280 mm 111/8in. high shall be provided. A steel

35、 container cover shall also be provided. The container and cover shall conform with the details given in Figure 3. 8.3.1. The remainder of the apparatus is identical with that given for Method A. 9. VIBRATING CYCLE 9.1. The vibrating cycle shall be as follows: Power on for 3 s, power off 30 s. Howev

36、er, due to the coasting of the motor after the power is turned off, the period of perceptible vibration is approximately 7 s (Figure 1). 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 158-5 AASH

37、TO Figure 1Vibrating Platform and Timer 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 158-6 AASHTO Figure 2Detail of Vibrating Platform Apparatus 2016 by the American Association of State Highw

38、ay and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 158-7 AASHTO Figure 3Container and Cover 10. TEST SPECIMEN 10.1. The sample shall be prepared as described for Method A. 10.2. The sample shall be placed in the container to a depth equal to app

39、roximately one-half the average diameter of the container. The size of the test sample can best be regulated by mass; a sample weighing with a mass of 20 0.5 kg 45 1 lb usually meets the requirements for the apparatus described herein (Figure 2). 2016 by the American Association of State Highway and

40、 Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 158-8 AASHTO 11. PROCEDURE 11.1. Consolidation of Test SpecimenConsolidate the sample in the container by means of vibration of only that duration required to affect the desired degree of compaction.

41、Sufficient vibration has been applied as soon as the surface of the concrete has become relatively smooth. Stop the consolidating procedure immediately upon the first appearance of free water segregating from the concrete, as indicated by the development of a water sheen on its surface. For some unu

42、sually wet or plastic mixtures, no consolidating effort will be needed beyond that supplied by placing the sample in the container and handling the container during the operations of determining the mass and placing it on the platform for test. 11.2. Intermittent VibrationPlace the cover on the cont

43、ainer and the container on the vibrating platform. Clamp the container and cover down tightly. Note and record the time and start the motor. Continue intermittent vibration for 1 h. 11.3. Determination of Bleeding WaterThe intermittent periods of vibrations do not permit the determination of bleedin

44、g water at a number of different time intervals. Determine the total volume of bleeding water as described for Method A. 12. CALCULATIONS 12.1. Calculate the percentage bleeding water as described for Method A. 13. PRECISION AND BIAS 13.1. Precision: 13.1.1. Method AData are not available to evaluat

45、e the precision of Method A directly. However, there is reason to believe that the precision for Method A is at least as good as that for Method B. The values given for Method B shall be used as maximum precision limits for Method A. 13.1.2. Method BThe single operator-day-multibatch standard deviat

46、ion (1s) has been found to be 0.71 percent for a bleeding range from 200 to 10 percent, 1.06 percent for a bleeding range from 10 to 20 percent, and 1.77 percent for more than 20 percent. Therefore, results of two properly conducted tests by the same operator on the same day on different batches of

47、the same mixture should not deviate by more than 2.0 percent (d2s) for a bleeding range from 200 to 10 percent, 3.0 percent for a range from 10 to 20 percent, and 5.0 percent for more than 20 percent. (See Note 2.) Note 2These numbers represent, respectively, the (1s) and (d2s) limits as described i

48、n ASTM C670 for preparing Precision and Bias Statements for Test Methods for Construction Materials. 13.2. BiasThe test methods have no bias because the values determined can be defined only in terms of the test methods. 14. KEYWORDS 14.1. Bleeding; concrete, bleeding of. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.