AASHTO T 345-2012 Standard Method of Test for Passing Ability of Self-Consolidating Concrete (SCC) by J-Ring.pdf

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1、Standard Method of Test for Passing Ability of Self-Consolidating Concrete (SCC) by J-Ring AASHTO Designation: T 345-12 (2016)1 Release: Group 1 (April 2016) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3b T 345

2、-1 AASHTO Standard Method of Test for Passing Ability of Self-Consolidating Concrete (SCC) by J-Ring AASHTO Designation: T 345-12 (2016)1Release: Group 1 (April 2016) 1. SCOPE 1.1. This test method covers determination of the passing ability (Note 1) of self-consolidating concrete (SCC) by the J-Rin

3、g method, both in the laboratory and in the field. SCC is defined as a highly workable concrete that can flow through densely reinforced or complex structural elements under its own weight without vibration and adequately fill voids without experiencing segregation or excessive bleeding. Note 1Passi

4、ng ability is defined as the ability of SCC to flow through openings such as the spaces between reinforcing bars without segregation or without aggregate blocking. Blocking is defined as the condition in which pieces of coarse aggregate combine to form elements large enough to obstruct the flow of t

5、he SCC between reinforcing bars or other obstructions in the concrete formwork. 1.2. The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equival

6、ents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.3. 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

7、 standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: R 60, Sampling Freshly Mixed Concrete T 119M/T 119, Slump of Hydraulic Cement Concrete T 347, Slump Flow of Self-Conso

8、lidating Concrete (SCC) 3. SUMMARY OF TEST METHOD 3.1. The J-Ring apparatus consists of a rigid ring connecting 100-mm 4-in. vertical smooth bars. The ring is held to a base plate and an inverted slump cone is placed in its center. A sample of freshly mixed SCC is allowed to flow from the inverted s

9、lump cone through the bars of the J-Ring apparatus. The final average diameter of the slump flow patty after flowing through the bars compared to the average slump flow measured without the J-Ring is a measure of the passing ability of the SCC, and the difference in height of the SCC inside and outs

10、ide of the ring provides an indication of blocking. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 345-2 AASHTO 4. SIGNIFICANCE AND USE 4.1. This test method is applicable to SCC, defined in Sec

11、tion 1.1. 4.2. This test method is intended to provide the user with a procedure to assess the passing ability without blocking of SCC. The test gives an indication of the ability of the SCC to flow around and between reinforcement without blocking. 4.3. This test method is applicable to SCC having

12、coarse aggregate up to 25 mm 1 in. 5. APPARATUS 5.1. J-Ring ApparatusThe J-Ring consists of a rigid ring connecting 100-mm 4-in. vertical smooth bars. The J-Ring shall be of dimensions shown in Figure 1, with tolerances as shown in Table 1. The J-Ring shall be made of steel or some other rigid, nona

13、bsorbent material not readily attacked by the cement paste. The 16 vertical round bars shall be spaced as shown in Figure 1 and of diameter of 16 mm 5/8in. Connections of the round bars to the ring may be of any type that provides sufficient rigidity to maintain consistent clear spacing between the

14、bars. Threaded, welded, or interference fit connections may be suitable, but care should be taken that heat deformation during welding does not deform the ring and lead to out-of-plumb bars with incorrect clear spacing. Figure 1J-Ring Dimensions 25 mm1 in.16 round bars,diameter = 16 mm 5/8 in.Steel

15、RingO.D. = 319 mm 129/16 in.I.D. = 281 mm 11 in.300 mm1113/16 in.22.543 mm 111/16 in.clear distance102 mm4 in. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 345-3 AASHTO Table 1J-Ring Dimension

16、s and Tolerances Dimension in. mm Ring diameter (centerline) 1113/16 1/8300 3.3 Ring width 19/16 1/1638 1.5 Bar diameter 5/8 1/3216 3.3 Bar spacing (clear distance) 111/16 1/3243 1.0 Ring thickness 1 1/1625 1.5 Bar length 4 1/4102 6.0 5.2. Slump Cone MoldThe SCC shall be placed in an inverted slump

17、cone mold conforming to the applicable requirements of T 119M/T 119. 5.3. Base PlateThe base plate shall be made of a stiff, nonabsorbing material, at least 820 mm 32 in. square and marked with both a circle indicating the central location for the slump cone and a concentric circle with a diameter o

18、f 500 mm 20 in. 5.4. Scoop. 5.5. Strike-off bar. 5.6. Tape measure containing increments of 6 mm 0.25 in. or less. 6. SAMPLING, TEST SPECIMENS, AND TEST UNITS 6.1. Approximately 6 L 0.2 ft3 of SCC is needed to perform the slump flow and J-Ring test, sampled normally. 6.2. The sample of concrete shal

19、l be obtained in accordance with R 60. 7. PROCEDURE 7.1. Moisten the base plate and the inside of the slump cone. 7.2. Place the base plate on a level, stable surface. Place the J-Ring centrally on the base plate and the inverted slump cone centrally inside it (Figure 2). 2016 by the American Associ

20、ation of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 345-4 AASHTO Figure 2J-Ring Test Apparatus 7.3. From the sample of concrete obtained in accordance with Section 6, fill the entire mold continuously. The mold shall be held f

21、irmly in place during filling. 7.4. Do not rod or tamp the SCC. Do not tap or vibrate the cone. 7.5. Use the strike-off bar to strike off the SCC level with the top of the cone. 7.6. Remove any spilled or struck-off SCC from around the base of the cone to preclude interference with the flowing SCC.

22、7.7. Raise the cone vertically 230 mm 75 mm 9 in. 3 in. above the base plate with no lateral or torsional motion within a time period of 3 s 1 s, and allow the SCC to flow out freely from within. Complete procedures in Sections 7.3 through 7.7 within 21/2min. 7.8. After the concrete flow has stopped

23、, measure the final diameter of the SCC in two perpendicular directions to the nearest 6 mm 0.25 in. (Note 2). The average of the two measured diameters is the slump flow in millimeters inches. Any border of mortar without coarse aggregate or a bleed water “halo” shall be included in the slump flow

24、diameter. Note 2Measure the largest diameter of the slump flow as one diameter and the perpendicular diameter as the second to ensure consistency between tests. If the two values differ in diameter by more than 51 mm 2 in., the test is considered invalid and must be repeated because it is likely tha

25、t the cone was raised with lateral motion. 7.9. Measure the height of the SCC just inside the ring at four locations to an accuracy of 6 mm 0.25 in. (heights are designated ha1through ha4). Measure the height of the SCC just outside the ring at four locations to an accuracy of 6 mm 0.25 in. (heights

26、 are designated hb1through hb4). A flat bar or tamping rod placed horizontally across the top of the J-Ring apparatus may be used as a reference to determine the height of the SCC. 7.10. Measure the difference in height between the slump flow patty at the center of the ring (h1) and just inside the

27、ring at four locations to accuracy of 6 mm 0.25 in. A flat bar or tamping rod placed horizontally across the top of the J-Ring apparatus may be used as a reference to determine the height of the SCC. 7.11. Conduct the slump flow test in accordance with T 347, using SCC from the same sample as used f

28、or this J-Ring test so the results of the J-Ring test may be compared with the results from the slump flow test. Base PlateInverted Slump ConeJ-Ring 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b

29、T 345-5 AASHTO 8. CALCULATION OF RESULTS 8.1. Calculate the average of the two measured diameters of the SCC patty after flowing through the J-Ring apparatus. This average value is the J-Ring flow. In general, greater J-Ring flow values indicate greater passing ability. 8.2. Calculate the average of

30、 the two measured diameters of the SCC after unrestricted flowing, without the J-Ring in place, by T 347. This average value is the slump flow. 8.3. Calculate the difference between the J-Ring flow and the slump flow. This value is an indication of the passing ability of the SCC. A difference of les

31、s than 25 mm 1 in. indicates good passing ability, and a difference greater than 51 mm 2 in. indicates poor passing ability. 8.4. Calculate the average of the four measured heights inside the ring as hamand calculate the average of the four measured heights outside the ring as hbm. Calculate the dif

32、ference in mean heights between the inside and the outside of the J-Ring as hab= (ham hbm). 8.5. Calculate the difference between the height of the SCC at the center of the ring and the mean height of the SCC inside the ring as (h1 ham). 8.6. Calculate the J-Ring test value, J, as 2(hab) (h1 ham). A

33、 J-Ring test value less than 15 mm 0.6 in. indicates satisfactory passing ability without blockage. 9. REPORT 9.1. Record the J-Ring flow to the nearest 6 mm 0.25 in. 9.2. Record the slump flow (without the J-Ring in place) measured by T 347. 9.3. Record the difference between the J-Ring flow and th

34、e slump flow to the nearest 6 mm 0.25 in. 9.4. Record hab= (ham hbm), the difference in mean heights between the inside and the outside of the J-Ring, to the nearest 6 mm 0.25 in. 9.5. Record (h1 ham), the average of the four measured differences in height between the SCC at the center of the ring a

35、nd the SCC just inside the bars, to the nearest 6 mm 0.25 in. 9.6. Record the J-Ring test value, 2(hab) (h1 ham), to the nearest 6 mm 0.25 in. 10. PRECISION AND BIAS 10.1. No precision and bias statements are available at this time. 11. KEYWORDS 11.1. Flowability; passing ability; reinforcement; SCC; self-consolidating concrete; workability. 1Formerly AASHTO Provisional Standard TP 74. First published as a full standard in 2012. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.