AASHTO T 335-2009 Standard Method of Test for Determining the Percentage of Fracture in Coarse Aggregate《测定粗集料断裂百分比的标准试验方法》.pdf

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1、Standard Method of Test for Determining the Percentage of Fracture in Coarse Aggregate AASHTO Designation: T 335-09 (2013)1American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1c T 335-1 AASHTO Standard Method of Test f

2、or Determining the Percentage of Fracture in Coarse Aggregate AASHTO Designation: T 335-09 (2013)11. SCOPE 1.1. This test method covers the determination of the percentage, by mass, of a coarse aggregate sample that consists of fractured particles meeting specified requirements. 1.2. This standard m

3、ay involve hazardous materials, operations, and equipment. 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 appropriate safety and health practices and determine the applicability of regul

4、atory limitations prior to use. 1.3. The text of the standard reference notes provides explanatory material. These notes (excluding those in tables and figures) shall not be considered as requirements of the standard. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 92, Wire-Cloth Sieves for Testing

5、 Purposes M 231, Weighing Devices Used in the Testing of Materials T 2, Sampling of Aggregates T 11, Materials Finer Than 75-m (No. 200) Sieve in Mineral Aggregates by Washing T 27, Sieve Analysis of Fine and Coarse Aggregates T 248, Reducing Samples of Aggregate to Testing Size T 255, Total Evapora

6、ble Moisture Content of Aggregate by Drying 3. SUMMARY OF TEST METHOD 3.1. A sample of aggregate is separated using the designated size of screen conforming to the specification controlling the determination of coarse and fine aggregate. The coarse aggregate particles are visually evaluated to deter

7、mine their conformance to the defined fracture. The percentage of conforming particles, by mass, is determined for comparison to standard specifications. 4. APPARATUS 4.1. BalanceMeeting the requirements of M 231 for general-purpose balance required for the principal sample mass being tested. 2015 b

8、y the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 335-2 AASHTO 4.2. SievesMeeting the requirements of M 92. 4.3. SplitterMeeting the requirements of T 248. 5. TERMINOLOGY 5.1. Definitions: 5.1.1. fractur

9、ed facean angular, rough, or broken surface of an aggregate particle created by crushing, or by other means. A face is considered a “fractured face” whenever one-half or more of the projected area, when viewed normal to that face, is fractured with sharp and well-defined edges (this excludes small n

10、icks). 5.1.2. fractured particlea particle of aggregate having at least the minimum number of fractured faces specified (usually one or two). 6. SAMPLING 6.1. Sample the aggregate in accordance with T 2 and reduce the sample in accordance with T 248. 7. SAMPLE PREPARATION 7.1. Where the specificatio

11、ns list only a total fracture percentage, the sample shall be prepared in accordance with Method 1. When the specifications require that the fracture be counted and reported on each sieve, the sample shall be prepared in accordance with Method 2. 7.2. Method 1Combined Fracture Determination: 7.2.1.

12、Dry the sample sufficiently to obtain a clean separation of fine and coarse material in the sieving operation. Sieve the sample in accordance with T 27 over the 4.75-mm (No. 4) sieve, or the appropriate sieve listed in the agency specifications for this material. Note 1Where necessary, wash the samp

13、le over the sieve designated for the determination of fractured particles to remove any remaining fine material and dry the sample to a constant mass in accordance with T 255. 7.2.2. Reduce the sample using a splitter in accordance with T 248 to the appropriate size for test. This size of test sampl

14、e should be slightly larger in mass than that shown in Table 1 to account for additional loss of fines after washing. Table 1Sample Size (Method 1, Combined Sieve Fracture) Nominal Maximum Particle Size Minimum Sample Mass Retained 4.75-mm (No. 4) Sieve 37.5 mm (11/2in.) 25.0 mm (1 in.) 2500 g (6 lb

15、) 1500 g (3.5 lb) 19.0 mm (3/4in.) 1000 g (2.2 lb) 12.5 mm (1/2in.) 700 g (1.5 lb) 9.5 mm (3/8in.) 400 g (0.9 lb) 4.75 mm (No. 4) 200 g (0.5 lb) 7.3. Method 2Individual Sieve Fracture Determination: 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. D

16、uplication is a violation of applicable law.TS-1c T 335-3 AASHTO 7.3.1. Dry the sample sufficiently to obtain a clean separation of fine and coarse material in the sieving operation. A washed sample from the gradation determination (T 11 and T 27) may be used. If not, sieve the sample in accordance

17、with T 27 over the appropriate sieves listed in the specifications for this material. Select a representative portion from each sieve by splitting or quartering in accordance with T 248 to the appropriate size for testing. This size of test sample for each sieve should be at least as large as shown

18、in Table 2. Table 2Sample Size (Method 2, Individual Sieve Fracture) Nominal Maximum Particle Size Minimum Sample Mass Retained 4.75-mm (No. 4) Sieve 31.5 mm (11/4in.) 1500 g (3.5 lb) 25.0 mm (1 in.) 1000 g (2.2 lb) 19.0 mm (3/4in.) 700 g (1.5 lb) 16.0 mm (5/8in.) 500 g (1.0 lb) 12.5 mm (1/2in.) 300

19、 g (0.7 lb) 9.5 mm (3/8in.) 200 g (0.5 lb) 6.3 mm (1/4in.) 100 g (0.2 lb) 4.75 mm (No. 4) 100 g (0.2 lb) 2.36 mm (No. 8) 25 g (0.1 lb) 2.00 mm (No. 10) 25 g (0.1 lb) Note 2Where necessary, wash the sample over the sieves designated for the determination of fractured particles to remove any remaining

20、 fine material and dry the sample to a constant mass in accordance with T 255. Note 3If fracture is determined on a sample obtained for gradation, use the mass retained on the individual sieves unless less than 5 percent of the total mass is retained on that sieve. In that case, place the material w

21、ith that retained on the next smaller sieve size. If a smaller specification sieve does not exist, this material shall not be included in the fracture determination. 8. PROCEDURE 8.1. Spread the dried, cooled test sample on a clean flat surface large enough to permit careful inspection of each parti

22、cle. To verify that a particle meets the fracture criteria, hold the aggregate particle so that the face is viewed directly. (See Section 5.1.) 8.2. To aid in making the fracture determination, separate the sample into three categories: (1) fractured particles meeting the above criteria, (2) particl

23、es not meeting specification criteria, and (3) questionable or borderline particles. 8.3. Determine the mass of particles in the fractured category, the mass of questionable particles, and the mass of the unfractured particles. 8.4. If on any of the determinations more than 15 percent of the total m

24、ass of the sample is placed in the questionable category, repeat the determination until no more than 15 percent is present in that category. 9. REPORT 9.1. Report the following information: 9.1.1. Calculate the mass percentage of fracture faces to the nearest 1 percent as follows: 2015 by the Ameri

25、can Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 335-4 AASHTO 2100QFPFQN+= +(1) where: P = percentage of fracture, F = mass of fractured particles, Q = mass of questionable or borderline particles, and N = mass of

26、 unfractured particles. 10. PRECISION AND BIAS 10.1. No precision data is available using this method. 1Formerly AASHTO Provisional Standard TP 61. First published as a full standard in 2009. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.