1、Standard Method of Test for Lightweight Pieces in Aggregate AASHTO Designation: T 113-151ASTM Designation: C123/C123M-12 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1c T 113-1 AASHTO Standard Method of Test for
2、 Lightweight Pieces in Aggregate AASHTO Designation: T 113-151ASTM Designation: C123/C123M-12 1. SCOPE 1.1. This method covers the determination of the percentage of lightweight pieces in aggregate by means of sink-float separation in a heavy liquid of suitable specific gravity. 1.2. The values stat
3、ed in SI units are to be regarded as the standard. 1.3. This standard involves hazardous materials, operations, or equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate s
4、afety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see Note 1. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 6, Fine Aggregate for Hydraulic Cement Concrete M 80, Coarse Aggregate for Hydraulic Cement Concrete M 92,
5、Wire-Cloth Sieves for Testing Purposes M 231, Weighing Devices Used in the Testing of Materials R 16, Regulatory Information for Chemicals Used in AASHTO Tests T 2, Sampling of Aggregates T 84, Specific Gravity and Absorption of Fine Aggregate T 85, Specific Gravity and Absorption of Coarse Aggregat
6、e T 248, Reducing Samples of Aggregate to Testing Size 2.2. ASTM Standards: D3665, Standard Practice for Random Sampling of Construction Materials E100, Standard Specification for ASTM Hydrometers 3. SIGNIFICANCE AND USE 3.1. This method is used to determine conformance with provisions of M 6 and M
7、80 pertaining to the amount of lightweight material in fine and coarse aggregates. A heavy liquid with a specific gravity of 2.0 is used to separate particles, which may be classified as coal or lignite. Heavier liquids are used to check the percentages of other lightweight pieces, such as chert hav
8、ing a specific gravity less than 2.40. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 113-2 AASHTO 3.2. The method is useful in identifying porous aggregate particles in research activities or i
9、n petrographic analyses. 4. APPARATUS 4.1. BalanceThe balance shall have sufficient capacity, be readable to 0.1 percent of the sample mass, or better, and conform to the requirements of M 231. 4.2. Containers suitable for drying the aggregate sample, and containers suitable for holding the heavy li
10、quid during the sink-float separation. 4.3. SkimmerA piece of 300-m (No. 50) sieve cloth, conforming to M 92, of suitable size and shape for separating the floating pieces from the heavy liquid. 4.4. Hot Plate or OvenOf appropriate size capable of maintaining a uniform temperature of 110 5C (230 9F)
11、. 4.5. Sieves300-m (No. 50) and 4.75-mm (No. 4) conforming to M 92. 4.6. Specific Gravity MeasurementA hydrometer conforming to the physical requirement sections for individual hydrometers of ASTM E100 or a suitable combination of graduated glassware and balance, capable of measuring the liquid spec
12、ific gravity within 0.01. 5. HEAVY LIQUID 5.1. The heavy liquid shall be able to achieve the required specific gravity and be readily removable from the sample. The heavy liquid shall consist of one of the following: (See Note 1.) 5.1.1. A solution of zinc chloride in water (for materials having a s
13、pecific gravity less than 2.0). 5.1.2. A mixture of kerosene with 1,1,2,2 tetrabromoethane, proportioned to produce desired specific gravities (1,1,2,2-tetrabromoethane has a specific gravity of about 2.95). 5.1.3. A solution of zinc bromide in water (for materials having a specific gravity less tha
14、n 2.6). 5.2. The specific gravity of the heavy liquid shall be maintained within 0.01 of the specified value at all times during the test. Note 1Caution: The chemicals listed in Section 5.1.2 are toxic, both by absorption through the skin and by inhalation. They shall be used only in a hood (prefera
15、bly of the downdraft type) or out-of-doors, and care shall be taken to avoid inhalation or contact with the eyes or skin. There is no particular hazard from the fumes of zinc chloride solution (Section 5.1.1) or zinc bromide solution (Section 5.1.3), but goggles and gloves shall be worn to prevent c
16、ontact with the eyes or skin. 1,1,2,2-tetrabromoethane is highly toxic and extremely dangerous to use and when heated emits highly toxic fumes of bromine, hydrogen bromide, and carbonyl bromide. It should be handled only by personnel trained and qualified in its use. Its storage should be in a secur
17、ed location, away from noncompatible chemicals. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 113-3 AASHTO 6. SAMPLING 6.1. Secure a field sample of the aggregate in accordance with T 2 and AST
18、M D3665. Reduce the sample to test portion size in accordance with T 248. 6.2. Dry the test portion to constant mass at a temperature of 110 5C (230 9F) before testing. The minimum size of the test specimen shall be as follows: Nominal Maximum Size of Aggregate (Square-Opening Sieves) Minimum Mass o
19、f Sample, g 4.75 mm (No. 4) 200 9.5 mm (3/8in.) 1500 19.0 mm (3/4in.) 3000 37.5 mm (11/2in.) 5000 75 mm (3 in.) 10000 If the nominal maximum size of the aggregate to be tested is not listed above, the next largest size shall be used to determine the sample size. 7. PROCEDURE 7.1. Fine AggregateAllow
20、 the dried test specimen of fine aggregate to cool to room temperature and then sieve over a 300-m (No. 50) sieve until less than 1 percent of the retained material passes the sieve in 1 min of continuous sieving. Determine the mass of the material coarser than the 300-m sieve to the nearest 0.1 g a
21、nd bring this material to a saturated surface-dry condition (Note 2) by means of the procedure specified in T 84 (Section 7.1.1), then introduce it into the heavy liquid (Note 1) in a suitable container. The volume of liquid shall be at least three times the absolute volume of the aggregate. Pour th
22、e liquid, including the floating pieces, into a second container, passing it through the skimmer, taking care that only the floating pieces are poured off with the liquid and that none of the fine aggregate that sinks is decanted onto the skimmer. Return to the first container the liquid that has be
23、en collected in the second container and, after further agitation of the sample by stirring, repeat the decanting process just described until the specimen is free of floating pieces. Wash the decanted pieces contained on the skimmer in an appropriate solvent to remove the heavy liquid. Alcohol is a
24、ppropriate for 1,1,2,2-tetrabromoethane and water for the zinc chloride and zinc bromide solutions. After the decanted pieces have been washed allow them to dry (Section 7.1.2). Brush the dry decanted pieces from the skimmer onto the balance pan and determine the mass to the nearest 0.1 g. If more p
25、recise determination is required, the decanted particles shall be dried to constant mass at 110 5C to determine the value of W1used for the calculation in Section 8.1. (See Section 7.1.3.) 7.1.1. If the absorption as determined in accordance with T 84 is known, the fine aggregate is permitted to be
26、prepared for test by adding to a known mass of dry sand the amount of water it will absorb, mixing thoroughly, and permitting the sand to stand in a covered pan for 30 min before use. 7.1.2. Drying shall take place in the hood or out-of-doors if other than zinc chloride or zinc bromide is used. An o
27、ven or hot plate is permitted to be used to accelerate the drying providing that it is done in the hood or that the oven is forced-air ventilated and that a temperature of 115C is not exceeded. 7.1.3. Normally the discrepancy between oven-dry mass and saturated surface-dry mass of the decanted parti
28、cles will not significantly affect the calculated percentage of lightweight pieces. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 113-4 AASHTO 7.2. Coarse AggregateAllow the dried test specimen
29、 of coarse aggregate to cool to room temperature and sieve over a 4.75-mm sieve. Determine the mass of the material coarser than the No. 4 sieve to the nearest 1 g, and bring to a saturated surface-dry condition (Note 2) by means of the procedure specified in T 85; then introduce it into the heavy l
30、iquid in a suitable container. The volume of liquid shall be at least three times the absolute volume of the aggregate. Using the skimmer, remove the pieces that float to the surface, and save them. Repeatedly agitate the remaining pieces, and remove the floating pieces until no additional pieces ri
31、se to the surface. Wash the pieces that are skimmed off in an appropriate solvent to remove the heavy liquid (see Section 7.1). After the heavy liquid has been removed, allow the pieces to dry (Section 7.1.2). Determine the mass of the decanted pieces to the nearest 1 g. If a more precise determinat
32、ion is required, dry the particles to constant mass at 110 5C to determine the value of W1used for the calculation in Section 8.1. (See Section 7.1.3.) Note 2If material undergoes degradation in water, the material does not have to be brought to a saturated surface-dry condition. 8. CALCULATION 8.1.
33、 Calculate the percentage of lightweight pieces (pieces floating on the heavy liquid) as follows: For fine aggregate: ( )12100L WW= (1) For coarse aggregate: ( )13100L WW= (2) where: L = percentage of lightweight pieces, W1= dry mass of pieces that float, W2= dry mass of portion of specimen coarser
34、than 300-m (No. 50) sieve, and W3= dry mass of portion of specimen coarser than the 4.75-mm (No. 4) sieve. 9. REPORT 9.1. The report shall include the following: 9.1.1. The mass of the test sample used. 9.1.2. Identification of the aggregate as to source, type, and nominal maximum size. 9.1.3. Type
35、and specific gravity of heavy liquid used for the test. 9.1.4. Percentage of lightweight pieces calculated to nearest 0.1 percent. 10. PRECISION AND BIAS 10.1. PrecisionNo interlaboratory or intralaboratory studies have been conducted using this test method to determine precision indices. The commit
36、tee is seeking pertinent data from users of the test method. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 113-5 AASHTO 10.2. BiasBias of the test method may be estimated by running separate sp
37、ecific gravity and absorption determinations on individual pieces of the separate sink, or float fractions, or both. 1Except for giving preference to SI units and Section 5, this test method is technically equivalent with ASTM C123/C123M-12. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
