1、Standard Method of Test for Aggregate Durability Index AASHTO Designation: T 210-151 ASTM Designation: D3744/D3744M-11a American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1c T 210-1 AASHTO Standard Method of Test for
2、Aggregate Durability Index AASHTO Designation: T 210-151ASTM Designation: D3744/D3744M-11a 1. SCOPE 1.1. This method describes the procedure for determining the durability of aggregates. The durability index is a value indicating the relative resistance of an aggregate to produce detrimental claylik
3、e fines when subjected to the prescribed mechanical methods of degradation. 1.2. The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3. This standard may involve hazardous materials, operations, and equipment. This standard do
4、es not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AA
5、SHTO Standards: M 92, 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 27, Sieve Analysis of Fine and Coarse Aggregates T 85, Specific Gravity and Absorption o
6、f Coarse Aggregate T 176, Plastic Fines in Graded Aggregates and Soils by Use of the Sand Equivalent Test T 248, Reducing Samples of Aggregate to Testing Size 2.2. ASTM Standard: C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials 3. SUMMAR
7、Y OF METHOD 3.1. This method was developed to permit prequalification of aggregates proposed for use in the construction of transportation facilities. The test establishes an aggregates resistance to generating fines when agitated in the presence of water. Separate and different test procedures are
8、used to evaluate the coarse and the fine portions of a material. 3.2. A sample of coarse aggregate is prepared to a specific grading and then washed in a mechanical washing vessel for a 2-min agitation time. After discarding the minus 4.75-mm (No. 4) material, the washed test sample is dried and pre
9、pared to the final test grading. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 210-2 AASHTO 3.3. The coarse aggregate test sample is then agitated in the mechanical washing vessel for a period
10、of 10 min. A representative portion of the resulting wash water and minus 75-m (No. 200) size fines are collected and mixed with a stock calcium chloride solution and placed in a plastic cylinder. After a 20-min sedimentation time, the level of the sediment column is read. The height of the sediment
11、 value is then used to calculate the durability index of the coarse aggregate (Dc). 3.4. The fine aggregate sample is prepared by washing a specific quantity of the material in the mechanical washing vessel for a 2-min agitation period. All minus 75-m (No. 200) size material is washed from the sampl
12、e through a 75-m (No. 200) sieve and discarded. The plus 75-m (No. 200) fraction is dried. 3.5. The fine aggregate test sample is tested by T 176 except for a modification to the duration of the shaking time. The mechanical shaker method is required. A shaking time of 10 min instead of 45 s is used.
13、 3.6. This method includes procedures for testing aggregates exhibiting a wide range in specific gravity, including lightweight and porous coarse aggregates, and also procedures for testing small maximum-size aggregate that is too fine to test as a coarse aggregate and too coarse to consider as a fi
14、ne aggregate, such as a pea gravel or a very coarse sand. 3.7. The durability index for coarse aggregate (Dc) or for fine aggregate (Df) is calculated, as applicable, by appropriate equations presented in the method. The durability index of a well-graded aggregate containing both coarse and fine fra
15、ctions is defined as the lowest of the two values, Dcor Df, obtained by the test. This value is recommended to be the controlling value for specification purposes. 4. SIGNIFICANCE AND USE 4.1. This test assigns an empirical value to the relative amount, fineness, and character of claylike material t
16、hat may be generated in an aggregate when subjected to mechanical degradation. 4.2. The procedure has been used in limited geographical areas of the United States and the results have been correlated with aggregate performance in various construction applications, including: aggregate base, permeabl
17、e material for backfill, fine concrete aggregate, and riprap for rock slope protection.2,34.3. A minimum durability index is permitted to be specified to prohibit the use of an aggregate that is prone to degradation and will result in generation of claylike fines in various construction applications
18、. 4.4. This method provides a rapid test for evaluation of the quality of a new aggregate source. Research has indicated it may also be suitable for use instead of the sodium sulfate soundness test for evaluating the durability characteristics of fine aggregate for use in portland cement concrete, t
19、hereby reducing the need for time-consuming and expensive soundness tests.24.5. Although the application of this method has been limited to aggregates for specific construction uses, the possibility exists for expanding the application of this method to control the quality of aggregates used in othe
20、r areas of construction, such as aggregates for use in bituminous paving mixtures, coarse aggregate for use in portland cement concrete, and aggregate for use as railroad ballast. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a vio
21、lation of applicable law.TS-1c T 210-3 AASHTO 5. APPARATUS 5.1. Mechanical Washing Vessel (Pot)A flat-bottomed, straight-sided cylindrical vessel conforming to the specifications and dimensions shown in Figure 1. Dimensional Equivalents mm in. mm in. mm in. 242.1 917/32199.2 727/326.4 1/4219.1 85/88
22、8.9 31/21.6 1/16216.3 833/6463.5 21/20.8 1/32200.8 729/3219.0 3/40.40 1/64200.0 77/814.3 9/16Notes: 1. The gasket will be 3.2-mm (1/8-in.) neoprene rubber, having an inside diameter of 199.23 0.40 mm (727/32 1/64in.) and an outside diameter of 216.30 0.40 mm (833/64 1/64in.). 2. The pot shall be a f
23、lat bottom, straight-sided, cylindrical vessel with a capacity of approximately 7 L (2 gal). The top edge shall be flared outward to form a seal for the gasket and lid. 3. Three trunk clamps are required and shall be placed at one-third intervals. The clamps shall be attached to the pot by rivets or
24、 welds so that the pot remains watertight. When fitted with the 3.2-mm (1/8-in.) gasket and clamped in place, the lid shall form a watertight seal with the flared edge of the pot. 4. The vessel shall be 0.9-mm (20-gauge) stainless steel, unless otherwise noted. All dimensions shall be within 0.8 mm
25、(1/32in.), unless otherwise noted. 5. The bottom side inside radius shall be no larger than 6.4 mm (1/4in.) with an allowable tolerance of 0.8 mm (1/32in.). Figure 1Mechanical Washing Vessel 5.2. Collection PanA round pan at least 250 mm (10 in.) in diameter and at least 100 mm (4 in.) deep, suitabl
26、e to collect the wash water from the washed sample. The pan shall have vertical or nearly vertical sides and shall be equipped as necessary to hold the wire mesh of a 203-mm (8-in.) diameter sieve at least 76 mm (3 in.) above the bottom. An adaptor that will not allow loss of fines Handle 1.6 mm bel
27、owedge of Lid Lid19.0 mm1.6 mmGasket(See Note 1.)Pot(See Note 2.)Trunk Clamps(See Note 3.)4.3 mm63.5 mm88.9 mm200 0.40 mm219.1 mm200.8 mm242.1 mm219.1 mm6.5-mm R(See Note 5.) 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violatio
28、n of applicable law.TS-1c T 210-4 AASHTO or wash water may be used to nest the sieve with the container, or the sieve may be nested with a blank sieve frame resting in the bottom of the pan. 5.3. AgitatorA mechanical device designed to hold the wash vessel in an upright position while subjecting it
29、to a lateral reciprocating motion at a rate of 285 10 complete cycles per minute. The reciprocating motion shall be produced by means of an eccentric in the base of the carrier and the length of the stroke shall be 45 0.6 mm (1.75 0.25 in.). The clearance between the cam and follower of the eccentri
30、c shall be 0.25 to 1.02 mm (0.001 to 0.004 in.). 5.4. All equipment required to perform T 176. 5.5. SievesThe sieves shall conform to M 92. 5.6. BalanceConforming to the requirements of M 231, Class G 2. 6. REAGENTS AND MATERIALS 6.1. Calcium chloride solutions-use stock and working calcium chloride
31、 solutions as specified in Section 7 of T 176. 6.2. Water: Use distilled or demineralized water for the normal performance of this method. The test results are likely to be affected by certain minerals dissolved in water. However, if it is determined that local tap water is of such purity that it do
32、es not affect the test results, the use of tap water is permissible in place of distilled or demineralized water. For referee purposes, distilled or demineralized water shall be used for all steps in the test. 7. TEMPERATURE CONTROL 7.1. This test is normally performed without strict temperature con
33、trol; however, for referee purposes, retest the material with the temperature of the distilled or demineralized water and the working calcium chloride solution at 22 3C (72 5F). 8. SAMPLING 8.1. Obtain samples of the aggregate to be tested in accordance with T 2. 9. INITIAL SAMPLE PREPARATION 9.1. D
34、ry aggregate samples sufficiently to permit a complete separation on the 4.75-mm (No. 4) sieve and to develop a free-flowing condition in the portion passing the sieve. Perform drying by any method that does not heat the aggregate in excess of 60C (140F) or cause degradation of the particles. The us
35、e of sunlight, ovens, or forced drafts of warm air are the most common drying methods. 9.2. If the sample contains an appreciable amount of clay, turn the aggregate frequently during the drying process to obtain even drying throughout and prevent the formation of hard clay lumps. 9.3. Break up any h
36、ard clods and remove coatings of fines from the coarse aggregate particles by any means that will not appreciably reduce the natural individual particle sizes. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable
37、 law.TS-1c T 210-5 AASHTO 9.4. Determine the sample grading by sieving in accordance with T 27 on the 19.0-, 12.5-, 9.5-, 4.75-, 2.36-, and 1.18-mm (3/4-, 1/2-, 3/8-in. and Nos. 4, 8, and 16) sieves. Discard any material that is retained on the 19.0-mm (3/4-in.) sieve. 9.5. Determine the test proced
38、ures to be used for establishing the durability index of the aggregate based upon the grading of the aggregate as determined in Section 9.4. 9.5.1. If less than 10 percent of the aggregate passes the 4.75-mm (No. 4) sieve, test coarse aggregate (Procedure A) only. 9.5.2. If less than 10 percent of t
39、he aggregate is coarser than the 4.75-mm (No. 4) sieve, test fine aggregate (Procedure B) only. 9.5.3. When both coarse and fine aggregate fractions are each present in quantities equal to or greater than 10 percent and if the percent passing the 1.18-mm (No. 16) sieve is greater than 10 percent, us
40、e both Procedures A and B on the appropriate aggregate sizes. If the percent passing the 1.18-mm (No. 16) sieve is less than or equal to 10 percent, use Procedure A or Procedure C. 9.5.4. If most of the aggregate (75 to 80 percent) is retained between the 9.5- and 1.18-mm (3/8-in. and No. 16) sieves
41、, use Procedure C only. PROCEDURE ACOARSE AGGREGATE 10. TEST SAMPLE PREPARATION 10.1. Prepare a 2550 25-g (air-dry) preliminary test sample using the grading given below: Aggregate Size Air Dry Mass, g 19.0 to 12.5 mm (3/4to 1/2in.) 1070 10 12.5 to 9.5 mm (1/2to 3/8in.) 570 10 9.5 to 4.75 mm (3/8in.
42、 to No. 4) 910 5 2550 25 For materials with less than 10 percent in any of the fractions specified in the above table, prepare the test specimen using the actual calculated percentage for the deficient fraction and proportionally increase the weights of the remaining fractions to obtain the 2550-g t
43、est specimen. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 210-6 AASHTO Example 1Less than 10 percent of 19.0- to 12.5-mm (3/4- to 1/2-in.) material in aggregate. Aggregate Sieve Size Percent
44、Each Size Calculations Air Dry Weight, g 19.0 to 12.5 mm (3/4in. to 1/2in.) 6 0.06 2550 153 10 12.5 to 9.5 mm (1/2in. to 3/8in.) 36 ( )570 2550 153570 910+923 10 9.5 to 4.75 mm (3/8in. to No. 4) 58 ( )910 2550 153570 910+1474 5 Totals 100 2550 25 Example 2Less than 10 percent of 19.0- to 12.5-mm (3/
45、4- to 1/2-in.) and 12.5- to 9.5-mm (1/2- to 3/8-in.) material in aggregate. Aggregate Sieve Size Percent Each Size Calculations Air Dry Weight, g 19.0 to 12.5 mm (3/4in. to 1/2in.) 4 0.04 2550 102 10 12.5 to 9.5 mm (1/2in. to 3/8in.) 7 0.07 2550 179 10 9.5 to 4.75 mm (3/8in. to No. 4) 89 2550 (102 +
46、 179) 2269 5 Totals 100 2550 25 Example 3No 19.0- to 12.5-mm (3/4- to 1/2-in.) material in aggregate. Aggregate Sieve Size Percent Each Size Calculations Air Dry Weight, g 19.0 to 12.5 mm (3/4in. to 1/2in.) None present 0 2550 0 12.5 to 9.5 mm (1/2in. to 3/8in.) 39 ( )570 2550 0570 910+982 10 9.5 to
47、 4.75 mm (3/8in. to No. 4) 61 ( )910 2550 0570 910+1568 10 Totals 100 2550 25 Dry the preliminary test sample to constant mass at a temperature of 110 5C (230 9F), allow to cool, and determine the mass. Record the resulting mass, W. Note 1If an adjustment of the test specimen mass or volume of wash
48、and test water (Section 10.3), or both, is not required, it is not necessary to oven-dry the test sample prior to the initial wash. 10.2. Place the preliminary test sample in the mechanical washing vessel, and add 1000 5 mL of distilled or demineralized water. Note 2Sections 10.3 through 10.3.4 are
49、only necessary if the preliminary test sample is not completely inundated after the specified amount of water is added to the washing vessel pot. 10.3. Because of the low specific gravity or high absorption rate, or both, of some aggregates, the proportions of aggregate to water will not provide the intended interparticle abrasion. Testing of these materials will require adjustment of the test specimen mass or volume of both wash and test water, or both. 1
