1、Standard Method of Test for The Qualitative Detection of Harmful Clays of the Smectite Group in Aggregates Using Methylene Blue AASHTO Designation: T 330-07 (2015)1American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1c
2、 T 330-1 AASHTO Standard Method of Test for The Qualitative Detection of Harmful Clays of the Smectite Group in Aggregates Using Methylene Blue AASHTO Designation: T 330-07 (2015)11. SCOPE 1.1. The purpose of this standard is to identify the presence of harmful clays of the smectite group (poor minu
3、s 75-m material) and to provide an indication of the surface activity of the aggregate. 1.2. This standard may 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
4、 this procedure to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standard: M 231, Weighing Devices Used in the Testing of Materials 3. SUMMARY OF TEST METHOD 3.1. Methylene Blue solutio
5、n is titrated in increments into distilled water containing sample material passing the 75-m (No. 200) sieve in increments. A small amount of water containing the sample material and titrated Methylene Blue is removed via a glass rod and dropped onto filter paper. When the clay fraction of the sampl
6、e aggregate can no longer absorb more Methylene Blue, a blue ring is formed on the filter paper. 4. SIGNIFICANCE AND USE 4.1. The Methylene Blue Value determined by this standard can be used to estimate the amount of harmful clays and organic matter present in an aggregate. A high value for Methylen
7、e Blue Value indicates a large amount of clay or organic material present in the sample. Note 1Research (Aschenbrener, 1992) has developed the following relationship of methylene blue values and anticipated hot mix asphalt pavement performance as related to moisture susceptibility. (See Table 1.) 20
8、15 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 330-2 AASHTO Table 1Expected Performance of Methylene Blue Methylene Blue (mg/g) Expected Performance 6 Excellent 712 Marginally acceptable 1319 Prob
9、lems/possible failures 20 Failure 5. APPARATUS 5.1. Amber-colored buret of at least 50-mL capacity with 0.1-mL graduations. 5.2. Magnetic mixer with stir bar. 5.3. Balance complying with M 231, Class G1. 5.4. Glass rod of approximately 250-mm (10-in.) length and approximately 8-mm (0.3-in.) diameter
10、 5.5. Timer or stopwatch. 5.6. Pan and 75-m (No. 200) sieve. 5.7. Volumetric flask of 1000-mL capacity. 5.8. Whatman No. 2 filter paper. 5.9. Three 500-mL griffin beakers. 5.10. Methylene Blue, reagent grade-dated and stored for no more than four months in a brown bottle wrapped with foil in a dark
11、 cabinet at lab temperature. Note 2One gram of Methylene Blue is dissolved in enough distilled water to produce 200 mL of solution, with each 1 mL of solution containing 5 mg of Methylene Blue. 5.11. Distilled water at lab temperature. 5.12. Oven capable of maintaining 110 5C (230 9F). Note 3For the
12、 purposes of this procedure, lab temperature is defined as 15 to 25C (60 to 77F). 6. SAMPLE PREPARATION 6.1. This test shall be performed on a sample of material passing the 75-m (No. 200) sieve, taken from the washed portion of a representative sample of individual or combined material (as required
13、). The material shall be washed through the 75-m (No. 200) sieve and collected in a clean container. This container shall be large enough to hold several gallons of water and material passing the 75-m (No. 200) sieve. Allow the material to settle and remove the excess water. The portion passing the
14、75-m (No. 200) sieve is collected, transferred to a smaller container, and dried for testing. The collected material is mixed thoroughly prior to testing. The minimum oven-dry mass of the collected material shall be at least 30 g to ensure enough material for a possible retest. 2015 by the American
15、Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 330-3 AASHTO 7. PROCEDURE 7.1. Place 10.0 g (0.05 g) of the minus 75-m (No. 200) material that has been dried to constant mass in a 500-mL griffin beaker. 7.2. Add 30 m
16、L of distilled water and stir with the mixer to make a slurry. 7.3. With the slurry still mixing, fill the buret with the Methylene Blue solution, add 0.5 mL of the solution to the slurry, and stir for 1 min. 7.4. Remove a drop of the slurry, using the glass stirring rod, and place on the filter pap
17、er. 7.5. Observe the appearance of the drop on the filter paper. The end point is indicated by the formation of a light blue halo around the drop. Continue adding the Methylene Blue solution to the slurry in 0.5-mL increments with 1-min stirring after each addition, then testing, until the end point
18、 is reached. 7.6. After the end point is reached, continue stirring for 5 min and retest. Note 4With experience, the person performing the test can reach the end point more quickly by skipping early increments. 8. CALCULATION 8.1. Example: M CV W= (1) where: M = Methylene Blue Value in mg of solutio
19、n per g of the minus 75-m (No. 200) material; C = mg of Methylene Blue/mL of solution; V = mL of Methylene Blue solution required for titration; and W = grams of dry material. 8.2. The calculation may be simplified by inserting the mg of Methylene Blue per mL of solution and the grams of dry materia
20、l. ( )5 10MV= (2) 05M .V= (3) 9. REPORT 9.1. The report shall include the following: 9.1.1. Type and source of the material tested, and 9.1.2. Methylene Blue value to the nearest 0.1 mg/g. 10. PRECISION AND BIAS 10.1. PrecisionNo precision has been established for this test. 10.2. BiasNo bias can be
21、 established because no reference material is available for this test. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 330-4 AASHTO 11. KEYWORDS 11.1. Clay and organic material; fine aggregate; m
22、ethylene blue; moisture susceptibility. 12. REFERENCES 12.1. Aschenbrener, T. “Comparison of Colorado Component Hot Mix Asphalt Materials with Some European Specifications.” In Research Report CDOT-DTD-R-92-14. Colorado Department of Transportation, Denver, CO, December 1992, p. 65. 12.2. Aschenbren
23、er, T. and R. Zamora. “Evaluation of Specialized Tests for Aggregates Used in Hot Mix Asphalt Pavements in Colorado.” In Transportation Research Record 1486. Transportation Research Board Business Office, Washington, DC, January 1995, pp. 130136. 12.3. Aschenbrener, T., R. Terrel, and R. Zamora. “Co
24、mparison of the Hamburg Wheel Tracking Device and the Environmental Conditioning System to Pavements of Known Stripping Performance.” In Research Report CDOT-DTD-R-94-1. Colorado Department of Transportation, Denver, CO, January 1994, p. 110. 1Formerly AASHTO Provisional Standard TP 57. First published as a full standard in 2007. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
