AASHTO TP 57-06 pdf free download
AASHTO TP 57-06 pdf free download.The Qualitative Detection of Harmful Clays of the Smectite Group in Aggregates Using Methylene Blue.
1. SCOPE
1.1. The purpose of this standard is to identify the presence of harmful clays of the smectite group (poor quality 75-tm material) and to provide an indication of the surface activity of the aggregate.
1 .2. This standard mar involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. Ills the responsibility of the user of this procedure to establish appropriate sa/?tV and health practices and to determine the applicability of regulatory limitations prior to use.
2. REFERENCED DOCUMENTS
2.1. AASIITO Standard:
• M 231, Weighing Devices Used in the Testing of Materials
3. SUMMARY OF TEST METHOD
3.1. Methylene Blue solution is titrated into distilled water containing sample material passing the
75-rim (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 sample 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 large value for Methylene Blue Value indicates a large amount of clay or organic material present in the sample.
Note 1—Research (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.)
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 cabinet at lab temperature.
Note 2—One gram of Methylene Blue is dissolved in enough distilled water to produce 200 mL of solution, with each one rnL of solution containing 5 mg of Methylene Blue.
5.11. Distilled water at lab temperature.
5.12. Oven capable of maintaining 110 ± 5°C (230 ± 9°F).
Note 3—For the purposes of this procedure, lab temperature is defined as 15—25°C (60—77°F).
6. SAMPLE PREPARATION
6.1. This test shall be performed on a sample of material passing the 75iirn (No. 200) sieve, taken from the washed portion of a representative sample of individual or combined material (as required). The material shall be washed through the 75-rim (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-rim (No. 200) sieve. Allow the material to settle and remove the excess water. The portion passing the 75-.im (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 ovendry mass of the collected material shall be at least 30 g to ensure enough material for a possible retest.
7. PROCEDURE
7.1. Place 10.0 g (±0.05 g) of the minus 75-.tm (No. 200) material that has been dried to constant mass and place in a 500-rnL griffin beaker.
7.2. Add 30 mL of distilled water and stir with the mixer to make a slurry.
7.3. With the slurry still mixing, fill the burette with the Methylene Blue solution, add 0.5 mL of the solution to the slurry, and stir for one minute.AASHTO TP 57-06 pdf download.
