AASHTO T11-20 pdf free download
AASHTO T11-20 pdf free download.MaterialsI FinerThan 75-um (No.200) Sieve in Mineral Aggregates by Washing.
3. SUMMARY OF METHOD
3.1. A sample of the aggregate is washed in a prescribed manner, using either plain water or water containing a wetting agent, as specified. The decanted wash water, containing suspended and dissolved material, is passed through a 75-p.m (No. 200) sieve. The loss in mass resulting from the wash treatment is calculated as mass percent of the original sample and is reported as the percentage of material finer than a 75-p.m (No. 200) sieve by washing.
4. SIGNIFICANCE AND USE
4.1. Material finer than the 75-p.m (No. 200) sieve can be separated from larger particles much more efficiently and completely by wet sieving than through the use of dry sieving. Therefore, when accurate determinations of material finer than 75 p.m in fine or coarse aggregate are desired, this test method is used on the sample prior to dry sieving in accordance with T 27. The results of this test method are included in the calculation in T 27, and the total amount of material finer than
75 urn by washing, plus that obtained by dry sieving the same sample, is reported with the results
of T 27. Usually the additional amount of material finer than 75 p.m obtained in the dry-sieving
process is a small amount. If it is large, the efficiency of the washing operation should be checked.
A large amount of material could also be an indication of the degradation of the aggregate.
4.2. Plain water is adequate to separate the material finer than 75 p.m from the coarser material in most aggregates. In some cases, the finer material is adhered to the larger particles, such as in some clay coatings and coatings on aggregates that have been extracted from bituminous mixtures. In these cases, the fine material will be separated more readily with a wetting agent in the water.
5. APPARATUS AND MATERIALS
5.1. Balance—The 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.
5.2. Sieves—A nest of two sieves, the lower being a 75-p.m (No. 200) sieve and the upper being a sieve with openings in the range of 2.36 mm(No. 8)to 1.18 mm(No. 16), both conforming to the requirement of ASTM El 1.
5.3. Container—A pan or vessel of a size sufficient to contain the sample covered with water and to permit vigorous agitation without loss of any part of the sample or water.
5.4. Oven—An oven of sufficient size, capable of maintaining a uniform temperature of 110 ± 5°C
(230 ± 9°F).
5.5. Wetting Agent—Any dispersing agent, such as liquid dishwashing detergents, that will promote separation of the fine materials.
5.6. Mechanical Washing Apparatus (Optiona!i—A mechanical apparatus that aids in the washing process.
8.2. If the applicable specification requires that the amount passing the 75-μm (No. 200) sieve shall be determined on a portion of the sample passing a sieve smaller than the nominal maximum size of the aggregate, separate the sample on the designated sieve and determine the mass of the material passing the designated sieve to 0.1 percent of the mass of this portion of the test sample. Use this mass as the original dry mass of the test sample in Section 10.1. Note 2- Some specifications for aggregates with a nominal maximum size of 50 mm or greater, for example, provide a limit for material passing the 75-um (No.200) sieve determined on that portion of the sample passing the 25.0-mm sieve. Such procedures are necessary because it is impractical to wash samples of the size required when the same test sample is to be used for sieve analysis by T 27. AASHTO T11-20 pdf download.
