DETERMINING THE AMOUNT OF MATERIAL

FINER THAN THE No. 200 (SIEVE IN AGGREGATE

SCOPE

This test method outlines the procedure for determining the quantity of material finer than a No. 200 sieve by washing and dry sieving.

PROCEDURE

A. Apparatus

1. A No. 200 sieve (wash sieve)

2. A wash pan large enough to prevent loss of water and material

3. Oven or drying stove

4. Balance accurate to 0.1 percent of the sample weight (mass)

5. A set of 8-in. or 12-in. diameter sieves for dry sieving

B. Test Sample

1. Select the test sample from the material to be tested by an appropriate method as outlined in Materials IM 336.

2. When determination of specification compliance is needed on each or any of the following sieves: No. 16, No. 30, No. 50, or No. 100, subject the entire sample to this test procedure.

3. When determination of specification compliance is needed for only the amount of material finer than the No. 200 sieve, reduce the remaining portion of the field sample from which the original test sample was selected, by the appropriate method as outlined in IM 336. A representative sample, sufficient to yield not less than the appropriate mass of dried material, as shown in the following table shall be selected:

Sieve Analysis

Sample Weight (Mass) kg                                Appropriate Minimum

(See Materials IM 301) Weight (Mass) kg of Sample

5.0 kg                                                              2.5 kg

3.5 kg                                                              2.5 kg

2.0 kg                                                              1.0 kg

1.5 kg                                                                   *

1.0 kg                                                                   *

0.5 kg                                                                   *

0.2 kg                                                                   *

*Use entire sample.

C. Test Procedure

1. Place the sample in the oven at 230˚F (110˚C) or on the stove and dry to a constant weight (mass). Care must be taken in drying the sample to avoid overheating causing the sample to “pop” or “sputter.”

2. Allow the sample to cool, weigh and record as the Original Dry weight (mass).

3. Place the sample in the wash pan and add a sufficient amount of water to cover it. A detergent, dispersing agent, or other wetting solution may be added to the water to ensure a thorough separation of fine material from the coarser particles.

4. Agitate the sample vigorously using a rotary motion of the pan for five to ten seconds.

5. Pour off the water through the No. 200 wash sieve. When washing samples with a high silt content, it may be necessary to vibrate or lightly tap the wash sieve in order to keep the mesh open so the water and the minus No. 200 sieve material may pass through freely. Repeat this operation until the wash water appears almost clear.

6. Rinse any material retained on the No. 200 sieve back into the sample and decant as much water as possible by carefully pouring the water through the No. 200 sieve.

7. Dry the washed sample, allow to cool, weigh and record as the Dry weight (mass) of the washed sample.

8. When determining only the amount passing the No. 200 sieve, screen the sample over the No. 8 sieve and discard the retained material. Place the portion of material passing the No. 8 sieve on a nest of sieves including the No. 50, No. 100 and No. 200 sieves and the pan. The sieves larger than the No. 200 sieve are included for protection of the No. 200 sieve. Place the nest of sieves in the mechanical sieve shaker and sieve to completion (normally five minutes or less). Weigh and record only the material retained in the pan.

9. When a complete sieve analysis is required, test the entire sample using the appropriate method as outlined in IM 302.

D. Calculations

% Passing No. 200 sieve =