AASHTO T128 pdf free download

AASHTO T128 pdf free download.Fineness of Hydraulic Cement by the 1 50-μm (No. 100) and 75-μm (No. 200) Sieves.
5. PROCEDURE
5.1. Place a 50-g sample of the cement on the clean, dry 150-μm (No. 100) or 75-μm (No. 200) sieve with the pan attached. Do not use washers, shot, slugs, or coins on the sieve. While holding the sieve and uncovered pan in both hands, sieve with a gentle wrist motion until most of the fine material has passed through and the residue looks fairly clean. This operation usually requires only three or four minutes. When the residue appears clean place the cover on the sieve and remove the pan. Then, with the sieve and cover held firmly in one hand, gently tap the side of the sieve with the handle of the brush used for cleaning the sieve. Dust adhering to the sieve will thus be dislodged and the underside of the sieve may then be swept clean. Empty the pan and thoroughly wipe it out with a cloth or waste, replace the sieve in the pan, and carefully remove the cover. Return any coarser material that has been caught in the cover during the tapping to the sieve.
5.2. Continue the sieving without the cover as described in Section 5.1 for 5 or 10 minutes, depending on the condition of the cement. The gentle wrist motion involves no danger of spilling the residue, which shall be kept well spread out on the sieve. Continuously rotate the sieve throughout the sieving. This open sieving may usually be continued safely for nine minutes or more, but take care that it is not continued too long. Then replace the cover and clean, following the same process as described in Section 5.1. If the cement is in proper condition, there should now be no appreciable dust remaining in the residue nor adhering to the sieve or pan.
5.3. Make one-minute tests as follows: Hold the sieve, with pan and cover attached, in one hand in a slightly inclined position and move it forward and backward in the plane of inclination; at the same time gently strike the side about 150 times/minute against the palm of the other hand on the upstroke. Perform the sieving over a white paper. Return any material escaping from the sieve or pan and collecting on the paper to the sieve. After every 25 strokes, turn the sieve about one-sixth of a revolution, in the same direction. (See Note 1.) Continue the sieving operation until not more than 0.05 g of the material passes through in one minute of continuous sieving. Then transfer the residue on the sieve to the balance pan, taking care to brush the sieve cloth thoroughly from both sides to ensure the removal of all the residue from the sieve.
Note 1—Sieve covers may be marked with three straight lines, intersecting at 60 deg, through the center. If one of the lines is marked with an arrowhead and the habit of starting with this point under the right hand has been formed, one can easily follow the progress of the one-minute tests. Be certain to take a full 10 seconds for the 25-stroke period. This will mean that the 150 strokes, plus turning the sieve, will take more than one minute total. It is important that a full minute of sieving takes place.AASHTO T128 pdf download.