AASHTO T89-10 pdf free download
AASHTO T89-10 pdf free download.Determining the Liquid Limit of Soils.
5. ADJUSTMENT OF LIQUID UMF DEVICE
5.1. The Liquid Limit Device shall be inspected to determine that the device is in good working order:
that the pin connecting the cup is not worn sufficiently to permit side play; that the screws connecting the cup to the hanger arm are tight; that the points of contact on the cup and base are not excessively worn; that the lip of the cup is not excessively worn; and that a groove has not been worn in the cup through long usage. The grooving tool shall be inspected to determine that the critical dimensions are as shown in Figure 1 of this method or ASTM D 4318, Figure 2.
Note 3—Wear is considered excessive when the point of contact on the cup or base exceeds approximately 13 mm in diameter, or when any point on the rim of the cup is worn to approximately ‘/2 the original thickness. Although a slight groove in the center of the cup is noticeable, it is not objectionable. If the groove becomes pronounced before other signs of wear appear, the cup should be considered excessively worn. Excessively worn cups shall be replaced. A base that is excessively worn may be refinished a long as the thickness does not exceed the tolerance shown in Figure 1 by more than —2.5 mm and the distance between the cup at the cam follower and the base is maintained within the tolerances specified in Figure 1.
5.2. Adjust the height of drop of the cup so that the point on the cup that comes in contact with the base rises to a height of 10.0 ± 0.2 mm. See Figure 2 for proper location of the gauge relative to the cup during adjustment.
Note 4—A convenient procedure for adjusting the height of drop is as follows: place a piece of masking tape across the outside bottom of the cup parallel with the axis of the cup hanger pivot. The edge of the tape away from the cup hanger should bisect the spot on the cup that contacts the base. For new cups, placing a piece of carbon paper on the base and allowing the cup to drop several times will mark the contact spot. Attach the cup to the device and Lurn the crank until the cup is raised to its maximum height. Slide the height gauge under the cup from the front, and observe whether the gauge contacts the cup or the tape. See Figure 2. If the tape and cup are both contacted, the height of drop is approximately correct. If not, adjust the cup until simultaneous contact is made. Check adjustment by turning the crank at two revolutions per second while holding the gauge in position against the tape and cup. If a ringing or clicking sound is heard without the cup rising from the gauge, the adjustment is correct. If no ringing is heard or if the cup rises from the gauge, readjust the height of drop. If the cup rocks on the gauge during this checking operation, the cam follower pivot is excessively worn and the worn parts should be replaced. Always remove tape after completion of adjustment operation.
6. PROCEDURE USING THE CURVED GROOVING TOOL
6.1. The soil sample shall be placed in the mixing dish and thoroughly mixed with 15 to 20 mL of distilled or demineralized water by alternately and repeatedly stirring, kneading, and chopping with a spatula. Further additions of water shall be made in increments of I to 3 mL. Each increment of water shall be thoroughly mixed with the soil as previously described before another increment of water is added. Once testing has begun. no additional dry soil should be added to the moistened soil. The cup of the Liquid Limit Device shall not be used for mixing soil and water. If too much moisture has been added to the sample, the sample shall either be discarded, or mixed and kneaded until natural evaporation lowers the closure point into an acceptable range.AASHTO T89-10 pdf download.
