AASHTO T 89-2013 Standard Method of Test for Determining the Liquid Limit of Soils.pdf

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1、Standard Method of Test for Determining the Liquid Limit of Soils AASHTO Designation: T 89-13 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1a T 89-1 AASHTO Standard Method of Test for Determining the Liquid Limi

2、t of Soils AASHTO Designation: T 89-13 1. SCOPE 1.1. The liquid limit of a soil is that water content, as determined in accordance with the following procedure, at which the soil passes from a plastic to a liquid state. 1.2. The following applies to all specified limits in this standard: For the pur

3、poses of determining conformance with these specifications, an observed value or a calculated value shall be rounded off “to the nearest unit” in the last right-hand place of figures used in expressing the limiting value, in accordance with ASTM E29. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M

4、231, Weighing Devices Used in the Testing of Materials R 58, Dry Preparation of Disturbed Soil and Soil-Aggregate Samples for Test T 146, Wet Preparation of Disturbed Soil Samples for Test T 265, Laboratory Determination of Moisture Content of Soils 2.2. ASTM Standards: D4318, Standard Test Methods

5、for Liquid Limit, Plastic Limit, and Plasticity Index of Soils E29, Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications 3. APPARATUS 3.1. DishA porcelain dish, preferably unglazed, or similar mixing dish, about 115 mm in diameter. 3.2. SpatulaA sp

6、atula or pill knife having a blade about 75 to 100 mm in length and about 20 mm in width. 3.3. Liquid Limit Device: 3.3.1. Manually OperatedA device consisting of a brass dish and carriage, constructed according to the plan and dimensions shown in Figure 1. (See Note 1.) 2015 by the American Associa

7、tion of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 89-2 AASHTO Liquid Limit Device Grooving Tool Cup Assembly Base Curved End Gauge Dimension A B C N K L M a b c d e* Description Radius of Cup Thickness of Cup Depth of Cup Cup

8、 at Cam Follower to Base Thickness Length Width Thickness Cutting Edge Width Depth Length Metric, mm 54 2.0 27 47 50 150 125 10.0 2.0 13.5 10.0 15.9 Tolerance, mm 2 0.1 1 1.5 5 5 5 0.1 0.1 0.1 0.2 Note: Plate “H” may be designed for using one (1) securing screw (I). An additional wear tolerance of 0

9、.1 mm shall be allowed for dimension “b” for used grooving tools. Feet for base shall be of resilient material. (*) Nominal dimensions. All tolerances specified are plus or minus () except as noted above. Figure 1Manual Liquid Limit Device 3.3.2. Mechanically OperatedA motorized device equipped to p

10、roduce the rise and rate of shocks to a brass cup as described in Sections 5.2 and 6.3 of this procedure, respectively. The cup and the critical dimensions of the device shall conform to those shown in Figure 1 of this procedure. The device shall give the same liquid limit values as obtained with th

11、e manually operated device (Note 1). Note 1The base of the liquid limit device should have a resilience of at least 80 percent and not more than 90 percent when determined in accordance with the procedure given in the Appendix. 3.4. Grooving Tool: 3.4.1. Curved Grooving ToolA grooving tool conformin

12、g to the critical dimensions shown in Figure 1. The gauge need not be part of the tool. Shaft - (*) 76.2 mmOptionalRound end25.4-mm DiaNominal22.2-mm RadEnd Square60Grooving ToolabcdddeABCKIMHard RubberBrassNLFH 2015 by the American Association of State Highway and Transportation Officials.All right

13、s reserved. Duplication is a violation of applicable law.TS-1a T 89-3 AASHTO 3.4.2. Flat Grooving Tool (Alternate)A grooving tool made of plastic or noncorroding metal conforming to the critical dimensions shown in ASTM D4318, Figure 3. The gauge need not be part of the tool (Note 2). Note 2The flat

14、 grooving tool should not be used interchangeably with the curved grooving tool. There are some data that indicate that the liquid limit is slightly increased when the flat tool is used instead of the curved tool. 3.5. GaugeA gauge, whether attached to the grooving tool or separate, conforming to th

15、e critical dimension “d” shown in Figure 1 of this test method or “K” in Figure 3 of ASTM D4318, and may be, if separate, a metal bar 10.0 0.2 mm thick and approximately 50 mm long. 3.6. ContainersSuitable containers made of material resistant to corrosion and not subject to change in mass or disint

16、egration on repeated heating and cooling. Containers shall have close-fitting lids to prevent loss of moisture from samples before initial mass determination and to prevent absorption of moisture from the atmosphere following drying and before final mass determination. One container is needed for ea

17、ch moisture content determination. 3.7. BalanceThe balance shall have sufficient capacity and conform to M 231, Class G 1. 3.8. OvenA thermostatically controlled drying oven capable of maintaining temperatures of 110 5C for drying moisture samples. METHOD A 4. SAMPLE 4.1. A sample with a mass of abo

18、ut 100 g shall be taken from the thoroughly mixed portion of the material passing the 0.425-mm sieve that has been obtained in accordance with R 58 or T 146; for structural analysis use T 146, Method B. 5. ADJUSTMENT OF LIQUID LIMIT DEVICE 5.1. The Liquid Limit Device shall be inspected to determine

19、 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

20、 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 test method or ASTM D4318, Figure 3. Note 3Wear is considered excessive when the point of contact on the cup or ba

21、se exceeds approximately 13 mm in diameter, or when any point on the rim of the cup is worn to approximately one half of 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 appea

22、r, the cup should be considered excessively worn. Excessively worn cups shall be replaced. A base that is excessively worn may be refinished as long as the thickness does not exceed the tolerance shown in Figure 1 of this test method by more than 2.5 mm and the distance between the cup at the cam fo

23、llower 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 adjustm

24、ent. Check the height of drop of the cup prior to each days testing. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 89-4 AASHTO Figure 2Calibration for Height of Drop Note 4A convenient procedur

25、e 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 o

26、f 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 turn 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

27、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

28、 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 t

29、he 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 s

30、tirring, kneading, and chopping with a spatula. Further additions of water shall be made in increments of 1 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 shou

31、ld 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

32、. Note 5Some soils are slow to absorb water; therefore, it is possible to add the increments of water so fast that a false liquid limit value is obtained. This can be avoided if more mixing and/or time is allowed. Tap water may be used for routine testing if comparative tests indicate no differences

33、 in results between using tap water and distilled or demineralized water. However, referee or disputed tests shall be performed using distilled or demineralized water. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of ap

34、plicable law.TS-1a T 89-5 AASHTO 6.2. When sufficient water has been thoroughly mixed with the soil to form a uniform mass of stiff consistency, a sufficient quantity of this mixture shall be placed in the cup above the spot where the cup rests on the base and shall be squeezed and spread with the s

35、patula to level and at the same time trimmed to a depth of 10 mm at the point of maximum thickness. As few strokes of the spatula as possible shall be used, care being taken to prevent the entrapment of air bubbles within the mass. The excess soil shall be returned to the mixing dish and covered to

36、retain the moisture in the sample. The soil in the cup of the device shall be divided by a firm stroke of the grooving tool along the diameter through the centerline of the cam follower so that a clean sharp groove of the proper dimensions will be formed as shown in Figure 3. To avoid tearing of the

37、 sides of the groove or slipping of the soil cake on the cup, up to six strokes from front to back or from back to front counting as one stroke, shall be permitted. The depth of the groove should be increased with each stroke and only the last stroke should scrape the bottom of the cup. Figure 3Liqu

38、id Limit Device with Soil Sample in Place 6.3. The cup containing the sample prepared as described in Section 6.2 shall be lifted and dropped by turning the crank F at the rate of approximately two revolutions per second until the two sides of the sample come in contact at the bottom of the groove a

39、long a distance of about 13 mm. The number of shocks required to close the groove this distance shall be recorded. The base of the machine shall not be held with the free hand while the crank F is turned. Note 6Some soils tend to slide on the surface of the cup instead of flowing. If this occurs, mo

40、re water should be added to the sample and remixed, then the soilwater mixture placed in the cup, a groove cut with the grooving tool and Section 6.2 repeated. If the soil continues to slide on the cup at a lesser number of blows than 25, the test is not applicable and a note should be made that the

41、 liquid limit could not be determined. 6.4. A slice of soil approximately the width of the spatula, extending from edge to edge of the soil cake at right angles to the groove and including that portion of the groove in which the soil flowed together, shall be removed and placed in a suitable contain

42、er. The soil in the container shall be dried in accordance with T 265 to determine the moisture content, and the results recorded. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 89-6 AASHTO 6.5.

43、 The soil remaining in the cup shall be transferred to the mixing dish. The cup and grooving tool shall then be washed and dried in preparation for the next trial. 6.6. Repeat the foregoing operations, adding sufficient water to bring the soil to a more fluid condition. Obtain the first sample in th

44、e range of 25 to 35 shocks, the second sample in the range of 20 to 30 shocks, and the third sample in the range of 15 to 25 shocks. The range of the three determinations shall be at least 10 shocks. 7. ALTERNATE PROCEDURE USING THE FLAT GROOVING TOOL 7.1. The procedure shall be the same as prescrib

45、ed in Sections 6.1 through 6.6, except for the procedure in Section 6.2 for forming the groove. Form a groove in the soil pat in accordance with Section 11.2 of ASTM D4318. 8. CALCULATION 8.1. The water content of the soil shall be expressed as the moisture content in percentage of the mass of the o

46、ven-dried soil and shall be calculated as follows: mass of waterpercentage moisture 100mass of oven-dried soil= (1) 8.1.1. Calculate the percentage of moisture to the nearest whole percent. 9. PREPARATION OF FLOW CURVE 9.1. A “flow curve” representing the relation between moisture content and corres

47、ponding number of shocks shall be plotted on a semilogarithmic graph with the moisture contents as abscissae on the arithmetical scale, and the number of shocks as ordinates on the logarithmic scale. The flow curve shall be a straight line drawn as nearly as possible through the three or more plotte

48、d points. 10. LIQUID LIMIT 10.1. The moisture content corresponding to the intersection of the flow curve with the 25-shock ordinate shall be taken as the liquid limit of the soil. Report this value to the nearest whole number. 2015 by the American Association of State Highway and Transportation Off

49、icials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 89-7 AASHTO METHOD B 11. SAMPLE 11.1. A sample with a mass of about 50 g shall be taken as described in Section 4.1. 12. PROCEDURE 12.1. Using the curved grooving tool (Section 6) or the flat grooving tool (Section 7) the procedure shall be the same as prescribed in Sections 6.1 through 6.5 except that the initial amount of water to be added in accordance with Section 6.1 shall be approximately 8 to 10 mL and the moisture sample taken in accordance with S