ASTM D4318-10e1 pdf free.Standard Test Methods For Liquid Limit, Plastic Limit, And Plasticity Index Of Soils.
These test methods cover the determination of the liquid limit, plastic limit, and the plasticity index of soils as defined in Section 3 on Terminology.
The methods described herein are performed only on that portion of a soil that passes the 425-μm (No. 40) sieve. Therefore, the relative contribution of this portion of the soil to the properties of the sample as a whole must be considered when using these tests to evaluate properties of a soil.
4. Sunimary of Test Method
4.1 The specimen is processed to remove any material retained on a 425-urn (No. 40) sieve. The liquid limit is determined by performing trials in which a portion of the specimen is spread in a brass cup. divided in two by a grooving tool. and then allowed to flow together from the shocks caused by repeatedly dropping the cup in a standard mechanical device. The multipoint liquid limit, Method A, requires three or more trials over a range of water contents to be performed and the data from the trials plotted or calculated Lo make a relationship from which the liquid limit is determined. The one—point liquid limit, Method B. uses the data from two trials at one water content multiplied by a correction factor to determine the liquid limit.
4.2 The plastic limit is determined by alternately pressing together and rolling into a 3.2-mm (½-in.) diameter thread a small portion of plastic soil until its water content is reduced to a point at which the thread crumbles and can no longer be pressed together and re-rolled. The water content of’ the soil at this point is reported as the plastic limit.
4.3 The plasticity index is calculated as the difference between the liquid limit and the plastic limit.
9. Calibration of Apparatus
9. 1 liispeciion of 11ar:
9. 1. 1 Liquid Limil Device—Determine that the liquid limit device is clean and in goxi working order. Check the following specific points.
9.1 .1.1 Wear of Base—The spot on the base where the cup makes contact should be worn no greater than 10 mm (3/8 in.) in diameter. If the wear spot is greater than this, the base can be machined to remove the worn spot provided the resurfacing does not make the base thinner than specified in 6.1 and the other dimensional relationships are maintained.ASTM D4318-10e1 pdf free download.