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Definition Atterberg limits are boundary water contents. Depending on these limits, fine : - grained soils can be TEST divided^3 :^ ATTERBERG LIMITS into four states of consistency, namely
solid, semisolid, plastic and liquid states. In current engineering usage, the term the liquid limit, plastic limit, in some references, the shrinkage limit Liquid Limit ( small disturbi Plastic Limit ( ๐ณ๐ณng force๐ท๐ณ ): the water content at which ): the water content at which the soil. โAtterberg limitsโ the soils will flow under a specified usually refers only tocan be deformed: plastically Plasticity index ( plastic condition. Shrinkage Limit ( and attains a constant volume.. ๐บ๐ณ๐ท๐ฐ Where )):: (^) the water content at which the soil stops shrinkis the range of water content over which the soil is in the ๐๐ผ = ๐ฟ๐ฟ โ ๐๐ฟ age further
Volume state Solid ๐บ๐ณ Semi state-solid ๐ท๐ณ Plastic state ๐ท๐ฐ (^) ๐ณ๐ณLiquid state (^) Water content
Purpose โข โข โข and significance To determ grained soils.It is usedIt is used hydraulic conductivity (permeability), totoine the classifycorrelate with engineering behavior such as compressibility, : Liquidthe fine limit-grained, plastic limit soils .compatibility, shrink and plasticity index-swell, and of fine- Standard Reference: ASTM D 4318 Plasticity Index of Soils^ shear strength. - Standard Test Method for Liquid Limit, Plastic Limit, and
Test Procedure 1. Using a spatula, place a portion of the previously prepared soil in the cup of the liquid limit device at the point base cup to a depth of about form an approximately horizontal surface. : Casagrande apparatus. Squeeze it down to eliminate air bubbles 1 cm โ (^) Mult at its deepest point ipoint method where the cup rests on the and spread it into the. The soil pat should
- Form a groove in the soil pat straight groove the cup. The tool should remain perpendicular to the surface of the cup as groove is being made.Turn the crank of the apparatus at a rate of of drops required from back to front through the sample to close the groove along a using the groov 2 rps. Cing tool distance of 13 mmount atto the center of cut a cleanthe number. If
4. the number of drops exceeds 50, then go directly to step^ record the number of dropsTake a sample, using the spatula, from edge to edge of t where determination immediately weigh the the groove. Place the s came containerample^ (๐ต )^ on the data sheet.into into a with contact container of the wet for soil, record its knownwater^5 , otherwisehe soil patmass ( content mass๐๐),
5. (^ then weigh the container containing the dry soil (^ soil remaining in the cup to the dish. Wash^ grooving tooRemix the entire soil specimen in the of distilled water to increase the water content๐๐+๐๐), and placel^ for the next trial^ it^ into the oven. Leave. mixing^ it in the ovendish. Add a small amount^ and dry the cup and and๐๐+ ๐
๐^ overnightdecrease).^ Return the^ andthe
- number of drops required to close the groove.Repeat suc recommended that ( 20 - cessively 30 ) andthe previous (15lower-25), respectively numbersthesteps for at least two additional trials producing three oftrials. drops cover the drops range of to close the groove. ( 25 It- 35 is)
Calculation The 1. liquid limit Determine the water content ( trial : using the following equation: can be determined as ๐ = ๐ค๐ ๐ค+๐๐ค๐ + follows๐๐๐ โ) โ from data๐ค ๐ค๐:+๐๐๐ ร 100 of step 4 and for each
2. 3. 4. Using a semi ( abscissa (on log scale)Draw the best straight line fitting the plotted points. This is called the โFlowDraw a vertical line representing 25 blows and where it intersects theon linear lineโ. scale) and the corresponding number of drops-logarithmic chart plot the water content (๐) as ordinate (๐ต) as
flow this value of water content as the liquid limit of the soil and round the nearest whole number. line draw the horizontal line to the water content axis. Read off it to (^1020300)
Water content, W (%) (^10) Number of blows, N 25 LL^ Flow line 20 30 40 50
LL = 32%
- Repeat the process of alternate rolling and kneading until the thread crumbles and theCollect the pieces of the crumbled soil thread content container, andRepeat the procedure holding at least 6 g of soil soil can no longer be rolled into thread. on another specimen to make another container determine its water content., and determine its water (at least 6 g) content in a moisture.
Calculation: The 1. plastic limit can be determined as Determine the water content ( 5 and 6) using the following equation: ๐ = ๐ค๐ ๐ค+๐๐ค๐ +๐๐๐ follows)โ forโ ๐ค ๐ค๐the two+๐:๐๐ ร 100 trials (from data of step
Calculate the plasticity index,^ 2.^ Compute the average of the^ nearest whole number^ Note that^ the whole test.^ If the two^ water contents,^ this value is the plastic limit,^ two water contents and round to the^ differ by more than 0.5 %^ ๐ท๐ณ. ,^ repeat where: ๐ฟ๐ฟ ๐๐ฟ = liquid li= plastic limit (whole number).mit (whole number), and^ ๐ท๐ฐ^ =^ ๐ณ๐ณ^ โ^ ๐ท๐ณ
Date tested: Tested by: Class: Specimen number ATTERBERG LIMITS 1 - Liquid Limit Test^ DATA SHEET^ DETERMINATION
Container number Mass of container, Mass of container and wet specimen, Mass of container and oven dry specimen, Water content, Number of drops, ( ๐ค (%) ๐ค๐๐) (g) ๐ค๐+๐ค๐ ๐ค (^) ๐(g)+๐๐ (g) Specimen number Container number Mass of container, Mass of container and wet specimen, Mass of container and oven dry specimen, ๐ค๐ (g)^1 -^ Plastic ๐ค๐+๐ค๐ ^ Limit Test ๐ค (^) ๐(g)+๐๐ (g) Group names:^ Water content, 12 - -^ ๐ค^ (%) 345 - -- Supervisor signature
