Experiment%207-Atterberg%20Limits

Experiment%207-Atterberg%20Limits - 60 EXPERIMENT 7...

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Engineering Properties of Soils Based on Laboratory Testing Prof. Krishna Reddy, UIC 60 EXPERIMENT 7 ATTERBERG LIMITS Purpose : This lab is performed to determine the plastic and liquid limits of a fine- grained soil. The liquid limit (LL) is arbitrarily defined as the water content, in percent, at which a pat of soil in a standard cup and cut by a groove of standard dimensions will flow together at the base of the groove for a distance of 13 mm (1/2 in.) when subjected to 25 shocks from the cup being dropped 10 mm in a standard liquid limit apparatus operated at a rate of two shocks per second. The plastic limit (PL) is the water content, in percent, at which a soil can no longer be deformed by rolling into 3.2 mm (1/8 in.) diameter threads without crumbling. Standard Reference : ASTM D 4318 - Standard Test Method for Liquid Limit, Plastic Limit, and Plasticity Index of Soils Significance : The Swedish soil scientist Albert Atterberg originally defined seven “limits of consistency” to classify fine-grained soils, but in current engineering practice only two of the limits, the liquid and plastic limits, are commonly used. (A third limit, called the shrinkage limit, is used occasionally.) The Atterberg limits are based on the moisture content of the soil. The plastic limit is the moisture content that defines where the soil changes from a semi-solid to a plastic (flexible) state. The liquid limit is the moisture content that defines where the soil changes from a plastic to a viscous fluid state. The shrinkage limit is the moisture content that defines where the soil volume will not reduce further if the moisture content is reduced. A
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Engineering Properties of Soils Based on Laboratory Testing Prof. Krishna Reddy, UIC 61 wide variety of soil engineering properties have been correlated to the liquid and plastic limits, and these Atterberg limits are also used to classify a fine-grained soil according to the Unified Soil Classification system or AASHTO system. Equipment : Liquid limit device, Porcelain (evaporating) dish, Flat grooving tool with gage, Eight moisture cans, Balance, Glass plate, Spatula, Wash bottle filled with distilled water, Drying oven set at 105 ° C.
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Engineering Properties of Soils Based on Laboratory Testing Prof. Krishna Reddy, UIC 62
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Engineering Properties of Soils Based on Laboratory Testing Prof. Krishna Reddy, UIC 63 Test Procedure : Liquid Limit : (1) Take roughly 3/4 of the soil and place it into the porcelain dish. Assume that the soil was previously passed though a No. 40 sieve, air-dried, and then pulverized. Thoroughly mix the soil with a small amount of distilled water until it appears as a smooth uniform paste.
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This note was uploaded on 05/22/2011 for the course CIVIL ENGI 171A taught by Professor Aryani during the Spring '11 term at CSU Sacramento.

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Experiment%207-Atterberg%20Limits - 60 EXPERIMENT 7...

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