Plastic limit of clayey soils and its subjective determination

Sokurov, V.V.; Ermolaeva, A. N.; Matroshilina, T. V.

doi:10.1007/s11204-011-9128-6

“…The Atterberg plastic limit 1 is a very important parameter in soils, mainly because it is widely used for geotechnical purposes 10,11,12 . The standard thread rolling test for PL determination has been widely criticized because it is highly dependent on the skill and judgment of the operator who is conducting the test and consequently new approaches to obtain the PL are claimed 6,7,9,13,[15][16][17][18][19][20][23][24][25] . However the simplicity, low cost and quick performance of the standard PL test give it an advantage over the unsuccessful alternatives proposed to date, despite the fact that the subjectivity of the operator is reduced in most of alternative methods, like those carried out by fall cones [15][16][17][18][19][20] .…”

Section: Discussionmentioning

confidence: 99%

“…PL is a very important parameter for geotechnical purposes, since Plasticity Index (PI) is obtained from it (PI = LL -PL); PI is used to classify the soil in accordance with the Plasticity Chart shown in ASTM D 2487 10 , based on the research of Casagrande 11,12 . Errors in the PL affect negatively this classification 13 , and for this reason, a new test for PL determination is required.…”

Section: Introductionmentioning

confidence: 99%

A Bending Test for Determining the Atterberg Plastic Limit in Soils

Moreno-Maroto

¹

,

Alonso-Azcárate

²

2016

JoVE

View full text Add to dashboard Cite

The thread rolling test is the most commonly used method to determine the plastic limit (PL) in soils. It has been widely criticized, because a considerable subjective judgment from the operator that carries out the test is involved during its performance, which may affect the final result significantly. Different alternative methods have been put forward, but they cannot compete with the standard rolling test in speed, simplicity and cost. In an earlier study by the authors, a simple method with a simple device to determine the PL was presented (the "thread bending test" or simply "bending test"); this method allowed the PL to be obtained with minimal operator interference. In the present paper a version of the original bending test is shown. The experimental basis is the same as the original bending test: soil threads which are 3 mm in diameter and 52 mm long are bent until they start to crack, so that both the bending produced and its related moisture content are determined. However, this new version enables the calculation of PL from an equation, so it is not necessary to plot any curve or straight line to obtain this parameter and, in fact, the PL can be achieved with only one experimental point (but two experimental points are recommended). The PL results obtained with this new version are very similar to those obtained through the original bending test and the standard rolling test by a highly experienced operator. Only in particular cases of high plasticity cohesive soils, there is a greater difference in the result. Despite this, the bending test works very well for all types of soil, both cohesive and very low plasticity soils, where the latter are the most difficult to test via the standard thread rolling method.

show abstract

“…The Atterberg plastic limit 1 is a very important parameter in soils, mainly because it is widely used for geotechnical purposes 10,11,12 . The standard thread rolling test for PL determination has been widely criticized because it is highly dependent on the skill and judgment of the operator who is conducting the test and consequently new approaches to obtain the PL are claimed 6,7,9,13,[15][16][17][18][19][20][23][24][25] . However the simplicity, low cost and quick performance of the standard PL test give it an advantage over the unsuccessful alternatives proposed to date, despite the fact that the subjectivity of the operator is reduced in most of alternative methods, like those carried out by fall cones [15][16][17][18][19][20] .…”

Section: Discussionmentioning

confidence: 99%

“…PL is a very important parameter for geotechnical purposes, since Plasticity Index (PI) is obtained from it (PI = LL -PL); PI is used to classify the soil in accordance with the Plasticity Chart shown in ASTM D 2487 10 , based on the research of Casagrande 11,12 . Errors in the PL affect negatively this classification 13 , and for this reason, a new test for PL determination is required.…”

Section: Introductionmentioning

confidence: 99%

A Bending Test for Determining the Atterberg Plastic Limit in Soils

Moreno-Maroto

¹

,

Alonso-Azcárate

²

2016

JoVE

1

0

View full text Add to dashboard Cite

The thread rolling test is the most commonly used method to determine the plastic limit (PL) in soils. It has been widely criticized, because a considerable subjective judgment from the operator that carries out the test is involved during its performance, which may affect the final result significantly. Different alternative methods have been put forward, but they cannot compete with the standard rolling test in speed, simplicity and cost.In an earlier study by the authors, a simple method with a simple device to determine the PL was presented (the "thread bending test" or simply "bending test"); this method allowed the PL to be obtained with minimal operator interference. In the present paper a version of the original bending test is shown. The experimental basis is the same as the original bending test: soil threads which are 3 mm in diameter and 52 mm long are bent until they start to crack, so that both the bending produced and its related moisture content are determined. However, this new version enables the calculation of PL from an equation, so it is not necessary to plot any curve or straight line to obtain this parameter and, in fact, the PL can be achieved with only one experimental point (but two experimental points are recommended).The PL results obtained with this new version are very similar to those obtained through the original bending test and the standard rolling test by a highly experienced operator. Only in particular cases of high plasticity cohesive soils, there is a greater difference in the result. Despite this, the bending test works very well for all types of soil, both cohesive and very low plasticity soils, where the latter are the most difficult to test via the standard thread rolling method.

show abstract