Geotechnical investigation and testing - Laboratory testing of soil - Part 12: Determination of liquid and plastic limits (ISO 17892-12:2018)

This document specifies methods for the determination of the liquid and plastic limits of a soil. These
comprise two of the Atterberg limits for soils.
The liquid limit is the water content at which a soil changes from the liquid to the plastic state.
This document describes the determination of the liquid limit of a specimen of natural soil, or of
a specimen of soil from which material larger than about 0,4 mm has been removed. This document
describes two methods: the fall cone method and the Casagrande method.
NOTE The fall cone method in this document should not be confused with that of ISO 17892-6.
The plastic limit of a soil is the water content at which a soil ceases to be plastic when dried further.
The determination of the plastic limit is normally made in conjunction with the determination of the
liquid limit. It is recognized that the results of the test are subject to the judgement of the operator, and
that some variability in results will occur.

Geotechnische Erkundung und Untersuchung - Laborversuche an Bodenproben - Teil 12: Bestimmung der Zustandsgrenzen (ISO 17892-12:2018)

Diese Internationale Norm legt Verfahren zur Bestimmung der Fließ- und Ausrollgrenze von durchmischten Böden fest. Dies umfasst zwei der Zustandsgrenzen für Böden nach Atterberg.
Die Fließgrenze ist der Wassergehalt, bei dem der Boden vom flüssigen in den plastischen Zustand übergeht.
Dieses Dokument beschreibt die Bestimmung der Fließgrenze an einer Probe von natürlichem Boden oder einer Bodenprobe, bei denen die Körner mit einem Korndurchmesser größer als 0,4 mm entfernt wurden. Dieses Dokument beschreibt zwei Methoden: Die Fallkegelmethode und die Methode von Casagrande.
ANMERKUNG   Die Fallkegelmethode in dieser Norm sollte nicht mit der in ISO 19892 6 verwendeten verwechselt werden.
Die Ausrollgrenze ist der Wassergehalt, bei dem der Boden bei weiterer Trocknung aufhört, plastisch zu sein.
Die Bestimmung der Ausrollgrenze erfolgt normalerweise in Verbindung mit der Bestimmung der Fließgrenze. Es wird anerkannt, dass die Ergebnisse der Prüfung dem Urteil des Prüfers unterliegen und dass in den Ergebnissen eine gewisse Variabilität auftreten wird.

Reconnaissance et essais géotechniques - Essais de laboratoire sur les sols - Partie 12: Détermination des limites de liquidité et de plasticité (ISO 17892-12:2018)

Le présent document spécifie les méthodes de détermination des limites de liquidité et de plasticité d'un sol. Celles-ci constituent deux des limites d'Atterberg applicables aux sols.
La limite de liquidité est la teneur en eau à laquelle un sol passe de l'état liquide à l'état plastique.
Le présent document décrit la détermination de la limite de liquidité d'un échantillon de sol naturel, ou d'un échantillon de sol duquel les matériaux de dimension supérieure à 0,4 mm ont été retirés. Ce document décrit deux méthodes: la méthode du cône tombant et la méthode de Casagrande.
NOTE       La méthode du cône tombant dans ce document ne devrait pas être confondue avec celle de la norme ISO 17892‑6.
La limite de plasticité d'un sol est la teneur en eau à laquelle ce sol cesse d'être plastique lorsque l'on continue à le sécher.
La détermination de la limite de plasticité est normalement faite en parallèle avec celle de la limite de liquidité. Il est reconnu que les résultats de l'essai sont sujets à l'appréciation de l'opérateur, et qu'une certaine dispersion des résultats pourra se produire.

Geotehnično preiskovanje in preskušanje - Laboratorijsko preskušanje zemljin - 12. del: Ugotavljanje meje tekočine in plastičnosti (ISO 17892-12:2018)

Ta dokument določa metode za ugotavljanje meje tekočine in plastičnosti zemljine, ki zajemajo dve od Atterbergovih mejnih vrednosti za zemljine.
Meja tekočine je vsebnost vode, pri kateri se stanje zemljine spremeni iz tekočega v plastično. Ta dokument opisuje ugotavljanje meje tekočine vzorca naravne zemljine ali vzorca zemljine, iz katerega je odstranjen material večji od približno 0,4 mm. Ta dokument opisuje dve metodi: metodo s konusom in Casagrandejevo metodo.
OPOMBA: Metoda s konusom v tem dokumentu se ne sme zamenjevati z metodo iz standarda ISO 17892-6. Meja plastičnosti zemljine je vsebnost vode, pri kateri zemljina pri nadaljnjem sušenju preneha biti plastična. Ugotavljanje meje plastičnosti običajno poteka v povezavi z ugotavljanjem meje tekočine. Ugotovljeno je, da so rezultati preskusa odvisni od presoje upravljavca in da bo pri rezultatih prišlo do nekaterih razlik.

General Information

Status
Published
Public Enquiry End Date
14-Mar-2017
Publication Date
10-Oct-2018
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
29-Aug-2018
Due Date
03-Nov-2018
Completion Date
11-Oct-2018

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SLOVENSKI STANDARD
SIST EN ISO 17892-12:2018
01-november-2018
1DGRPHãþD
SIST-TS CEN ISO/TS 17892-12:2004
SIST-TS CEN ISO/TS 17892-12:2004/AC:2010
*HRWHKQLþQRSUHLVNRYDQMHLQSUHVNXãDQMH/DERUDWRULMVNRSUHVNXãDQMH]HPOMLQ
GHO8JRWDYOMDQMHPHMHWHNRþLQHLQSODVWLþQRVWL ,62
Geotechnical investigation and testing - Laboratory testing of soil - Part 12:
Determination of liquid and plastic limits (ISO 17892-12:2018)
Geotechnische Erkundung und Untersuchung - Laborversuche an Bodenproben - Teil
12: Bestimmung der Zustandsgrenzen (ISO 17892-12:2018)

Reconnaissance et essais géotechniques - Essais de laboratoire sur les sols - Partie 12:

Détermination des limites de liquidité et de plasticité (ISO 17892-12:2018)
Ta slovenski standard je istoveten z: EN ISO 17892-12:2018
ICS:
13.080.20 Fizikalne lastnosti tal Physical properties of soils
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
SIST EN ISO 17892-12:2018 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 17892-12:2018
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SIST EN ISO 17892-12:2018
EN ISO 17892-12
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2018
EUROPÄISCHE NORM
ICS 13.080.20; 93.020 Supersedes CEN ISO/TS 17892-12:2004
English Version
Geotechnical investigation and testing - Laboratory testing
of soil - Part 12: Determination of liquid and plastic limits
(ISO 17892-12:2018)

Reconnaissance et essais géotechniques - Essais de Geotechnische Erkundung und Untersuchung -

laboratoire sur les sols - Partie 12: Détermination des Laborversuche an Bodenproben - Teil 12: Bestimmung

limites de liquidité et de plasticité (ISO 17892- der Zustandsgrenzen (ISO 17892-12:2018)

12:2018)
This European Standard was approved by CEN on 15 June 2018.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17892-12:2018 E

worldwide for CEN national Members.
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SIST EN ISO 17892-12:2018
EN ISO 17892-12:2018 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 17892-12:2018
EN ISO 17892-12:2018 (E)
European foreword

This document (EN ISO 17892-12:2018) has been prepared by Technical Committee ISO/TC 182

"Geotechnics" in collaboration with Technical Committee CEN/TC 341 “Geotechnical Investigation and

Testing” the secretariat of which is held by BSI.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by January 2019, and conflicting national standards shall

be withdrawn at the latest by January 2019.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes CEN ISO/TS 17892-12:2004.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
Endorsement notice

The text of ISO 17892-12:2018 has been approved by CEN as EN ISO 17892-12:2018 without any

modification.
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SIST EN ISO 17892-12:2018
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SIST EN ISO 17892-12:2018
INTERNATIONAL ISO
STANDARD 17892-12
First edition
2018-06
Geotechnical investigation and
testing — Laboratory testing of soil —
Part 12:
Determination of liquid and plastic
limits
Reconnaissance et essais géotechniques — Essais de laboratoire sur
les sols —
Partie 12: Détermination des limites de liquidité et de plasticité
Reference number
ISO 17892-12:2018(E)
ISO 2018
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SIST EN ISO 17892-12:2018
ISO 17892-12:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
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SIST EN ISO 17892-12:2018
ISO 17892-12:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Apparatus ..................................................................................................................................................................................................................... 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Fall cone method ................................................................................................................................................................................... 3

4.3 Casagrande method ............................................................................................................................................................................ 5

4.4 Plastic limit equipment .................................................................................................................................................................... 6

5 Test procedure ........................................................................................................................................................................................................ 7

5.1 Choice of liquid limit method ..................................................................................................................................................... 7

5.2 Specimen preparation ...................................................................................................................................................................... 7

5.3 Determination of liquid limit by the fall cone method ......................................................................................... 8

5.4 Determination of liquid limit by the Casagrande method ..............................................................................10

5.5 Determination of plastic limit .................................................................................................................................................12

6 Test results ...............................................................................................................................................................................................................13

6.1 Proportion of sample smaller than 0,4 mm ................................................................................................................13

6.2 Liquid limit by the fall cone method ..................................................................................................................................13

6.3 Liquid limit by the Casagrande method .........................................................................................................................15

6.4 Plastic limit ..............................................................................................................................................................................................15

6.5 Plasticity index .....................................................................................................................................................................................16

7 Test report ................................................................................................................................................................................................................16

7.1 Mandatory reporting ......................................................................................................................................................................16

7.2 Optional reporting ............................................................................................................................................................................16

Annex A (normative) Calibration, maintenance and checks ....................................................................................................18

Annex B (normative) Additional parameters ...........................................................................................................................................25

Bibliography .............................................................................................................................................................................................................................27

© ISO 2018 – All rights reserved iii
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SIST EN ISO 17892-12:2018
ISO 17892-12:2018(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following

URL: www .iso .org/iso/foreword .html.

This document was prepared by the European Committee for Standardization (CEN) Technical

Committee CEN/TC 341 Geotechnical investigation and testing, in collaboration with ISO Technical

Committee TC 182, Geotechnics, in accordance with the Agreement on technical cooperation between

ISO and CEN (Vienna Agreement).

This first edition of ISO 17892-12 cancels and replaces ISO/TS 17892-12:2004, which has been

technically revised. It also incorporates ISO/TS 17892-12:2004/Cor.1:2006.
A list of all the parts in the ISO 17892 series can be found on the ISO website.
iv © ISO 2018 – All rights reserved
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SIST EN ISO 17892-12:2018
ISO 17892-12:2018(E)
Introduction

This document covers areas in the international field of geotechnical engineering never previously

standardised internationally. It is intended that this document presents broad good practice and

significant differences with national documents is not anticipated. It is based on international practice

(see Reference [1]).
© ISO 2018 – All rights reserved v
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SIST EN ISO 17892-12:2018
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SIST EN ISO 17892-12:2018
INTERNATIONAL STANDARD ISO 17892-12:2018(E)
Geotechnical investigation and testing — Laboratory
testing of soil —
Part 12:
Determination of liquid and plastic limits
1 Scope

This document specifies methods for the determination of the liquid and plastic limits of a soil. These

comprise two of the Atterberg limits for soils.

The liquid limit is the water content at which a soil changes from the liquid to the plastic state.

This document describes the determination of the liquid limit of a specimen of natural soil, or of

a specimen of soil from which material larger than about 0,4 mm has been removed. This document

describes two methods: the fall cone method and the Casagrande method.

NOTE The fall cone method in this document should not be confused with that of ISO 17892-6.

The plastic limit of a soil is the water content at which a soil ceases to be plastic when dried further.

The determination of the plastic limit is normally made in conjunction with the determination of the

liquid limit. It is recognized that the results of the test are subject to the judgement of the operator, and

that some variability in results will occur.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth

ISO 14688-1, Geotechnical investigation and testing — Identification and classification of soil — Part 1:

Identification and description

ISO 17892-1, Geotechnical investigation and testing — Laboratory testing of soil — Part 1: Determination

of water content
3 Terms and definitions

For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain

terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https: //www .electropedia .org/
— ISO Online browsing platform: available at https: //www .iso .org/obp
3.1
liquid limit

water content at which a soil passes from the liquid to the plastic state, as determined by the liquid

limit test
© ISO 2018 – All rights reserved 1
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SIST EN ISO 17892-12:2018
ISO 17892-12:2018(E)
3.2
plastic limit

water content at which a specimen ceases to be plastic when dried further, as determined by the plastic

limit test
3.3
plasticity index
numerical difference between the liquid limit and the plastic limit of a soil
3.4
non plastic soil

soil which has a plasticity index of zero or one for which the plastic limit cannot be determined

4 Apparatus
4.1 General

See also Annex A for more manufacturing tolerances (where appropriate), calibration, maintenance and

checks on the equipment.
4.1.1 Balance.

The balance shall have an accuracy of 0,01 g or 0,1 % of the weighed mass whichever value is the greater.

4.1.2 Test specimen containers.

Test specimen containers shall be made of a material that does not change mass as a result of repeated

drying cycles. Glass, porcelain and corrosion-resistant metals have been found to be suitable. Containers

shall have a capacity large enough to hold the mass of sample to be dried without spillage, but should

not be so large that the mass of the empty container is significantly in excess of that of the specimen.

Containers used for plastic limit determinations shall have close fitting lids.
4.1.3 Water.

Water should be distilled, de-ionized or demineralized. Where distilled is referred to in this document,

the terms are interchangeable.
4.1.4 Ancillary apparatus.
4.1.4.1 Spatulas.
4.1.4.2 Spray bottle (preferably of plastic).
4.1.4.3 Evaporating dishes.
4.1.4.4 Sieves complying with ISO 3310-1.
4.1.4.5 Flat mixing plate, for example glass.
4.1.4.6 Metal straightedge about 100 mm long.
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SIST EN ISO 17892-12:2018
ISO 17892-12:2018(E)
4.2 Fall cone method
4.2.1 Fall cone apparatus.

4.2.1.1 The fall cone apparatus is shown schematically in Figure 1. It shall permit the cone to be

held firmly initially and to be released instantaneously to fall freely in a vertical direction into the soil

specimen.
Key
1 vertical adjustment mechanism
2 penetration measurement device
3 fall cone
4 lock/release button
5 specimen cup
Figure 1 — Schematic of a fall cone apparatus

4.2.1.2 The fall cone apparatus shall have a vertical adjustment mechanism which allows the cone to

be raised or lowered and adjusted so that the tip of the cone just touches the surface of the specimen

before the cone is released.

4.2.1.3 The fall cone apparatus shall be equipped with a method of measuring the penetration of the

cone into the specimen after release to a resolution of 0,1 mm (or better), within the range 5 mm to

20 mm if the 60 g/60° cone is used, or within the range 10 mm to 30 mm if the 80 g/30° cone is used.

© ISO 2018 – All rights reserved 3
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SIST EN ISO 17892-12:2018
ISO 17892-12:2018(E)
4.2.2 Cones.
4.2.2.1 A typical cone is shown schematically in Figure 2.
Key
1 cone
2 shaft
3 cone tip
a deviation from the geometrical tip at manufacturing
b maximum tip wear
h height of the conical tip
β tip angle
Figure 2 — Example of liquid limit fall cone penetrometer (60° cone)

4.2.2.2 Either a 60 g/60° cone or a 80 g/30° cone complying with the requirements of Table 1 may be

used as it has been shown that both cones give essentially the same value for the liquid limit. Other cone

devices may be adopted provided they can be shown to give comparable results to those obtained from

the tests described herein.

Table 1 — Set of fall cones — Typical manufacturing specifications for masses and dimensions

Mass of cone plus shaft g 60 ± 0,06 80 ± 0,08
Tip angle β ° 60 ± 0,2 30 ± 0,2
Height of the cone tip h mm ≥20 ≥30
The deviation a from the geometrical tip at manufacturing mm <0,1 <0,1

4.2.2.3 The cone shall be manufactured of or coated with a corrosion resistant material such as

stainless steel or chromium, and should have smooth polished surfaces with an average roughness Ra of

less than 0,8 μm as a manufacturing specification. The cone surface has to remain smooth with use, and

should be replaced if the smooth surface is noticeably damaged.
4.2.2.4 The maximum wear b shall be less than 0,3 mm (see Figure 2).
4.2.3 Sample cup.

The sample cup shall be made of non-corrodible and rigid material, spherical or cylindrical in shape. If

cylindrical, it shall have a base parallel to the rim with a diameter of at least 50 mm and a depth of at

least 25 mm if the 60 g/60° cone is used and a depth of at least 40 mm if the 80 g/30° cone is used.

4 © ISO 2018 – All rights reserved
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ISO 17892-12:2018(E)
4.2.4 Timing device.
A clock or stop-watch, or similar, capable of being read to the nearest 1 s.
4.3 Casagrande method
4.3.1 Casagrande apparatus.

The Casagrande apparatus is shown schematically in Figure 3. The apparatus consists of a specimen cup

which is raised by a cam and then dropped a specified distance onto a base. The device may be operated

by either a hand crank or electric motor. Dimensions, manufacturing specifications and tolerances are

included in Annex A. A Casagrande apparatus and grooving tool in accordance with other specifications

may be adopted provided it can be shown to give comparable results.
Key
1 specimen cup (= bowl)
2 hanger
3 carriage with pin
4 cam (turned by handle or motor)
5 base
6 rubber feet
7 point of contact
Figure 3 — Schematic of the Casagrande apparatus
4.3.2 Base and rubber feet.

The base and feet shall be made of rubber complying with the requirements of Table 2. The feet

supporting the base, are designed to provide isolation of the base from the work surface.

Table 2 — Base and feet — Rubber requirements
Hardness of the feet Hardness of the base Resilience of the base
Shore A value Resilience (rebound value)
Shore D value of at least 80
between 62 and 65 between S = 0,80 and S = 0,90
© ISO 2018 – All rights reserved 5
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SIST EN ISO 17892-12:2018
ISO 17892-12:2018(E)

Measurement of hardness (Shore A and Shore D) and resilience S is defined in A.3.7.5.

4.3.3 Specimen Cup.

The specimen cup should be made of brass or stainless steel. The shape of the cup shall be a segment of

a sphere. Dimensions, manufacturing specifications and tolerances are included in Annex A.

The cup should not be polished. The surface has to remain smooth with use, and should be replaced if

the smooth surface is noticeably damaged.
4.3.4 Cam.

The cam shall raise the cup smoothly and continuously to its maximum height, by increasing the radius

of the cam over at least 180° of cam rotation. The final portion of the cam shall be shaped so that the cup

does not develop an upward or downward velocity when the cam follower leaves the cam. A logarithmic

spiral design has been found to be satisfactory.
4.3.5 Carriage.

The carriage is constructed in a way that allows convenient but secure adjustment of the 10 mm height-

of-drop of the cup.
4.3.6 Motor drive (optional).

The apparatus may be equipped with a motor to turn the cam and if used shall operate at 2 ± 0,25

revolutions per second. The motor shall be isolated from the rest of the device by rubber mounts or in

some other way that prevents vibration from the motor being transmitted to the rest of the apparatus.

4.3.7 Grooving tool.

A flat or curved tool made of plastic or non-corroding-metal. The grooving tool shall have a bevelled tip

(see Annex A). The design of the tool may vary as long as the essential dimensions are maintained. The

tool may, but need not incorporate the gauge for adjusting the height-of-drop of the liquid limit device.

4.4 Plastic limit equipment
4.4.1 Mixing plate.

The mixing plate shall be flat, clean and smooth, and should be free from significant scratches which

affect the behaviour during rolling of the threads. A glass plate of about 10 mm thick and 300 mm

square has been found to be convenient.
4.4.2 Rod or gauge.

Either a rod with a diameter between 3 mm and 3,5 mm, or a gauge with an opening of the same size,

shall be used.
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SIST EN ISO 17892-12:2018
ISO 17892-12:2018(E)
5 Test procedure
5.1 Choice of liquid limit method

Two independent test methods are included in this document for the determination of the liquid limit.

The fall cone method provides results with higher repeatability, and is the preferred method. However,

there is a long history of use of the Casagrande method and its use is equally permitted.

NOTE 1 The two methods are known to give a difference in results. Experience has shown that the liquid limit

determined by the fall cone and the Casagrande apparatus are in general agreement at a w of around 30 % to

40 %. At higher values of w , the Casagrande apparatus generally gives slightly greater values of liquid limit. At

lower values of w , the Casagrande apparatus generally gives slightly smaller values of liquid limit.

For both liquid limit methods either a four-point test, or a one-point test, may be used. The four-point

test is described here and is preferred. However the one-point method may be appropriate in soils

whose plasticity is well understood and for which robust correlation factors have been established.

NOTE 2 In the four point liquid limit method the test is carried out at four different water contents whereas in

the one point method the test is carried out at a single water content.

The choice of test method to be used shall be agreed with the client and reported.

5.2 Specimen preparation

5.2.1 Whenever possible the tests shall be carried out on soil from its natural state. About 200 g of soil

finer than 0,4 mm is required for the determination of the liquid limit by either method. Sieves with an

aperture of 0,425 mm or an aperture of 0,400 mm are acceptable for removing the coarser material.

NOTE Where, further in this document, a 0,4 mm or nearest sieve is mentioned, sieves with an aperture of

0,425 mm or an aperture of 0,400 mm, are acceptable.

Soils should not normally be oven-dried before testing, but if this is necessary it shall be reported.

For soils that are susceptible to oxidation when exposed to air, the tests should either be determined

immediately after extrusion, or if done at a later time, the specimen shall be sealed until the test is

performed.

5.2.2 If the sample does not include material larger than about 0,4 mm, go to 5.2.8.

5.2.3 If the sample includes material larger than about 0,4 mm, this coarser fraction should be removed

as in 5.2.4 to 5.2.7.

5.2.4 Determine the water content (w) of a representative specimen of the original sample according

to ISO 17892-1.

5.2.5 Weigh a representative specimen of undried soil that will give at least 200 g of soil passing a

0,4 mm or nearest sieve. Weigh this representative specimen of undried soil to 0,1 % of its mass or 0,01 g,

whichever is the greater (m ).

5.2.6 If the fraction larger than 0,4 mm consists of a small number of discrete coarse particles, these

may be removed by hand, dried at 105 °C to 110 °C and weighed (m ).

5.2.7 If the coarse fraction cannot readily be removed by hand, the particles shall be removed using the

wet separation method as follows.

5.2.7.1 Place the specimen in a container and add just enough distilled water to cover it, and then stir

until it forms a slurry.
© ISO 2018 – All rights reserved 7
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SIST EN ISO 17892-12:2018
ISO 17892-12:2018(E)

5.2.7.2 Pour the slurry through a 0,4 mm or nearest sieve. A larger aperture guard sieve may be used

to protect this sieve. Wash the material retained on the sieve with a minimum amount of distilled water

until the water passing the 0,4 mm or nearest sieve is virtually clear. Re
...

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