ISO 1920-8:2009
(Main)Testing of concrete — Part 8: Determination of drying shrinkage of concrete for samples prepared in the field or in the laboratory
Testing of concrete — Part 8: Determination of drying shrinkage of concrete for samples prepared in the field or in the laboratory
ISO 1920-8:2009 specifies a method for determining the length changes of concrete specimens due to drying in air, and the method of preparing and curing the concrete specimens to be tested.
Essais du béton — Partie 8: Détermination du retrait de séchage du béton d'échantillons préparés sur le terrain ou en laboratoire
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 1920-8
First edition
2009-04-01
Testing of concrete —
Part 8:
Determination of drying shrinkage of
concrete for samples prepared in the field
or in the laboratory
Essais du béton —
Partie 8: Détermination du retrait de séchage du béton d'échantillons
préparés sur le terrain ou en laboratoire
Reference number
©
ISO 2009
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2009 – All rights reserved
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Principle. 2
5 Apparatus . 2
6 Test samples and specimens . 7
6.1 Sampling. 7
6.2 Test specimens . 8
7 Procedure . 8
7.1 Measurement of consistence and temperature of concrete. 8
7.2 Preparation and filling of the moulds . 8
7.3 Compacting of concrete. 8
7.4 Curing of specimens . 9
7.5 Drying and measurement of specimens. 10
8 Calculation and expression of results. 12
9 Test report . 12
10 Precision for laboratory-prepared specimens. 14
Annex A (informative) A suitable horizontal length comparator. 15
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 1920-8 was prepared by Technical Committee ISO/TC 71, Concrete, reinforced concrete and pre-
stressed concrete, Subcommittee SC 1, Test methods for concrete.
ISO 1920 consists of the following parts, under the general title Testing of concrete:
⎯ Part 1: Sampling of fresh concrete
⎯ Part 2: Properties of fresh concrete
⎯ Part 3: Making and curing test specimens
⎯ Part 4: Strength of hardened concrete
⎯ Part 5: Properties of hardened concrete other than strength
⎯ Part 6: Sampling, preparing and testing of concrete cores
⎯ Part 7: Non-destructive tests on hardened concrete
⎯ Part 8: Determination of drying shrinkage of concrete for samples prepared in the field or in the laboratory
⎯ Part 9: Determination of creep of concrete cylinders in compression
The following part is under preparation:
⎯ Part 10: Determination of static modulus of elasticity in compression
iv © ISO 2009 – All rights reserved
INTERNATIONAL STANDARD ISO 1920-8:2009(E)
Testing of concrete —
Part 8:
Determination of drying shrinkage of concrete for samples
prepared in the field or in the laboratory
1 Scope
This part of ISO 1920 specifies a method for determining the length changes of concrete specimens due to
drying in air, and the method of preparing and curing the concrete specimens to be tested.
It is applicable for the testing of specimens prepared in the laboratory or in the field, in which the maximum
nominal size of aggregate in the concrete, in accordance with ISO 6274, does not exceed 25 mm.
The precision statement in Clause 10 does not apply to specimens that have had non-standard initial curing
(normally field-prepared specimens). In addition, this part of ISO 1920 requires that field-prepared specimens
be marked, recorded and reported as such.
NOTE 1 This test method is not always suitable for very low slump concrete (less than 20 mm), primarily due to the
difficulties in obtaining adequate compaction. Provided adequate compaction is obtained, the method is applicable.
NOTE 2 The method is specifically developed for measurement of drying shrinkage of concrete, but it is capable of
adaptation for measurement of length changes of specimens subjected to a variety of environmental conditions.
2 Normative references
The following referenced documents are essential for the application of this part of ISO 1920. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 1920-1, Testing of concrete — Part 1: Sampling of fresh concrete
ISO 1920-2, Testing of concrete — Part 2: Properties of fresh concrete
ISO 1920-3:2004, Testing of concrete — Part 3: Making and curing test specimens
ISO 6274, Concrete — Sieve analysis of aggregates
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
preparing laboratory
laboratory responsible for sampling of concrete, moulding of specimens, initial curing in moulds, demoulding,
initial moist curing and transport to measuring laboratory (if required)
3.2
measuring laboratory
laboratory responsible for completion of initial moist curing, storage in drying room and measurement of
specimens
NOTE In some instances, the preparing and measuring laboratories will be the same.
4 Principle
Specimens are cured and air dried for a specified time, and the change in length is measured.
5 Apparatus
5.1 Drying room, with suitably controlled temperature, humidity and air circulation, for storing specimens in
air and for measuring their length.
The room shall meet the following requirements.
a) Air shall be circulated through the room in a uniform manner, so that the specified conditions are
attained adjacent to all specimens under test.
b) The temperature in the drying room shall be maintained at (22 ± 2) °C.
c) The relative humidity in the drying room shall be maintained at (55 ± 5) % at all times.
d) The room shall be fitted with recording devices, capable of rapid response to changes in room
conditions, which will continuously record the temperature and the relative humidity.
The recording detectors shall be verified against a standardized Assmann hygrometer at intervals of time
that will assure compliance with the temperature and humidity requirements specified in 5.1, b) and c).
NOTE 1 A suitable rapid response device for recording temperature and humidity uses a combined detector with a
thin-film capacitor for humidity and a platinum resistance thermocouple for temperature measurement. Response
time for this type of detector is measured in seconds and is virtually instantaneous within the narrow range required
for this test method.
NOTE 2 Most thermo hygrographs are unsuitable for the purpose, as the response is too slow to detect the full
extent of fluctuations, particularly with the hair type of humidity detector.
e) The rate of air movement in the drying room shall be determined and controlled by sensors in order
to maintain the rate of evaporation at (12 ± 5) ml per 24 h. The evaporation rates shall be determined
by measuring the loss in weight of water in 400 ml low-form beakers of internal diameter
(78 ± 5) mm, initially containing approximately 375 g of water at a temperature of (20 ± 2) °C. The
weight of water in the beaker shall not fall below 325 g. Each beaker shall be placed midway
between test specimens on the storage racks with the water level at approximately the same height
as the top of the specimens.
Systematic checks shall be carried out on the sensors or on the evaporation rates by varying the location
of the beakers within the drying room at least monthly, or where conditions have changed. The results
shall be recorded.
f) The requirements for temperature, humidity and evaporation rate apply to each storage position.
Only positions that conform to these requirements shall be used for storage of test specimens.
g) The drying room shall be fitted with suitable racks for storing specimens. The racks shall permit free
circulation of air around specimens, except for necessary supports, and shall be so situated with
respect to the nearest wall or other obstruction that air circulation is not restricted in the intervening
2 © ISO 2009 – All rights reserved
space. The horizontal supports shall consist of non-absorptive members having a total bearing width
supporting the specimen of not more than 25 mm.
5.2 Moulds, made of non-absorbent material that does not react with cement paste and their internal
surfaces; shall have a smooth finish.
The moulds shall be substantial enough to hold their form without distortion and shall be substantially leak proof.
They shall meet the following requirements.
5.2.1 General
Each mould shall be provided with a base plate, two end plates and two side plates which are securely
fastened to the end plates, and two partially loose end plates which act as gauge stud holders. Each gauge
stud holder shall fit inside the end of the mould and shall locate and secure a gauge stud during the setting
period of the concrete. Each gauge stud holder shall be held in position against the end plate by a retaining
screw and shall be capable of release after compaction of the concrete. The opposite side plates shall be
parallel.
The dimensions of the mould shall be one of the following.
a) For specimens having dimensions of 75 mm × 75 mm × 280 mm (see 6.2.2)
⎯ the distance between the opposite side plates shall be (75 ± 1) mm, and
⎯ the inside height shall be (75 ± 1) mm;
b) For specimens having dimensions of 100 mm × 100 mm × 400 mm
⎯ the distance between the opposite side plates shall be (100 ± 1) mm, and
⎯ the inside height shall be (100 ± 1) mm.
5.2.2 Construction of the mould
The mould shall be aligned coaxially along the central axis of the mould.
a) For specimens having dimensions of 75 mm × 75 mm × 280 mm:
⎯ the distance between the inner ends of the two studs shall be (250 ± 0,5) mm;
⎯ the distance between the outer ends of the gauge studs shall be (295 ± 1) mm;
⎯ gauge studs shall protrude from the gauge stud holders to a distance of (15 ± 1) mm.
b) For specimens having dimensions of 100 mm × 100 mm × 400 mm:
⎯ the distance between the inner ends of the two studs shall be (360 ± 0,5) mm;
⎯ the distance between the outer ends of the gauge studs shall be (420 ± 1) mm;
⎯ gauge studs shall protrude from the gauge stud holders to a
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.