Testing of concrete — Part 9: Determination of creep of concrete cylinders in compression

ISO 1920-9:2009 specifies a method for determining the creep of standard concrete test cylinders subjected to a sustained longitudinal compressive load.

Essais du béton — Partie 9: Détermination du fluage de cylindres de béton en compression

General Information

Status
Published
Publication Date
23-Mar-2009
Current Stage
9093 - International Standard confirmed
Completion Date
03-Dec-2019
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ISO 1920-9:2009 - Testing of concrete
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INTERNATIONAL ISO
STANDARD 1920-9
First edition
2009-04-01


Testing of concrete —
Part 9:
Determination of creep of concrete
cylinders in compression
Essais du béton —
Partie 9: Détermination du fluage de cylindres de béton en compression





Reference number
ISO 1920-9:2009(E)
©
ISO 2009

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ISO 1920-9:2009(E)
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ii © ISO 2009 – All rights reserved

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ISO 1920-9:2009(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
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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 1920-9 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

© ISO 2009 – All rights reserved iii

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INTERNATIONAL STANDARD ISO 1920-9:2009(E)

Testing of concrete —
Part 9:
Determination of creep of concrete cylinders in compression
1 Scope
This part of ISO 1920 specifies a method for determining the creep of standard concrete test cylinders
subjected to a sustained longitudinal compressive load.
NOTE The conditions for curing and storage (see 6.1) can be varied to suit different requirements, e.g. early
pre-stress. The time of loading (see 6.2) can also be varied to give an indication of other properties. These variations,
however, will not conform to the requirements for a creep test as specified in this part of ISO 1920 and it is necessary that
any deviation from the standard procedure be recorded in the test report.
2 Normative references
The following referenced documents are essential for the application 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 1920-3:2004, Testing of concrete — Part 3: Making and curing test specimens
ISO 1920-4:2005, Testing of concrete — Part 4: Strength of hardened concrete
ISO 1920-8:2009, Testing of concrete — Part 8: Determination of drying shrinkage of concrete for samples
prepared in the field or in the laboratory
3 Principle
The creep of the concrete is obtained by determining the total combined creep and drying shrinkage of the
loaded specimens and subtracting from this value the drying shrinkage of the unloaded specimens, all
specimens being stored in the same environmental conditions. This part of ISO 1920 details the fixed
environmental conditions for carrying out the test, which allows comparison with previously tested specimens
and specimens tested in other laboratories.
4 Apparatus
4.1 Loading frame, capable of applying and maintaining the required load on the specimen or group of
specimens for the duration of the test. The means of maintaining the load may be either a spring or system of
springs; alternatively, a hydraulic ram or capsule may be used.
A schematic diagram of a loading frame operated by a hydraulic arrangement is given in Figure 1. A similar
arrangement can also be used for a spring-loaded system in which the system of loading only will be different.
NOTE The arrangement shown in Figure 1 employs the vertical loading of specimens. Horizontal loading of
specimens is also frequently employed.
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ISO 1920-9:2009(E)

Key
1 test cylinders
2 end plates
3 gauge reference points
4 load cell
5 hemispherical seat
6 load sustaining cell
7 pressure gauge
a
To pump.
Figure 1 — Schematic arrangement for testing creep of concrete

Where the load-maintaining system comprises a spring or a system of springs, initial compression shall be
applied by means of a portable jack or testing machine.
Where a system of springs is used for load maintenance, care should be taken in the selection of springs,
which should be long and suitably matched for the purpose.
2 © ISO 2009 – All rights reserved

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ISO 1920-9:2009(E)
Means shall be provided for measuring the load to the nearest 2 % of the total applied load. Suitable means of
measuring the load are by
a) a permanently installed hydraulic load cell with calibrated pressure gauge,
b) a calibrated hydraulic jack with pressure gauge, or
c) a calibrated load cell inserted in the frame at the time of loading or when the load is adjusted.
All end plates of the loading frame shall be sufficiently rigid to ensure uniform loading of the cylinders. At one
end of the specimen or group of specimens a suitable spherical seating device shall be provided between the
specimens and the end plates. Bearing surfaces of any plates in contact with the loaded specimens shall not
depart from a plane by more than 0,05 mm.
In any loading frame, a group of specimens may be stacked for simultaneous loading.
4.2 Strain-measuring device, which meets the following requirements.
a) A suitable apparatus shall be provided for the measurement of longitudinal strain in each specimen to the
nearest 10 microstrain. The apparatus may be attached or portable. In all cases, reference gauge points
shall be positively attached to the specimen. Gauges relying on friction contact shall not be used.
b) Deformations shall be measured on gauge lines spaced uniformly around the periphery of the specimen.
The gauge reference points shall be evenly spaced at about the mid-height of the specimen. The number
of gauge lines shall be not less than two for control specimens and not less than three for loaded
specimens.
c) The effective gauge length shall be not less than three times the maximum aggregate size and not
greater than
1) 260 mm for large specimens without end plates, and 160 mm for small specimens without end
plates, and
2) 150 mm for large specimens having attached end plates, and 100 mm for small specimens having
attached end plates.
NOTE 1 A “small specimen” made of concrete is one having the maximum nominal size of the aggregate not
greater than 25 mm, while a “large specimen” made of concrete is one having the maximum nominal size of the
aggregate greater than 25 mm.
d) The strain-measuring device shall be capable of measuring the range of strains over one year without
change in calibration.
NOTE 2 Systems in which the varying strains are compared with a constant-length standard bar are considered
the most reliable.
5 Test specimens
5.1 General
Cylinders of 100 mm diameter may be used for creep determinations, but the specimen size shall be selected
so that requirements in respect to maximum agg
...

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