SIST EN 12390-13:2021
(Main)Testing hardened concrete - Part 13: Determination of secant modulus of elasticity in compression
Testing hardened concrete - Part 13: Determination of secant modulus of elasticity in compression
This document specifies the method for the determination of the secant modulus of elasticity in compression of hardened concrete on test specimens which can be cast or taken from a structure.
The test method allows the determination of two secant moduli of elasticity: the initial modulus, EC,0 measured at first loading and the stabilized modulus, EC,S measured after three loading cycles.
Two different test methods are given. The first (Method A) is for determination of both initial and stabilized moduli, the second (Method B) is for determination of stabilized modulus only.
Prüfung von Festbeton - Teil 13: Bestimmung des Elastizitätsmoduls unter Druckbelastung (Sekantenmodul)
Dieses Dokument legt das Verfahren zur Bestimmung des Elastizitätsmoduls von Festbeton als Sekantenmodul unter Druckbelastung unter Verwendung von in Form hergestellten oder aus Bauwerken entnommenen Probekörpern fest.
Dieses Prüfverfahren ermöglicht die Bestimmung von zwei Elastizitätsmoduln: dem anfänglichen Modul EC,0, der bei der ersten Belastung, und dem stabilisierten Modul EC,S, der nach drei Belastungszyklen gemessen wird.
Es werden zwei unterschiedliche Prüfverfahren angegeben. Das erste Verfahren (Verfahren A) dient zur Bestimmung sowohl des anfänglichen als auch des stabilisierten Elastizitätsmoduls, während das zweite Verfahren (Verfahren B) nur zur Bestimmung des stabilisierten Elastizitätsmoduls dient.
Essais pour béton durci - Partie 13 : Détermination du module sécant d’élasticité en compression
Le présent document spécifie la méthode de détermination du module sécant d’élasticité en compression du béton durci, en utilisant des éprouvettes pouvant avoir été moulées ou prélevées dans une structure.
La méthode d’essai permet de déterminer deux modules sécants d’élasticité : le module initial, EC,0, mesuré lors de la première application de la charge et le module stabilisé, EC,S, mesuré après trois cycles de chargement.
Deux méthodes d’essai différentes sont indiquées. La première (méthode A) porte sur la détermination à la fois du module initial et du module stabilisé, la seconde (méthode B) concerne la détermination du module stabilisé uniquement.
Preskušanje strjenega betona - 13. del: Določanje sekantnega modula elastičnosti pri tlačni obremenitvi
General Information
RELATIONS
Standards Content (sample)
SLOVENSKI STANDARD
SIST EN 12390-13:2021
01-september-2021
Nadomešča:
SIST EN 12390-13:2014
Preskušanje strjenega betona - 13. del: Določanje sekantnega modula elastičnosti
pri tlačni obremenitvi
Testing hardened concrete - Part 13: Determination of secant modulus of elasticity in
compressionPrüfung von Festbeton - Teil 13: Bestimmung des Elastizitätsmoduls unter
Druckbelastung (Sekantenmodul)
Essais pour béton durci - Partie 13 : Détermination du module sécant d’élasticité en
compressionTa slovenski standard je istoveten z: EN 12390-13:2021
ICS:
91.100.30 Beton in betonski izdelki Concrete and concrete
products
SIST EN 12390-13:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------SIST EN 12390-13:2021
---------------------- Page: 2 ----------------------
SIST EN 12390-13:2021
EN 12390-13
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2021
EUROPÄISCHE NORM
ICS 91.100.30 Supersedes EN 12390-13:2013
English Version
Testing hardened concrete - Part 13: Determination of
secant modulus of elasticity in compression
Essais pour béton durci - Partie 13 : Détermination du Prüfung von Festbeton - Teil 13: Bestimmung des
module sécant d'élasticité en compression Elastizitätsmoduls unter Druckbelastung
(Sekantenmodul)This European Standard was approved by CEN on 7 June 2021.
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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, 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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12390-13:2021 E
worldwide for CEN national Members.---------------------- Page: 3 ----------------------
SIST EN 12390-13:2021
EN 12390-13:2021 (E)
Contents Page
European foreword ....................................................................................................................................................... 3
1 Scope .................................................................................................................................................................... 5
2 Normative references .................................................................................................................................... 5
3 Terms, definitions, symbols and abbrivations ..................................................................................... 5
3.1 Terms and definitions ................................................................................................................................... 5
3.2 Symbols and abbreviations ......................................................................................................................... 6
4 Principle ............................................................................................................................................................. 7
5 Apparatus ........................................................................................................................................................... 7
5.1 Test machine ..................................................................................................................................................... 7
5.2 Instrumentation .............................................................................................................................................. 7
5.3 Gauge length...................................................................................................................................................... 8
6 Test specimens ................................................................................................................................................. 8
6.1 Shape and dimensions of specimens ........................................................................................................ 8
6.2 Curing, storage and conditioning .............................................................................................................. 8
7 Method ................................................................................................................................................................ 8
7.1 Specimen instrumentation and positioning .......................................................................................... 8
7.2 Determination of compressive strength ................................................................................................. 9
7.3 Determination of secant modulus of elasticity ..................................................................................... 9
7.3.1 Method A – Determination of initial and stabilized secant modulus of elasticity ................... 9
7.3.2 Method B – determination of stabilized secant modulus of elasticity ...................................... 11
8 Calculation of secant modulus of elasticity ......................................................................................... 13
8.1 Initial secant modulus of elasticity (Method A) ................................................................................ 13
8.2 Stabilized secant modulus of elasticity (Method A and B) ............................................................ 13
9 Test report ...................................................................................................................................................... 14
10 Precision .......................................................................................................................................................... 14
Bibliography ................................................................................................................................................................. 15
---------------------- Page: 4 ----------------------SIST EN 12390-13:2021
EN 12390-13:2021 (E)
European foreword
This document (EN 12390-13:2021) has been prepared by Technical Committee CEN/TC 104 “Concrete
and related products”, the secretariat of which is held by SN.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 2022, and conflicting national standards shall
be withdrawn at the latest by January 2022.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 EN 12390-13:2013.The following amendments have been made in comparison to the former edition:
— upper limit of lower stress increased to prevent sample unloading when testing low strength
concrete;— change to the loading profile in Method B.
This document is based on an extensive investigation and comparison of existing National Standards:
ASTM, BS, DIN, ISO, NORD TEST and UNI followed by the analysis of a test programme involving five
laboratories carried out by UNI.This document is one of a series on testing concrete.
EN 12390, Testing hardened concrete, consists of the following parts:
— Part 1: Shape, dimensions and other requirements for specimens and moulds
— Part 2: Making and curing specimens for strength tests
— Part 3: Compressive strength of test specimens
— Part 4: Compressive strength – Specification for testing machines
— Part 5: Flexural strength of test specimens
— Part 6: Tensile splitting strength of test specimens
— Part 7: Density of hardened concrete
— Part 8: Depth of penetration of water under pressure
— Part 10: Determination of the carbonation resistance of concrete at atmospheric levels of carbon dioxide
— Part 11: Determination of the chloride resistance of concrete, unidirectional diffusion
— Part 12: Determination of the potential carbonation resistance of concrete: Accelerated carbonation
method— Part 13: Determination of secant modulus of elasticity in compression
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SIST EN 12390-13:2021
EN 12390-13:2021 (E)
— Part 14: Semi-adiabatic method for the determination of heat released by concrete during its hardening
process— Part 15: Adiabatic method for the determination of heat released by concrete during its hardening
process— Part 16: Determination of shrinkage of concrete
— Part 17: Determination of creep of concrete in compression
— Part 18: Determination of chloride migration coefficient (in preparation)
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.---------------------- Page: 6 ----------------------
SIST EN 12390-13:2021
EN 12390-13:2021 (E)
1 Scope
This document specifies the method for the determination of the secant modulus of elasticity in
compression of hardened concrete on test specimens which can be cast or taken from a structure.
The test method allows the determination of two secant moduli of elasticity: the initial modulus, E
C,0measured at first loading and the stabilized modulus, E measured after three loading cycles.
C,STwo different test methods are given. The first (Method A) is for determination of both initial and
stabilized moduli, the second (Method B) is for determination of stabilized modulus only.
2 Normative referencesThe 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.
EN 12390-1, Testing hardened concrete - Part 1: Shape, dimensions and other requirements for specimens
and mouldsEN 12390-2, Testing hardened concrete - Part 2: Making and curing specimens for strength tests
EN 12390-3, Testing hardened concrete - Part 3: Compressive strength of test specimens
EN 12390-4, Testing hardened concrete - Part 4: Compressive strength - Specification for testing machines
EN 12504-1, Testing concrete in structures - Part 1: Cored specimens - Taking, examining and testing in
compressionEN 12620, Agregates for concrete
EN ISO 9513, Metallic materials - Calibration of extensometer systems used in uniaxial testing (ISO 9513)
3 Terms, definitions, symbols and abbrivations3.1 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
3.1.1
initial secant modulus of elasticity
C,0
secant slope of the stress strain curve at first loading
3.1.2
stabilized secant modulus of elasticity
C,S
secant slope of the stress strain curve after three loading cycles
---------------------- Page: 7 ----------------------
SIST EN 12390-13:2021
EN 12390-13:2021 (E)
3.1.3
gauge length
base length
length used as reference base for strain measurement
3.1.4
measuring line
straight line laying on the lateral surface of the specimen and parallel to the vertical axis (see Figure 1)
Key1 measuring line
Figure 1 — Measuring line on cylinder and prismatic specimens
3.2 Symbols and abbreviations
For the purposes of this document, the following symbols apply.
d Specimen diameter or width
D Upper sieve size (for definition of aggregates size, see EN 12620)
D Declared value of D of the coarsest fraction of aggregates actually used in the concrete
maxf Compressive strength of concrete determined by testing companion specimens – cylinders,
prisms, cubes or cores – or estimated from non-destructive testsE Initial secant modulus of elasticity
C,0
E Stabilized secant modulus of elasticity
C,S
ε Measured strain
ε Strain along each measuring line at upper stress
ε Average strain at upper stress on loading cycle n
a, n
ε Strain along each measuring line at lower stress
ε Average strain at lower stress on loading cycle n
b, n
Δε Strain difference during third loading cycle
Δε Strain difference during first loading cycle
L Specimen length
---------------------- Page: 8 ----------------------
SIST EN 12390-13:2021
EN 12390-13:2021 (E)
L Initial gauge length of instrument
ΔL Change in measured length
σ Nominal upper stress = f / 3
a c
σ Nominal lower stress – arbitrary value between 10 % and 20 % of f
b c
σ Nominal preload stress – arbitrary value between 0,5 MPa and σ
p b
Measured stress corresponding to nominal upper stress, σ
Measured stress corresponding to nominal lower stress, σ
m m
Difference between measured stresses σ and σ
a b
4 Principle
A test specimen is loaded under axial compression, the stresses and strains are recorded and the slope of
the secant to the stress-strain curve is determined at first loading (Method A only) and after three loading
cycles (Methods A and B).The secant slope is known as the secant modulus of elasticity in compression.
The test specimens may be either cast or taken from an existing structure.
5 Apparatus
5.1 Test machine
Compression testing machine conforming to EN 12390-4 with following additional requirements:
a) suitable for execution of programmable loading cycles;b) able to increase and decrease the load at a constant rate within a given tolerance (see 7.3.1 and 7.3.2);
c) able to maintain a constant load at selectable nominal values with a maximum variation within ± 5 %;
d) calibrated as Class 1 to EN 12390-4 over the working range from the lower stress to the upper stress
as defined in 7.3.1 and 7.3.2.NOTE The test lends itself to the use of automatic control test machines. However, if manual control test
machines can be shown to comply with b), c) and d) above, they can be used.5.2 Instrumentation
Instrumentation measuring the strain of the specimen under axial compression along a measuring line
shall be Class 2 as determined in accordance with EN ISO 9513 in the range from 0 μm/m to 1 000 μm/m.
The instrumentation can measure strain directly (e.g. resistive strain gauges) or take the form of
measuring length change from which the strain, ε, is calculated with Formul...
SLOVENSKI STANDARD
oSIST prEN 12390-13:2019
01-november-2019
Preskušanje strjenega betona - 13. del: Določanje sekantnega modula elastičnosti
pri tlačni obremenitvi
Testing hardened concrete - Part 13: Determination of secant modulus of elasticity in
compressionPrüfung von Festbeton - Teil 13: Bestimmung des Elastizitätsmoduls unter
Druckbelastung (Sekantenmodul)
Essais pour béton durci - Partie 13 : Détermination du module sécant d’élasticité en
compressionTa slovenski standard je istoveten z: prEN 12390-13
ICS:
91.100.30 Beton in betonski izdelki Concrete and concrete
products
oSIST prEN 12390-13:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------oSIST prEN 12390-13:2019
---------------------- Page: 2 ----------------------
oSIST prEN 12390-13:2019
DRAFT
EUROPEAN STANDARD
prEN 12390-13
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2019
ICS 91.100.30 Will supersede EN 12390-13:2013
English Version
Testing hardened concrete - Part 13: Determination of
secant modulus of elasticity in compression
Essais pour béton durci - Partie 13: Détermination du Prüfung von Festbeton - Teil 13: Bestimmung des
module sécant d¿élasticité en compression Elastizitätsmoduls unter Druckbelastung
(Sekantenmodul)This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 104.If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12390-13:2019 E
worldwide for CEN national Members.---------------------- Page: 3 ----------------------
oSIST prEN 12390-13:2019
prEN 12390-13:2019 (E)
Contents Page
European foreword ....................................................................................................................................................... 3
1 Scope .................................................................................................................................................................... 4
2 Normative references .................................................................................................................................... 4
3 Terms, definitions, symbols and abbrivations ..................................................................................... 4
3.1 Terms and definitions ................................................................................................................................... 4
3.2 Symbols and abbreviations ......................................................................................................................... 5
4 Principle ............................................................................................................................................................. 6
5 Apparatus ........................................................................................................................................................... 6
5.1 Test machine ..................................................................................................................................................... 6
5.2 Instrumentation .............................................................................................................................................. 6
5.3 Gauge length...................................................................................................................................................... 7
6 Test specimens ................................................................................................................................................. 7
6.1 Shape and dimensions of specimens ........................................................................................................ 7
6.2 Curing, storage and conditioning .............................................................................................................. 7
7 Method ................................................................................................................................................................ 7
7.1 Specimen instrumentation and positioning .......................................................................................... 7
7.2 Determination of compressive strength ................................................................................................. 8
7.3 Determination of secant modulus of elasticity ..................................................................................... 8
7.3.1 Method A – Determination of initial and stabilized secant modulus of elasticity ................... 8
7.3.2 Method B – determination of stabilized secant modulus of elasticity ...................................... 10
8 Calculation of secant modulus of elasticity ......................................................................................... 12
8.1 Initial secant modulus of elasticity (Method A) ................................................................................ 12
8.2 Stabilized secant modulus of elasticity (Method A and B) ............................................................ 12
9 Test report ...................................................................................................................................................... 13
10 Precision .......................................................................................................................................................... 13
Bibliography ................................................................................................................................................................. 14
---------------------- Page: 4 ----------------------oSIST prEN 12390-13:2019
prEN 12390-13:2019 (E)
European foreword
This document (prEN 12390-13:2019) has been prepared by Technical Committee CEN/TC 104
“Concrete and related products”, the secretariat of which is held by SN.This document is currently submitted to the CEN Enquiry.
It is based on an extensive investigation and comparison of existing National Standards: ASTM, BS, DIN,
ISO, NORD TEST and UNI followed by the analysis of a test programme involving five laboratories carried
out by UNI.This document will supersede EN 12390-13:2013.
This document is one of a series on testing concrete.
EN 12390, Testing hardened concrete, consists of the following parts:
— Part 1: Shape, dimensions and other requirements for specimens and moulds
— Part 2: Making and curing specimens for strength tests
— Part 3: Compressive strength of test specimens
— Part 4: Compressive strength – Specification for testing machines
— Part 5: Flexural strength of test specimens
— Part 6: Tensile splitting strength of test specimens
— Part 7: Density of hardened concrete
— Part 8: Depth of penetration of water under pressure
— Part 10: Determination of the carbonation resistance of concrete at atmospheric levels of carbon dioxide
— Part 11: Determination of the chloride resistance of concrete, unidirectional diffusion
— Part 12: Determination of the potential carbonation resistance of concrete: Accelerated carbonation
method (in preparation)— Part 13: Determination of secant modulus of elasticity in compression
— Part 14: Semi-adiabatic method for the determination of heat released by concrete during its hardening
process— Part 15: Adiabatic method for the determination of heat released by concrete during its hardening
process— Part 16: Determination of shrinkage of concrete (in preparation)
— Part 17: Determination of creep of concrete in compression (in preparation).
The following amendments have been made to the former edition:
— upper limit of lower stress increased to prevent sample unloading when testing low strength
concrete;— change to the loading profile in Method B.
---------------------- Page: 5 ----------------------
oSIST prEN 12390-13:2019
prEN 12390-13:2019 (E)
1 Scope
This document specifies the method for the determination of the secant modulus of elasticity in
compression of hardened concrete on test specimens which can be cast or taken from a structure.
The test method allows the determination of two secant moduli of elasticity: the initial modulus, E
C,0measured at first loading and the stabilized modulus, E measured after three loading cycles.
C,STwo different test methods are given. The first (Method A) is for determination of both initial and
stabilized moduli, the second (Method B) is for determination of stabilized modulus only.
2 Normative referencesThe 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.
EN 12390-1, Testing hardened concrete — Part 1: Shape, dimensions and other requirements for specimens
and mouldsEN 12390-2, Testing hardened concrete — Part 2: Making and curing specimens for strength tests
EN 12390-3, Testing hardened concrete — Part 3: Compressive strength of test specimens
EN 12390-4, Testing hardened concrete — Part 4: Compressive strength — Specification for testing
machinesEN 12504-1, Testing concrete in structures —Part 1: Cored specimens — Taking, examining and testing in
compressionEN ISO 9513, Metallic materials — Calibration of extensometer systems used in uniaxial testing (ISO 9513)
3 Terms, definitions, symbols and abbrivations3.1 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 http://www.electropedia.org/— ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
initial secant modulus of elasticity
C,0
secant slope of the stress strain curve at first loading
3.1.2
stabilized secant modulus of elasticity
C,S
secant slope of the stress strain curve after three loading cycles
---------------------- Page: 6 ----------------------
oSIST prEN 12390-13:2019
prEN 12390-13:2019 (E)
3.1.3
gauge length
base length
length used as reference base for strain measurement
3.1.4
measuring line
straight line laying on the lateral surface of the specimen and parallel to the vertical axis (see Figure 1)
Key1 measuring line
Figure 1 — Measuring line on cylinder and prismatic specimens
3.2 Symbols and abbreviations
For the purposes of this document, the following symbols apply.
d Specimen diameter or width
D Upper sieve size (for definition of aggregates size, see EN 12620)
D Declared value of D of the coarsest fraction of aggregates actually used in the concrete
maxf Compressive strength of concrete determined by testing companion specimens –
cylinders, prisms, cubes or cores – or estimated from non-destructive tests
E Initial secant modulus of elasticity
C,0
Stabilized secant modulus of elasticity
C,S
ε Measured strain
ε Strain along each measuring line at upper stress
ε Average strain at upper stress on loading cycle n
a, n
ε Strain along each measuring line at lower stress
ε Average strain at lower stress on loading cycle n
b, n
Δε Strain difference during third loading cycle
Δε Strain difference during first loading cycle
L Specimen length
---------------------- Page: 7 ----------------------
oSIST prEN 12390-13:2019
prEN 12390-13:2019 (E)
L Initial gauge length of instrument
ΔL Change in measured length
σ Nominal upper stress = f / 3
a c
σ Nominal lower stress – arbitrary value between 10 % and 20 % of f
b c
σ Nominal preload stress – arbitrary value between 0,5 MPa and σ
p b
Measured stress corresponding to nominal upper stress, σ
Measured stress corresponding to nominal lower stress, σ
m m
Difference between measured stresses σ and σ
a b
4 Principle
A test specimen is loaded under axial compression, the stresses and strains are recorded and the slope of
the secant to the stress-strain curve is determined at first loading (Method A only) and after three loading
cycles (Methods A and B).The secant slope is known as the secant modulus of elasticity in compression.
The test specimens may be either cast or taken from an existing structure.
5 Apparatus
5.1 Test machine
Compression testing machine conforming to EN 12390-4 with following additional requirements:
a) suitable for execution of programmable loading cycles;b) able to increase and decrease the load at a constant rate within a given tolerance (see 7.3.1 and 7.3.2);
c) able to maintain a constant load at selectable nominal values with a maximum variation within ± 5 %;
d) calibrated as Class 1 to EN 12390-4 over the working range from the lower stress to the upper stress
as defined in 7.3.1 and 7.3.2.NOTE The test lends itself to the use of automatic control test machines. However, if manual control test
machines can be shown to comply with b), c) and d) above, they can be used.5.2 Instrumentation
Instrumentation measuring the strain of the specimen under axial compression along a measuring line
shall be Class 2 as determined in accordance with EN ISO 9513 in the range from 0 μm/m to 1 000 μm/m.
The instrumentation can measure strain directly (e.g. resistive strain gauges) or take the form of
measuring length change from which the strain, ε, is calculated with F...
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