EN 12697-46:2020

SLOVENSKI STANDARD
01-maj-2020
Nadomešča:
SIST EN 12697-46:2012
Bitumenske zmesi - Preskusne metode - 46. del: Odpornost proti razpokam pri
nizkih temperaturah z enoosnimi nateznimi preskusi
Bituminous mixtures - Test methods - Part 46: Low temperature cracking and properties
by uniaxial tension tests
Asphalt - Prüfverfahren - Teil 46: Widerstand gegen Kälterisse und
Tieftemperaturverhalten bei einachsigen Zugversuchen
Mélanges bitumineux - Méthodes d'essai - Partie 46: Fissuration à basse température et
les propriétés des tensions uni axiaux par des tests
Ta slovenski standard je istoveten z: EN 12697-46:2020
ICS:
93.080.20 Materiali za gradnjo cest Road construction materials
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 12697-46
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2020
EUROPÄISCHE NORM
ICS 93.080.20 Supersedes EN 12697-46:2012
English Version
Bituminous mixtures - Test methods - Part 46: Low
temperature cracking and properties by uniaxial tension
tests
Mélanges bitumineux - Méthodes d'essai - Partie 46 : Asphalt - Prüfverfahren - Teil 46: Widerstand gegen
Fissuration et propriétés à basse température par des Kälterisse und Tieftemperaturverhalten bei
essais de traction uniaxiale einachsigen Zugversuchen
This European Standard was approved by CEN on 18 November 2019.

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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12697-46:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Principle . 8
5 Apparatus . 9
5.1 Testing device for conducting UTST, TSRST, RT and TCT . 9
5.1.1 General . 9
5.1.2 Load device . 9
5.1.3 Deformation measurement system . 11
5.1.4 Load measurement system . 11
5.1.5 Recording equipment . 11
5.1.6 Thermostatic chamber . 12
5.2 Testing device for conducting UCTST . 12
5.2.1 Dynamic testing device . 12
5.2.2 Monitoring system . 12
5.2.3 Electronic signal amplifier . 13
5.2.4 Thermostatic chamber . 13
5.2.5 Recording equipment . 13
6 Calibration . 13
6.1 Testing device for conducting UTST, TSRST, relaxation test and tensile creep test . 13
6.2 Testing device for conducting UCTST . 13
7 Specimen preparation . 14
7.1 Number of samples . 14
7.2 Dimensions . 14
7.3 Preparation . 14
7.4 Bulk density . 14
7.5 Drying . 15
7.6 Storage . 15
7.7 Mounting . 15
7.8 Installation and conditioning . 16
8 Procedure. 16
8.1 Uniaxial tension stress test (UTST) . 16
8.2 Thermal stress restrained specimen test (TSRST) . 17
8.3 Relaxation test (RT) . 17
8.4 Tensile creep test (TCT) . 17
8.5 Uniaxial cyclic tensile stress test (UCTST) . 18
8.5.1 Test temperature and test frequency . 18
8.5.2 Base stress . 18
8.5.3 Peak stress . 18
9 Evaluation . 19
9.1 Tension strength reserve . 19
9.2 Uniaxial cyclic tensile stress test (UCTST) . 21
10 Test report . 22
10.1 General . 22
10.2 General information . 22
10.3 Information on specimen. 22
10.4 Information on test method . 22
10.5 Information on the test and results . 22
10.5.1 Uniaxial tension stress test (UTST) . 22
10.5.2 Thermal stress restrained specimen test (TSRST) . 23
10.5.3 Tension strength reserve . 23
10.5.4 Relaxation test (RT) . 23
10.5.5 Tensile creep test (TCT) . 23
10.5.6 Uniaxial cyclic tensile stress test (UCTST) . 23
11 Precision . 24
Bibliography . 25

European foreword
This document (EN 12697-46:2020) has been prepared by Technical Committee CEN/TC 227 “Road
materials”, 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 August 2020, and conflicting national standards shall
be withdrawn at the latest by August 2020.
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 12697-46:2012.
The following is a list of significant technical changes since the previous edition:
— the title no longer makes the method exclusively for hot mix asphalt;
— [ge] editorial update according to current standard template;
— [ge] NOTEs modified and adjusted to normal text where appropriate according to ISO/IEC
Directives – Part 2:2016, 24.5;
— [Clause 4] changed order of indent 3 and 4 for consistency with Clause 8.3 and 8.4;
— [5.1.4] clause amended to read: Load measurement system, capable of monitoring the axial load up
to (25 ± 0,025) kN with resolution of 0,001 kN or better and with an accuracy of ±0,01 kN or better.
— [5.1.4] excessive and incorrect NOTE deleted;
— [5.2.1] accuracy for Dynamic testing device (0,1 Hz) completed with “±”;
— [5.2.1] correction of keys for Figure 8;
— [5.2.5] clarified that temperature is measured on a dummy specimen;
— [6.1.1] clarified that the main reason for required calibration is to obtain correct loading condition;
— [7.3.1] added description for sawing of prismatic specimen to ensure a precise cross section;
— [7.3.2] added description for thickness to enable sawing of prismatic specimens;
— [8.2.2] clarified that the results of the test evaluation are measured (not failure stress and failure
temperature;
— [8.5.1]; NOTE modified and adjusted to normal text according to ISO/IEC Directives – Part 2:2016,
24.5. Added description of suitable test temperature and testing frequency for intermediate low
temperatures;
— [8.5.3.6] the reason for measuring clarified.
A list of all parts in the EN 12697 series 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.
1 Scope
This document specifies uniaxial tension tests for characterizing the resistance of an asphalt mixture
against low temperature cracking. The results of the uniaxial tension tests can be used to evaluate the
following:
— tensile strength at a specified temperature, using the uniaxial tension stress test (UTST);
— minimum temperature that the asphalt can resist before failure, using the thermal stress restrained
specimen test (TSRST);
— tensile strength reserve at a specified temperature (using a combination of TSRST and UTST);
— relaxation time, using the relaxation test (RT);
— creep curve to back calculate rheological parameters, using the tensile creep tests (TCT);
— fatigue resistance at low temperatures due to the combination of cryogenic and mechanical loads,
using the uniaxial cyclic tension stress tests (UCTST).
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.
EN 12697-6, Bituminous mixtures — Test methods — Part 6: Determination of bulk density of bituminous
specimens
EN 12697-27, Bituminous mixtures — Test methods — Part 27: Sampling
EN 12697-33, Bituminous mixtures — Test method — Part 33: Specimen prepared by roller compactor
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 http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp/ui
3.1
tensile strength
β
t
maximum tensile stress measured in a tensile stress test
3.2
tensile failure strain
ε
failure
tensile strain that is measured when the tensile strength has been reached
3.3
cryogenic stress
σ (T)
cry
tension stress, induced by prohibited thermal shrinkage, at the temperature T
3.4
failure stress
σ
cry, failure
cryogenic stress that causes a failure of the specimen in the thermal stress restrained specimen test
(TSRST)
3.5
failure temperature
T
failure
temperature at which the cryogenic stress causes a failure of the specimen in the thermal stress
restrained specimen test (TSRST)
3.6
tensile strength reserve
Δβ
t
difference between the tensile strength and the cryogenic stress at the same temperature T where
∆β ()TTβ ()−σ ()T
t t cry
3.7
time of relaxation
t
rel
time until the stress decreases to 36,8 % (1/e) of its initial value
3.8
remaining tension stress
(t)
σ
rem
remaining stress after the time t in the relaxation test
3.9
initial complex modulus
E*
complex modulus after 100 load cycles, calculated according to EN 12697-26
3.10
conventional failure criterion
N
f/50
number of load cycles reducing the complex modulus E* to half of its initial value E* (fatigue criterion)
3.11
additional failure criterion
N
failure
number of load cycles leading to the development of a visible and recognisable crack in the asphalt
specimen (fracture criterion)
=
4 Principle
The low-temperature performance of asphalt specimens can be tested using different test methods:
— In the uniaxial tension stress test (UTST), a specimen is pulled with a constant strain rate at a
constant temperature until failure. Results of the UTST are the maximum stress (tensile strength)
β (T) and the corresponding tensile failure strain ε (T) at the test temperature T (see
t failure
Figure 1).
— In the thermal stress restrained specimen test (TSRST), a specimen, whose length is held constant,
is subjected to a temperature decrease with a constant temperature rate. Due to the prohibited
thermal shrinkage, cryogenic stress is built up in the specimen. The results are the progression of
the cryogenic stress over the temperature σ (T) and the failure stress σ at the failure
cry cry, failure
temperature T (see Figure 2).
failure
— In the relaxation test (RT), the specimen is subjected to a spontaneous strain ε, which is held on a
constant level. The decrease of tension stress by relaxation over the testing time is monitored. The
results are the time of relaxation t and the remaining tension stress σ after the test has ended
rel rem
(see Figure 3).
— In the tensile creep test (TCT), the specimen is subjected to a constant tension stress σ at a constant
temperature T. The progression of the strain ε is measured. After a given time, the stress is
withdrawn. Rheological parameters describing the elastic and viscous properties of the asphalt can
be determined by interpreting the strain measurements (see Figure 4).
— In the uniaxial cyclic tension stress test (UCTST), a specimen is subjected to a cyclic tensile stress
which is characterized by a sinusoidal stress to simulate the dynamic loading condition by traffic in
combination with a constant stress, which symbolises the cryogenic stress. During the test, the
strain response is monitored and the course of the stiffness is recorded until fatigue failure. Results
and the number of load cycles
of the tests are the number of applied load cycles until failure N
failure
until the conventional fatigue criterion is reached N (see Figure 5).
f/50
Figure 1 — Test principle of UTST

Figure 2 — Test principle of TSRST
Figure 3 — Test principle of RT

Figure 4 — Test principle of TCT

Figure 5 — Test principle of UCTST
Key for Figures 1 to 5:
Y1 strain
X time
Y2 temperature
Y3 stress
5 Apparatus
5.1 Testing device for conducting UTST, TSRST, RT and TCT
5.1.1 General
Figures 6 and 7 show suitable testing devices for conducting uniaxial tension stress, thermal stress
restrained specimen, relaxation and tensile creep tests, at low temperatures.
5.1.2 Load device
The load device shall be able to generate movements with an accuracy of 0,1 µm. In order to avoid
radial and/or transversal forces as well as moments in the test specimen, the specimen is connected to
the loading device by two gimbal suspensions.
Key
1 load cell 5 gimbal suspension
2 displacement transducer 6 adapter
3 thermal indifferent measurement base 7 specimen
4 crossbeam 8 gear box with stepping motor
Figure 6 — Example of a test device for uniaxial tension tests at low temperatures
Key
1 load cell 8 temperature sensor
2 load frame 9 invar rod
3 swivel jig 10 environmental chamber
4 clamp 11 dummy with temperature sensor
5 specimen 12 fan
6 end plate 13 displacement transducer
7 loading rod 14 step motor
Figure 7 — Example 2 for a test device for uniaxial tension tests at low temperatures
5.1.3 Deformation measurement system
The deformation of the specimen shall be measured in a range of ±2,5 mm and ±0,5 µm. Because the
test equipment is exposed to the same thermal changes as the examined specimens with thermal
shrinkage and expansion, accurate measuring of the actual strain in the specimen requires a basis with
constant length at various temperatures (e.g. special carbon fibre reinforced plastic or invar steel).
Several single measurements may be averaged into one mean value, which shall fulfil the accuracy
requirement. This mean value shall be used for the closed-loop circuit for controlling the tests.
5.1.4 Load measurement system
Load measurement system, capable of monitoring the axial load up to (25 ± 0,025) kN with resolution
of 0,001 kN or better and with an
...