EN 14771:2023

SLOVENSKI STANDARD
01-november-2023
Nadomešča:
SIST EN 14771:2012
Bitumen in bitumenska veziva - Ugotavljanje upogibne togosti - Reometer z
nosilcem, obremenjenim na upogib (BBR)
Bitumen and bituminous binders - Determination of the flexural creep stiffness - Bending
Beam Rheometer (BBR)
Bitumen und bitumenhaltige Bindemittel - Bestimmung der Biegekriechsteifigkeit -
Biegebalkenrheometer (BBR)
Bitumes et liants bitumineux - Détermination du module de rigidité en flexion -
Rhéomètre à flexion de barreau (BBR)
Ta slovenski standard je istoveten z: EN 14771:2023
ICS:
75.140 Voski, bitumni in drugi naftni Waxes, bituminous materials
proizvodi and other petroleum products
91.100.50 Veziva. Tesnilni materiali Binders. Sealing materials
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 14771
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2023
EUROPÄISCHE NORM
ICS 75.140; 91.100.50 Supersedes EN 14771:2012
English Version
Bitumen and bituminous binders - Determination of the
flexural creep stiffness - Bending Beam Rheometer (BBR)
Bitumes et liants bitumineux - Détermination du Bitumen und bitumenhaltige Bindemittel -
module de rigidité en flexion - Rhéomètre à flexion de Bestimmung der Biegekriechsteifigkeit -
barreau (BBR) Biegebalkenrheometer (BBR)
This European Standard was approved by CEN on 28 May 2023.

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, Türkiye 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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14771:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 6
5 Apparatus . 6
6 Preparation of test samples . 7
6.1 General. 7
6.2 Preparation of moulds . 7
6.3 Preparation of test specimen . 8
7 Procedure . 8
7.1 Measurement . 8
7.2 Deflection in a valid determination . 9
8 Calculation . 9
8.1 General. 9
8.2 Measured stiffness . 10
8.3 Calculated stiffness . 10
8.4 m-value . 10
8.5 Validity of the results . 11
9 Expression of results . 11
10 Precision . 11
10.1 Repeatability, r . 11
10.2 Reproducibility, R . 11
11 Test report . 11
Annex A (informative) Calculation of T (m = 0,300), T (S = 300 MPa) and respective m-value
at T (S = 300 MPa) . 15
Annex B (informative) Calculation of ΔT . 18
c
Bibliography . 19
European foreword
This document (EN 14771:2023) has been prepared by Technical Committee CEN/TC 336 “Bituminous
binders”, the secretariat of which is held by AFNOR.
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 2024, and conflicting national standards shall
be withdrawn at the latest by January 2024.
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 14771:2012.
In comparison with the previous edition, the main technical changes are:
a) Scope aligned with other test standards;
b) reference to EN 14023 moved from normative references to bibliography;
c) Notes in 3.3 and 3.4 updated with reference to SI unit;
d) wording of test specimen and sample applied consistently;
e) 5.1.1.1 reworded to provide more clarity;
f) 5.1.3 Note updated;
g) former 5.2.1, now 5.3, reworded to provide more clarity;
h) numbering in Clause 5 aligned with CEN-CENELEC Internal regulations: former 5.2.1, now 5.3;
i) 6.1 Sample preparation aligned with EN 12594 and reference to scope added in note;
j) 6.2: reference to plastic films added in Note 2;
k) 6.2: Note 3 turned into standard text and moved before notes;
l) 6.3 clarified with regards to pouring, and inconsistencies in the description of storage removed;
Note 1 deleted as in conflict with standard text;
m) text on heated moulds moved from 6.3 to 6.2;
n) description reworded to provide more clarity; timing of trimming adjusted;
o) information to discard damaged or distorted test specimen added in 6.3, in c) wording aligned with
5.1.1.1;
p) information added in 7.1 to place test specimen 5 minutes apart into testing bath, wording aligned;
q) description of flexural creep stiffness worded more precisely in keys to formulae in 8.2 and 8.3;
r) writing of decimal logarithm aligned with ISO 80000-2:2019 [6] in 8.3, 8.4 and Annex A;
t) Keys in Figures 1 to 4 updated and formatted;
u) Figure 5: load in legend and in figure renamed as P, also consistent with Formula (1);
v) Annex A added;
w) Annex B added;
x) Bibliography updated with EN 1427.
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, Türkiye and the United
Kingdom
1 Scope
This document specifies a method for the determination of the flexural creep stiffness of bitumen and
bituminous binders in the range of 30 MPa to 1 GPa by means of the bending beam rheometer.
The method can be applied to a variety of bitumens, including unmodified as well as modified binders, as
fresh (unused) binders, as well as binders after laboratory ageing conditioning (e.g. EN 12607-1,
EN 14769), and also binders that have been recovered from asphalt mixtures.
WARNING — The use of this document can involve hazardous materials, operations and equipment. This
document does not purport to address all of the safety problems associated with its use. It is the
responsibility of the user of this document to establish appropriate safety and health practices and to
determine the applicability of regulatory limitations prior to use.
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 58, Bitumen and bituminous binders - Sampling bituminous binders
EN 12594, Bitumen and bituminous binders - Preparation of test samples
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
flexural creep stiffness
S(t)
ratio obtained by dividing the bending stress by the bending strain, given in MPa
Note 1 to entry: The strain will increase with the loading time and therefore the flexural creep stiffness will also be
a function of time.
3.2
m-value
absolute value of the slope of the curve of the logarithm of the stiffness versus the logarithm of time
3.3
contact load
P
c
load required to maintain positive contact between the test specimen, supports and the loading shaft
Note 1 to entry: The SI unit for the load is N, however for practical reasons loads are given in mN for this test. The
contact load of 25 mN to 45 mN is used in this method.
3.4
test load
P
t
load used to determine the stiffness of the bituminous binder being tested
Note 1 to entry: The SI unit for the load is N, however for practical reasons loads are given in mN for this test. The
test load of 930 mN to 1 030 mN is used in this method.
4 Principle
The bending beam rheometer is used to measure the mid-point deflection, in three-point bending, of a
beam of bituminous binder. A constant load is applied to the mid-point of the test specimen for a specified
loading time and the deflection is measured as a function of time. A low temperature liquid bath is used
to control the temperature. The stiffness of the test specimen for the specific loading times is calculated
from the bending stress and strain.
5 Apparatus
5.1 Bending Beam Rheometer (BBR), consisting of a loading frame with test specimen supports, a
controlled temperature liquid bath and a data acquisition system.
5.1.1 Loading frame, consisting of a set of specimen supports, a blunt-nosed shaft to apply the load to
the mid-point of the test specimen, a load cell mounted in line with the loading shaft, a means for zeroing
the load applied to the test specimen, a means for applying a constant load to the test specimen and a
deflection measuring transducer attached to the loading shaft. A schematic picture of the device is shown
in Figure 1.
5.1.1.1 Loading system, which shall be capable of applying a contact load of 25 mN to 45 mN to the
test specimen and maintaining a constant test load from within the range of 930 mN to 1 030 mN with a
tolerance of ± 10 mN. The rise time from the contact load to the test load shall be less than 0,5 s. Details
of the loading pattern are shown in Figure 2.
5.1.1.2 Loading shaft, which shall be continuous and in line with the load cell and deflection
measuring transducer with a spherically shaped end (6,3 ± 0,3) mm in radius.
5.1.1.3 Load cell, which shall have a minimum capacity of no less than 2,0 N and a resolution of at
least 2,5 mN.
5.1.1.4 LVD-transducer, or other suitable device to measure the deflection of the test specimen that
shall have a linear range of at least 6 mm, and be capable of resolving linear movement of 2,5 μm.
NOTE LVD stands for Linear Variable Differential, also called Linear Variable Displacement. The transducer is
sometimes also called transformer.
5.1.1.5 Specimen supports, which shall consist of two non-corrosive metal supports with a
(3,0 ± 0,3) mm contact radius and spaced 101 mm to 103 mm apart. The spacing of the supports shall be
measured to 0,3 mm (see Figure 3).
5.1.2 Temperature measurement device, used as a calibrated temperature transducer that shall be
capable of measuring the temperature with an accuracy of ± 0,1 °C, over the range of - 36 °C to 0 °C. The
measuring head shall be mounted within 50 mm of the mid-point of the test specimen.
5.1.3 Liquid bath, capable of maintaining the desired test temperature near the test specimen within
± 0,2 °C during isothermal conditioning and during the test procedure in the range of -36 °C to 0 °C. Bath
liquid shall not affect the properties of the bituminous binder being tested. The density of the liquid shall
at the test temperature.
not exceed 1 050 kg/m
NOTE 95 % (volume fraction) ethanol or methanol have been found to be suitable as a bath liquid. Attention is
drawn to the WARNING in the Scope (see Clause 1), Safety Data Sheets and risk assessments.
5.1.3.1 Bath agitator, which shall be used for maintaining the required temperature homogeneity
with agitation intensity so that the fluid currents do not disturb the testing process.
5.1.3.2 Circulating bath, an optional separate bath unit, cooling the test bath liquid.
5.1.4 Data acquisition and control system, which resolves loads to at least 2,5 mN, test specimen
deflection to at least 2,5 μm, and bath liquid temperature to the nearest 0,1 °C. The software shall control
the measuring system and record time, load deflection and temperature during the test. All the load and
deflection readings shall be an average of at least five points within ± 0,2 s of the reporting time.
5.2 Test specimen moulds, with the interior dimensions (6,4 ± 0,1) mm wide, (12,7 ± 0,1) mm deep
and (127 ± 5) mm long, fabricated from a suitable metal as shown in Figure 4. The thickness of the two
end pieces used for each mould shall not vary from each other in thickness by more than 0,1 mm.
NOTE Small errors in thickness of the test specimen can have a large effect on the calculated modulus because
the calculated modulus is a function of the thickness raised to the third power.
5.3 Plastic strips, or strips from silicone paper or similar material that does not adhere to the test
specimen and does not interact with the bituminous binder, to cover those sections of the test specimen
moulds which will come in contact with test specimen during their preparation, except for the end pieces.
6 Preparation of test samples
6.1 General
NOTE BBR testing can be done on a variety of binders and ageing/conditioning stages (see Scope); for
specification purposes BBR testing is typically carried out on long-term aged binders.
Take the laboratory sample in accordance with EN 58, taking all necessary safety precautions, and
ensuring that the test sample is representative of the laboratory sample from which it is taken. Ensure
that the laboratory sample is homo
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