SIST EN 12697-24:2018
(Main)Bituminous mixtures - Test methods - Part 24: Resistance to fatigue
Bituminous mixtures - Test methods - Part 24: Resistance to fatigue
This European Standard specifies the methods for characterizing the fatigue of bituminous mixtures using alternative tests, including bending tests and direct and indirect tensile tests. The tests are performed on compacted bituminous material under a sinusoidal loading or other controlled loading, using different types of specimens and supports.
The procedure is used:
a) to rank bituminous mixtures on the basis of resistance to fatigue;
b) as a guide to relative performance in the pavement;
c) to obtain data for estimating the structural behaviour of the road; and
d) to judge test data according to specifications for bituminous mixtures.
Because this European Standard does not impose a particular type of testing device, the precise choice of the test conditions depends on the possibilities and the working range of the device used. For the choice of specific test conditions, the requirements of the product standards for bituminous mixtures need to be respected. The applicability of this document is described in the product standards for bituminous mixtures.
Asphalt - Prüfverfahren - Teil 24: Beständigkeit gegen Ermüdung
Diese Europäische Norm legt die Verfahren zur Charakterisierung der Ermüdung von Asphalt durch verschiedene Prüfungen, einschließlich Biegeprüfungen und Prüfungen der direkten sowie der indirekten Zugfestigkeit, fest. Die Prüfungen werden an verdichtetem Asphalt unter sinusförmiger oder einer anderen kontrollierten Belastung unter Verwendung verschiedener Probekörpertypen und Auflagerungen vorgenommen.
Das Verfahren dient:
a) zur Einstufung von Asphalt nach seiner Beständigkeit gegen Ermüdung;
b) als Hinweis auf das relative Leistungsvermögen von Asphalt in der Fahrbahnbefestigung;
c) dazu, Daten zur Abschätzung des Tragverhaltens in der Straße zu erhalten; und
d) zur Beurteilung der Prüfdaten nach den für Asphalt geltenden Festlegungen.
Da diese Europäische Norm keinen bestimmten Prüfgerätetyp vorschreibt, hängt die genaue Auswahl der Prüfbedingungen von den Möglichkeiten und dem Arbeitsbereich der im betreffenden Fall verwendeten Prüfeinrichtung ab. Bei der Auswahl der jeweiligen Prüfbedingungen müssen die Anforderungen der Produktnormen für Asphalt berücksichtigt werden. Die Anwendbarkeit dieses Dokumentes ist in den Produktnormen für Asphalt beschrieben.
Mélanges bitumineux - Méthodes d'essai pour mélange hydrocarboné à chaud - Partie 24 : Résistance à la fatigue
La présente Norme européenne spécifie les méthodes qui sont utilisées pour caractériser la fatigue des mélanges bitumineux par différents types d'essais, dont des essais de flexion et des essais de traction directe et indirecte. Les essais sont réalisés sur des matériaux bitumineux compactés, au moyen d'une charge sinusoïdale ou d'une autre charge contrôlée, en utilisant différents types d'éprouvettes et de supports.
La procédure est utilisée :
a) pour classer les mélanges bitumineux selon leur résistance à la fatigue ;
b) comme guide comparatif des performances dans les structures de chaussée ;
c) pour obtenir des données permettant d'estimer le comportement structurel du matériau de la chaussée ; et
d) pouvoir juger les résultats d'essais en fonction des spécifications des mélanges bitumineux.
Comme la présente Norme européenne n'impose pas un type de dispositif d'essai particulier, le choix précis des conditions d'essai dépend des possibilités et de la plage de fonctionnement du dispositif utilisé. Pour le choix des conditions d'essai spécifiques, il est nécessaire de respecter les critères des normes produit des mélanges bitumineux. L'applicabilité du présent document est décrite dans les normes produit des mélanges bitumineux.
Bitumenske zmesi - Preskusne metode - 24. del: Odpornost proti utrujanju
Ta evropski standard določa metode za karakterizacijo utrujenosti bitumenskih zmesi z alternativnimi preskusi, skupaj s preskusi upogiba ter preskusi direktne in indirektne nateznosti. Preskusi se izvajajo na zgoščenem bitumenskem materialu pod sinusnim obremenjevanjem ali pod nadzorovanim obremenjevanjem z različnimi vrstami preskušancev in podpor.
Postopek se uporablja:
a) za razvrščanje bitumenskih zmesi na podlagi odpornosti proti utrujanju;
b) kot smernica v zvezi z relativnimi lastnostmi v voziščni konstrukciji;
c) za pridobivanje podatkov z namenom vrednotenja strukturnega obnašanja ceste; in
d) za ocenjevanje preskusnih podatkov glede na specifikacije bitumenskih zmesi.
Ker ta evropski standard ne predpisuje posebne preskusne naprave, je natančna izbira preskusnih pogojev odvisna od možnosti in delovnega obsega uporabljene naprave. Pri izbiri specifičnih preskusnih pogojev je treba upoštevati standarde za izdelke za bitumenske zmesi. Uporabnost tega dokumenta je opisana v standardih za izdelke za bitumenske zmesi.
Rezultati, pridobljeni z različnimi preskusnimi metodami ali z uporabo različnih meril odpovedi, niso nujno primerljivi.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2018
1DGRPHãþD
SIST EN 12697-24:2012
Bitumenske zmesi - Preskusne metode - 24. del: Odpornost proti utrujanju
Bituminous mixtures - Test methods - Part 24: Resistance to fatigue
Asphalt - Prüfverfahren - Teil 24: Beständigkeit gegen Ermüdung
Mélanges bitumineux - Méthodes d'essai pour mélange hydrocarboné à chaud - Partie
24 : Résistance à la fatigue
Ta slovenski standard je istoveten z: EN 12697-24:2018
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 12697-24
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2018
EUROPÄISCHE NORM
ICS 93.080.20 Supersedes EN 12697-24:2012
English Version
Bituminous mixtures - Test methods - Part 24: Resistance
to fatigue
Mélanges bitumineux - Méthodes d'essai pour mélange Asphalt - Prüfverfahren - Teil 24: Beständigkeit gegen
hydrocarboné à chaud - Partie 24: Résistance à la Ermüdung
fatigue
This European Standard was approved by CEN on 26 February 2018.
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12697-24:2018 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms, definitions, symbols and abbreviations . 5
3.1 General . 6
3.2 Two-point bending test on trapezoidal shaped specimens (2PB-TR) . 6
3.3 Two-point bending test on prismatic shaped specimens (2PB-PR) . 7
3.4 Three-point bending test on prismatic shaped specimens (3PB-PR) . 9
3.5 Four-point bending test on prismatic shaped specimens (4PB-PR) . 10
3.6 Symbols for indirect tensile test on cylindrical shaped specimens (IT-CY) . 15
3.7 Symbols for Cyclic Indirect tensile Test on cylindrical shaped specimen (CIT-CY) . 15
4 Sample preparation . 16
4.1 Storage of the specimens . 16
4.2 Drying of the specimens . 16
4.3 Dimensions and bulk density of the specimens . 17
5 Failure . 17
6 Selection test conditions . 17
7 Summary of the procedures . 17
7.1 Two-point bending test on trapezoidal shaped specimens (2PB-TR) . 17
7.2 Two-point bending test on prismatic shaped specimens (2PB-PR) . 17
7.3 Three-point bending test on prismatic shaped specimens (3PB-PR) . 17
7.4 Four-point bending test on prismatic shaped specimens (4PB-PR) . 18
7.5 Indirect tensile test on cylindrical shaped specimens (IT-CY) . 18
7.6 Cyclic Indirect tensile test on cylindrical shaped specimens (CIT-CY) . 18
8 Checking of the testing equipment . 18
9 Test report . 19
Annex A (normative) Two-point bending test on trapezoidal shaped specimens (2PB-TR) . 20
A.1 Principle . 20
A.2 Equipment . 21
A.3 Specimen preparation . 21
A.4 Procedure. 24
A.5 Calculation and expression of results . 25
A.6 Test report . 26
A.7 Precision . 26
Annex B (normative) Two-point bending test on prismatic shaped specimens (2PB-PR) . 28
B.1 Principle . 28
B.2 Equipment . 28
B.3 Specimen preparation . 29
B.4 Procedure. 29
B.5 Calculation and expression of results . 30
B.6 Test report . 32
B.7 Precision . 32
Annex C (normative) Three-point bending test on prismatic shaped specimens (3PB-PR) . 33
C.1 Principle . 33
C.2 Equipment . 33
C.3 Specimen preparation . 34
C.4 Procedure . 34
C.5 Calculation and expression of results . 35
C.6 Test report . 38
C.7 Precision . 39
Annex D (normative) Four-point bending test on prismatic shaped specimens (4PB-PR) . 40
D.1 Principle . 40
D.2 Equipment . 42
D.3 Specimen preparation . 43
D.4 Procedure . 44
D.5 Calculation and expression of results . 46
D.6 Test report . 46
D.7 Precision . 47
Annex E (normative) Indirect tensile test on cylindrical shaped specimens (IT-CY) . 48
E.1 Principle . 48
E.2 Equipment . 48
E.3 Specimen preparation . 51
E.4 Procedure . 52
E.5 Calculation and reporting of results . 53
E.6 Test report . 56
E.7 Precision . 56
Annex F (normative) Cyclic indirect tensile test on cylindrical shaped specimens (CIT-CY) . 57
F.1 Principle . 57
F.2 Equipment . 57
F.3 Specimen preparation . 59
F.4 Procedure . 60
F.5 Calculation and reporting of results . 62
F.6 Test report . 63
F.7 Precision . 63
Bibliography . 64
European foreword
This document (EN 12697-24:2018) has been prepared by Technical Committee CEN/TC 227 “Road
materials”, the secretariat of which is held by DIN.
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 December 2018, and conflicting national standards
shall be withdrawn at the latest by December 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN not be held responsible for identifying any or all such patent rights.
This document supersedes EN 12697-24:2012.
Compared with EN 12697-24:2012, the following changes have been made:
— the series title no longer makes the method exclusively for hot mix asphalt [Title];
— editing of several text sections in order to clarify the procedures [Ge];
— “load applications” amended to “load cycles" [Ge];
— Figure A.1 corrected: Key 3 pointing at the groove [A.1.2];
— completion of Figure E.3: Line 1 added to extensiometer in front view figure [E.2.5.3];
— introduction of new annex for cyclic indirect tensile test on cylindrical specimens (CIT-CY) [Annex F].
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
1 Scope
This European Standard specifies the methods for characterizing the fatigue of bituminous mixtures
using alternative tests, including bending tests and direct and indirect tensile tests. The tests are
performed on compacted bituminous material under a sinusoidal loading or other controlled loading,
using different types of specimens and supports.
The procedure is used:
a) to rank bituminous mixtures on the basis of resistance to fatigue;
b) as a guide to relative performance in the pavement;
c) to obtain data for estimating the structural behaviour of the road; and
d) to judge test data according to specifications for bituminous mixtures.
Because this European Standard does not impose a particular type of testing device, the precise choice
of the test conditions depends on the possibilities and the working range of the device used. For the
choice of specific test conditions, the requirements of the product standards for bituminous mixtures
need to be respected. The applicability of this document is described in the product standards for
bituminous mixtures.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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 for hot mix asphalt — Part 6: Determination of bulk
density of bituminous specimens
EN 12697-7, Bituminous mixtures — Test methods for hot mix asphalt — Part 7: Determination of bulk
density of bituminous specimens by gamma rays
EN 12697-8, Bituminous mixtures — Test methods for hot mix asphalt — Part 8: Determination of void
characteristics of bituminous specimens
EN 12697-26, Bituminous mixtures — Test methods — Part 26: Stiffness
EN 12697-27, Bituminous mixtures — Test methods — Part 27: Sampling
EN 12697-29, Bituminous mixtures — Test method for hot mix asphalt — Part 29: Determination of the
dimensions of a bituminous specimen
EN 12697-31, Bituminous mixtures — Test methods for hot mix asphalt — Part 31: Specimen preparation
by gyratory compactor
EN 12697-33, Bituminous mixtures —Test methods — Part 33: Specimen prepared by roller compactor
3 Terms, definitions, symbols and abbreviations
For the purposes of this document, the following terms, definitions, symbols and abbreviations apply.
3.1 General
3.1.1
fatigue
reduction of strength of a material under repeated loading when compared to the strength under a
single load
3.1.2
conventional criteria of failure
number of load cycles, N , when the absolute value of the complex stiffness modulus S (stiffness
f/50 mix
modulus) has decreased to half its initial value S
mix,0
Note 1 to entry: In this standard not only the conventional criteria of failure, based on the reduction of stiffness,
is presented. Also other failure criteria like the occurrence of macro cracks or the energy-based failure mechanism
are used.
Note 2 to entry: Different test methods and different failure criteria might lead to results that are not
comparable.
Note 3 to entry: In a displacement controlled fatigue test the reduction to half of the initial stiffness is a gradual
process. In a force controlled test in most cases there will be a progressive collapse of the specimen.
3.1.3
initial complex stiffness modulus
complex stiffness modulus, S , after 100 load cycles
mix,0
3.2 Two-point bending test on trapezoidal shaped specimens (2PB-TR)
3.2.1
constant relative to maximum strain
constant that enables the head displacement z of the trapezoidal specimen of dimensions [B, b, e, h], to
which a bending strain level ε is applied, to be converted into maximum strain
Note 1 to entry: The following formulae express K and its relationship with the parameters mentioned above:
ε
Kz⋅=ε (1)
ε
()B − b
ii
K = (2)
ε j
(bB−⋅) (3B− b ) B
i i ii i
8⋅⋅bh + ln
ii
b
2 ⋅B
i
i
3.2.2 Symbols
−6
Where a strain of 1 microstrain (μstrain) is equal to 10 by convention, the symbols are as follows:
i the index of the specimen for an element test (varies from 1 to n);
h is the height, in millimetres (mm);
i
B is the large base, in millimetres (mm);
i
b is the small base, in millimetres (mm);
i
e is the thickness, in millimetres (mm);
i
v is the void content of the specimen i by geometric method, in percent (%);
i
K −1
εi is the constant, relative to the maximum strain, in inverse millimetres (mm );
z is the amplitude of displacement imposed at the head of specimen i, in millimetres (mm);
i
ε is the maximum relative strain of specimen i corresponding with the displacement imposed at
i
the head;
N is the conventional fatigue life of specimen i;
i
a is the ordinate of the fatigue line according to the formula lg(N) = a + (1/b) lg(ε);
r is the linear correlation coefficient (lg(N ), lg(ε ));
2 i i
1/b is the slope of the fatigue line;
lg(ε) is the average value of lg(ε );
i
S is the standard deviation of lg(ε );
lg(ε) i
S is the standard deviation of lg(N );
lg(N) i
ε 6
6 is the strain corresponding to 10 cycles;
s is the estimation of the residual standard deviation of the decimal logarithms of fatigue lives;
N
Δε is the quality index of the test;
n is the number of specimens.
3.3 Two-point bending test on prismatic shaped specimens (2PB-PR)
3.3.1
constants for consideration of the geometry of specimen
constants that enable the strength of the head P of the specimen i of dimensions b , e and h to which a
ij i i i,
bending strength is applied, to calculate the maximum tension
Note 1 to entry: The following formulae express K and its relationship with the parameters mentioned above:
σ i
KP⋅=σ (3)
σ i ij jmax
where
-2
K is the constant for consideration of the geometry of specimen at constant strength (mm );
σi
P is the amplitude of the strength, with which the head is applied, in Newtons (N);
ij
σ is the greatest relative tension of the specimen, corresponding to the strength, with which
jmax
the head is applied.
6 h
i
K = (4)
σ i
be⋅
ii
where
K is the constant for consideration of the geometry of specimen at constant strength (factor in
σi
accordance with EN 12697–26);
b is the base, in millimetres (mm);
i
h is the height, in millimetres (mm);
i
e is the width, in millimetres (mm).
i
3.3.2 Symbols
−6
Where a strain of 1 microstrain (μstrain) is equal to 10 by convention, the symbols are as follows:
3.3.2.1 Sample i
h is the height, in millimetres (mm);
i
b is (A) small base or (B) base, in millimetres (mm);
i
e is the thickness, in millimetres (mm);
i
m is the mass, in grams (g);
i
v % is the vacuum, achieved by the geometric method as a proportion of atmospheric
i
pressure, in percent (%);
Kσ is the constant for consideration of the geometry of specimen at constant strength, in
i
−1
inverse millimetres (mm ).
3.3.2.2 Strength at head and greatest tension at specimen i at level of tension σ
j max
P is the amplitude of the strength with which the head is applied, in Newtons (N);
ij
σ is the greatest relative tension of the specimen, corresponding to the strength, with
j max
which the head is applied, in megapascal (MPa).
3.3.2.3 Fatigue life of a specimen i at the level of tension σ
j max
Nσ is the fatigue life in a force controlled test.
ji
3.3.2.4 Fatigue life relative to sample i at the strain level ε
j
Nԑ is the conventional fatigue life in a displacement controlled test.
ji
3.3.2.5 Fatigue line
p is the slope of fatigue line ln(σ ) = f (ln(N ));
σ j max ij
ˆ 6
σ
is the tension corresponding to 10 cycles, in megapascals (MPa);
s is the estimation of the residual standard deviation of the natural logarithms of
σ x/y
fatigue lives;
ˆ ˆ
∆σ is the confidence of σ for a probability of 95 %, in megapascal (MPa);
6 6
N is the number of element tests (number of specimens at the level of tension σ
j max
times the number of levels) where N = n*l;
s is the estimation of the standard deviation of ln(N ).
N ij
3.3.2.6 Fatigue life of a series of n specimens (A) at a strain level ε or (B) at the level of
jmax
tension σ
j max
N is the average number of cycles obtained at the level of tension stress σ
σjmax j max;
N is the average number of cycles obtained at the level of tension strain ε
εjmax i max
3.4 Three-point bending test on prismatic shaped specimens (3PB-PR)
3.4.1 Symbols
The symbols are as follows:
2A is the amplitude of the approximate stress function, in megapascals (MPa);
t
2A is the amplitude of the approximate strain function, in meter per meter (m/m);
ε
B is the measuring base of the extensometer, in millimetres (mm);
B is the phase angle of the approximate stress function, in radians (rad);
t
B is the phase angle of the approximate strain function, in radians (rad);
ε
D is the displacement at instant t, in micrometres (μm);
c
2D is the total amplitude of displacement function, in micrometres (μm);
DDE is the density of dissipated energy, in megapascals (MPa) or megajoules per cubic
metre (MJ/m );
DDE (x) is the density of dissipated energy at cycle x, in megajoules per cubic metre
(MJ/m );
EXT is the instant extensometer signal, in millimetres (mm);
L is the distance between supports, in millimetres (mm);
MD is the dynamic modulus, in megapascals (MPa);
N is the number of cycles at the end of the test;
P is the instant load, in megapascals (MPa);
W is the total density of dissipated energy throughout the whole test, in megajoules
per cubic metre (MJ/m );
b is the width of the specimen, in millimetres (mm);
e is the thickness of specimen, in millimetres (mm);
f is the wave frequency, in Hertz (Hz);
m is (N − 200)/500;
t is the time, in seconds (s);
-6
ε is the instant strain or half-cyclic amplitude of strain function at cycle 200, in 10
(µm/m);
-6
ε is the approximate strain function value, in 10 (µm/m);
a
-6
ε is the cyclic amplitude of strain function, in 10 (µm/m);
c
ε 6
-6
6 is the strain at 10 cycles, in 10 (µm/m);
σ is the instant stress, in megapascals (MPa);
σ is the approximate stress function value, in megapascals (MPa);
a
σ is the cyclic amplitude of stress function, in megapascals (MPa);
c
Φ is the phase difference angle, in degrees (°).
3.5 Four-point bending test on prismatic shaped specimens (4PB-PR)
3.5.1
(complex) stiffness modulus
iϕ
ratio S = S × e of the calculated stress and strain during cycle n in the specimen
mix,n
Note 1 to entry: The stiffness modulus defines the relationship between stress and strain for a linear
viscoelastic material subjected to sinusoidal loading.
3.5.2
initial (complex) stiffness modulus
Initial value S in megapascals (MPa) of the (complex) stiffness modulus and for the the initial
mix,0
th
phase angle ϕ in degrees (°) of the complex modulus taken at the 100 load cycle
3.5.3
fatigue life N of a specimen
i,j,k
number of cycles for specimen i, corresponding with the chosen failure criteria j (e.g. conventional
failure j = f/50) at the set of test conditions k (temperature, frequency and loading mode)
Note 1 to entry: A loading mode could be constant deflection level, or constant force level, and or any other
constant loading condition.
3.5.4
test condition k
set of conditions under which a specimen is tested
Note 1 to entry: This set contains the applied frequency f, the test temperature Θ and the loading mode
(constant deflection, or constant force, and or constant dissipated energy per cycle.
3.5.5
total length L
tot
total length of the prismatic specimen, in millimetres (mm)
3.5.6
effective length L
distance between the two outer clamps, in millimetres (mm)
3.5.7
width B
width of the prismatic specimen, in millimetres (mm)
3.5.8
height H
height of the prismatic specimen, in millimetres (mm)
3.5.9
mid-span length a
distance between the two inner clamps, in millimetres (mm)
3.5.10
co-ordinate A
distance between the left outer (x = 0) and left inner clamp (x = A), in millimetres (mm)
3.5.11
co-ordinate x
distance between x and the left outer clamp (0 ≤ x ≤ L/2), in millimetres (mm)
3.5.12
co-ordinate x
s
co-ordinate x where the deflection is measured (A ≤ x ≤ L/2), in millimetres (mm)
s
3.5.13
density ρ
geometrical density of the specimen, in kilograms per cubic metre (kg/m ):
M ⋅10
beam
ρ = (5)
()H⋅⋅LB
3.5.14
mass M
beam
total mass of the prismatic beam, in kilograms (kg)
3.5.15
damping coefficient T
coefficient needed for calculation of the system losses, in kilograms per second (kg/s)
Note 1 to entry: This coefficient can only be established by tuning the equipment with a reference beam of
which the stiffness modulus and (material) phase angle are known. In good working equipment, the coefficient T
can be neglected (adopting a zero value).
3.5.16
weighing function R(x)
dimensionless function depending on the distance x to the left outer clamp, the co-ordinate A of the left
inner clamp and the effective length L between the two outer clamps:
12 L
=
Rx() (6)
2 2
A⋅(3Lx⋅− 3x − A )
3.5.17
equivalent mass M
eq
weighed mass in kilograms (kg) of the moving parts of beam (M ), sensor (M ) and clamps
beam sensor
(M ) whose values depend on the place where the deflection Z(x ) is measured:
clamp s
Rx() Rx()
ss
M= ⋅ M +⋅ MM+ (7)
eq beam clamp sensor
RA( )
π
3.5.18
equivalent coefficient for damping
weighed coefficient for the damping in the system in kilograms per second (kg/s), the value of which
depends on the place where the deflection Z(x ) is measured:
s
Rx
( )
s
T ⋅T
(8)
eq
RA
( )
3.5.19
deflection Z(x )
s
amplitude of the deflection of the beam during one cycle, measured on or between the two inner clamps
at a distance x from the left outer clamp, in millimetres (mm)
s
Note 1 to entry: With a perfect sinusoidal signal is the peak-peak value twice the amplitude of the signal.
3.5.20
force F
amplitude of the total force at the two inner clamps, in Newtons (N)
3.5.21
frequency f [Hz] and circular frequency ω [rad/s]
0 0
frequency of the applied sinusoidal load:
ωπ2 ⋅ f (9)
3.5.22
inertia function I(x )
s
dimensionless function depending on the distance x used to account for mass inertia effects:
s
Zx()
2 −3
s
Ix( ) M ⋅ ⋅⋅ω 10 (10)
s eq 0
F
3.5.23
damping function J(x )
s
dimensionless function depending on the distance x used to account for damping (non-viscous) effects
s
in the system (system losses):
Zx
( )
s −3
J x = T ⋅ ⋅⋅ω 10 (11)
( )
s eq 0
F
3.5.24
measured phase lag φ*(x )
s
measured phase lag in degrees (°) during one cycle between the applied sinusoidal load and the
measured deflection Z(x )
s
3.5.25
system phase lag θ (x )
s
calculated phase lag in degrees (°) during one cycle representing the system losses:
=
=
=
T ⋅ ω
π
eq 0
tan θ⋅= (12)
M ⋅ ω
eq 0
3.5.26
phase lag ϕ
calculated phase lag in degrees (°) during one cycle between the occurring stress and strain in the
specimen at the applied frequency:
π
*
sin φ x⋅− Jx
( ) ( )
s s
π 180
tan φ⋅= (13)
180 π
*
cos φ x⋅+ I x
( ) ( )
s s
3.5.27
the complex (stiffness) modulus or dynamic stiffness modulus S
mix
calculated modulus of the complex modulus for the specimen during one cycle, in megapascals (MPa):
12FL⋅
0 ** 22
S ⋅+1 2[cos(φφ()xI)⋅ ()x − sin(x())⋅ J ()x ]+ [Ix()+ J ()x ] (14)
mix s s s s s s
Z()x ⋅ R()x ⋅⋅B H
ss
3.5.28
constant K relative to (maximum) strain
constant that enables the calculation of the maximum bending strain amplitude at the place where the
–1
deflection is measured, in inverse millimetres (mm ):
HA⋅
K()x ⋅Rx() (15)
ss
4L
3.5.29
strain amplitude ε = ε (x )
s
maximum strain amplitude during one cycle which occurs between the two inner clamps, in
micrometres per metre (μm/m):
ε= K()x⋅ Zx()⋅10 (16)
ss
3.5.30
stress amplitude σ
maximum stress amplitude during one cycle which occurs between the two inner clamps, in
megapascals (MPa):
−6
σεS ⋅ ⋅10 (17)
mix
3.5.31
dissipated energy per cycle
dissipated viscous energy in the beam per unit volume ΔW and per cycle, in kilojoules per cubic
dis
metre (kJ/m ) that, for sinusoidal strain and stress signals, is:
π
−3
(18)
∆Wx10 ⋅ π⋅ ε ⋅ σ ⋅sin φ ⋅
( )
dis s
=
=
=
=
3.5.32
cumulated dissipated energy
summation of the dissipated energies per cycle up to cycle n:
n
W ∆W (19)
∑
dis,n(m) dis,i
i = 1
Note 1 to entry: If the measurements are taken at intervals n(i), it is recommended to use the trapezium rule:
m
(20)
W n(1)⋅∆W + ∑ 0,5 ⋅ n(i + 1) − n(i) ⋅ ∆W + ∆W
( )
)
dis,n(m) dis,n(1) ( dis,n(i)
dis, n(i + 1)
i =1
3.5.33
amplitude
half the difference between the maximum and the minimum of a (sinusoidal) signal measured during
one cycle
3.5.34
measuring error
difference between the true value of a physical quantity and the value indicated by the measuring
instrument, expressed as a proportion of the true value, in percent (%)
3.5.35
accuracy class
permissible measuring error in the output signal of a transducer or sensor
3.5.36 Symbols
The symbols are as follows:
A is the estimate of the slope, p;
A is the estimation of the level of loading, Q;
B is the width of the prismatic specimen, in millimetres (mm);
D is the maximum nominal grain size of the mixture being tested, in millimetres (mm);
H is the height of the prismatic specimen, in millimetres (mm);
L is the effective length of the prismatic specimen, in millimetres (mm);
L is the total length of the prismatic specimen, in millimetres (mm);
tot
M is the mass of the whole beam without the masses of the mounted clamps, in kilograms
beam
(kg);
M is the masses of the two inner clamps, including the mass of the adhesive, and the mass of
clamps
the load frame between the load cell and the jack, in kilograms (kg);
M is the mass of the moving parts of the sensor, in kilograms (kg);
sensor
M is the equivalent mass, in kilograms (kg);
eq
Ni,j,k is the length of life for specimen number i, the chosen failure criteria j and the set of test
conditions k in cycles;
N is the number of load cycles at conventional failure when the modulus of the (complex)
f/50
stiffness modulus has decreased to half its initial value;
=
=
Q 6
is the level of the loading mode test condition corresponding to 10 cycles for the fatigue
life according to the chosen failure criteria, k;
ΔQ is the confidence interval relative to Q;
S is the initial value of the calculated modulus, in megapascal (MPa);
mix
S is the estimation of the standard deviation of the residual dispersion of the natural
x/y
logarithms of fatigue lives, σ
x/y;
T is the coefficient for the system losses in the interpretation formulae for Young’s
modulus;
p is the slope of the fatigue line;
r is the correlation coefficient of the regression;
x is the distance from end of sample, in millimetres (mm);
x is the distance from the end of the specimen to where the sensor is placed, in millimetres
s
(mm);
ε th -6
i is the initial strain amplitude measured at the 100 load cycle, in 10 (µm/m);
f is the test frequency in Hertz (Hz);
ω the angular speed, in radians per seconds (rad/s);
Θ is the test temperature, in degrees Celsius (°C).
3.6 Symbols for indirect tensile test on cylindrical shaped specimens (IT-CY)
The symbols are as follows:
F is the measured amplitude of the force, in Newtons (N);
t is the specimen thickness, in millimetres (mm);
Ω is the specimen diameter, in millimetres (mm);
ΔH is the total horizontal deformation between pulse 60 and 100, in millimetres (mm);
ΔH is the resilient horizontal deformation amplitude at pulse n, in millimetres (mm);
R,n
ν is Poisson’s ratio;
σ is the tensile stress amplitude at the centre of the specimen, in megapascals (MPa);
o
ε is the initial strain at the centre of the specimen, in micrometres per metre (µm/m);
ε is the resilient strain amplitude at load cycle n during cyclic loading, in micrometres per
R,n
metre (µm/m);
S is the stiffness modulus at pulse n, in megapascals (MPa);
mix,n
W is the energy ratio;
n
n is number of load cycles
N is the number of load cycles using the resilient approach;
f,w
k , n are material constants using the resilient approach.
w w
3.7 Symbols for Cyclic Indirect tensile Test on cylindrical shaped specimen (CIT-CY)
F is the medium vertical force, in kilonewtons (kN);
m
F is the lower vertical force, in kilonewtons (kN)
l
F is the vertical force amplitude, in kilonewtons (kN);
a
f is the load frequency, in hertz (Hz);
t is the test time, in seconds (s);
σ is the maximum horizontal tensile stress in the middle of the specimen, in megapascals
(MPa);
Ω is the specimen diameter, in millimetres (mm);
h is the specimen thickness, in millimetres (mm);
u is the mean horizontal displacement, in millimetres (mm);
m
u is the horizontal displacement amplitude, in millimetres (mm);
a
u is the horizontal displacement rate, representing the viscoplastic deflections, in millimetres
d
per second (mm/s).
σ is the amplitude of the horizontal tensile stress in the middle of the specimen, in
a
megapascals (MPa);
ε is maximum horizontal strain amplitude in the middle of the specimen, in meters/meters
a
(m/m);
Δε is the maximum strain difference in the middle of the specimen, in millimetres/meter
(mm/m);
ν is the Poisson ratio, without dimension (-);
φ is the phase angle between vertical force and horizontal displacement function, in degrees.
S stiffness modulus as calculated for the load interval n, in megapascal (MPa).
mix,n
n load cycle number representing the recorded interval, (-)
ER(n) energy ratio for load interval represented by load cycle number n, (-)
N is the number of load cycles until fracture life according to energy criterion, (-);
f,w
k , n are material constants of the fatigue function.
ε ε
4 Sample preparation
4.1 Storage of the specimens
Prior to the start of testing, the specimens shall be stored on a flat surface at a temperature of not more
than 20 °C for between 14 days and 42 days from the time of their manufacture. In the case of samples
requiring cutting and/or gluing, the cutting shall be performed no more than 8 days after compaction of
the asphalt and the gluing shall be performed at least 2 weeks after cutting. The time of manufacture for
these samples is the time when they are cut.
NOTE 1 The storage time influences the mechanical properties of the specimen.
NOTE 2 For test purposes other than for CE marking, different storage times can be applied.
4.2 Drying of the specimens
After sawing and before gluing and/or testing, the specimens shall be dried to constant mass in air at a
relative air humidity of less than 80 % and at a temperature not more than 20 °C. A test specimen shall
be considered to be dry when two weighings performed at a minimum of 4 h apart differ by less than
0,1 %.
NOTE If a specimen has been stored under cover in the dry for at least 14 days, it can be assumed to be dry.
4.3 Dimensions and bulk density of the specimens
The dimensions of the specimens shall be measured according to EN 12697-29. The bulk density shall
be determined in accordance with EN 12697-6 or EN 12697-7. For CE-marking purposes, the bulk
density of each specimen shall not differ by more than 1 % from the average density of the batch. If it
does differ outside this tolerance, the specimen shall be rejected. For other purposes, larger differences
are allowed. However, this has an effect on the accuracy of the test results.
5 Failure
The conventional failure criterion for the type of test undertaken, as defined in 3.1.2, shall be used to
determine the failure life of a material unless otherwise prescribed. In such cases, the criterion used
shall be included the test report.
6 Selection test conditions
For fatigue tests according to Annexes A to D, the test loads, deformations and frequencies shall be
selected so that the ε -value is calculated by interpolation and not by extrapolation. At least 20 % of the
measurements shall be at either side of the calculated result.
For tests according to Annexes E and F, the procedure for finding suitable test conditions is described in
the individual annexes.
7 Summary of the procedures
7.1 Two-point bending test on trapezoidal shaped specimens (2PB-TR)
This method characterizes the behaviour of bituminous mixtures under fatigue loading with controlled
displacement by two-point bending using trapezoidal shaped specimens. The method can be used for
bituminous mixtures with a maximum aggregate size of up to 20 mm on specimens prepared in a
laboratory or obtained from road layers with a thickness of at least 40 mm. For mixtures with an upper
size D between 20 mm and 40 mm, the test can be performed using the same principle but with adapted
specimen sizes. For a given frequency of sinusoidal displacement, the method shall be carried out on
several elements tested in a ventilated atmosphere at a controlled temperature.
7.2 Two-point bending test on prismatic shaped specimens (2PB-PR)
This method characterizes the behaviour of bituminous mixtures under fatigue loading by 2-point-
bending using square-prismatic shaped specimens. The method can be used for bituminous mixtures
with a maximum aggregate size of up to 20 mm and on specimens prepared in a laboratory or obtained
from road layers with a thickness of at least 40 mm.
7.3 Three-point bending test on prismatic shaped specimens (3PB-PR)
This method characterizes the behaviour of bituminous mixes under fatigue loading, with controlled
displacement by three-point bending using prismatic beam shaped specimens. The behaviour is
characterized through the determination of the fatigue law in terms of strain (relation between strain
and number of load cycles at failure) and the associated energy law. The method can be used for
bituminous mixture specimens with a maximum aggregate size of 22 mm or for samples from road
layers with a thickness of at least 50 mm. For a given frequency of sinusoidal displacement, the method
shall be carried out on several elements tested at a controlled temperature.
7.4 Four-point bending test on prismatic shaped specimens (4PB-PR)
This method characterizes the behaviour of bituminous mixtures under fatigue loading in four-point
bending test equipment in which the inner and outer clamps are symmetrically placed and slender
rectangular shaped specimens (prismatic beams) are used. The prismatic beams shall be subjected to
four-point periodic bending with free rotation and translation at all load and reaction points. The
bending shall be realized by loading the two inner load points (inner clamps) in the vertical direction,
perpendicular to the longitudinal axis of the beam. The vertical position of the end-bearings (outer
clamps) shall be fixed. This load configuration shall create a constant moment, and hence a constant
strain, between the two inner clamps. The applied load shall be sinusoidal. During the test, the load
needed for the bending of the specimen, the deflection and the phase lag between these two signals
shall be measured as a function of time. The fatigue characteristics of the material test
...
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