SIST EN 12697-25:2005
(Main)Bituminous mixtures - Test methods for hot mix asphalt - Part 25: Cyclic compression test
Bituminous mixtures - Test methods for hot mix asphalt - Part 25: Cyclic compression test
This document describes two test methods (A and B) for determining the resistance of bituminous mixtures to permanent deformation.
Test method A describes the method for determining the creep characteristics of bituminous mixtures by means of an uniaxial cyclic compression test with some confinement present. In this test a cylindrical specimen is subjected to a cyclic axial stress. To achieve a certain confinement, the diameter of the loading platen is taken smaller than that of the sample.
NOTE Confinement of the sample is necessary to predict realistic rutting behaviour, especially for gap-graded mixes with a large stone fraction.
Test method B describes the method for determining the creep characteristics of bituminous mixtures by means of the triaxial cyclic compression test. In this test a cylindrical specimen is subjected to a confining stress and a cyclic axial stress. This test is most often used for the purpose of evaluation and development of new types of mixtures.
This document applies to specimens prepared in the laboratory or cored from the road. The maximum size of the aggregates is 32 mm.
This European Standard applies to specimens prepared in the laboratory or cored from the road. The maximum size of the aggregates is 32 mm.
Asphalt - Prüfverfahren für Heißasphalt - Teil 25: Druckschwellversuch
Diese Europäische Norm beschreibt zwei Prüfverfahren (A und B) zur Bestimmung der Beständigkeit von
Asphalt gegen bleibende Verformung.
Das Prüfverfahren A beschreibt das Verfahren zur Bestimmung der Kriecheigenschaften von Asphalt mit Hilfe
eines einaxialen Druckschwellversuchs mit begrenzter Behinderung der Querdehnung. Bei dieser Prüfung
wird ein zylindrischer Probekörper einer zyklischen Axialbelastung ausgesetzt. Um eine bestimmte Behinde-
rung der Querdehnung zu erreichen, wird für die Lastplatte ein Durchmesser gewählt, der kleiner ist als der
des Probekörpers.
ANMERKUNG Die Behinderung der Querdehnung des Probekörpers ist erforderlich, um das tatsächliche Spurrinnen-
bildungsverhalten, besonders für Mischgüter mit Ausfallkörnung mit einem großen Splitt-Anteil, vorherzusagen.
Das Prüfverfahren B beschreibt das Verfahren zur Bestimmung der Kriecheigenschaften von Asphalt mit Hilfe
des triaxialen Druckschwellversuchs. Bei dieser Prüfung wird ein zylindrischer Probekörper einem Druck zur
Behinderung der Querdehnung (Stützdruck) und einer zyklischen Axialbelastung ausgesetzt. Die Prüfung wird
für die Bewertung und die Entwicklung neuer Arten von Mischgütern verwendet.
Diese Europäische Norm gilt für Probekörper, die entweder im Labor hergestellt oder durch
Bohrkernentnahme aus der Straße gewonnen wurden. Die maximale Korngröße beträgt 32 mm.
Mélanges bitumineux - Méthodes d'essai pour mélange hydrocarboné a chaud - Partie 25 : Essai de compression cyclique
La présente Norme européenne décrit deux méthodes d'essai (A et B) destinées a déterminer la résistance a la déformation permanente de mélanges bitumineux.
La méthode d'essai A décrit le mode opératoire pour déterminer les caractéristiques de fluage de mélanges bitumineux au moyen d'un essai de compression cyclique uniaxial sous un certain confinement. Lors de cet essai, une éprouvette cylindrique est soumise a une contrainte axiale cyclique. Pour obtenir un certain confinement, le diametre du piston de chargement est pris inférieur a celui de l'éprouvette.
NOTE Le confinement de l'éprouvette est nécessaire pour prévoir un comportement a l'orniérage réaliste, en particulier pour les mélanges a granulométrie discontinue avec une fraction importante de gravillons.
La méthode d'essai B décrit le mode opératoire pour déterminer les caractéristiques de fluage de mélanges bitumineux au moyen d'un essai de compression cyclique triaxial. Lors de cet essai, une éprouvette cylindrique est soumise a une contrainte de confinement et a une contrainte axiale cyclique. Cet essai est le plus souvent utilisé dans le but d'évaluer et de développer de nouveaux types de mélanges.
La présente Norme européenne s'applique aux éprouvettes préparées en laboratoire ou extraites de la chaussée. La dimension maximale des granulats est de 32 mm.
Bitumenske zmesi – Preskusne metode za vroče asfaltne zmesi – 25. del: Ciklični tlačni preskus
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 12697-25:2005
01-julij-2005
%LWXPHQVNH]PHVL±3UHVNXVQHPHWRGH]DYURþHDVIDOWQH]PHVL±GHO &LNOLþQL
WODþQLSUHVNXV
Bituminous mixtures - Test methods for hot mix asphalt - Part 25: Cyclic compression
test
Asphalt - Prüfverfahren für Heißasphalt - Teil 25: Druckschwellversuch
Mélanges bitumineux - Méthodes d'essai pour mélange hydrocarboné a chaud - Partie
25 : Essai de compression cyclique
Ta slovenski standard je istoveten z: EN 12697-25:2005
ICS:
93.080.20 Materiali za gradnjo cest Road construction materials
SIST EN 12697-25:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 12697-25:2005
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SIST EN 12697-25:2005
EUROPEAN STANDARD
EN 12697-25
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2005
ICS 93.080.20
English version
Bituminous mixtures - Test methods for hot mix asphalt - Part
25: Cyclic compression test
Mélanges bitumineux - Méthodes d'essai pour mélange Asphalt - Prüfverfahren für Heißasphalt - Teil 25:
hydrocarboné à chaud - Partie 25 : Essai cyclique de Druckschwellversuch
compression
This European Standard was approved by CEN on 15 March 2005.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12697-25:2005: E
worldwide for CEN national Members.
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SIST EN 12697-25:2005
EN 12697-25:2005 (E)
Contents page
Foreword .3
Introduction.6
1 Scope .7
2 Normative references .7
3 Terms and definitions.7
4 Test method A — Uniaxial cyclic compression test with confinement.9
4.1 Principle.9
4.2 Apparatus .10
4.3 Specimen preparation .13
4.4 Conditioning.14
4.5 Test procedure .14
4.6 Calculation and expression of results.15
4.7 Test report .16
4.8 Precision.16
5 Test method B — Triaxial cyclic compression test.17
5.1 Principle.17
5.2 Apparatus .19
5.3 Specimen preparation .22
5.4 Conditioning.23
5.5 Test procedure .24
5.6 Calculation and expression of results.25
5.7 Test report .27
5.8 Precision.28
Bibliography.29
2
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SIST EN 12697-25:2005
EN 12697-25:2005 (E)
Foreword
This document (EN 12697-25:2005) 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 October 2005, and conflicting national standards shall be withdrawn at
the latest by October 2005.
This European Standard is one of a series of standards as listed below:
EN 12697-1, Bituminous mixtures — Test methods for hot mix asphalt — Part 1: Soluble binder content.
EN 12697-2, Bituminous mixtures - Test method for hot mix asphalt - Part 2: Determination of particle size
distribution.
EN 12697-3, Bituminous mixtures - Test methods for hot mix asphalt - Part 3: Bitumen recovery: Rotary
evaporator.
EN 12697-4, Bituminous mixtures - Test methods for hot mix asphalt - Part 4: Bitumen recovery: Fractionating
column.
EN 12697-5, Bituminous mixtures — Test methods for hot mix asphalt — Part 5: Determination of the
maximum density.
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 12697-9, Bituminous mixtures — Test methods for hot mix asphalt — Part 9: Determination of the
reference density.
EN 12697-10, Bituminous mixtures — Test methods for hot mix asphalt — Part 10: Compactability.
EN 12697-11, Bituminous mixtures - Test methods for hot mix asphalt - Part 11: Determination of the affinity
between aggregate and bitumen.
EN 12697-12, Bituminous mixtures - Test methods for hot mix asphalt - Part 12: Determination of the water
sensitivity of bituminous specimens.
EN 12697-13, Bituminous mixtures — Test methods for hot mix asphalt — Part 13: Temperature
measurement.
EN 12697-14, Bituminous mixtures — Test methods for hot mix asphalt — Part 14: Water content.
EN 12697-15, Bituminous mixtures - Test methods for hot mix asphalt - Part 15: Determination of the
segregation sensitivity.
EN 12697-16, Bituminous mixtures — Test methods for hot mix asphalt — Part 16: Abrasion by studded tyres.
3
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EN 12697-25:2005 (E)
EN 12697-17, Bituminous mixtures - Test methods for hot mix asphalt - Part 17: Particle loss of porous
asphalt specimen.
EN 12697-18, Bituminous mixtures — Test methods for hot mix asphalt — Part 18: Binder drainage.
EN 12697-19, Bituminous mixtures — Test methods for hot mix asphalt — Part 19: Permeability of specimen.
EN 12697-20, Bituminous mixtures — Test methods for hot mix asphalt — Part 20: Indentation using cube or
Marshall specimens.
EN 12697-21, Bituminous mixtures — Test methods for hot mix asphalt — Part 21: Indentation using plate
specimens.
EN 12697-22, Bituminous mixtures — Test methods for hot mix asphalt — Part 22: Wheel tracking.
EN 12697-23, Bituminous mixtures - Test methods for hot mix asphalt - Part 23: Determination of the indirect
tensile strength of bituminous specimens.
EN 12697-24, Bituminous mixtures — Test methods for hot mix asphalt — Part 24: Resistance to fatigue.
EN 12697-25, Bituminous mixtures — Test methods for hot mix asphalt — Part 25: Cyclic compression test.
EN 12697-26, Bituminous mixtures — Test methods for hot mix asphalt — Part 26: Stiffness.
EN 12697-27, Bituminous mixtures — Test methods for hot mix asphalt — Part 27: Sampling.
EN 12697-28, Bituminous mixtures — Test methods for hot mix asphalt — Part 28: Preparation of samples for
determining binder content, water content and grading.
EN 12697-29, Bituminous mixtures — Test methods for hot mix asphalt — Part 29: Determination of the
dimensions of a bituminous specimen.
EN 12697-30, Bituminous mixtures - Test methods for hot mix asphalt - Part 30: Specimen preparation by
impact compactor.
EN 12697-31, Bituminous mixtures - Test methods for hot mix asphalt - Part 31: Specimen preparation by
gyratory compactor.
EN 12697-32, Bituminous mixtures — Test methods for hot mix asphalt — Part 32: Laboratory compaction of
bituminous mixtures by vibratory compactor.
EN 12697-33, Bituminous mixtures - Test methods for hot mix asphalt - Part 33: Specimen prepared by roller
compactor.
EN 12697-34, Bituminous mixtures — Test methods for hot mix asphalt — Part 34: Marshall test.
EN 12697-35, Bituminous mixtures — Test methods for hot mix asphalt — Part 35: Laboratory mixing.
EN 12697-36, Bituminous mixtures - Test methods for hot mix asphalt - Part 36: Determination of the
thickness of a bituminous pavement.
EN 12697-37, Bituminous mixtures - Test methods for hot mix asphalt - Part 37: Hot sand test for the
adhesivity of binder on precoated chippings for HRA.
EN 12697-38, Bituminous mixtures — Test methods for hot mix asphalt — Part 38: Common equipment and
calibration.
EN 12697-39, Bituminous mixtures — Test methods for hot mix asphalt — Part 39: Binder content by ignition.
4
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EN 12697-25:2005 (E)
prEN 12697-40, Bituminous mixtures — Test methods for hot mix asphalt — Part 40: In-situ drainability.
prEN 12697-41, Bituminous mixtures — Test methods for hot mix asphalt — Part 41: Resistance to de-icing
fluids.
prEN 12697-42, Bituminous mixtures — Test methods for hot mix asphalt — Part 42: Amount of foreign
matters in reclaimed asphalt.
prEN 12697-43, Bituminous mixtures — Test methods for hot mix asphalt — Part 43: Resistance to fuel.
No existing European Standard is superseded.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.
5
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SIST EN 12697-25:2005
EN 12697-25:2005 (E)
Introduction
This European Standard contains two test methods to determine the resistance to permanent deformation of a
bituminous mixture by cyclic compression tests with confinement. The tests make it possible to rank various
mixes or to check on the acceptability of a given mix. They do not allow making a quantitative prediction of
rutting in the field to be made. The choice for confinement was made in order to obtain realistic test results for
gap-graded mixes.
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SIST EN 12697-25:2005
EN 12697-25:2005 (E)
1 Scope
This European Standard describes two test methods (A and B) for determining the resistance of bituminous
mixtures to permanent deformation.
Test method A describes the method for determining the creep characteristics of bituminous mixtures by
means of an uniaxial cyclic compression test with some confinement present. In this test a cylindrical
specimen is subjected to a cyclic axial stress. To achieve a certain confinement, the diameter of the loading
platen is taken smaller than that of the sample.
NOTE 1 Confinement of the sample is necessary to predict realistic rutting behaviour, especially for gap-graded mixes with a large
stone fraction.
Test method B describes the method for determining the creep characteristics of bituminous mixtures by
means of the triaxial cyclic compression test. In this test a cylindrical specimen is subjected to a confining
stress and a cyclic axial stress. This test is most often used for the purpose of evaluation and development of
new types of mixtures.
This European Standard applies to specimens prepared in the laboratory or cored from the road. The
maximum size of the aggregates is 32 mm.
NOTE 2 For purposes of compliance with EN 13108, the test conditions are given in prEN 13108-20.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 12697-6, Bituminous mixtures - Test methods for hot mix asphalt - Part 6: Determination of bulk density of
bituminous specimens.
EN 12697-27, Bituminous mixtures — Test methods for hot mix asphalt — Part 27: Sampling.
EN 12697-29, Bituminous mixtures — Test methods for hot mix asphalt — Part 29: Determination of the
dimensions of a bituminous specimen.
EN 12697-30, Bituminous mixtures — Test methods for hot mix asphalt — Part 30: Specimen preparation by
impact compactor.
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 for hot mix asphalt - Part 33: Specimen prepared by roller
compactor.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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EN 12697-25:2005 (E)
3.1
accuracy class
permissible measuring error, expressed as a percentage, in the output signal of a transducer
3.2
contact area
that portion of the pressure platen that is in contact with the test specimen
3.3
creep curve
display of the cumulative axial strain, expressed in %, of the specimen as a function of the number of load
applications
NOTE Generally the following stages can be distinguished (see Figure 1)
stage 1: the (initial) part of the deformation curve, where the slope of the curve decreases with increasing number of
loading cycles;
stage 2: the (middle) part of the deformation curve, where the slope of the curve is quasi constant and with a turning
point in the deformation curve;
stage 3: the (last) part of the deformation curve, where the slope increases with increasing number of loading cycles.
Depending on the testing conditions and on the mix, one or more stages may be absent.
Key
ε Cumulative axial strain 1 Stage 1
N
2 Stage 2
n Number of load repetitions
3 Stage 3
4 Turning point
Figure 1 — Example of a creep curve
3.4
precision
the closeness of agreement between independent test results obtained under stipulated conditions
NOTE 1 Precision depends only on the distribution of random errors and does not relate to the true value or the
specified value.
NOTE 2 The measure of precision is usually expressed in terms of imprecision and computed as a standard deviation
of the test results. Less precision is reflected by a larger standard deviation.
8
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EN 12697-25:2005 (E)
NOTE 3 “Independent test results” means results obtained in a manner not influenced by any previous result on the
same or similar test object. Quantitative measures of precision depend critically on the stipulated conditions. Repeatability
and reproducibility conditions are particular sets of extreme conditions.
3.5
repeatability
precision under repeatability conditions
3.6
repeatability conditions
conditions where independent test results are obtained with the same method on identical test items in the
same laboratory by the same operator using the same equipment within short intervals of time
3.7
repeatability limit
the value less than or equal to which the absolute difference between two test results obtained under
repeatability conditions may be expected to be within probability of 95 %
NOTE The symbol used is r.
3.8
reproducibility
precision under reproducibility conditions
3.9
reproducibility conditions
conditions where test results are obtained with the same method on identical test items in different
laboratories with different operators using different equipment
3.10
reproducibility limit
the value less than or equal to which the absolute difference between two test results obtained under
reproducibility conditions may be expected to be with a probability of 95 %
NOTE The symbol used is R.
3.11
single test result
the value obtained by applying the standard test method fully, once to a single specimen; it may be the mean
of two or more observations or the result of a calculation from a set of observations as specified by the
standardized test method
3.12
measuring error
difference between the true value of the physical quantity and the value indicated on the measuring instrument,
expressed as a percentage of the true value
3.13
permanent deformation
cumulative axial deformation of the specimen after a given number of load applications
4 Test method A — Uniaxial cyclic compression test with confinement
4.1 Principle
This test method determines the resistance to permanent deformation of a cylindrical specimen of bituminous
mixture by repeated load. The specimens may be either prepared in the laboratory or be cored from a
pavement.
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EN 12697-25:2005 (E)
A cylindrical test specimen with a diameter of 150 mm, maintained at elevated conditioning temperature, is
placed between two plan parallel loading platens. The upper platen has a diameter of 100 mm (by an
inclination the pressure area against the specimen has a real diameter of 96 mm). A schematic representation
of the test device is given in Figure 2. The specimen is subjected to a cyclic axial block-pulse pressure, as
represented in Figure 3. There is no additional lateral confinement pressure applied.
During the test the change in height of the specimen is measured at specified numbers of load applications.
From this, the cumulative axial strain ε (permanent deformation) of the test specimen is determined as a
N
function of the number of load applications. The results are represented in a creep curve as given in Figure 3.
From this, the creep characteristics of the specimen are computed.
The test does not allow a quantitative prediction of the rutting. Nevertheless, the test makes it possible to rank
various mixes or to check on the acceptability of a given mix.
Figure 2 — Test apparatus
4.2 Apparatus
4.2.1 Test system
4.2.1.1 Compression apparatus
A suitable test apparatus to generate a square (see Figure 3 and Figure 4) and periodical loading pulse, with a
frequency of 0,5 Hz and a load of (100 ± 2) kPa. The load cell shall have a capacity of at least 2 000 N. All
components shall be constructed out of corrosion-resistant steel.
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EN 12697-25:2005 (E)
Key
1 Strain, microstrain t Time
2 Stress, kPa A Strain at preload, microstrain
ε Irreversible strain (permanent deformation)
3 Preload
irr
Figure 3 — Stress and strain curve
Key
1 Load
2 Duration of the pulse
x + x + x + x < 20 % of the whole pulse
1 2 3 4
Figure 4 — Loading curve
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EN 12697-25:2005 (E)
4.2.1.2 Loading configuration
The lower platen shall have an area that stretches at least 5 mm outside the specimen. The dimensions of the
upper platen shall be as follows: diameter (100 ± 0,5) mm, thickness (25 ± 0,5) mm and mass (1,55 ± 0,05) kg.
The platen shall at the lower edge have an inclination as shown in Figure 5, which gives a loading circular
surface with a diameter of (96 ± 1) mm. The upper platen shall be fitted with hemispherical self-aligning
seating while the lower platen shall be fixed or held in place by e.g. a spigot/slot system. Both the bottom
surface (the lower platen) and the upper platen shall be made from hardened corrosion-resistant steel with a
polished (flat and smooth) surface.
NOTE The inclination of the lower edge can also be rounded off.
Figure 5 — Lower edge of the platen
4.2.1.3 Control and measuring system
(PC and software) for controlling, reading and collecting necessary data. The control system shall guarantee
that during the test the physical parameter to be controlled (force) shows no oscillations.
NOTE It is recommended that the control system should include a programmable function generator and a control
circuit with which the desired loading signal can be generated.
4.2.1.4 Displacement transducers
The deformation measurement system shall include two displacement transducers for measuring and
recording the cumulative axial deformation to the test specimen, by measuring the change in distance
between the loading platens throughout the test. The transducers shall conform to accuracy class 0,2. The
measuring range of the transducers shall be 5 mm at least.
4.2.1.5 Thermostatic chamber
A thermostatic chamber to maintain the sample at the specified test temperature. The accuracy of the
temperature control shall be ±1 °C or higher.
NOTE It is recommended that a sufficiently large thermostatic chamber should be chosen, so that during the test
additional test specimens can be acclimatised inside the thermostatic chamber
4.2.2 Measuring instruments and accessories needed
4.2.2.1 Balance and other equipment required to determine the bulk density in accordance with
EN 12697-6.
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4.2.2.2 Vernier callipers or other suitable apparatus to determine the specimen dimensions in accordance
with EN 12697-29.
4.2.2.3 Drying cabinet or room, temperature between 15 °C and 25 °C.
4.2.2.4 Storage area, temperature between 5 °C and 25 °C.
4.2.2.5 Silicon oil with lubricants or a mixture of glycerine and talcum for coating of the planoparallel areas
of the specimen.
4.3 Specimen preparation
4.3.1 At least five test specimens shall be prepared for testing.
4.3.2 Each test specimen shall have the shape of a cylinder. The end of the test specimen shall be even
and plan parallel, which is achieved by sawing both ends of the specimen. A diamond saw equipped with
parallel blades is recommended. The ends shall be parallel and perpendicular to the cylinder axis (i.e. a right-
angle not more than about 2° to 3°. For a rough control of evenness brush the hand over the surface. If it feels
even without blemishes it shall be considered adequate, otherwise it shall be polished. After sawing/polishing
the specimen shall be dried at a temperature not exceeding 25 °C.
NOTE A test specimen should be considered to be dry after at least 8 h drying time and when two weightings
performed minimum 4 h apart differ by less than 0,1 %.
4.3.3 The following dimensions, measured on the dry test specimen according to EN 12697-6, procedure D
(EN 12967-29, using a vernier calliper) shall apply:
the specimen shall have a height of (60 ± 2) mm and a diameter of (148 ± 5) mm;
the height shall not vary by more than 1,0 mm and the diameter shall not vary by more than 2 mm.
4.3.4 The test shall be performed on
test specimens prepared in the laboratory by gyratory compaction (EN 12697-31);
test specimens drilled from laboratory-prepared slab of asphalt (EN 12697-33);
test specimens prepared from drilled core specimen taken from the road (EN 12697-27);
test specimens prepared in the laboratory by impact compactor (EN 12697-30).
NOTE 1 The way of compaction has a considerable impact on the results.
NOTE 2 For type testing: the compaction method is given in prEN 13108-20.
4.3.5 The bulk density of the test specimen shall be measured in accordance with EN 12697-6.
4.3.6 In case of cored specimens from the road and if the height of the individual specimen is not high
enough, two specimens may be put one on top of the other (but not more than two). The same demands for
evenness and plan-parallelism as for one specimen shall be met for each of the specimens as for the two put
together. Each of the specimens shall have a height of at least 25 mm (the two specimens put together shall
still have a height of (60 ± 2) mm). The specimens are put together without the use of any kind of substance.
4.3.7 Damage to the test specimen shall be avoided in all stages of sampling, transport and preparation
before testing. During transport and storage the slab and drilled core specimen shall be fully supported to
prevent deformation or damage.
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EN 12697-25:2005 (E)
4.4 Conditioning
4.4.1 The specimens shall be stored at a temperature between 5 °C and 25 °C. Test specimens shall be
fully supported and not be stacked on top of each other. Any damage shall be prevented.
4.4.2 Testing shall start not before 2 days after compaction in the laboratory or on the road.
4.4.3 Specimens shall be cleaned if necessary by brushing or washing, as required.
4.4.4 The specimens shall be dried at ambient temperature to constant mass.
NOTE Constant mass is obtained after at least 8 h drying time and when the change of mass between two
determinations at an interval of at least 4 h is less than 0,1 %.
4.4.5 To minimize the friction between the loading platens and the test specimen, the end faces of the
specimen shall be smooth and plain. Brush the hand over the specimens’ surface. If it feels even without
blemishes, it shall be considered adequate, otherwise it shall be polished or ground.
NOTE 1 An adequate way to coat the end faces of the specimen and minimise the friction with the platens is to apply a
mixture of glycerine and talcum (or silicone oil with lubricants) to the faces, in order to obtain a smooth surface. Any
surplus might be removed using an absorbent tissue.
NOTE 2 Does not apply for the surface between two specimens (see 4.3.6).
Stabilize the specimen to the test temperature to within ±1,0 °C for at least 4 h and not more than 7 h.
4.4.6
NOTE It is an advantage to be able to do this in the thermostatic chamber.
4.5 Test procedure
4.5.1 For a standard creep investigation at least five specimens shall be tested.
4.5.2 The test temperature shall be kept constant to within ±1,0 °C during the duration of the test.
NOTE 1 A typical test temperature is 40 °C.
NOTE 2 For testing according to prEN 13108-20, the temperature is given in that standard.
4.5.3 The test specimen shall be positioned well centred coaxially with the test axis between the two
platens. Two displacement transducers shall be positioned on the loading platen, one opposite to the other.
Then a preload shall be applied for 10 min (600 s). The accuracy on the preload control shall be ±10 % or
better.
4.5.4 The deformation shall be registered after the preloading.
–3
NOTE 1 A typical value of the preload is (72 ± 7) × 10 kN (this corresponds to a pre-stress of (10 ± 1) kPa on a
specimen with a diameter of the loading surface of 96 mm).
NOTE 2 The upper platen gives a constant static load (about 2 kPa), which however is not included in the cyclic load.
4.5.5 Immediately after the preloading time has ended, the periodic load shall be applied with a loading time
for each pulse (1 ± 0,05) s. The accuracy on the period load shall be ±10 % or better. The loading pulse can
be seen in Fig
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