SIST EN 12697-25:2016
(Main)Bituminous mixtures - Test methods - Part 25: Cyclic compression test
Bituminous mixtures - Test methods - Part 25: Cyclic compression test
This European Standard describes three test methods (A1, A2 and B) for determining the resistance of bituminous mixtures to permanent deformation by cyclic compression tests with confinement. The tests make it possible to rank various mixtures or to check on the acceptability of a given mixture. They do not allow making a quantitative prediction of rutting in the field to be made.
Test methods A1 and A2 describe methods for determining the creep characteristics of bituminous mixtures by means of a uniaxial cyclic compression test with some confinement present. In this test a cylindrical specimen is subjected to a cyclic axial stress. Method A2 is preferred for mastic asphalt and method A1 for other asphalt mixtures. 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 simulate realistic rutting behaviour, especially for gap-graded mixtures with a large stone fraction.
In test method A1, the specimen is loaded by block-pulses whereas in method A2 haversine loading with rest time is applied.
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 EN 13108-20.
Asphalt - Prüfverfahren - Teil 25: Druckschwellversuch
Diese Europäische Norm beschreibt drei Prüfverfahren (A1, A2 und B) zur Bestimmung der Beständigkeit von Asphalt gegen bleibende Verformung mit Hilfe von Druckschwellversuchen mit Behinderung der Quer-dehnung. Diese Prüfungen erlauben es, verschiedene Mischgüter einzustufen oder die Annehmbarkeit eines bestimmten Mischgutes zu prüfen. Sie gestatten keine quantitative Vorhersage hinsichtlich der Spurrinnen-bildung auf der Straße.
Die Prüfverfahren A1 und A2 beschreiben 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. Das Verfahren A2 wird für Mastixasphalte bevorzugt, während Verfahren A1 bei allen anderen Asphalten anzuwenden ist. Um eine bestimmte Behinderung der Querdehnung zu erreichen, wird für die Lastplatte ein Durchmesser gewählt, der kleiner ist als der des Probekörpers.
ANMERKUNG 1 Die Behinderung der Querdehnung des Probekörpers ist erforderlich, um das tatsächliche Verhalten bei der Spurrinnenbildung, besonders für Mischgüter mit Ausfallkörnung mit einem großen Splittanteil, zu simulieren.
Bei Prüfverfahren A1 wird der Probekörper durch trapezförmige Belastungsimpulse beansprucht, während bei Verfahren A2 ein Belastungsimpuls in Form eines halben Sinusversus mit Ruhephasen angewendet wird.
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 Bohrkern-entnahme aus der Straße gewonnen wurden. Die maximale Korngröße beträgt 32 mm.
ANMERKUNG 2 Zum Zweck der Übereinstimmung mit EN 13108 sind die Prüfbedingungen in EN 13108 20 beschrieben.
Mélanges bitumineux - Méthodes d'essai - Partie 25 : Essai de compression cyclique
La présente Norme européenne décrit trois méthodes d’essai (A1, A2 et B) destinées à déterminer la résistance à la déformation permanente de mélanges bitumineux par des essais de compression cyclique sous confinement. Les essais permettent de classifier différents mélanges ou de vérifier l’acceptabilité d’un mélange donné. Ils ne permettent pas de réaliser une prédiction quantitative de l’orniérage sur le terrain.
Les méthodes d’essai A1 et A2 décrivent les modes opératoires pour déterminer les caractéristiques de fluage de mélanges bitumineux au moyen d’un essai de compression cyclique uni-axial sous un certain confinement. Lors de cet essai, une éprouvette cylindrique est soumise à une contrainte axiale cyclique. La méthode A2 est recommandée pour l'asphalte coulé routier et la méthode A1 pour les autres mélanges hydrocarbonés. Pour obtenir un certain confinement, le diamètre du piston de chargement est pris inférieur à celui de l’éprouvette. Dans la méthode A1, l'éprouvette est mise en charge en créneau alors que, dans la méthode A2, une mise en charge par impulsion sinusoïdale avec décalage d'origine et un temps de repos est appliquée.
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 à une contrainte de confinement et à 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.
NOTE 1 Le confinement de l’éprouvette est nécessaire pour simuler un comportement à l’orniérage réaliste, en particulier pour les mélanges à granulométrie discontinue avec une fraction importante de gravillons.
NOTE 2 Dans le cas de spécifications conformes aux normes EN 13108, les conditions d’essai sont données dans l'EN 13108-20.
Bitumenske zmesi - Preskusne metode - 25. del: Ciklični tlačni preskus
Ta evropski standard opisuje tri preskusne metode (A1, A2 in B) za določanje odpornosti bitumenskih zmesi na trajno deformacijo s cikličnimi tlačnimi preskusi z osamitvijo. Preskusi omogočajo razvrščanje različnih zmesi ali preverjanje njihove sprejemljivosti. Ne uporabljajo se za predvidevanje o količini kolesnic.
Preskusni metodi A1 in A2 opisujeta metode za določanje značilnosti lezenja bitumenskih zmesi s pomočjo enoosnih cikličnih tlačnih preskusov z nekaj osamitve. Pri tem preskusu je cilindrični primerek podvržen ciklični osni napetosti. Metoda A2 je priporočljiva za liti asfalt, metoda A1 pa za druge asfaltne zmesi. Za dosego osamitve se uporabi manjši premer obremenilne plošče kot pri vzorcu.
OPOMBA 1: Osamitev vzorca je nujno potrebna za realno simulacijo kolesnic, posebej za granulatne zmesi z večjo frakcijo.
Pri preskusni metodi A1 preskušanec obremenimo z blokovnimi pulzi, v metodi A2 pa s sinusnimi obremenitvami in počivanjem.
Preskusna metoda B opisuje metodo za določanje značilnosti lezenja bitumenskih zmesi s pomočjo triosnih cikličnih tlačnih preskusov. Pri tem preskusu je cilindrični preskušanec izpostavljen pritisku na obod in ciklični osni napetosti. Ta preskus se najpogosteje uporablja za ocenjevanje in razvoj novih tipov zmesi.
Ta evropski standard se uporablja za preskušance, pripravljene v laboratoriju ali pridobljene s ceste. Največja velikost skupka je 32 mm.
OPOMBA 2: Za namene skladnosti s standardom EN 13108 so preskusni pogoji podani v standardu EN 13108-20.
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.HVNXVAsphalt - Prüfverfahren - Teil 25: DruckschwellversuchMélanges bitumineux - Méthodes d'essai - Partie 25 : Essai de compression cycliqueBituminous mixtures - Test methods - Part 25: Cyclic compression test93.080.20Materiali za gradnjo cestRoad construction materialsICS:Ta slovenski standard je istoveten z:EN 12697-25:2016SIST EN 12697-25:2016en,fr,de01-november-2016SIST EN 12697-25:2016SLOVENSKI
STANDARDSIST EN 12697-25:20051DGRPHãþD
SIST EN 12697-25:2016
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12697-25
July
t r s x ICS
{ uä r z rä t r Supersedes EN
s t x { yæ t wã t r r wEnglish Version
Bituminous mixtures æ Test methods æ Part
t wã Cyclic compression test Mélanges bitumineux æ Méthodes d 5essai æ Partie
t w ã Essai de compression cyclique
Asphalt æ Prüfverfahren æ Teil
t wã DruckschwellversuchThis European Standard was approved by CEN on
s { May
t r s xä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä
EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels
9
t r s x CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
s t x { yæ t wã t r s x ESIST EN 12697-25:2016
EN 12697-25:2016 (E) 2 Contents Page European foreword . 4 1 Scope . 8 2 Normative references . 8 3 Terms and definitions . 9 4 Principle . 10 5 Equipment . 10 5.1 Control and loading system . 10 5.2 Displacement transducers . 10 5.3 Data registration equipment . 10 5.4 Thermostatic chamber . 10 5.5 Measuring instruments and accessories needed. 11 6 Test specimen preparation. 11 6.1 Number of test specimen . 11 6.2 Test specimen compaction . 11 6.3 Preparation of mastic asphalt test specimen . 11 6.3.1 Accessories for test specimen preparation . 11 6.3.2 Procedure for moulded test specimen . 12 6.3.3 Procedure for cored test specimen . 12 6.4 Preparation of test specimen surfaces . 12 6.5 Determination of bulk density . 12 6.6 Drying of the test specimen . 12 6.7 Dimensions . 12 7 Test method A — Uniaxial cyclic compression test with confinement . 13 7.1 Principle . 13 7.2 Test method A1 – block pulse loading . 13 7.2.1 Upper loading plate . 13 7.2.2 Loading pulse . 13 7.3 Test method A2 – Haversine pulse loading . 15 7.3.1 Upper loading plate . 15 7.3.2 Loading pulse . 16 7.4 Test specimen . 17 7.5 Conditioning . 17 7.5.1 Storing conditions . 17 7.5.2 Cleaning and drying of test specimens . 18 7.5.3 Reduction of friction to loading platens . 18 7.5.4 Temperature conditioning . 18 7.6 Test procedure . 18 7.6.1 Test temperature . 18 7.6.2 Positioning of test specimen in test device . 18 7.6.3 Testing of test specimen . 18 7.6.4 Measurement of permanent deformation . 19 7.6.5 End of loading . 19 7.7 Calculation and expression of results . 19 7.7.1 Permanent deformation . 19 SIST EN 12697-25:2016
EN 12697-25:2016 (E) 3 7.7.2 Creep rate and creep modulus . 20 7.8 Test report . 21 7.8.1 General . 21 7.8.2 Information on the test specimens . 21 7.8.3 Information on test conditions . 21 7.8.4 Test results . 21 7.9 Precision . 22 8 Test method B — Triaxial cyclic compression test . 22 8.1 Principle . 22 8.2 Apparatus and test system . 24 8.2.1 General . 24 8.2.2 Loading platens . 27 8.2.3 Control system . 27 8.2.4 Load cell . 27 8.2.5 Height measurements . 27 8.2.6 Temperature conditioning . 27 8.3 Test specimen preparation . 28 8.3.1 Dimensions . 28 8.3.2 Handling . 28 8.4 Conditioning . 28 8.4.1 Storing conditions . 28 8.4.2 Cleaning and drying . 28 8.4.3 Reduction of friction to loading platens . 29 8.4.4 Temperature conditioning . 29 8.5 Test procedure . 29 8.5.1 Number of tests . 29 8.5.2 Test temperature . 29 8.5.3 Positioning of test specimen in test device . 29 8.5.4 Testing of test specimen . 29 8.5.5 Loading conditions . 30 8.5.6 Measurements of permanent deformation . 30 8.6 Calculation and expression of results . 31 8.6.1 Cumulative strain . 31 8.6.2 Creep curve . 31 8.7 Test report . 32 8.7.1 General . 32 8.7.2 Information on the test specimens . 33 8.7.3 Information on the test conditions. 33 8.7.4 Test results . 33 8.8 Precision . 33 Annex A (informative)
Procedure for correction of test results obtained from test specimen of varied age . 35
SIST EN 12697-25:2016
EN 12697-25:2016 (E) 4 European foreword This document (EN 12697-25:2016) has been prepared by Technical Committee CEN/TC 227 “Road materials”, the secretariat of which is held by DIN. This document supersedes EN 12697-25:2005. 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 2017, and conflicting national standards shall be withdrawn at the latest by January 2017. 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. Compared with EN 12697-25:2005 the following changes have been made: a) addition of uniaxial compression test with confinement for mastic asphalt; b) precision of friction-reducing system for loading surfaces; c) definition of loading signal for triaxial tests by identifying loading time and rest time, to be considered in EN 13108-20; d) implementation of digit numbers for test results; e) clarification of formulae and definitions. 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 methods — 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 — 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 SIST EN 12697-25:2016
EN 12697-25:2016 (E) 5 — 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 — Part 16: Abrasion by studded tyres — 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 — 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 cylindrical specimens (CY) — 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 — Part 25: Cyclic compression test (this document) — 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 SIST EN 12697-25:2016
EN 12697-25:2016 (E) 6 — 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 specimens 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 — 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 — EN 12697-40, Bituminous mixtures — Test methods for hot mix asphalt — Part 40: In situ drainability — EN 12697-41, Bituminous mixtures — Test methods for hot mix asphalt — Part 41: Resistance to de-icing fluids — EN 12697-42, Bituminous mixtures — Test methods for hot mix asphalt — Part 42: Amount of foreign matters in reclaimed asphalt — EN 12697-43, Bituminous mixtures — Test methods for hot mix asphalt — Part 43: Resistance to fuel — EN 12697-44, Bituminous mixtures — Test methods for hot mix asphalt — Part 44: Crack propagation by semi-circular bending test — EN 12697-45, Bituminous mixtures — Test methods for hot mix asphalt — Part 45: Saturation ageing tensile stiffness (SATS) conditioning test — EN 12697-46, Bituminous mixtures — Test methods for hot mix asphalt — Part 46: Low temperature cracking and properties by uniaxial tension tests — EN 12697-47, Bituminous mixtures — Test methods for hot mix asphalt — Part 47: Determination of the ash content of natural asphalts SIST EN 12697-25:2016
EN 12697-25:2016 (E) 7 — prEN 12697-48, Bituminous mixtures — Test methods — Part 48: Interlayer bonding1) — EN 12697-49, Bituminous mixtures — Test methods for hot mix asphalt — Part 49: Determination of friction after polishing — CEN/TS 12697-50, Bituminous mixtures — Test methods — Part 50: Resistance to scuffing — FprCEN/TS 12697-51, Bituminous mixtures — Test methods — Part 51: Surface shear strength test2) — prCEN/TS 12697-52, Bituminous mixtures — Test methods — Part 52: Conditioning to address oxidative ageing3) — prEN 12697-53, Bituminous mixtures — Test methods — Part 53: Cohesion increase by spreadability-meter method1) 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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
1) Currently at Enquiry stage. 2) In preparation. 3) In preparation for CEN/TS or EN. SIST EN 12697-25:2016
EN 12697-25:2016 (E) 8 1 Scope This European Standard specifies three test methods (A1, A2 and B) for determining the resistance of bituminous mixtures to permanent deformation by cyclic compression tests with confinement. The tests make it possible to rank various mixtures or to check on the acceptability of a given mixture. They do not allow making a quantitative prediction of rutting in the field to be made. Test methods A1 and A2 describe methods for determining the creep characteristics of bituminous mixtures by means of a uniaxial cyclic compression test with some confinement present. In this test a cylindrical test specimen is subjected to a cyclic axial stress. Method A2 is preferred for mastic asphalt and Method A1 for other asphalt mixtures. To achieve a certain confinement, the diameter of the loading platen is taken smaller than that of the test specimen. In test method A1, the test specimen is loaded by block-pulses whereas in method A2 haversine loading with rest time is applied. 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 test specimen is subjected to a defined 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 test specimens prepared in the laboratory or cored from the road. The maximum size of the aggregates is 32 mm. NOTE 1 Confinement of the test specimen is necessary to simulate realistic rutting behaviour, especially for gap-graded mixtures with a large stone fraction. NOTE 2 For the purpose of Type Testing, the test conditions are given in EN 13108–20. 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 12697-27, Bituminous mixtures - Test methods for hot mix asphalt - 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 12697-30, 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 EN 12697-35, Bituminous mixtures - Test methods - Part 35: Laboratory mixing EN 13108-20, Bituminous mixtures - Material specifications - Part 20: Type Testing SIST EN 12697-25:2016
EN 12697-25:2016 (E) 9 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 contact area portion of the pressure platen that is in contact with the test specimen 3.2 creep curve display of the cumulative axial strain, expressed in %, of the test specimen as a function of the number of loading cycles Note 1 to entry: Generally the following stages can be distinguished (see Figure 1): — stage 1: the (initial) part of the creep curve, where the slope of the curve decreases with increasing number of loading cycles; — stage 2: the (middle) part of the creep curve, where the slope of the curve is quasi constant and can be expressed by the creep rate fc (See key 5 of Figure 1). The exact turning point of the creep curve lies within this stage; — stage 3: the (last) part of the creep curve, where the slope increases with increasing number of loading cycles. Depending on the testing conditions and on the mixture, one or more stages may be absent.
Key n cumulative axial strain n number of loading cycles 1 stage 1 2 stage 2 3 stage 3 4 turning point 5 creep rate fc Figure 1 — Example of creep curve 3.3 Creep rate slope of axial strain of the test specimen after a given number of loading cycles SIST EN 12697-25:2016
EN 12697-25:2016 (E) 10 3.4 permanent deformation cumulative axial deformation of the test specimen after a given number of loading cycles 4 Principle This test method determines the resistance to permanent deformation of a cylindrical test specimen of bituminous mixture by repeated load. The test specimens may be either prepared in the laboratory or be cored from a pavement. During the test, the change in height of the test specimen is measured at specified numbers of loading cycles. From this, the cumulative axial strain n of the test specimen is determined as a function of the number of loading cycles. The results are represented in a creep curve as given in Figure 1. From this, the creep characteristics of the test specimen are computed. 5 Equipment 5.1 Control and loading 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 over-modulation. The load cell shall have a capacity of at least 5000 N with a precision of ± 10 N. All components shall be constructed out of hardened corrosion-resistant steel. The load cell should be able to generate a block or haversine loading pulse with or without rest periods. Resonance frequencies of the load cell, as mounted, shall be at least 10 times higher as the test frequency. Test frequencies in the range of 0,5 Hz to 5 Hz are most often applied. 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. 5.2 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 of the upper loading plate position during the test. The transducers sha
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