Bituminous mixtures - Test methods - Part 31: Specimen preparation by gyratory compactor

This document specifies the method for compaction of cylindrical specimens of bituminous mixtures using a gyratory compactor.
The method is used for:
- determination of the air voids content of a mixture for a given number of gyrations or derivation of a curve density (or void content) versus number of gyrations;
- preparation of specimens of given height and/or at a predetermined density, for subsequent testing of their mechanical properties.
Annex A and Annex B describe method of complying for the equipment.
This document applies to bituminous mixtures (both those made up in laboratory and those resulting from work site sampling), with an upper aggregate size not larger than 31,5 mm.

Asphalt - Prüfverfahren - Teil 31: Herstellung von Probekörpern mit dem Gyrator-Verdichter

Dieses Dokument legt das Verfahren zur Verdichtung von zylindrischen Asphalt-Probekörpern mit einem Gyrator-Verdichter fest.
Das Verfahren wird angewendet für:
   die Bestimmung des Hohlraumgehalts eines Asphalts für eine gegebene Anzahl der Achsendrehungen oder für die Ableitung einer Kurve der Raumdichte (oder des Hohlraumgehalts) im Verhältnis zur Anzahl der Achsendrehungen;
   die Herstellung von Probekörpern mit einer vorgegebenen Höhe und/oder einer bestimmten Raumdichte für die nachfolgende Prüfung ihrer mechanischen Eigenschaften.
Anhang A und Anhang B beschreiben das Verfahren für die Übereinstimmung der Prüfeinrichtung.
Dieses Dokument gilt für Asphalt (sowohl im Labor hergestellten als auch für solchen, von dem auf der Baustelle Proben entnommen wurden) mit einer maximalen Korngröße der Gesteinskörnung von nicht mehr als 31,5 mm.

Mélanges bitumineux - Méthodes d'essai - Partie 31 : Confection d'éprouvettes à la presse à compactage giratoire

Ce document spécifie la méthode de compactage des éprouvettes cylindriques de mélanges bitumineux à l’aide d’une presse à compactage giratoire.
Cette méthode est utilisée pour :
—   la détermination de la teneur en vides d’air d’un mélange pour un nombre de girations donné ou pour la détermination de la courbe de la masse volumique (ou de la teneur en vide) en fonction du nombre de girations ;
—   la confection d’éprouvettes d’une hauteur donnée et/ou à une masse volumique prédéterminée, pour réaliser par la suite des essais concernant leurs propriétés mécaniques.
L'Annexe A et l’Annexe B décrivent une méthode de mise en conformité des équipements.
Ce document s’applique aux mélanges bitumineux (à la fois ceux confectionnés en laboratoire et ceux provenant d’un prélèvement de chantier), ayant une dimension granulaire maximale n’excédant pas 31,5 mm.

Bitumenske zmesi - Preskusne metode - 31. del: Priprava preskušancev z vrtljivim zgoščevalnikom

Ta evropski standard določa metodo za zgoščevanje valjastih preskušancev bitumenskih zmesi z vrtljivim zgoščevalnikom. Tako zgoščevanje se doseže s kombinacijo učinka rotacijskega striženja in navpične rezultante sile, vzpostavljene z mehansko glavo.
Metoda se uporablja za:
– ugotavljanje vsebnosti zračnih votlin v zmesi za določeno število vrtljajev ali izpeljavo gostote krivulje (ali vsebnosti votlin) v primerjavi s številom vrtljajev;
– pripravo preskušancev z določeno višino in/ali pri vnaprej določeni gostoti za naknadno preskušanje njihovih mehanskih lastnosti.
V dodatku A, dodatku B in/ali dodatku C je opisana metoda skladnosti za opremo.
Ta evropski standard se uporablja za bitumenske zmesi (za tiste, izdelane v laboratoriju, in za tiste, ki izhajajo iz vzorčenja na delovišču) z velikostjo zgornjega agregata največ 31,5 mm.

General Information

Status
Published
Publication Date
05-Mar-2019
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
06-Mar-2019
Completion Date
06-Mar-2019

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.]JRãþHYDOQLNRPAsphalt - Prüfverfahren - Teil 31: Herstellung von Probekörpern mit dem Gyrator-VerdichterMélanges bitumineux - Méthodes d'essai - Partie 31 : Confection d'éprouvettes à la presse à compactage giratoireBituminous mixtures - Test methods - Part 31: Specimen preparation by gyratory compactor93.080.20Materiali za gradnjo cestRoad construction materialsICS:Ta slovenski standard je istoveten z:EN 12697-31:2019SIST EN 12697-31:2019en,fr,de01-maj-2019SIST EN 12697-31:2019SLOVENSKI

STANDARDSIST EN 12697-31:20071DGRPHãþD
SIST EN 12697-31:2019
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12697-31
March
t r s { ICS
{ uä r z rä t r Supersedes EN
s t x { yæ u sã t r r yEnglish Version
Bituminous mixtures æ Test methods æ Part

u sã Specimen preparation by gyratory compactor Mélanges bitumineux æ Méthodes d 5essai æ Partie

u s ã Confection d 5éprouvettes à la presse à compactage giratoire
Asphalt æ Prüfverfahren æ Teil

u sã Herstellung von Probekörpern mit dem GyratoræVerdichter This European Standard was approved by CEN on

s { November
t r s zä

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 Serbiaá 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:
Rue de la Science 23,
B-1040 Brussels

t r s { 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 u sã t r s { ESIST EN 12697-31:2019

EN 12697-31:2019 (E) 2 Contents Page European foreword ....................................................................................................................................................... 4 1 Scope .................................................................................................................................................................... 6 2 Normative references .................................................................................................................................... 6 3 Terms, definitions and symbols ................................................................................................................. 6 3.1 Terms and definitions ................................................................................................................................... 6 3.2 Symbols ............................................................................................................................................................... 7 4 Principle ............................................................................................................................................................. 9 5 Apparatus ........................................................................................................................................................... 9 5.1 Test device ......................................................................................................................................................... 9 5.2 Metallic moulds ............................................................................................................................................. 10 5.3 Round metallic inserts ............................................................................................................................... 10 5.4 Device for measuring the distance between inserts ....................................................................... 10 5.5 Device for counting the number of rotations with a precision of one revolution ................ 10 5.6 Other usual equipments ............................................................................................................................ 10 6 Preparation of specimens ......................................................................................................................... 11 6.1 Mass of mixture to be introduced in the mould ................................................................................ 11 6.1.1 Preparation of specimens for further mechanical testing ............................................................ 11 6.1.2 Preparation of specimens for void content requirement .............................................................. 11 6.2 Preparation of mixtures ............................................................................................................................ 12 7 Test procedure .............................................................................................................................................. 13 7.1 Preliminary setting ...................................................................................................................................... 13 7.1.1 Pre-load stress .............................................................................................................................................. 13 7.1.2 Stress ................................................................................................................................................................ 13 7.1.3 Setting of the angle of inclination ........................................................................................................... 13 7.1.4 Speed of rotation .......................................................................................................................................... 13 7.1.5 Temperature .................................................................................................................................................. 13 7.2 Compaction ..................................................................................................................................................... 13 7.2.1 Start of compaction...................................................................................................................................... 13 7.2.2 Specimens for void content requirement ............................................................................................ 13 7.2.3 Specimens for further testing .................................................................................................................. 14 8 Precision .......................................................................................................................................................... 14 9 Test report ...................................................................................................................................................... 15 Annex A (normative)

Procedure for setting the stress for types of gyratory compactor for compactability test ...................................................................................................................................... 16 A.1 General ............................................................................................................................................................. 16 A.2 Principle .......................................................................................................................................................... 16 A.3 Gyratory-type testing procedure ............................................................................................................ 16 A.3.1 Force adjustment ......................................................................................................................................... 16 A.3.2 Angle ................................................................................................................................................................. 16 SIST EN 12697-31:2019

EN 12697-31:2019 (E) 3 Annex B (normative)

Procedure to evaluate the gyratory compactor (GC) internal angle of gyration and related parameters using simulated loading ........................................................... 17 B.1 General ............................................................................................................................................................. 17 B.2 Principle ........................................................................................................................................................... 17 B.3 Procedure ........................................................................................................................................................ 17 B.3.1 Calibration procedure with internal load simulator device ......................................................... 17 B.3.2 Calibration procedure with dynamic angle validator device ....................................................... 17 B.4 Calculation of results ................................................................................................................................... 18 B.4.1 Calculation of results for calibration procedure with internal load simulator device ....... 18 B.4.2 Calculation of results for calibration procedure with dynamic angle validator device ..... 19 B.5 Compliance ...................................................................................................................................................... 20 B.6 Precision and bias ........................................................................................................................................ 20 B.7 Report ............................................................................................................................................................... 21 Bibliography ................................................................................................................................................................. 23

SIST EN 12697-31:2019

EN 12697-31:2019 (E) 4 European foreword This document (EN 12697-31:2019) has been prepared by Technical Committee CEN/TC 227 “Road materials”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 2019, and conflicting national standards shall be withdrawn at the latest by September 2019. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 12697-31:2007. The following is a list of significant technical changes since the previous edition: — The series title no longer makes the method exclusively for hot mix asphalt; — Definition of force-angle calibration chain and internal angle deleted; — [Clause 1] Advice on use of alternative calibration Annexes revised and changed from Note to normative; — [3.2] A number of symbols added and the symbol for water content amended to “w” throughout the standard; — [5.1] System to collect excess moisture added to requirements for test device; — [5.6] Ventilated oven, balance and thermometer added to list of equipment; — [6.1.2] Existing preparation of specimens made for dry mixtures and separate method for wet mixtures added; — New subclause [6.1.2.1] calculation of mass of dry mixture modified; — New subclause [6.1.2.2] calculation of mass of wet mixture added; — [6.2] Preparation of mixtures revised; — [7.1.1] and [7.2.3] Value of force replaced by stress; — [7.1.3] NOTE to setting angle of inclination deleted and extra line added; — [7.2.1] Start of compaction revised; — [7.2.2] Number of gyrations at which measurements made clarified; — [Clause 8] Additional precision data given. — [Clause 9] Water content added as optional in test reports; — [A.3.1] Modified to delete reference materials and to specify calibration stress; SIST EN 12697-31:2019

EN 12697-31:2019 (E) 5 — [A.3.1] Value of force replaced by stress; — Annex B deleted and Annex C has become new Annex B; — [New Annex B] Compliance requirements clarified; — [Annex A] and [New Annex B] Same Internal Effective Angle for both Annexes (0,82 ± 0,02)°. — [New Annex B] Precision statement updated; A list of all parts in the EN 12697 series can be found on the CEN website. According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, 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. SIST EN 12697-31:2019

EN 12697-31:2019 (E) 6 1 Scope This document specifies the method for compaction of cylindrical specimens of bituminous mixtures using a gyratory compactor. The method is used for: — determination of the air voids content of a mixture for a given number of gyrations or derivation of a curve density (or void content) versus number of gyrations; — preparation of specimens of given height and/or at a predetermined density, for subsequent testing of their mechanical properties. Annex A and Annex B describe method of complying for the equipment. This document applies to bituminous mixtures (both those made up in laboratory and those resulting from work site sampling), with an upper aggregate size not larger than 31,5 mm. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 12697-5, Bituminous mixtures — Test methods— 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 12697-8, Bituminous mixtures — Test methods

— Part 8: Determination of void characteristics of bituminous specimens EN 12697-27, Bituminous mixtures — Test methods — Part 27: Sampling EN 12697-35, Bituminous mixtures — Test methods — Part 35: Laboratory mixing EN 12697-38, Bituminous mixtures — Test methods for hot mix asphalt — Part 38: Common equipment and calibration EN ISO 4287, Geometrical product specifications (GPS) — Surface texture: Profile method — Terms, definitions and surface texture parameters (ISO 4287) EN ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method (ISO 6508-1) 3 Terms, definitions and symbols 3.1 Terms and definitions For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — IEC Electropedia: available at http://www.electropedia.org/ — ISO Online browsing platform: available at http://www.iso.org/obp SIST EN 12697-31:2019

EN 12697-31:2019 (E) 7 3.1.1 gyratory compactor type representative model of a given production compactor 3.1.3 internal top angle angle between the internal mould cross-sectional plane and the upper metallic insert as a mould is gyrated in a gyratory compactor 3.1.4 internal bottom angle angle between the internal mould cross-sectional plane and the lower metallic insert as a mould is gyrated in a gyratory compactor 3.1.5 internal effective angle average of the internal top angle and the internal bottom angle 3.1.6 eccentricity distance, e, away from the axis of gyration at which a force, F, is acting at one end of a gyratory compactor mould Note 1 to entry: The eccentricity is explained in Figure B.1. 3.1.7 tilting moment product of the eccentricity, e, and the force, F, acting at one end of a gyratory compactor mould in a direction parallel to the axis of gyration Note 1 to entry: The tilting moment is explained in Figure B.1. 3.1.8 cold mixture asphalt produced at ambient temperature in which the binder is added in the form of a bituminous emulsion 3.2 Symbols For the purposes of this document, the following symbols apply. Ö is the angle of incline of axis of test piece, in degrees (°); F is the axial resultant force applicable to the ends of the test pieces, in newton (N); D is the internal diameter of the mould, in millimetres (mm); M is the mass of a dry mixture to be introduced in the mould, in grams (g); Mw is the mass of a wet mixture to be introduced in the mould, in grams (g); M is the maximum density of the mixture, in Megagrams per cubic metre (Mg/m3); hmin is the minimum height of compacted specimen, corresponding to zero percent of voids, in millimetres (mm); h(ng) is the height of specimen after a number of gyrations ng, in millimetres (mm); SIST EN 12697-31:2019

EN 12697-31:2019 (E) 8 v % is the void content, in percent (%); e is the eccentricity, in millimetres (mm); ITA1…4 is the measured internal top angle (4 individual measurements); ITAmin is the minimum measured internal top angle (of 4 measurements); ITAmax is the maximum measured internal top angle (of 4 measurements); ITA is the internal top angle (average of 4 measurements) ITAm1 is the internal top angle at tilting moment m1 (m1 between 180 Nm and 240 Nm tilting moment); ITAm2 is the internal top angle at tilting moment m2 (m2 between 250 Nm and 425 Nm tilting moment); IBA1….4 is the measured internal bottom angle (4 individual measurements); IBAmin is the minimum measured internal bottom angle (of 4 measurements); IBAmax is the maximum measured internal bottom angle (of 4 measurements); IBA is the internal bottom angle (average of n measurements); IBAm1 is the internal bottom angle at tilting moment m1 (m1 between 180 Nm and 240 Nm tilting moment); IBAm2 is the internal bottom angle at tilting moment m2 (m2 between 250 Nm and 425 Nm tilting moment; IEA is the internal effective angle (average of ITA and IBA); IEAm1 is the internal effective angle at tilting moment m1 (m1 between 180 Nm and 240 Nm tilting moment); IEAm2 is the internal effective angle at tilting moment m2 (m2 between 250 Nm and 425 Nm tilting moment); IEA240 is the internal effective angle at 240 Nm tilting moment; IEA425 is the internal effective angle at 425 Nm tilting moment; TB(m1) is the difference between ITA and IBA at m1; TB(m2) is the difference between ITA and IBA at m2; TB(240) is the difference between ITA and IBA at 240 Nm; TB(425) is the difference between ITA and IBA at 425 Nm; cs is the variation coefficient of the angle measurement between tilting moment m1 and m2; LH is the difference between IEA240 and IEA425; w is the water content (if present) in percent of the mass of the dry mixture; SMA Stone Mastic Asphalt; AC Asphalt concrete. SIST EN 12697-31:2019

EN 12697-31:2019 (E) 9 4 Principle The bituminous mixture is contained within a cylindrical mould limited by inserts and kept at a constant temperature within specified tolerances throughout the whole duration of the test. Compaction is achieved by the simultaneous action of a low static compression, and of the shearing action resulting from the motion of the axis of the sample which generates a conical surface of revolution, of apex O and of 2 Ö angle at the apex, while the ends of the test piece should ideally remain perpendicular to the axis of the conical surface (see Figure 1).

Key F axial resultant force
h (ng) height of specimen after a number of gyrations
Ö angle

Figure 1 — Test piece motion diagram When the specimen is taken out of the equipment for use in other mechanical tests, the temperature and stress will change and can affect the measured density. The density should then be measured in accordance with the relevant part of EN 12697-6. 5 Apparatus 5.1 Test device Test device: — capable of compacting the test specimen according to the principle described in Clause 4 and in accordance with the requirements of Clause 7, concerning the angle and the stress; — capable of maintaining at least one point in the vicinity of the mid-plane, located between 30 mm and 45 mm from the mould axis, at within ± 10 °C of the prescribed temperature during the test; — capable of maintaining the speed of rotation constant during the test to ± 10 % at a speed lower or equal to 32 rev/min. When testing mixtures with a high moisture content, the test device shall be equipped with a system able to collect the excess of moisture draining from the mix during compaction. The stress shall conform to the provisions of Annex A or Annex B. SIST EN 12697-31:2019

EN 12697-31:2019 (E) 10 5.2 Metallic moulds Metallic moulds: — having a surface hardness greater than 48 HRC according to EN ISO 6508-1; — having either: — a roughness Ra less than 1 m according to EN ISO 4287 or — an initial roughness under 0,8 µm according to EN ISO 4287 and no defects, scratches or traces visible to the naked eye; — having in the zone in contact with the material during the compaction, an internal diameter of (150,0 ± 0,1) mm or (160,0 ± 0,1) mm or (100,0 ± 0,1) mm; — having a height compatible with the volume of material of the specimens under test; — having a thickness greater than 7,5 mm. 5.3 Round metallic inserts Round metallic inserts: — having an even active surface to within ± 0,1 mm (that surface intended to be in contact with the material); — having a surface hardness not less than 55 HRC according to EN ISO 6508-1; — having either: — a roughness Ra under 1 µm according to EN ISO 4287 or — an initial roughness under 0,8 µm according to EN ISO 4287 and subject to no defects, scratches or traces visible to the naked eye; — having a shape appropriate to the kinetics of the motion and a diameter resulting in an insert/mould play between 0,1 mm and 0,6 mm; — the different top round metallic inserts used on the same machine shall have average heights not differing by more than 0,1 mm; — the different bottom round metallic inserts used on the same machine shall have average heights not differing by more than 0,1 mm. 5.4 Device for measuring the distance between inserts 5.5 Device for counting the number of rotations with a precision of one revolution 5.6 Other usual equipments 5.6.1 Ventilated oven for heating mould, metallic inserts and bituminous mixture to the accuracy given in EN 12697-38. 5.6.2 Balance capable of measuring the mass of the mould and the bituminous mixture to the accuracy given in EN 12697-38. SIST EN 12697-31:2019

EN 12697-31:2019 (E) 11 5.6.3 Device capable of measuring the temperature inside the bituminous mixture to the accuracy given in EN 12697-38. 6 Preparation of specimens 6.1 Mass of mixture to be introduced in the mould 6.1.1 Preparation of specimens for further mechanical testing The mass M of the mixture to be introduced in the mould shall be calculated from the required density and the volume of the specimens. 6.1.2 Preparation of specimens for void content requirement 6.1.2.1 Dry mixtures The mass M of the mixture to be introduced in the mould shall be determined using Formula (1) from the maximum density M of the mixture determined according to EN 12697-5, method A using water, and the minimum height of the compacted specimen hmin corresponding to zero percent of voids. πρ−=23minMM104Dh (1) where M is the mass of a dry mixture to be introduced in the mould, in grams (g); D is the internal diameter of the mould, in millimetres (mm); hmin is the minimum height of compacted specimen, corresponding to zero percent of voids, in millimetres (mm); M is the maximum density of the mixture, in Megagrams per cubic metre (Mg/m3). For a given type of gyratory compactor, hmin will be constant. The ratio of hmin to the internal diameter of the mould D shall be in the interval 0,66 to 1,05. 6.1.2.2 Mixtures with a water content w The mass Mw of a wet mixture to be introduced in the mould shall be determined from Formula (2) from the maximum density M of the mixture determined according to EN 12697-5, method A using water, and the minimum height of the compacted specimen hmin corresponding to zero percent of voids. πρ−+=×23minM100104100wDwMh (2) where Mw is the mass of a wet mixture to be introduced in the mould, in grams (g); w is the water content of the mixture in percent (%); D is the internal diameter of the mould, in millimetres (mm); hmin is the minimum height of compacted specimen, corresponding to zero percent of voids, in millimetres (mm); M is the maximum density of the mixture, in Megagrams per cubic metre (Mg/m3). For a given type of gyratory compactor, hmin will be constant. The ratio of hmin to the internal diameter of the mould D shall be in the interval 0,66 to 1,05. SIST EN 12697-31:2019

EN 12697-31:2019 (E) 12 6.2 Preparation of mixtures The bituminous mixture shall be: — prepared in the laboratory, according to EN 12697-35; — sampled at a plant or worksite in loose uncompacted form according to EN 12697-27; — cut or cored in a compacted layer according to EN 12697-27. If it is cut or cored in a compacted layer, the size of the sample shall be such that the mass M prescribed in 6.1.2 can be taken from it or more than one sample shall be combined to obtain the mass M. If the nominal maximum size of the aggregates is 16 mm or less, the diameter of the specimens shall be 100 mm, 150 mm or 160 mm. If the maximum size of the aggregates is more than 16 mm, the diameter of the specimens shall be 150 mm or 160 mm. The following operations shall be carried out: — except for cold mix asphalt, place moulds and inserts for at least 2 h within an enclosure brought to the reference compaction temperature ± 5 °C; — lubricate moulds with a coating of glycerised soda oleate applied with a brush, or of silicon grease; — if the sample has been cut or cored in a compacted layer, bring it to a temperature at which the bituminous mixture is loose enough, so that the sample can be carefully crumbled without crushing any stones and the prescribed mass M can be taken; — bring the bituminous mixture to a temperature of at least the reference compaction temperature, but not exceeding this temperature by more than 20 °C, for which the heating time shall not be longer than necessary in order to avoid additional ageing of the loose mixture; — if the mixture is cut or cored from a compacted layer, the cutting of stones will have an impact of the grading. To minimize or exclude this effect, the ratio of the cut surface to the volume of the sample shall be as small as possible (for example by taking cores with a larger diameter) or the cut surfaces shall be carefully removed; — if necessary, mix manually to minimize possible segregation, weigh the mould and inserts, fill the mould with the mixture by means of a funnel in one operation only and weigh the mould and inserts plus the mixture in the mould, so that the prescribed mass M or Mw of bituminous mixture in the mould is obtained with an accuracy of 0,1 %; — alternatively, weigh the mass M or Mw of the bituminous mixture in an intermediate container, to an accuracy of 0,1 %, and introduce the bituminous mixture into the mould by means of a funnel in one operation only; — for cold mix asphalt, the mixture shall be kept at least 15 min in the mould before the start of the test; — except for cold mix asphalt, measure the temperature of the mixture in the centre of the mould. When the temperature is more than 5 °C below the reference compaction temperature, the filled mould and the inserts shall be replaced in the oven at the reference compaction temperature ± 5 °C for between 30 min and 2 h. However, for SMA there is a risk for drainage. SIST EN 12697-31:2019

EN 12697-31:2019 (E) 13 7 Test procedure 7.1 Preliminary setting 7.1.1 Pre-load stress In case of a pre-load stress, it shall be between 20 kPa and 382 kPa for 100 mm diameter specimens or between 8 kPa and 150 kPa inclusive for 150 mm or 160 mm diameter specimens. 7.1.2 Stress The stress shall conform to the provisions of Annex A or Annex B.

The stress is equal to the force F divided by the specimen cross-section. 7.1.3 Setting of the angle of inclination The angle shall conform to the provisions of Annex B. 7.1.4 Speed of rotation The speed of rotation shall be maintained constant during the test to ± 10 % at a speed lower or equal to 32 rev/min. 7.1.5 Temperature The compaction temperatures shall be as given in EN 12697-35. 7.2 Compaction 7.2.1 Start of compaction When the temperature is within the reference compaction temperature ± 5 °C, place the mould containing the mixture and the insert in the test device. If the mould is not kept in temperature by a heating system, the mould filled with the asphalt mixture shall be preheated for at least 15 min in order to minimize loss of temperature of the mixture. Except when compaction is performed at ambient temperature, the compaction procedure shall be commenced without delay and be completed within 8 min. In the case of a pre-load, it shall be applied in less than 30 s. With the mechanical head in contact with the upper insert, start the rotation

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