oSIST prEN 12697-31:2014

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

This European Standard specifies the method for compaction of cylindrical specimens of bituminous mixtures using a gyratory compactor. Such compaction is achieved by combining a rotary shearing action and a vertical resultant force applied by a mechanical head.
The method is used for:
a) 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;
b) preparation of specimens of given height and/or at a predetermined density, for subsequent testing of their mechanical properties.

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

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

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

General Information

• Status: Not Published
• Public Enquiry End Date: 29-Dec-2014
• ICS: 93.080.20 - Road construction materials
• Technical Committee: CES - Roads
• Current Stage: 98 - Abandoned project (Adopted Project)
• Start Date: 06-Mar-2017
• Due Date: 11-Mar-2017
• Completion Date: 06-Mar-2017
• Ref Project: prEN 12697-31 rev - Bituminous mixtures - Test methods - Part 31: Specimen preparation by gyratory compactor

Relations

• Revised: SIST EN 12697-31:2007 - Bituminous mixtures - Test methods for hot mix asphalt - Part 31: Specimen preparation by gyratory compactor
• Effective Date: 08-Jun-2022
• Revised: SIST EN 12697-31:2007 - Bituminous mixtures - Test methods for hot mix asphalt - Part 31: Specimen preparation by gyratory compactor
• Effective Date: 01-Dec-2014

Overview

prEN 12697-31 rev - Bituminous mixtures - Test methods - Part 31: Specimen preparation by gyratory compactor (CEN) specifies a laboratory method to compact cylindrical specimens of bituminous mixtures using a gyratory compactor. Compaction combines rotary shearing and a vertical resultant force applied by a mechanical head. The procedure is used to determine air voids content versus number of gyrations and to produce specimens at a specified height or density for subsequent mechanical testing.

Key topics and requirements

• Purpose: Preparation of compacted cylindrical specimens for void content measurement and for mechanical tests (stiffness, fatigue, indirect tensile, wheel-tracking, etc.).
• Principle: Compaction via simultaneous rotation and vertical force (gyratory action) to emulate field compaction and establish a density/gyration curve.
• Apparatus & moulds: Requirements for gyratory test device, metallic moulds, round inserts, rotation counting device and systems for collecting excess moisture. Equipment list also includes ventilated oven, balance and thermometer.
• Specimen preparation: Procedures for mass of mixture, separate methods for dry and wet mixtures, and preparation for either target void content or target specimen dimensions/density.
• Test procedure settings: Guidance on pre-load, applied force magnitude, angle of inclination, rotation speed, and test temperature. Start of compaction, number of gyrations at which measurements are recorded, and optional reporting of water content are defined.
• Calibration & verification: Normative annexes (A, B, C) provide procedures for compactor type-setting, measurement of the internal angle of gyration, simulated loading checks and periodic calibration/verification routines.
• Reporting & precision: Test report content and precision/accuracy information are specified.

Applications

• Quality control and mix design laboratories preparing specimens for mechanical testing.
• Pavement engineers and researchers assessing compactibility, density evolution and air void characteristics of hot mix asphalt and other bituminous mixtures.
• Contractors and material suppliers verifying production mixes meet target densities and compaction behaviour.
• Regulatory bodies using standardized specimen preparation for comparative performance testing and specifications compliance.

Related standards

• Part of the EN 12697 series for bituminous mixtures (e.g., EN 12697-5 maximum density, EN 12697-6 bulk density, EN 12697-10 compactibility, EN 12697-26 stiffness, EN 12697-30 impact compactor).
• prEN 12697-31 rev supersedes EN 12697-31:2007 and aligns specimen preparation practices with modern calibration and verification methods.

Keywords: gyratory compactor, bituminous mixtures, specimen preparation, air voids, density vs gyrations, EN 12697-31, asphalt testing, compaction method, pavement materials.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2014
%LWXPHQVNH]PHVL3UHVNXVQHPHWRGHGHO3ULSUDYDSUHVNXãDQFHY]YUWOMLYLP
]JRãþHYDOQLNRP
Bituminous mixtures - Test methods - Part 31: Specimen preparation by gyratory
compactor
Asphalt - Prüfverfahren - Teil 31: Herstellung von Probekörpern mit dem Gyrator-
Verdichter
Mélanges bitumineux - Méthodes d’essai - Partie 31: Confection d’éprouvettes à la
presse à compactage giratoire
Ta slovenski standard je istoveten z: prEN 12697-31 rev
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.

EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2014
ICS 93.080.20 Will supersede EN 12697-31:2007
English Version
Bituminous mixtures - Test methods - Part 31: Specimen
preparation by gyratory compactor
Mélanges bitumineux - Méthodes d'essai - Partie 31: Asphalt - Prüfverfahren - Teil 31: Herstellung von
Confection d'éprouvettes à la presse à compactage Probekörpern mit dem Gyrator-Verdichter
giratoire
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 227.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12697-31 rev:2014 E
worldwide for CEN national Members.

prEN 12697-31:2014 (E)
Contents Page
Foreword .4
1 Scope .8
2 Normative references .8
3 Terms, definitions and symbols .9
3.1 Terms and definitions .9
3.2 Symbols .9
4 Principle . 11
5 Apparatus . 12
5.1 Test device . 12
5.2 Metallic moulds . 12
5.3 Round metallic inserts . 13
5.4 Device for measuring the distance between inserts . 13
5.5 Device for counting the number of rotations to within one revolution . 13
6 Preparation of specimens . 13
6.1 Mass of mixture to be introduced in the mould . 13
6.1.1 Preparation of specimens for further mechanical testing . 13
6.1.2 Preparation of specimens for void content requirement. 13
6.2 Preparation of mixtures . 14
7 Test procedure . 15
7.1 Preliminary setting. 15
7.1.1 Pre-load . 15
7.1.2 Force F . 15
7.1.3 Setting of the angle of inclination . 15
7.1.4 Speed of rotation . 16
7.1.5 Temperature . 16
7.2 Compaction . 16
7.2.1 Start of compaction . 16
7.2.2 Specimens for void content requirement . 16
7.2.3 Specimens for further testing . 17
8 Test report . 17
9 Precision . 18
Annex A (normative) Procedure for setting the angle and force for types of gyratory compactor
using central reference material . 19
A.1 Scope . 19
A.2 Principle . 19
A.3 Gyratory-type testing procedure . 19
A.3.1 Central reference materials for gyratory-type testing. 19
A.3.2 Force . 20
A.3.3 Gyratory-type angle test . 21
A.4 Procedure to test the conformity of a gyratory compactor to a type . 21
A.5 Procedure for periodical check . 21
A.6 Summary of the gyratory calibration chain . 22
Annex B (normative) Procedure to evaluate the gyratory compactor internal angle of gyration

using a self-contained measurement unit . 23
B.1 Scope . 23
B.2 Principle . 23
prEN 12697-31:2014 (E)
B.3 Equipment . 23
B.3.1 Measurement instrument . 23
B.3.2 Static angle block . 23
B.4 Procedure . 24
B.4.1 General . 24
B.4.2 Determination of the bottom angle . 24
B.4.3 Determination of the top angle . 25
B.4.4 Repetitions of bottom and top angle determination . 26
B.5 Calculation . 26
B.6 Compliance . 27
B.7 Report . 28
B.8 Precision data . 28
B.9 Periodical check procedure . 28
Annex C (normative) Procedure to evaluate the gyratory compactor (GC) internal angle of
gyration and related parameters using simulated loading . 29
C.1 Scope . 29
C.2 Principle. 29
C.3 Procedure . 29
C.4 Calculation of results . 29
C.5 Compliance . 30
C.6 Report . 31
C.7 Precision and bias . 31
Bibliography . 33

prEN 12697-31:2014 (E)
Foreword
This document (prEN 12697-31:2014) has been prepared by Technical Committee CEN/TC 227 “Road
materials”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document will supersede 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;
 advice in Scope on use of alternative calibration Annexes revised and changed from Note to normative;
 definition of internal angle deleted;
 symbols Mw, ITA and IBA added and w made the symbol for water content throughout;
425 425
 system to collect excess moisture added to requirements for test device;
 ventilated oven, balance and thermometer added to list of equipment;
 existing preparation of specimens made for dry mixtures and separate method for wet mixtures added;
 preparation of mixtures revised;
 the magnitude of force F redefined;
 NOTE to setting angle of inclination deleted and extra line added;
 start of compaction revised;
 number of gyrations at which measurements made clarified;
 water content added as optional in test reports;
 proportion of aggregate fractions revised for Material A in Annex A;
 periodical checks added to Annex A, Annex B and Annex C;
 step 5 of calibration chain revised in Annex A;
 NOTE added allowing different internal angles in Annex B and Annex C;
 compliance requirements clarified in Annex C;
 precision statement updated in Annex C.
This document 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
prEN 12697-31:2014 (E)
EN 12697-2, Bituminous mixtures — Test methods 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 the 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 12697-10, Bituminous mixtures — Test methods for hot mix asphalt — Part 10: Compactibility
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
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
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
prEN 12697-31:2014 (E)
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 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 12697-32, Bituminous mixtures — Test methods for hot mix asphalt — Part 32: Laboratory compaction of
bituminous specimen 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
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 12397-44, Bituminous mixtures — Test methods for hot mix asphalt — Part 44: Crack propagation by
semi-circular bending test
prEN 12697-45, Bituminous mixtures — Test methods for hot mix asphalt — Part 45: Saturation ageing tensile
stiffness (SATS) conditioning test
prEN 12697-46, Bituminous mixtures — Test methods for hot mix asphalt — Part 46: Low temperature
cracking and properties by uniaxial tension tests
prEN 12697-31:2014 (E)
EN 12697-47, Bituminous mixtures — Test methods for hot mix asphalt — Part 47: Determination of the ash
content of natural asphalts
1)
prEN 12697-48, Bituminous mixtures — Test methods for hot mix asphalt — Part 48: Interlayer bonding
EN 12697-49, Bituminous mixtures — Test methods for hot mix asphalt — Part 49: Determination of friction
after polishing
prCEN/TS 12697-50, Bituminous mixtures — Test methods for hot mix asphalt — Part 50: Resistance to
1)
scuffing
1)
prEN 12697-51, Bituminous mixtures — Test methods — Part 51, Surface shear strength test
1)
prTS 12697-52, Bituminous mixtures — Test methods — Part 52, Conditioning to address oxidative ageing
prEN 12697-53, Bituminous mixtures — Test methods — Part 53, Cohesion increase by spreadability-meter
1)
method
1) In preparation.
prEN 12697-31:2014 (E)
1 Scope
This European Standard specifies the method for compaction of cylindrical specimens of bituminous mixtures
using a gyratory compactor. Such compaction is achieved by combining a rotary shearing action and a vertical
resultant force applied by a mechanical head.
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.
The equipment used for the method needs to comply with Annex A, Annex B or Annex C.
Annex A is especially suitable for compaction research and Annex A, Annex B and Annex C for the
preparation of specimens for mechanical testing and for void content evaluation.
This European Standard 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, 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 12697-5, Bituminous mixtures — Tests 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 12697-8, Bituminous mixtures — Test methods for hot mix asphalt — Part 8: Determination of void
characteristics of bituminous specimens
EN 12697-27, Bituminous mixtures — Test methods for hot mix asphalt — Part 27: Sampling
EN 12697-35, Bituminous mixtures — Test methods for hot mix asphalt — Part 35: Laboratory mixing
EN 13108-1, Bituminous mixtures — Material specifications — Part 1: Asphalt concrete
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 (scales A, B, C, D, E, F,
G, H, K, N, T) (ISO 6508-1)
prEN 12697-31:2014 (E)
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
gyratory compactor type
representative model of a given production compactor
3.1.2
force-angle calibration chain
force F and the angle φ determined for a type of gyratory compactor in order to comply with the central
reference material requirements in Table A.1
Note 1 to entry: Production gyratory compactors of the same type are adjusted using the determined values of F and
φ. The conformity of a production gyratory compactor to a type can be verified by doing a comparative test on a bituminous
mixture or by checking the variations of the internal angle as described in A.3.3.
3.1.3
central reference material
two bituminous mixtures, produced under defined conditions from constituents stored at a given site, of which
the compositions are not specified but the air voids content (the constancy of which is traceable) is at fixed
numbers of gyrations
Note 1 to entry: The characteristics of the central reference material are specified in Table A.1.
3.1.4
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
3.1.5
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
3.1.6
internal effective angle
average of the internal top angle and the internal bottom angle
3.1.7
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 C.1.
3.1.8
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 C.1.
3.2 Symbols
For the purposes of this document, the following symbols apply.
prEN 12697-31:2014 (E)
α is the internal angle, in degrees (°);
φ 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);
ω is the speed of rotation of the axis of symmetry of revolution of the test piece, in revolutions per
minute (rev/min);
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 kilograms (kg);
Mw is the mass of a wet mixture to be introduced in the mould, in kilograms (kg);
ρ is the maximum density of the mixture, in kilograms per cubic metre (kg/m );
M
h is the minimum height of compacted specimen, corresponding to a zero percentage of voids, in
min
millimetres (mm);
h(n ) is the height of specimen after a number of gyrations n , in millimetres (mm);
g g
ρ is the bulk density of specimen after a number of gyrations n , in kilograms per cubic metre
(ng) g
(kg/m );
P is the preload, initial value of F, in newton (N);
v is the void content, in percent (%);
%
e is the eccentricity, in millimetres (mm);
ITa is the measured internal top angle (4 individual measurements);
1…4
ITa is the minimum measured internal top angle (of 4 measurements);
min
ITa is the maximum measured internal top angle (of 4 measurements);
max
ITA is the internal top angle (average of 4 measurements)
ITA is the internal top angle at 240 Nm tilting moment;
ITA is the internal top angle at 425 Nm tilting moment;
IBa is the measured internal bottom angle (4 individual measurements);
1…4
IBa is the minimum measured internal bottom angle (of 4 measurements);
min
IBa is the maximum measured internal bottom angle (of 4 measurements);
max
IBA is the internal bottom angle (average of 4 measurements)
IBA is the internal bottom angle at 240 Nm tilting moment;
IBA is the internal bottom angle at 425 Nm tilting moment;
prEN 12697-31:2014 (E)
IEA is the internal effective angle (average of ITA and IBA);
IEA is the internal effective angle at 240 Nm tilting moment;
IEA is the internal effective angle at 425 Nm tilting moment;
δ is the difference between ITA and IBA at 240 Nm;
TB(240)
δ is the difference between ITA and IBA at 425 Nm;
TB(425)
δ is the difference between IEA and IEA ;
LH 240 425
w is the water content (if present) in percent of the mass of the dry mixture.
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 φ 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).
prEN 12697-31:2014 (E)
Key
F axial resultant force
h (n ) height of specimen after a number of gyrations
g
φ angle
Figure 1 — Test piece motion diagram
NOTE When the specimen is taken out of the equipment for use in other mechanical tests, the temperature and
pressure 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 force;
 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 speeds up 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 angle and the force F shall conform to the provisions of Annex A, Annex B or Annex C.
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 µm 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;
prEN 12697-31:2014 (E)
 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 0,8 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.
5.4 Device for measuring the distance between inserts
5.5 Device for counting the number of rotations to within one revolution
5.5.1 Ventilated oven for heating mould, metallic inserts and bituminous mixture to the accuracy given in
EN 12697-38
5.5.2 Balance capable of measuring the mass of the mould and the bituminous mixture to the accuracy
given in EN 12697-38
5.5.3 Thermometer 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 from Equation (1) from the
maximum density ρ of the mixture determined according to EN 12697-5, method A using water, and the
M
minimum height of the compacted specimen h corresponding to a zero percentage of voids.
min
prEN 12697-31:2014 (E)
D
−9
M = 10 π h ρ (1)
min M
where
M is the mass of a dry mixture to be introduced in the mould, in kilograms (kg);
D is the internal diameter of the mould, in millimetres (mm);
h is the minimum height of compacted specimen, corresponding to a zero percentage of voids, in
min
millimetres (mm);
ρ is the maximum density of the mixture, in kilograms per cubic metre (kg/m ).
M
For a given type of gyratory compactor calibrated using Annex A, h will be constant. The ratio of h to the
min min
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 Equation (2) from the
maximum density ρ of the mixture determined according to EN 12697-5, method A using water, and the
M
minimum height of the compacted specimen h corresponding to a zero percentage of voids.
min
 
D 100 + w
 
−9
 
M = 10 π h ρ ×   (2)
w min M
 
4 100
 
 
where
Mw is the mass of a wet mixture to be introduced in the mould, in kilograms (kg);
w is the water content of the mixture in percentage (%)
D is the internal diameter of the mould, in millimetres (mm);
h is the minimum height of compacted specimen, corresponding to a zero percentage of voids, in
min
millimetres (mm);
ρ is the maximum density of the mixture, in kilograms per cubic metre (kg/m ).
M
For a given type of gyratory compactor calibrated using Annex A, h will be constant. The ratio of h to the
min min
internal diameter of the mould D shall be in the interval 0,66 to 1,05.
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
prEN 12697-31:2014 (E)
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 mixture, place moulds and inserts for at least 2 h within an enclosure brought
to the reference compaction temperature ± 10 °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 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 mixture, 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 to at the reference compaction temperature ± 5 °C for
between 30 min and 2 h. However, for SMA there is a risk for segregation.
7 Test procedure
7.1 Preliminary setting
7.1.1 Pre-load
In case of a pre-load P, it shall be between 150 N and 3 000 N inclusive.
7.1.2 Force F
The force F shall conform to the provisions of Annex A, Annex B or Annex C.
7.1.3 Setting of the angle of inclination
The angle shall conform to the provisions of Annex A, Annex B or Annex C.
prEN 12697-31:2014 (E)
For Annex A, the setting of the angle φ of the type is verified on the basis of a test conducted on central
reference materials with the representative model according to the provisions of A.1. The minimal conditions
for compliance of a gyratory compactor model with a standard model are defined in A.2. The setting of the
angle of inclination α or φ is that which is determined for the gyratory compactor in accordance with A.2 to
within ± 0,02°.
If the gyratory angle has been changed, the equipment shall be recalibrated by a traceable calibration device.
7.1.4 Speed of rotation
The speed of rotation shall be maintained constant during the test to ± 10 %.
7.1.5 Temperature
The compaction temperatures shall be as given in EN 12697-35 ± 5 °C.
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.
In the case of a pre-load, it shall be applied during an interval of less than 30 s. With the mechanical head in
contact with the upper insert, start the rotation of the machine. The load F and the angle of incline φ shall be
applied within the first gyration.
In other cases, apply the load F and the angle of incline φ and start the rotation of the machine.
The compaction procedure shall be commenced without delay and be completed within 4 min if the mould is
not kept in temperature by an heating system.
7.2.2 Specimens for void content requirement
Without interrupting rotation, measure the height of the specimen h(n ), to ± 0,2 mm for the following numbers
g
of gyrations: 5, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100, 120, 150, 200, 300, 400 and 500 gyrations, stopping
after the required number of gyrations have been completed.
Calculate from Equation (2) the mean percentage of air voids v(n ) according to EN 12697-8, for each
g
specified number of gyrations n .
g
 
h (n ) − h
g min
v (n )% = 100 (3)
 
g
h (n )
 g 
 
where
v(n ) is the void content after a number of gyrations n , in percentage (%);
g g
h(n ) is the height of the specimen after a number of gyrations n , in millimetres (mm);
g g
h is the minimum height of the compacted specimen, corresponding to a zero percentage of voids,
min
in millimetres (mm).
prEN 12697-31:2014 (E)
Unless otherwise stated, if the result of the test is to be interpreted as a single result, a test result on a given
mixture shall be the mean value of at least three elementary determinations.
If the height of the specimens deviates more than 1,5 % from the mean value, when the number of gyrations
more than 20, the specimen shall be rejected.
7.2.3 Specimens for further testing
When the required height of the specimen is obtained stop the rotation of the machine.
If further tests are required, the ends of the specimen shall be adjusted such that they are perpendicular to its
axis using one of the three methods following:
 apply two to ten additional revolutions, while the angle φ is progressively or step by step set to zero;
 remove the mould from the gyratory compactor; apply a static load of (8 000 ± 500) N for 100 mm
diameter specimens or (20 000 ± 1 000) N for 150 mm or 160 mm diameter specimens, parallel to the
axis of the mould, on the inserts;
 cut by sawing.
Extrude the specimen from the mould using a jack.
Before using the specimen for further testing, if necessary, determine its density by the appropriate method
according to EN 12697-6.
8 Test report
The test report shall make reference to this European Standard, i.e. EN 12697-31 and shall include at least
the following information:
a) identification of the mixture;
b) method of manufacture of the mixture, or if it was sampled from a compacted layer, the size and location
of the sample;
c) type and model of gyratory compactor;
d) test conditions (diameter and height h of specimen, speed of rotation, temperature of the test, the
min
angle of inclination, force F);
e) method of calibration (Annex A, Annex B or Annex C).
f) if necessary the water content w of the mixture
If the procedure is used to prepare specimens:
g) height of the specimen and its bulk density.
If the test is used to derive a curve density or void content versus number of gyrations:
h) void content for the prescribed numbers of gyrations.
In both cases, the operational details not provided for in this European Standard, and anomalies, if any, which
might have affected the results.
prEN 12697-31:2014 (E)
9 Precision
Repeatability and reproducibility have determined using Annex A on the air voids content at 60 gyrations.
 Repeatability r = 0,950 % (variance V = 0,115).
r
 Reproducibility R = 1,384 % (variance V = 0,244).
R
The study of repeatability and reproducibility of the compaction test employing a gyrator compactor was
carried out by 20 laboratories working with the same type of test device in accordance with ISO 5725-2 under
the following conditions:
 h = 150 mm, diameter of moulds = 160 mm;
min
 a bituminous mixture;
 method of production of the mixture;
 number of replicates: 4.
prEN 12697-31:2014 (E)
Annex A
(normative)
Procedure for setting the angle and force for types of gyratory
compactor using central reference material
A.1 Scope
The procedure applies to models of a make of gyratory compactor and associated equipment as described in
the general part of this European Standard. The procedure applies to a single unit of a model of gyratory
compactor manufactured by an equipment supplier.
A.2 Principle
A unit of the gyratory compactor model has to be used to compact samples of two central reference asphalt
mixtures. The internal angle is adjusted to achieve air void content ranges after set numbers of gyrations
under a set force. The internal angle found that achieves the set criteria can be used for all units of that model
of gyratory compactor.
A.3 Gyratory-type testing proce
...