oSIST prEN 12697-49:2020

Bituminous mixtures - Test methods - Part 49: Determination of friction after polishing

This document describes a test method to determine the friction at 60 km/h after polishing during a fixed number of passes on surfaces of bituminous mixtures samples, or to follow its evolution as a function of the number of polishing passes.
The samples used are either produced in a laboratory or are cores taken from the site.
NOTE   This procedure was previously known as Wehner and Schulze method (see [1]).

Asphalt - Prüfverfahren - Teil 49: Messung der Griffigkeit nach dem Polieren

Dieses Dokument beschreibt ein Prüfverfahren zur Bestimmung der Griffigkeit bei 60 km/h nach dem Polieren während einer festgelegten Anzahl an Übergängen auf Oberflächen von Asphaltproben bzw. zur Verfolgung der Entwicklung der Griffigkeit in Abhängigkeit von der Anzahl der Übergänge.
Die verwendeten Probekörper werden entweder im Labor hergestellt oder sind vor Ort entnommene Bohrkerne.
ANMERKUNG   Dieses Verfahren war ehemals unter der Bezeichnung Wehner/Schulze Verfahren (siehe [1]) bekannt.

Mélanges bitumineux - Méthodes d’essai - Partie 49 : Détermination du coefficient de frottement après polissage

Le présent document décrit une méthode d'essai permettant de déterminer le coefficient de frottement à 60 km/h après polissage, après un nombre déterminé de passes sur les surfaces des échantillons de mélanges bitumineux ou de suivre cette évolution en fonction du nombre de passes de polissage.
Les échantillons utilisés sont soit des échantillons produits en laboratoire, soit des carottes prélevées sur le site.
NOTE   Ce mode opératoire était précédemment connu sous l'appellation « méthode de Wehner et Schulze » (voir [1]).

Bitumenske zmesi - Preskusne metode - 49. del: Ugotavljanje tornih sposobnosti po poliranju

General Information

• Status: Not Published
• Public Enquiry End Date: 19-Mar-2020
• ICS: 93.080.20 - Road construction materials
• Technical Committee: CES - Roads
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 04-Feb-2020
• Due Date: 23-Jun-2020
• Completion Date: 01-Apr-2020
• Ref Project: prEN 12697-49 - Bituminous mixtures - Test methods - Part 49: Determination of friction after polishing

RELATIONS

• Revised: SIST EN 12697-49:2014 - Bituminous mixtures - Test methods for hot mix asphalt - Part 49: Determination of friction after polishing
• Effective Date: 01-Mar-2020

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN 12697-49:2020
01-marec-2020
Bitumenske zmesi - Preskusne metode - 49. del: Ugotavljanje tornih sposobnosti
po poliranju

Bituminous mixtures - Test methods - Part 49: Determination of friction after polishing

Asphalt - Prüfverfahren - Teil 49: Messung der Griffigkeit nach dem Polieren

Mélanges bitumineux - Méthodes d’essai - Partie 49 : Détermination du coefficient de

frottement après polissage
Ta slovenski standard je istoveten z: prEN 12697-49
ICS:
93.080.20 Materiali za gradnjo cest Road construction materials
oSIST prEN 12697-49:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 12697-49:2020
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oSIST prEN 12697-49:2020
DRAFT
EUROPEAN STANDARD
prEN 12697-49
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2020
ICS 93.080.20 Will supersede EN 12697-49:2014
English Version
Bituminous mixtures - Test methods - Part 49:
Determination of friction after polishing

Mélanges bitumineux - Méthodes d'essai - Partie 49 : Asphalt - Prüfverfahren - Teil 49: Messung der

Détermination du coefficient de frottement après Griffigkeit nach dem Polieren
polissage

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, 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: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12697-49:2020 E

worldwide for CEN national Members.
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Contents Page

European foreword .................................................................................................................................................. 3

1 Scope ............................................................................................................................................................... 5

2 Normative references ............................................................................................................................... 5

3 Terms, definitions and symbols ............................................................................................................ 5

3.1 Terms and definitions .............................................................................................................................. 5

3.2 Symbols .......................................................................................................................................................... 5

4 Principle ........................................................................................................................................................ 6

5 Equipment .................................................................................................................................................... 6

5.1 Test device .................................................................................................................................................... 6

5.2 Glass plate for comparative measurements .................................................................................. 11

5.3 Sand-blasting-equipment ..................................................................................................................... 11

6 Other materials ........................................................................................................................................ 11

6.1 Quartz powder ......................................................................................................................................... 11

6.2 Water quartz powder mixture ........................................................................................................... 11

6.3 Corundum .................................................................................................................................................. 11

7 Test method .............................................................................................................................................. 12

7.1 Preparation of the specimens ............................................................................................................. 12

7.2 Polishing procedure ............................................................................................................................... 12

7.3 Friction measurement ........................................................................................................................... 13

8 Calculation and expression of the results ...................................................................................... 14

8.1 Friction result μ on a single specimen ..................................................................................... 14

FAP

8.2 Determination of FAP ............................................................................................................................ 14

9 Test report ................................................................................................................................................. 15

10 Precision ..................................................................................................................................................... 15

Annex A (informative) Example of polishing head and friction unit ................................................... 16

Bibliography ............................................................................................................................................................ 17

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European foreword

This document (prEN 12697-49:2020) has been prepared by Technical Committee CEN/TC 227 “Road

materials”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 12697-49:2014.
The following is a list of significant changes from the previous edition:

— [1] Possibility of following FAP evolution as a function of the number of polishing passes.

— [2] and [5.1.4.5] Change of normative reference to ISO 48-4 for the determination of Shore

hardness.

— [3.1.1] Rewording of the definition of pass, and information given as a Note to entry.

— [3.2] Introduction of the symbol µ, and rewording of μ definition.
FAP
— [5.1.1] Addition of reference to Annex A.

— [5.1.1] Completed with obligation to work in specified temperature and humidity room

conditions.

— [5.1.2.3] Introduction of additional requirements for polishing rollers storage.

— [5.1.4.2] Rewording of title, and correction of a unit error for inertia moment.

— [5.1.4.3] Modification of the tolerance for moment measurement.

— [5.1.4.5] Modification of the criteria for resilience of sliding blocks. Deletion of Table 1 and

following paragraph. Following tables renumbered accordingly.
— [5.1.4.5] In Figure 4, correction of the rotation radius value.
— [5.2] Rewording of title, and additional specification for μ value.
ref
— [5.3] Additional requirements for sand-blasting equipment.
— [6.1] Additional requirements for quartz powder.
— [6.2] Additional requirements for water/quartz-powder mixture.
— [6.3] Deletion of the Note about the supplier of corundum.

— [7.1.1] Addition of a new sub-heading "7.1.1 General". Following subclauses renumbered

accordingly.

— [7.1.1] Achievement – or no – of sandblasting according to the test and/or product context.

— [7.1.2] Rewriting of sandblasting procedure, and change of storage position.
— [7.1.3] Modification of thickness requirement and change of storage position.
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— [7.2] Additions in polishing procedure about conditioning, water/quartz-powder mixture,

washing.
— [7.3.1] Obligation of pre-test check for each specimen.

— [7.3.2] Additional dispositions about water introduction and control plate test.

— [8.1] Clause totally rewritten for more clarity and consistency.

— [8.2] Modification of the criterion for validating the test, and possibility of a curve FAP = f

(passes).

— [9] Correction of the number of decimals for FAP, mention the roller numbers, sandblasting, and

curve.

This document has been prepared under a mandate given to CEN by the European Commission and

the European Free Trade Association.
A list of all parts in the EN 12697 series can be found on the CEN website.
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1 Scope

This document describes a test method to determine the friction at 60 km/h after polishing during a

fixed number of passes on surfaces of bituminous mixtures samples, or to follow its evolution as a

function of the number of polishing passes.

The samples used are either produced in a laboratory or are cores taken from the site.

NOTE This procedure was previously known as Wehner and Schulze method (see [1]).
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 12697-27, Bituminous mixtures - Test methods - Part 27: Sampling

EN 12697-33, Bituminous mixtures - Test method - Part 33: Specimen prepared by roller compactor

ISO 4662, Rubber, vulcanized or thermoplastic - Determination of rebound resilience

ISO 48-4, Rubber, vulcanized or thermoplastic - Determination of hardness - Part 4: Indentation

hardness by durometer method (Shore hardness)
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:

• ISO Online browsing platform: available at https://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
3.1.1
pass

passage of a single roller of the polishing head on one given point of the sample surface

Note 1 to entry: A complete revolution of the rotating head is equivalent to three roller passes on one given

point of the sample surface.
3.2 Symbols
μ friction coefficient
μ friction coefficient at 60 km/h
μ mean value of the control plate before and after the friction measurement
μ known value of the Laboratory Skid Resistance of the control plate
ref
μ single result of friction measurement on a single specimen
FAP
FAP Friction After Polishing: average of two or more single results μ
FAP
∅ diameter in mm
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4 Principle

The sample is polished and the friction force is determined. The device comprises a polishing station

and a unit for measuring the friction. The polishing station, which is continuously supplied with a

mixture of water and quartz powder, contains three polishing rollers that can be lowered and that

move across the test surface at a predefined loading force.

In the friction measuring unit, a rotating measuring head is lowered onto the test surface while water

is being added. The measuring head is fitted with three sliding blocks and can be declutched

electronically. The moment generated by the contact between the rubber sliders and the surface is

continuously measured and recorded until the measuring head comes to a standstill. The friction is

subsequently calculated from the moment measured at 60 km/h.
5 Equipment
5.1 Test device
5.1.1 General

The test device consists of a unit to polish the sample, a specimen clamping system and a unit for

measuring its friction coefficient. (See an example of polishing head and friction unit in Annex A.) The

test apparatus shall be operated in laboratories with specified room temperature and relative

humidity.
5.1.2 Polishing unit
5.1.2.1 General

The polishing unit includes a polishing head with polishing rollers and a water-quartz powder mixture

projection system.
5.1.2.2 Polishing head

A polishing head equipped with three polishing rollers as indicated on Figure 1, able to be lowered

onto the test surface with loading force calibrated in static of (392 ± 3) N. The polishing head shall

move on the surface of the specimen during the polishing procedure and rotate at a rotation speed of

(500 ± 5) r/min.
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Dimensions in millimetres
Key
1 polishing roller
2 water quartz powder projection device
Figure 1 — Polishing head (view from below)
5.1.2.3 Polishing rollers

The rollers, as shown in Figure 2, consist of a circular, cone-shaped metal carrier housing covered with

an (8,5 ± 0,5) mm thick layer of rubber at the start of the test. Eight profile grooves with a depth of

(4,5 ± 0,5) mm and a width of (3,5 ± 0,5) mm are cut into this rubber layer.
The polishing rollers shall have the following characteristics:
— diameter D : (36 ± 1) mm and D : (80 ± 1) mm;
1 2
— height H (56,3 ± 0,1) mm;

— shore hardness (65 ± 3) Shore A at a temperature of (23 ± 2) °C, according to ISO 48-4.

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Dimensions in millimetres
Figure 2 — Polishing rollers — 3D view, cross and longitudinal section

The friction in the bearings of the polishing rollers should be checked periodically according to the

following procedure:

The torque moment measured on a sample made with a fine aggregate 0,2/0,4 mm or an asphalt

surface during 90 000 passes shall be constant to ± 10 % between 10 000 passes and 85 000 passes.

Any polishing rollers not used should be packed in film and stored in a dark place at a temperature of

4 °C to 10 °C for less than two years. Once the rollers are removed from their packaging, beyond

2 months at a temperature higher than 10 °C without any use, their rubber hardness shall be checked

again.
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