BSI Standards Publication BS EN 14770 2012 BS 2000 536 2012 Bitumen and bituminous binders — Determination of complex shear modulus and phase angle — Dynamic Shear Rheometer (DSR) BS EN 14770 2012 BRI[.]
BS EN 14770:2012 BS 2000-536:2012 BSI Standards Publication Bitumen and bituminous binders — Determination of complex shear modulus and phase angle — Dynamic Shear Rheometer (DSR) BS EN 14770:2012 BRITISH STANDARD National foreword This British Standard is the UK implementation of EN 14770:2012 It supersedes BS EN 14770:2005 which is withdrawn The UK participation in its preparation was entrusted to Technical Committee PTI/13, Petroleum Testing and Terminology A list of organizations represented on this committee can be obtained on request to its secretary Energy Institute, under the brand of IP, publishes and sells all Parts of BS 2000, and all BS EN petroleum test methods that would be Part of BS 2000, both in its annual publication “Standard methods for analysis and testing of petroleum and related products and British Standard 2000 Parts” and individually Further information is available from: Energy Institute, 61 New Cavendish Street, London W1G 7AR Tel: 020 7467 7100 Fax: 020 7255 1472 This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application © The British Standards Institution 2012 Published by BSI Standards Limited 2012 ISBN 978 580 75657 ICS 75.140; 91.100.50 Compliance with a British Standard cannot confer immunity from legal obligations This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 2012 Amendments issued since publication Date Text affected BS EN 14770:2012 EN 14770 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM May 2012 ICS 75.140; 91.100.50 Supersedes EN 14770:2005 English Version Bitumen and bituminous binders - Determination of complex shear modulus and phase angle - Dynamic Shear Rheometer (DSR) Bitumes et liants bitumineux - Détermination du module complexe en cisaillement et de l'angle de phase Rhéomètre cisaillement dynamique (DSR) Bitumen und bitumenhaltige Bindemittel - Bestimmung des komplexen Schermoduls und des Phasenwinkels Dynamisches Scherrheometer (DSR) This European Standard was approved by CEN on April 2012 CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the 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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels © 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref No EN 14770:2012: E BS EN 14770:2012 EN 14770:2012 (E) Contents Page Foreword 3 1 Scope 4 2 Normative references 4 3 Terms and definitions 4 4 Principle 5 5 Apparatus .5 6 Preparation of rheometers 6 7 Sample preparation .7 8 Procedure .8 9 Expression of results 10 10 Precision 11 11 Test report 11 Annex A (informative) Temperature verification procedure 12 Annex B (informative) Determining equilibration time 13 Annex C (informative) Determination of the viscoelastic linear range 14 Bibliography 15 BS EN 14770:2012 EN 14770:2012 (E) Foreword This document (EN 14770:2012) has been prepared by Technical Committee CEN/TC 336 “Bituminous binders”, the secretariat of which is held by AFNOR/BNPé 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 November 2012, and conflicting national standards shall be withdrawn at the latest by November 2012 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights This document supersedes EN 14770:2005 Compared with EN 14770:2005, the following changes have been made: a) Note added to 3.3; b) Principle application clarified in Clause 4; c) Note improved in 5.1; d) Rewording of 6.2 and previous Note deleted; e) 7.1 has been re-structured and requirements for reheating times added; f) requirement for reheating added in 7.2; g) sub-clause 7.3 added; h) Clause revised and Note added in 8.3; i) Annex C (informative) added This European standard is based on IP PM CM-02 [1] and XPT 66-065 [2] 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, 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 BS EN 14770:2012 EN 14770:2012 (E) Scope This European standard specifies a number of methods using a dynamic shear rheometer (DSR) capable of measuring the rheological properties of bituminous binders The procedure involves determining the complex shear modulus and phase angle of binders over a range of test frequencies and test temperatures when tested in oscillatory shear From the test, the norm of the complex shear modulus, IG*I, and its phase angle, δ, at a given temperature and frequency can be calculated, as well as the components G', G'', J' and J'' of the complex shear modulus and of the complex compliance This method is applicable to un-aged, aged and recovered bituminous binders, cut-backs and bituminous binders stabilised from emulsions WARNING — The use of this European Standard can involve hazardous materials, operations and equipment This European Standard does not purport to address all of the safety problems associated with its use It is the responsibility of the user of this European Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use 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 1427, Bitumen and bituminous binders — Determination of softening point — Ring and Ball method EN 12594, Bitumen and bituminous binders — Preparation of tests samples Terms and definitions For the purposes of this document, the following terms and definitions apply 3.1 norm of the complex shear modulus IG*I ratio of peak stress to the peak strain in harmonic sinusoidal oscillation 3.2 phase angle δ phase difference between stress and strain in harmonic oscillation 3.3 norm of the complex compliance IJ*I ratio of the peak strain to the peak stress in harmonic sinusoidal oscillation Note to entry: The real parts of the complex shear modulus IG*I and the complex shear compliance IJ*I are respectively G´ and J´ and are associated with the elastic part of material behaviour which represents energy stored during a shear cycle They are complex shear modulus or complex shear compliance multiplied with cosine of phase angle expressed in degrees The imaginary parts of the complex shear modulus and the complex shear compliance are respectively G´´ and J´´ and are associated with the viscous part of material behaviour which represents energy dissipated during a shear cycle They are complex shear modulus or complex shear compliance multiplied with sine of phase angle expressed in degrees BS EN 14770:2012 EN 14770:2012 (E) 3.4 isotherm equation or curve on a graph representing the behaviour of a material at a constant temperature 3.5 isochrone equation or curve on a graph representing the behaviour of a material at a constant frequency 3.6 region of linear viscoelastic behaviour region in which complex dynamic (shear) modulus is independent of (shear) stress or strain Principle A known oscillatory shear stress is applied to the temperature controlled test geometry, in which the bituminous test specimen is held The binder's strain response to the stress is measured Alternatively, a known oscillatory shear strain is applied to the test specimen and the resulting shear stress is measured Except for specific purposes, the test is performed in the region of linear viscoelastic behaviour Apparatus Usual laboratory apparatus and glassware, together with the following: 5.1 Dynamic Shear Rheometer (DSR), with either an integral temperature control system or temperature control attachments, capable of controlling the temperature over a minimum range of °C to 85 °C with an accuracy of ± 0,1 °C throughout the test period The rheometer shall be fitted with parallel plates, with a constant gap across the area of the plates The temperature control system shall encompass both plates to avoid temperature gradients across the plates When the test specimen is immersed in liquid other than water, ensure that the liquid does not affect the properties of the material being analysed The rheometer shall be able to determine G*, in the range of kPa to 10 MPa (± %) and the phase angle (δ), in the range 0° to 90° (± 0,1°) NOTE For rheometers using an air bearing, and to avoid damage, the air supply to the bearing should be switched on before the instrument is switched on When not in use, the spindle should be secured NOTE When liquid is used to immerse the test specimen, a water/glycol mixture has been found to be suitable The proportions used depend on how low the temperature intended for testing is Rheometers using radio frequency (RF) heating and/or liquid gas cooling or other heating/cooling systems should be used in accordance with the manufacturer's instructions NOTE Where the bottom plate is nominally the same diameter as the top plate, a visual check should be made to ensure the two plates are vertically aligned If there is any doubt as to the alignment of the top and bottom plates, the manufacturer, or a qualified technician, should re-align the plate geometry NOTE Diameters from mm to 25 mm and gap settings from 0,5 mm to 2,0 mm have been found to be suitable for bituminous binders In terms of operational ranges, 25 mm plates are generally suitable for stiffnesses in the range kPa to 100 kPa, and mm plates suitable for stiffnesses (|G*|) in the range 100 kPa to 10 MPa Plates of other diameters can also be used, providing compliance effects of the instrument not affect the results (see 6.1, Note 1) and the testing is done in the linear region (see Clause 8) NOTE The fact that the temperature control range is °C to 85 °C should not be taken to imply that accurate results will necessarily be obtained for all binders over this range (see 5.1, Note and 6.1, Note 1) Furthermore, temperatures outside this range can also be used, provided the results are not affected by machine compliance BS EN 14770:2012 EN 14770:2012 (E) 5.2 Moulds, sheet materials or vials, for the preparation of the test specimens The moulds or sheet material, where used, shall be of silicone or similar material, which does not adhere to the test specimen Vials or containers, where used, shall be of an appropriate material and size for the purpose NOTE The use of grease or other anti-stick products should be avoided because they can affect the adherence of the sample to the rheometer plates 5.3 Oven, ventilated laboratory model, capable of being controlled at temperatures between 50 °C and 200 °C with an accuracy of ± °C 6.1 Preparation of rheometers Set up Set up the rheometer in the sequence given in the manufacturer's instructions, including the procedure for the selecting and setting the correct geometry and gap Select the appropriate oscillation package, if applicable, from the software menu It is essential that the operational limits of stiffness for the selected geometry are determined NOTE The selection of system geometry may affect the accuracy of results The manufacturer may have determined the operational limits and this information may be available but, if not, it can be determined by running a test specimen over a range of test temperatures using all the test geometries likely to be used in practice, and plotting |G*| against either frequency or phase angle (δ) Where the divergence between the plots for each geometry exceeds 15 %, this is an indication that compliance effects are affecting one or more of the geometries The chosen geometry(ies) which shows the more rapid fall in |G*|, or the lower phase angle, indicates that its accuracy limit has been reached Also, for most rheometers generally used for this European Standard, irrespective of the geometry chosen, values of |G*| in excess of 10 Pa are likely to be suspect Software corrections to the stiffness may be acceptable provided appropriate validation is supplied to the operator NOTE The rheometer and temperature control system should be calibrated at regular intervals in accordance with the quality assurance procedure of the laboratory A suitable method is that the rheometer and temperature control system should be calibrated by a means traceable to a national standard Also, it is advisable to verify the accuracy of the temperature control system by means of a certified temperature-measuring device at regular intervals Take note that external devices read the accurate temperature value only if they are calibrated correctly A temperature verification procedure is described in Annex A NOTE The temperature in the test sample may differ from the temperature read by the device if insufficient equilibration time is used A procedure for determining equilibration time is described in Annex B 6.2 Zero gap setting Set the zero gap between the plates prior to loading the test specimen, with both plates at nominally the same temperature Carefully prepare the rheometer plates for receipt of the test specimen by cleaning with a suitable solvent and soft cleaning cloth or paper Do not use metal or any other materials, which may damage the surfaces of the plates, and take care not to bend the shaft of the upper plate NOTE Gap settings within the range 0,5 mm to 2,0 mm have been found to be suitable for bituminous binders over the temperature range of °C to 85 °C for parallel plate geometries Values of mm for 25 mm plates and mm for mm plates are recommended The gap set will change with temperature and appropriate steps will need to be taken to account for these changes If the DSR has an automatic gap compensation feature, the gap may be set at any temperature within the range to be covered If the DSR has no gap compensation feature, the gap should be set at a number of different midpoint temperatures not exceeding 15 °C intervals within the range to be tested A suitable means of correcting for gap changes for temperatures different from the gap setting temperature should be reported One way is to set the gap at each test temperature; another is to apply a software correction BS EN 14770:2012 EN 14770:2012 (E) Sample preparation CAUTION — This European Standard involves handling of apparatus and binders at very high temperatures Always wear protective gloves and eyeglasses when handling hot binder, and avoid contact with any exposed skin 7.1 Heating procedure for binders prepared above 100 °C This procedure is for all binders except cut-backs and stabilised binders from emulsions If the softening point of the binder is unknown, determine using EN 1427 Prepare pure, oxidised or special bitumens in accordance with EN 12594 NOTE If the specification grade of the binder is known, the upper softening point limit may be used Avoid prolonged heating of the bulk binder sample, and use the heating periods in EN 12594 as the maximum time prior to withdrawal of (a) sub-sample(s) For very large bulk samples, it is convenient to redistribute the binder in smaller bulk samples after heating and careful homogenisation Place the sample in the oven maintained at a temperature of (85 ± 5) °C above the softening point of the binder, or at 180 °C, whichever is the lower For polymer-modified binders, the temperature shall be in accordance with EN 12594 Binder samples shall not be reheated more than two times Reheating times for sub-samples shall conform to following requirements: 50 g to 100 g: max 30 min; 100 g to 500 g: max h; 500 g to kg: max h 7.2 Heating procedure for binders prepared at temperatures less than 100 °C This procedure is intended for cut-back binders and stabilised binders from emulsions Warm the binder sufficiently and for the minimum time required until it becomes sufficiently fluid either to prepare smaller bulk samples or to directly prepare vials or moulded test samples The binder shall not be heated above 100 °C NOTE Normally, warming the binder to its softening point is sufficient For heavily modified stabilised binders from emulsions, a temperature closed to 100 °C may be more appropriate For too viscous samples, a spatula may be used to remove small quantities at a time from the bulk to place onto the rheometer plate Binder samples shall not be reheated more than two times 7.3 7.3.1 Sample manufacturing and storage conditions Using moulds or sheet materials Moulds or sheet materials can be used for all types of binders When the binder reaches temperature after the heating period, stir and mix with a spatula to ensure homogeneity (especially for polymer modified binders); or after the heating period, remove a sub-sample of convenient size for handling safely and of sufficient volume, to prepare the required number of test specimens plus approximately 50 % BS EN 14770:2012 EN 14770:2012 (E) Pour into moulds or directly on to sheets Choose one or more test shapes that will give reliable measurements with the selected test apparatus The moulds, once cooled to ambient temperature, shall be pared using a suitable trimming tool to the desired height and shall be stored at ambient temperature Samples likely to contain volatiles shall be covered NOTE Paring should be avoided as much as possible by controlling the mass of binder to be poured into the moulds The following minimum and maximum storage durations before the de-moulding and testing procedure shall be observed: Minimum delay: h for pure bitumen; 12 h for PmB’s Maximum delay: days whatever the binder 7.3.2 Using vials Vials shall not be used in case of polymer-modified binders When the binder reaches temperature after the heating period, stir and mix with a spatula to ensure homogeneity; or after the heating period, remove a sub-sample of convenient size for handling safely and of sufficient volume, to prepare the required number of test specimens plus approximately 50 % Pour aliquots of the sub-sample into vials, filling each to the top, and place a cover on each vial Pour sufficient vials for the testing of the binder plus spares for possible repeat testing Store the covered vials at ambient temperature prior to use 8.1 Procedure Sample placing onto the rheometer When using vials, set the temperature of both plates to ambient temperature Heat a vial of binder to its softening point plus (85 ± 5) °C (to a maximum of 100 °C for cut-backs and stabilised binders from emulsions) Stir to ensure homogeneity, and pour sufficient binder from the vial onto the test geometry so that there is an excess appropriate to the measuring geometry chosen Discard any binder remaining in the vial If preferred, weigh the required quantity of binder directly on to the approximate centre of the measuring geometry being used A stabilising time of a minimum of h is required When using moulds or sheet material, the samples may be placed in the refrigerator (approximate temperature of °C) for a maximum time of 30 prior to de-moulding De-moulding and loading onto the rheometer should occur just after removal from the refrigerator BS EN 14770:2012 EN 14770:2012 (E) To re-heat the plates of the rheometer: set the temperature of both plates to a maximum of the softening point of the binder plus (20 ± 5) °C, or at (90 ± 5) °C, whichever is the lower, during a period time of at least 30 min, to enable satisfactory bonding of the test specimen to the plates If the upper plate has no heating, it can be warmed by contact with lower plate and/or using a water bath NOTE Alternative temperatures may be used for the temperature for both plates provided that adhesion takes place between the binder and the plate, and that the binder is sufficiently fluid to allow the gap to be achieved NOTE 8.2 Care should be taken to ensure adhesion of the binder to the rheometer test geometry Gap setting Bring the test specimen to the selected gap setting plus from 0,025 mm to 0,050 mm (for parallel plate geometries) Maintain at the bonding temperature for at least and trim any excess binder with a knife, a spatula or a special trimming tool After trimming, raise or lower the opposing plate to the set testing gap (± 0,01 mm) Do not trim at this stage If the test specimen does not cover the whole measuring plate (indicated by a slight bulging at the periphery of the test specimen), remove, re-prepare the rheometer plates, and prepare a fresh test specimen The entire process should not take more than 10 8.3 Temperature and frequency conditions selecting Set up the rheometer to test in the oscillatory mode to ensure a dynamic response from the specimen under test Select the test temperatures appropriate to the binder being tested Generally, the range will lie between 25 °C and 85 °C Sufficient temperatures should be selected within this range so that the binder can be adequately characterised with no temperature increment being greater than (10 ± 0,1) °C Equilibrate the test specimen within the test geometry at each test temperature before testing The equilibration time between test temperatures shall be stated in the report NOTE The procedure described in Annex B is useful to determine the necessary equilibrium time to homogenize the temperature in the test specimen For most rheometers and most purposes, 10 to 20 equilibration time has been found to be satisfactory in cases of loading a gap, and between 25 and 35 in cases of cylindrical specimens NOTE Alternative and/or additional temperatures may be tested in addition to those stated, provided equipment limitations are not reached NOTE Caution should be taken when testing at the lower test temperatures that the measured complex shear modulus values are not being affected by possible machine/geometry compliance, or by the test specimen de-bonding from the plates NOTE For binders that present crystallisation phenomena in the selected range of temperatures, results are affected by the thermal history undergone by the sample once mounted onto the rheometer In these cases, the procedure should be to cool down slowly the sample (no more than °C/min) to a low “reference” temperature (for instance 10 °C for a bitumen modified with a copolymer including ethylene) and stabilize at that temperature All test temperatures above that temperature would then be performed from low to high whereas all test temperatures below would be performed from that temperature downward The given rate for moving from one temperature to another could be °C/min Select the frequency range and number of frequencies to be tested Select either a discrete test frequency (within the range 0,1 Hz to 10,0 Hz) or a frequency range for testing For the frequency range, a minimum of two frequency decades shall be specified with any individual frequency being at ± 10 % of the set value NOTE For most purposes, ten equally spaced logarithmic steps including 0,1 Hz and 10,0 Hz, within the frequency range 0,1 Hz to 10,0 Hz, have been found to be suitable Select the strain (or stress) in order to ensure that the test specimen will be tested in the linear region over the temperature and frequency range chosen (see Annex C) If several test geometries are used, check for each of them that the chosen range of strain (or stress) remains in the adequate range of measurement of the apparatus BS EN 14770:2012 EN 14770:2012 (E) 8.4 Testing measurement procedure Commence testing at the first selected temperature, starting at the lowest frequency and proceeding to the highest After completion of the first test temperature, proceed to the next test temperature at a rate not exceeding °C per minute Continue testing until the shear complex modulus measured is outside the range of the particular test geometry chosen Once the compliance limits have been reached (see 6.1 Note 1), the testing shall be stopped and a new test geometry will be needed to continue testing over further temperatures For this, a new sample of the same material shall be required The preparation of the new test geometry shall be as described for the first test geometry and the first test temperature shall be at the temperature where the complex shear modulus measurements were not affected by machine compliance The testing shall be continued with this new test geometry for the remainder of the test temperatures or until the measurements of complex shear modulus are outside the range of the test geometry For any given test geometry, the testing shall be completed within h so as to minimise changes in binder properties NOTE It may be convenient to test over the whole temperature range with one test geometry, and then to review the results to determine the temperature at which a second, or further, test geometry is necessary The temperature at which both test geometries have been tested is known as the overlap temperature and is used in the determination of the acceptability criteria Examine the values of complex shear modulus (|G*|) and phase angle (δ) obtained at the temperature overlap temperature using the two different test geometries, and apply acceptability criteria as follows: a) the values of |G*| at the test frequency should not differ from the mean of |G*| from the two geometries by more than 15 %, and b) the values of δ at the test frequency should not differ from the mean of δ from the two geometries by more than 3° If either of the above are not met, repeat the whole test If more than one overlap temperature occurs with a single test specimen, the criteria given above shall be met at each overlap temperature If no change of geometry has been made, repeat the test at one of the test temperatures using the same geometry on a new test specimen If the acceptability criteria given above are not met, repeat the whole test Construct isotherms of |G*| (Pa) and δ (°) against frequency (Hz), or isochrones of |G*| (Pa) and δ (°) against temperature (°C) NOTE All results where the measured strain is outside of the linear range of the tested binder, or where the results have been affected by machine compliance, should be omitted NOTE Other parameters may be constructed, if desired Expression of results Report the test geometries, and the strain or stress conditions used in the test Report the test frequency(ies) and temperature(s), the values of complex shear modulus (|G*|) in Pa, to three significant figures, and values of phase angle (°), in degrees, to the nearest 0,1° If possible (and in case that a frequency sweep was performed), construct isotherms of |G*| (Pa) or J* (1/Pa) and δ (°) against frequency (Hz) to attach to the test report NOTE 10 Other parameters may be reported in addition to those stated BS EN 14770:2012 EN 14770:2012 (E) 10 Precision The precision of this test method has not yet been established However, tests carried out under repeatability conditions should meet the acceptability criteria given in Clause NOTE Tests under reproducibility conditions have been carried out using the similar AASHTO test according to SHRP protocols and also by RILEM using nominally the same method on a range of binders Preliminary indications are that the test is approximately as precise as the softening point test NOTE Results from a RILEM exercise on the measurement of complex modulus and phase angle, and limited to rotational DSRs with Parallel Plate sample geometries of 25 mm, mm gap and mm, mm gap, indicated that: – reproducibility of |G*| may be practically achieved in the range below 10 %, independently from the type of binder, pure or modified, and state of binder, original as well as aged RTFOT or PAV – reproducibility of phase angle may be practically achieved in the range below %, independently from the type of binder, pure or modified, and state of binder, original as well as aged RTFOT or PAV 11 Test report The test report shall contain at least the following information: a) reference to this European Standard; b) type and complete identification of the sample under test; c) testing conditions followed, including equilibration time; d) result of the test (see Clause 9); e) any deviation, by agreement or otherwise, from the procedure specified; f) date of the test 11 BS EN 14770:2012 EN 14770:2012 (E) Annex A (informative) Temperature verification procedure Thermal gradients within the rheometer and the difficulty of calibrating the DSR temperature instrument while it is mounted in the rheometer mean that a temperature verification of the DSR temperature transducer is required To this end, temperature measurements obtained from a dummy specimen with a calibrated thermal detector (to an accuracy of ± 0,02 °C) and the DSR temperature transducer can be compared A dummy specimen of bituminous binder or silicone wafer may be used NOTE Alternatively, use may be made of specially designed thermometers that can be inserted between the plates to verify the temperature Prepare the dummy specimen or use the silicon wafer following standard procedures Use the dummy specimen only for temperature verification measurements (DSR-measurements are not valid if a temperature detector is inserted into the asphalt binder.) Adjust the temperature in the chamber to the minimum temperature that will be used for testing and allow the chamber to come to thermal equilibrium Read the DSR-temperature and the temperature of the dummy specimen Increase the temperature in increments of not more than °C and repeat the measurements to cover the range of test temperatures The difference between the temperature probe and the temperature indicated by the DSR-transducer varies with temperature and depends on testing geometry Apply an appropriate temperature correction to the temperature measurement indicated by the DSR transducer if both readings not agree within ± 0,1 °C 12 BS EN 14770:2012 EN 14770:2012 (E) Annex B (informative) Determining equilibration time It takes some time for the temperature of the bituminous binder sample to reach thermal equilibrium This equilibrium time varies for different rheometers, depending upon the design of the rheometer and the type of heating-cooling unit and medium The equilibrium time can be determined by monitoring G* with time Phase angle is not very sensitive to changes in temperature and should not be used for this purpose To determine the equilibrium time, mount a binder sample in the DSR and run a test at a given frequency according to the described procedure Record the time required to bring G* to a constant value and add to The sum is the equilibration time NOTE Prolonged measurements can be influenced by internal heat in the sample generated by the vibration 13 BS EN 14770:2012 EN 14770:2012 (E) Annex C (informative) Determination of the viscoelastic linear range The determination of the linear region should be done for each selected geometry It is necessary to use a specific test specimen for this determination For a given geometry, determination of the linear region on the all selected temperature ranges shall consist, at least, of carrying out strain (or stress) sweep at the lowest temperature and at the highest frequency, strain (or stress) sweep at the highest temperature and at the lowest frequency, in order to select the adequate strain level To remain in the linear range, the value of G’ and G’’ must not differ by more than % of the initial value over the stress or strain range chosen The initial value can be taken as the intercept of a regression line fitted to the first measured values For the majority of binders, it has been found that testing within the strain range 0,005 to 0,100 lies within the linear range However, for polymer modified binders and chemically modified binders, the linear range may be much less If the binder is similar to one of the binders already tested on the same apparatus, it is possible to carry out a simplified procedure for linear range determination, for example by selecting only one temperature for each geometry 14 BS EN 14770:2012 EN 14770:2012 (E) Bibliography [1] IP PM CM-02, Determination of the complex shear modulus and phase angle of bituminous binders — dynamic shear rheometer (DSR) method (only available in English) [2] XP T 66-065, Hydrocarbon binders — Determination of the complex modulus (only available in French) 15 This page deliberately left blank BS 2000 Series Energy Institute Buying Parts of BS 2000 Orders for BS 2000 publications should be addressed to either: Energy Institute – Library and Information Service 61 New Cavendish Street London W1G 7AR Tel: +44 (0)20 7467 7100 Fax: +44 (0)20 7255 1472 www.energyinst.org.uk Order standards securely via: www.energyinstpubs.org.uk or: British Standards Institution – Customer Services 389 Chiswick High Road London W4 4AL Tel: +44 (0)20 8996 9001 Fax: +44 (0)20 8996 7001 www.bsi-global.com Order hard copy standards securely via: www.bsi-global.com/bsonline Copyright Copyright exists in all BS 2000 publications No part of this publication may be reproduced in any form without the prior permission in writing of BSI and the Energy Institute Enquiries about copyright should be made to the Secretary of PTI/13 at the Energy Institute PTI/13 This page deliberately left blank