BS EN 12697-11:2012 BSI Standards Publication Bituminous mixtures — Test methods for hot mix asphalt Part 11: Determination of the affinity between aggregate and bitumen BS EN 12697-11:2012 BRITISH STANDARD National foreword This British Standard is the UK implementation of EN 12697-11:2012 It supersedes BS EN 12697-11:2005 which is withdrawn The UK participation in its preparation was entrusted to Technical Committee B/510/1, Asphalt products A list of organizations represented on this committee can be obtained on request to its secretary 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 75914 ICS 93.080.20 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 12697-11:2012 EN 12697-11 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM April 2012 ICS 93.080.20 Supersedes EN 12697-11:2005 English Version Bituminous mixtures - Test methods for hot mix asphalt Part 11: Determination of the affinity between aggregate and bitumen Mélanges bitumineux - Méthodes d'essai pour mélange hydrocarboné chaud - Partie 11: Détermination de l'affinité granulat-bitume Asphalt - Prüfverfahren für Heißasphalt - Teil 11: Bestimmung der Affinität von Gesteinskörnungen und Bitumen This European Standard was approved by CEN on March 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 12697-11:2012: E BS EN 12697-11:2012 EN 12697-11:2012 (E) Contents Page Foreword 3 Scope 7 Normative references 7 Terms and definitions 7 Principle 8 5.1 5.2 5.2.1 5.2.2 5.2.3 5.3 5.4 5.5 5.6 5.7 Rolling bottle method 8 Equipment 8 Preparation of test specimens 11 Aggregate 11 Bitumen 12 Mixing aggregate and bitumen 12 Conditioning 13 Procedure 13 Calculation and expression of results 15 Report 15 Precision 16 6.1 6.2 6.3 6.3.1 6.3.2 6.4 6.5 6.6 6.7 Static method 16 Equipment 16 Solvent and other materials 17 Preparation of test specimens 17 Aggregate 17 Bitumen 17 Procedure 17 Calculation and expression of results 18 Report 18 Precision 18 7.1 7.2 7.3 7.3.1 7.3.2 7.3.3 7.4 7.5 7.5.1 7.5.2 7.5.3 7.6 7.6.1 7.6.2 7.7 7.8 Boiling water stripping method 18 General 18 Equipment and materials 19 Sample preparation 20 Aggregate 20 Bitumen 21 Mixing aggregate and bitumen 21 Conditioning 21 Test procedure 21 Establishing the acid/base equivalence factor 21 Establishing the calibration curve 22 Stripping test 23 Calculation and expression of results 24 Determination of the calibration curve 24 Calculation of the degree of bitumen coverage 25 Test report 26 Precision 26 Annex A (informative) Guidance for estimation of the degree of bitumen coverage 27 Bibliography 28 BS EN 12697-11:2012 EN 12697-11:2012 (E) Foreword This document (EN 12697-11:2012) has been prepared by Technical Committee CEN/TC 227 “Road materials”, the secretariat of which is held by DIN 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 October 2012, and conflicting national standards shall be withdrawn at the latest by October 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 12697-11:2005 List of main changes since this new edition: • Most clauses, subclauses, etc in the existing standard renumbered and headlines for methods A (rolling bottle), B (static immersion) and C (Boiling water stripping method) deleted (which may be confusing to users of previous version of standard!); • 5.1.12: Requirement to horizontally positioning of rolling machine added; • 5.2.2.1: Reference to EN 58 added for sampling; • 6.1.1: “Shallow trays” changed to “Flat bottomed container”; • 6.3.1 and 6.3.2: Original text for preparation of aggregate and bitumen changed to reference to similar clauses in the rolling bottle method; • 6.4.1: Now allowing use of 8-11,2 mm fraction alternatively, and definition of mixing temperature changed from 130 °C ± °C to 15°C less than the mixing temperature defined in EN 12697-35; • 6.6: In report, new list entry b) (sample identification number and date and time of testing, is added; • 7.2.1: Requirements for test sieves changed to reference to 5.2.1 (previously specified sieves and 14 mm deleted); • 7.5.1.1., 7.5.1.2, 7.6.1.1, and 7.6.2.1: the symbol “r” previously used for acid/base equivalent factor is changed to “feq” to avoid misunderstanding as “r” is also used for repeatability (change introduced with the latest comments); • 7.3.3.4: Use of (8-11,2) mm aggregates added; • Informative Annex A added This European Standard is one of a series of standards as listed below: — EN 12697-1, Bituminous mixtures — Test methods for hot mix asphalt — Part 1: Soluble binder content — EN 12697-2, Bituminous mixtures — Test method for hot mix asphalt — Part 2: Determination of particle size distribution — EN 12697-3, Bituminous mixtures — Test methods for hot mix asphalt — Part 3: Binder recovery: Rotary evaporator BS EN 12697-11:2012 EN 12697-11:2012 (E) — 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 specimen — EN 12697-7, Bituminous mixtures — Test methods for hot mix asphalt — Part 7: Determination of bulk density of bituminous specimens by gamma rays — EN 12697-8, Bituminous mixtures — Test methods for hot mix asphalt — Part 8: Determination of void characteristics of bituminous specimens — EN 12697-10, Bituminous mixtures — Test methods for hot mix asphalt — Part 10: Compactability — EN 12697-11, Bituminous mixtures — Test methods for hot mix asphalt — Part 11: Determination of the affinity between aggregates 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 — EN 12697-25, Bituminous mixtures — Test methods for hot mix asphalt — Part 25: Cyclic compression test BS EN 12697-11:2012 EN 12697-11:2012 (E) — EN 12697-26, Bituminous mixtures — Test methods for hot mix asphalt — Part 26: Stiffness — EN 12697-27, Bituminous mixtures — Test methods for hot mix asphalt — Part 27: Sampling — EN 12697-28, Bituminous mixtures — Test methods for hot mix asphalt — Part 28: Preparation of samples for determining binder content, water content and grading — EN 12697-29, Bituminous mixtures — Test methods for hot mix asphalt — Part 29: Determination of the dimensions of a bituminous specimen — 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 mixtures by a 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 coarse foreign matter in reclaimed asphalt — EN 12697-43, Bituminous mixtures — Test methods for hot mix asphalt — Part 43: Resistance to fuel — EN 12697-44, Bituminous mixtures Test methods for hot mix asphalt Part 44: Crack propagation by semi-circular bending test — FprEN 12697-45, Bituminous mixtures Test methods for hot mix asphalt Part 45: Saturation Ageing Tensile Stiffness (SATS) conditioning test — FprEN 12697-46, Bituminous mixtures Test methods for hot mix asphalt Part 46: Low temperature cracking and properties by uniaxial tension tests BS EN 12697-11:2012 EN 12697-11:2012 (E) — EN 12697-47, Bituminous mixtures Test methods for hot mix asphalt Part 47: Determination of the ash content of natural asphalts — prEN 12697-49, Bituminous mixtures Test methods for hot mix asphalt Part 49: Determination of friction after polishing 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 12697-11:2012 EN 12697-11:2012 (E) Scope This European Standard specifies procedures for the determination of the affinity between aggregate and bitumen and its influence on the susceptibility of the combination to stripping This property is intended to be of assistance to the designer for mixture design rather than as a type test Susceptibility to stripping, as determined by these procedures, is an indirect measure of the power of a binder to adhere to various aggregates, or of various binders to adhere to a given aggregate The procedures can also be used to evaluate the effect of moisture on a given aggregate-binder combination with or without adhesion agents including liquids, such as amines, and fillers, such as hydrated lime or cement In the rolling bottle method, the affinity is expressed by visual registration of the degree of bitumen coverage on uncompacted bitumen-coated mineral aggregate particles after influence of mechanical stirring action in the presence of water NOTE The rolling bottle test is a simple but subjective test and suitable for routine testing It is not appropriate for aggregates that are highly abrasive In the static test method, the affinity is expressed by visual registration of the degree of bitumen coverage on uncompacted bitumen-coated mineral aggregate particles after storage in water NOTE The static test is a simple, though subjective test that is generally less precise, but that can cope with high PSV-aggregates In the boiling water stripping test method, the affinity is expressed by determining the degree of bitumencoverage on uncompacted bitumen-coated aggregate after immersion in boiling water under specified conditions NOTE The boiling water stripping test is an objective test and has a high precision However, it is a more specialist test because it requires greater skill of the operatives and uses chemicals as reagent The latter point may also imply extra health and safety considerations NOTE The boiling water stripping test procedure can be used for any binder-aggregate combinations in which the mineral aggregate is calcareous, silico-calcareous or siliceous by nature 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 58, Bitumen and bituminous binders — Sampling bituminous binders EN 1426, Bitumen and bituminous binders — Determination of needle penetration EN 12697-2, Bituminous mixtures — Test method for hot mix asphalt — Part 2: Determination of particle size distribution EN 12697-35, Bituminous mixtures — Test methods for hot mix asphalt — Part 35: Laboratory mixing Terms and definitions For the purposes of this document, the following terms and definitions apply 3.1 acid/base equivalence factor feq ratio of the volume of base needed to neutralise 25 ml of acid BS EN 12697-11:2012 EN 12697-11:2012 (E) 3.2 affinity between aggregate and bitumen degree of bitumen coverage visually determined on uncompacted bitumen coated mineral aggregate particles after influence of mechanical stirring action in the presence of water 3.3 completely coated aggregate particle is completely coated by binder when there are no visible breaks, however small, in the film of binder covering the particle 3.4 degree of bitumen coverage average proportion of the surface area of the aggregate particles that are covered with bitumen, expressed as a percentage (equal to 100 minus the percentage of stripping) 3.5 normality N molar concentration expressed in hydrogen equivalent per dm of solution 3.6 percentage of stripping average proportion of the surface area of the aggregate particles from which the binder is soaked off due to the action of water, expressed as a percentage Principle An aggregate is sieved in accordance with EN 12697-2 The standard size is mm to 11,2 mm fraction (Basic set plus set 1) or 6,3 mm to 10 mm fraction (Basic set plus set 2) which is washed, dried and mixed with bitumen to obtain uniform, total coverage NOTE Other fractions may alternatively be used, but not smaller than the mm to mm fraction However, to avoid clusters, the above mentioned standard sizes should be used For the method described in Clause 5, the bitumen coated aggregate is placed loosely distributed on a metal plate or silicone coated paper, stored at ambient temperature overnight, and then divided into three part samples for analysis Each part sample is transferred to a bottle filled with water The bottle is sealed and placed on a bottle-rolling device The bottles are rolled at ambient temperature and at a specified speed At specified time intervals the degree of bitumen coverage on the aggregate particles is visually estimated by two technicians independently (or alternatively by automated system) For the method described in Clause 6, the bitumen coated aggregate is immersed in distilled water for 48 h and the number of particles that are no longer completely coated assessed For the method described in Clause 7, the bitumen coated aggregate is subjected to stripping in boiling water under specified conditions, using a simple device in which no local overheating can occur By contact with a chemical reagent, the consumption of which is proportional to the uncoated surface of the aggregate, the degree of bitumen coverage is determined with reference to a calibration curve established by a well-defined procedure The reagent used is hydrochloric acid for calcareous aggregates and hydrofluoric acid for silicocalcareous or siliceous aggregates Rolling bottle method 5.1 5.1.1 Equipment Test sieves Square openings conforming to EN 12697-2; 11,2 mm and mm or 6,3 mm and 10 mm BS EN 12697-11:2012 EN 12697-11:2012 (E) Key Y bitumen coverage (%) X rolling time (h) Figure — Example of graphical presentation 5.7 Precision The precision of this test has not yet been established officially The following precision data are estimated from normal practice: Repeatability, r: 20 %; Reproducibility, R: 30 % NOTE The obtainable precision may depend on the level of the result as determinations close to or 100 are easier visually to determine than „mid-range“ results between 25 % and 75 % Static method 6.1 6.1.1 Equipment Flat bottomed container The container shall be flat-bottomed and of sufficient width to allow for placing of 150 particles in a single layer, and of sufficient height to allow the particles to be completely submerged in water NOTE 6.1.2 A suitable container can be a flat bottomed glass bowl in accordance with 5.1.14 or a shallow tray Mixing bowl Capacity of 1,5 l 6.1.3 16 Heating apparatus BS EN 12697-11:2012 EN 12697-11:2012 (E) Equipment for separately heating the aggregate and the binder to a temperature within the range given in 6.4 6.2 Solvent and other materials Distilled water 6.3 6.3.1 Preparation of test specimens Aggregate Prepare the aggregate in accordance with 5.2.1.1 and 5.2.1.2 6.3.2 Bitumen Prepare the binder in accordance with 5.2.2.1 and 5.2.2.2 6.4 Procedure 6.4.1 Quarter and sieve out each sample of aggregate in accordance with EN 12697-2 to provide a single set of 150 particles each passing the 11,2 mm sieve and retained on the mm sieve (basic set plus set 1) or passing the 10 mm sieve and retained on the 6,3 mm sieve (basic set plus set 2) Heat the aggregate particles, the binder and the mixing bowl separately to a temperature 15 °C less than the mixing temperature defined in EN 12697-35 for mixtures, with a tolerance of ± °C Place the aggregate particles in the mixing bowl and add a quantity of binder equivalent to % by mass of the aggregate particles Mix the aggregate and binder by hand until complete coating of the aggregate is obtained 6.4.2 If any particles are not completely coated after of mixing, repeat 6.4.1 with new aggregate particles and an increased proportion of binder The binder shall be increased by steps of 0,5 % by mass of the aggregate particles until a mix giving complete coating of the aggregate is obtained 6.4.3 If necessary, apply a light coating of a mixture of equal parts of glycerol and dextrin, or similar agent, to one or more containers Place the coated specimen in the container(s), ensuring that each particle is completely separated from adjacent particles NOTE The application of mixture is to prevent adhesion of the binder to the container 6.4.4 Leave the flat bottomed container to stand for h ± min, then completely cover the coated specimen with distilled water at a set temperature of (19 ± 1) °C and maintain that temperature a set period of (48 ± 1) h NOTE Alternative immersion time and temperature can be used 6.4.5 After immersion for the set period, decant the water and allow the coated specimen to dry Examine the dried sample, particle by particle, while still in the container(s) for incomplete coating by the binder NOTE An additional procedure can be to determine the degree of bitumen coverage in accordance with 5.4.7 provided it is recorded in the test report 6.4.6 If more than three aggregate particles in a sample have an incomplete binder coating, repeat 6.4.1 to 6.4.5 on three further samples NOTE The replicate tests can be carried out concurrently 6.4.7 Repeat 6.3.2 and 6.4.1 to 6.4.6 for each source of supply to provide separate samples of aggregate from each source NOTE The tests on aggregates from different sources can be carried out concurrently 17 BS EN 12697-11:2012 EN 12697-11:2012 (E) 6.5 Calculation and expression of results The result for each aggregate source is the number of particles with an incomplete coating of binder In the case of tests that have been repeated under 6.4.6, the result shall be mean of the four result NOTE As an additional test result the mean value of the degree of bitumen coverage, rounded to the nearest % can be reported 6.6 Report The test report shall include the following information as appropriate: a) reference to this European Standard; b) sample identification number and date and time of testing; c) type and size (fraction) of aggregate used; d) type of bitumen used; e) any modifiers and/or adhesion agents and the proportion at which they were added; f) (mean) number of aggregate particles not completely coated by binder after immersion in water; g) (optional) the mean value of the degree of bitumen coverage expressed in %, rounded to the nearest %; h) observations of aggregate particles forming lumps; i) if the test was repeated, the number of aggregate particles not completely coated by binder at the end of each individual determination; j) name of the person(s) performing the test; k) notes including observations considered of importance for the test result Also note if only one operator has performed the visual determinations 6.7 Precision The precision of this test has not yet been established officially 7.1 Boiling water stripping method General WARNING — The method in Clause of this European Standard requires the use of chemicals such as hydrochloric acid (HCl) or hydrofluoric acid (HF) and phenolphthalein (as indicator) The reagents may be hazardous to health and safety and, in order to minimise the risk, it is recommended to purchase the acids as diluted solutions (0,1 N HCl and N HF) It is the responsibility of the user of this European Standard to establish appropriate safety and health procedures and determine the applicability of regulatory limitations prior to use SAFETY PRECAUTIONS — Use laboratory safety procedures when handling and using these chemicals It is highly recommended to work under a fume hood when using these reagents It is advised that adequate training should be given to staff employed in the use of these substances 18 BS EN 12697-11:2012 EN 12697-11:2012 (E) 7.2 7.2.1 Equipment and materials Test sieves Refer to 5.2.1 The test is usually carried out on the mm to 11,2 mm fraction (Basic set plus set 1) or 6,3 mm to 10 mm fraction (Basic set plus set 2) Alternatively, another fraction may be selected, and corresponding test sieves are necessary Test fractions smaller than mm to mm are not acceptable due to risk of particle clusters 7.2.2 Ventilated oven, thermostatically controlled, adjustable from 100 °C to 200 °C, able to maintain the sample at (110 ± 5) °C for drying procedure and at the specified mixing temperature ± °C 7.2.3 Temperature measuring device, capable of measuring the aggregate and bitumen temperature at a range of 110 °C to 200 °C with an accuracy of ± °C 7.2.4 Balance Capacity not less than 500 g, capable of determining the aggregate portion with an accuracy of ± g, and a balance with a capacity not less than 000 g with an accuracy of ± 0,05 g 7.2.5 Metal containers (tins) Suitable size for bitumen heating and addition of adhesion agent 7.2.6 Mixing device Metal bowl or other bowl with smooth non-absorbent surface, having a volume of about l Spatula, made of metal or other suitable, non-absorbent material for mixing of bitumen and aggregate NOTE 7.2.7 A planetary mixer with whisk and thermostatically controlled mixing bowl is recommended Glass and polyethylene beakers Volume not less than 800 ml, with cover glasses for the beakers and plastic sheet, paraffin or any other suitable sheet to protect the cover glasses 7.2.8 Titration burette Volume of 50 ml with 0,1 ml graduations, calibrated 25 ml glass and polyethylene pipettes, 250 ml to 300 ml glass and polyethylene cylinders or beakers (2 to 6) and rubber pipette control 7.2.9 Chronometer 7.2.10 Gloves Pair of heat-resistant gloves and pair of protective rubber gloves 7.2.11 Netting Supporting netting with hooks (see Figure 5), in the form of a wire cloth or a perforated plate with square openings (sides: mm to mm; distance between centres: about mm) NOTE If an aggregate fraction smaller than 5,6 mm to mm fraction (Basic set plus set 1) or 6,3 mm to 10 mm fraction (Basic set plus set 2) is used, these sizes should be adapted; e.g for a mm to 6,3 mm fraction the openings of the supporting netting should be reduced to mm and the distance between their centres to mm to 5,5 mm 19 BS EN 12697-11:2012 EN 12697-11:2012 (E) Dimensions in millimetres a) Supporting netting with hooks b) Test sample suspended in the beaker Figure — Experimental set up 7.2.12 Reagents Depending on the type of aggregate to be coated (see 7.5) 0,1 N hydrochloric acid (HCl); N hydrofluoric acid (HF); 0,1 N sodium hydroxide (NaOH); N (± %) potassium hydroxide (KOH); % by mass solution of phenolphthalein indicator in ethanol NOTE When the test is conducted with hydrofluoric acid, equipment in polyethylene or some other polymer chemically indifferent to that acid should be used, and safety instructions should be followed by working under a fume hood NOTE Analytical grade KOH contains about 85 % m KOH Normality of KOH should be controlled with N HCl, and N KOH should be adjusted if necessary (± %) Then, the normality of HF should be controlled with N KOH 7.2.13 Heating plate or Bunsen burner 7.2.14 Distilled or de-mineralised water 7.3 Sample preparation 7.3.1 7.3.1.1 Aggregate Separate at least 000 g of aggregate and prepare in accordance with 5.2.1.1 and 5.2.1.2 NOTE Alternatively other aggregate fractions can be used NOTE It may be practical to let the aggregate dry overnight 7.3.1.2 20 Place a portion of (1 500 ± 2) g aggregates in the mixing bowl BS EN 12697-11:2012 EN 12697-11:2012 (E) 7.3.2 Bitumen Put a sufficient amount of binder to be tested (about 50 g) into a suitable metal container 7.3.3 Mixing aggregate and bitumen 7.3.3.1 The mixing temperature shall be the reference temperature for mixtures as defined in EN 12697-35 7.3.3.2 Heat the aggregate in the mixing bowl to the mixing temperature by placing it in the ventilated oven set at the mixing temperature ± °C Maintain the temperature for a duration of not less than h 7.3.3.3 Heat the binder to the mixing temperature by placing a container with the binder in the ventilated oven set at a temperature corresponding to the mixing temperature ± °C when measured in the vicinity of the binder for a duration of (30 ± 5) Before mixing, manually stir the binder 7.3.3.4 Using mm to 11,2 mm aggregates (Basic set plus set 1), add a portion of (30,0 ± 0,2) g (2,0 % by mass) of bitumen into the mixing bowl Using 6,3 mm to 10 mm aggregates (Basic set plus set 2), add a portion of (31,5 ± 0,2) g (2,1 % by mass) of bitumen into the mixing bowl with aggregates NOTE The quantity of added bitumen ensures the complete coating of the aggregate NOTE If other aggregate fractions are used, the coating ratio will need to be adjusted because a smaller-sized aggregate of equal mass presents a greater surface area for coating The following percentage of binder may be adopted as a starting point (figure rounded off to the nearest 0,1 %): 0,3 + 5,2 d+D (2) where d and D are the lower and upper limits, respectively, of the tested aggregate size (in mm) The amount of bitumen to be added shall be corrected for actual aggregate density by multiplying by the factor α as defined in Equation (1) in 5.2.3.6 7.3.3.5 Mix the aggregates and binder intensively by means of a spatula to obtain a uniform coating Ensure that the surfaces of the aggregates are completely covered by bitumen 7.4 Conditioning 7.4.1 After mixing, dip the vessel in a cold water bath for rapid cooling, while shaking and tapping it now and then to prevent the binder from flowing and the aggregate from sticking together 7.4.2 After cooling, transfer the coated aggregate to a tray and weigh it in order to have an idea of the coating ratio achieved 7.5 7.5.1 Test procedure Establishing the acid/base equivalence factor 7.5.1.1 Use the same acid solution and the same base solution for all tests to be performed on a given binder/aggregate-combination A full procedure (calibration + stripping tests) will require about 1,7 l of acid and 0,5 l of base, the equivalence factor, feq, of which needs to be established: 0,1 N HCl/0,1 N NaOH or N HF/N KOH 21 BS EN 12697-11:2012 EN 12697-11:2012 (E) 7.5.1.2 Titrate 25 ml of acid three times with the corresponding base (three times) Determine the average value, accurate to 0,05 ml, from the three titrations Calculate the equivalence factor, feq, as follows to three decimal places: feq = 25,0 X0 (3) where X0 is the average value obtained from the three titrations NOTE 7.5.2 X0 should be between 24,5 ml and 25,5 ml Otherwise, the acid solution should be adjusted Establishing the calibration curve 7.5.2.1 The determination of the calibration curve is only necessary if a new binder/aggregate combination is tested If this calibration curve is already available, proceed to 7.5.3 7.5.2.2 After the aggregate has cooled down to room temperature (7.4.2), prepare six mixes of 200 g, with different percentages of stripping, each as indicated in Table Table — Proportion of stripping Mass of uncoated (bare) aggregate Mass of coated aggregate Corresponding % of uncoated aggregate g g % 200 (± 0,25) 20 (± 0,25) 180 (± 0,25) 10 40 (± 0,25) 160 (± 0,25) 20 60 (± 0,25) 140 (± 0,25) 30 100 (± 0,25) 100 (± 0,25) 50 200 (± 0,5) 100 Mix For uncoated calcareous aggregate and more particularly for mixes and 3, avoid taking stones with too many veins of calcite 7.5.2.3 For calcareous aggregates proceed as follows: Put each of the 200 g mixes described in Table into a contact (measured with a chronometer) with (200 ± 0,5) g of 0,1 N hydrochloric acid in an 800 ml glass beaker Homogenise the solution at the start and after 2,5 by a few rotations of the beaker After the contact time has elapsed, homogenise and separate the hydrochloric acid from the aggregate by pouring the solution gently into a (graduated) 250 ml cylinder Titrate with 0,1 N sodium hydroxide in the presence of phenolphthalein on a 25 ml aliquot portion pipetted from the upper half Repeat the titration on a second aliquot of 25 ml Determine the average volume in millilitres of 0,1 N NaOH required for the titration, to the nearest 0,05 ml 7.5.2.4 22 For silico-calcareous or siliceous aggregates proceed as follows: BS EN 12697-11:2012 EN 12697-11:2012 (E) Put each of the 200 g mixes described in Table into a (1 h ± min) contact with (200 ± 0,1) g of N hydrofluoric acid in an 800 ml polyethylene beaker capped with a cover glass protected by a thin plastic sheet or paraffin Perform the acid attack under agitation using a shaker with oscillating action Homogenise the solution at the start and after h by a few rotations of the beaker NOTE For agitation, an amplitude of 20 mm and a frequency of 100 min-1 in can be used NOTE Alternatively, if no oscillating action is used during the acid attack, the contact time is increased to h ± The reaction of some siliceous aggregates with hydrofluoric acid is very slow This appears from a low consumption of that acid: only of the order of a few millilitres, as opposed to about 10 ml for the reactive aggregate In such cases it is necessary to perform the acid attack under agitation using a shaker with oscillating action and to increase the contact time to (2 h ± min) After the contact time has elapsed, homogenise and separate the hydrofluoric acid from the aggregate by pouring the solution gently into a (graduated) 250 ml polyethylene cylinder Titrate with N potassium hydroxide in the presence of phenolphthalein on a 25 ml aliquot portion Repeat the titration on a second aliquot of 25 ml Determine the average volume in millilitres of N KOH required for the titration, to the nearest 0,05 ml 7.5.3 Stripping test 7.5.3.1 Two test samples (of 200 g) are used for testing 7.5.3.2 Suspend the supporting wire netting into an 800 ml glass beaker as shown in Figure 7.5.3.3 burner Pour 600 ml of de-mineralised water into the beaker and boil it on a heating plate or Bunsen 7.5.3.4 Lay (200 ± 0,5) g of the coated aggregate on a metal surface (e.g the cover of a metal box) and weigh this material to the nearest 0,1 g (M1) 7.5.3.5 As soon as the water is boiling, pour the 200 g of coated aggregate rapidly onto the netting suspended in the beaker while protecting your hands with rubber gloves, and start the chronometer 7.5.3.6 10 NOTE Bring the water rapidly (in about to maximum min) back to the boil and allow it to act for Boiling should be moderate and not too strong 7.5.3.7 Remove the supernatant bitumen by introducing a jet of cold water under the surface of the hot water in the beaker, pour off the water and empty the beaker on a mm sieve Allow some time for the aggregate to drain and cool off 7.5.3.8 Transfer the aggregate to a dry 800 ml beaker (in glass or polyethylene, depending on the acid used) and weigh it to the nearest 0,1 g (M2) 7.5.3.9 For calcareous aggregates proceed as follows: Put the aggregate into a contact (measured with a chronometer) with (200 ± 0,5) g of 0,1 N hydrochloric acid in an 800 ml glass beaker Homogenise the solution at the start and after 2,5 by a few rotations of the beaker After the contact time has elapsed, homogenise and separate the hydrochloric acid from the aggregate by pouring the solution gently into a (graduated) 250 ml cylinder Titrate with 0,1 N sodium hydroxide in the presence of phenolphthalein on a 25 ml aliquot portion pipetted from the upper half Repeat the titration on a second aliquot of 25 ml Determine the average volume in ml of 0,1 N NaOH required for the titration, to the nearest 0,05 ml 23 BS EN 12697-11:2012 EN 12697-11:2012 (E) For silico-calcareous or siliceous aggregates proceed as follows: Put the aggregate into a (1 h ± min) contact with 200 (± 0,1) g of N hydrofluoric acid in an 800 ml polyethylene beaker capped with a cover glass protected by a thin plastic sheet or paraffin Perform the acid attack under agitation using a shaker with oscillating action Homogenise the solution at the start and after h by a few rotations of the beaker NOTE For agitation, an amplitude of 20 mm and a frequency of 100 min-1 in can be used NOTE Alternatively, if no oscillating action is used during the acid attack, the contact time is increased to h ± The reaction of some siliceous aggregates with hydrofluoric acid is very slow This appears from a low consumption of that acid: only of the order of a few ml, as opposed to about 10 ml for the reactive aggregate In such cases it is necessary to perform the acid attack under agitation using a shaker with oscillating action and to increase the contact time to (2 h ± min) After the contact time has elapsed, homogenise and separate the hydrofluoric acid from the aggregate by pouring the solution gently into a (graduated) 250 ml polyethylene cylinder Titrate with N potassium hydroxide in the presence of phenolphthalein on a 25 ml aliquot portion Repeat the titration on a second aliquot of 25 ml Determine the average volume in ml of N KOH required for the titration, to the nearest 0,05 ml 7.6 Calculation and expression of results 7.6.1 Determination of the calibration curve This step is only necessary if a new aggregate/bitumen combination is tested If this curve is available, proceed to 7.6.2 7.6.1.1 Calculate the volumes of acid consumed as follows: acid consumed = 25,0 – feq × X (to the nearest 0,05 ml) (4) where feq is the acid/base equivalence factor and X is the average volume in ml of 0,1 N NAOH required for titration for the case of calcareous aggregates, or the volume in ml of N KOH required for titration for the case of silico-calcareous or siliceous aggregates 7.6.1.2 Plot the values on a graph representing the volume of acid consumed (for the scale take at least cm for ml in the case of 0,1 N HCl and at least cm for 0,5 ml in the case of N HF) against the percentage of stripped aggregate in the tested mix (scale: cm = 10 %) An example of a calibration curve is given in Figure 24 BS EN 12697-11:2012 EN 12697-11:2012 (E) Key Y N HF consumed (ml) X % of stripped aggregate The curve shows the affinity between porphyry and bitumen 50/70 Figure — Example of a calibration curve 7.6.2 Calculation of the degree of bitumen coverage 7.6.2.1 For the stripping test, calculate the volume of acid consumed, Ac, in ml to the nearest 0,05 ml from Equation (5): M − M1 Ac = 25,0 − 1 + × feq ×Y 200 (5) where M1 is the mass of coated aggregate (in grams), to the nearest 0,1 g; M2 is the mass of wet coated aggregate after testing (in grams), to the nearest 0,1 g; feq is the acid/base equivalence factor; Y NOTE is the average volume of 0,1 N NaOH or N KOH required to neutralise the 25 ml portion of acid in the stripping test (in millilitres) to the nearest 0,05 ml + (M2 – M1)/200 is a correction factor for dilution by the water remaining on the aggregate after testing 7.6.2.2 Plot the Ac value on the calibration curve and read the corresponding percentage of stripped aggregate This value rounded off to the nearest unity represents the percentage of stripping 7.6.2.3 Calculate the average of the two percentages of stripping obtained from the tests to the nearest unity If the individual values differ more than % in absolute terms from this average, perform a third stripping test and recalculate the average for the two corresponding tests 7.6.2.4 Calculate the degree of bitumen coverage as: 100 – % of stripping 25 BS EN 12697-11:2012 EN 12697-11:2012 (E) 7.7 Test report The test report shall contain the following information: a) reference to this European Standard; b) sample identification number and date and time of testing; c) type and size (fraction) of aggregate used; d) type of bitumen used; e) type of anti-stripping agent used (if any); f) type of reagent used; g) degree of bitumen coverage, expressed in %; h) notes including observations considered of importance for the test result 7.8 Precision 7.8.1 A repeatability coefficient of variation of 15 % of the determined value has been found, with an absolute precision threshold on the determination of the stripping percentage of % 7.8.2 26 Reproducibility data have not been established yet BS EN 12697-11:2012 EN 12697-11:2012 (E) Annex A (informative) Guidance for estimation of the degree of bitumen coverage Systematic evaluation of the degree of bitumen coverage on aggregate particles may be facilitated by reference to the figures shown below: Figure A.1 — Reference for estimation of degree of bitumen coverage Note that the presentations are not perfect and only examples for guidance The visual evaluation will a.o be influenced by the colour and brightness of the aggregate, with any loss being less obvious on darker aggregates 27 BS EN 12697-11:2012 EN 12697-11:2012 (E) Bibliography [1] EN 932-1, Tests for general properties of aggregates — Part 1: Methods for sampling [2] EN 932-2, Tests for general properties of aggregates — Part 2: Methods for reducing laboratory samples 28 This page deliberately left blank NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW British Standards Institution (BSI) BSI is the national body responsible for preparing British Standards and other standards-related publications, information and services BSI is incorporated by Royal Charter British Standards and other standardization products are published by BSI Standards Limited About us Revisions We bring together business, industry, 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