bds_en_12697-30 - 2012
TRANSCRIPT
БЪЛГАРСКИ ИНСТИТУТ ЗА СТАНДАРТИЗАЦИЯ
© БИС Българският институт за стандартизация е носител на авторските права. Всяко възпроизвеждане, включително и частично, е възможно само с писменото разрешение на БИС, 1797 София, кв. Изгрев, ул. “Лъчезар Станчев” №13
БЪЛГАРСКИ СТАНДАРТ
2012
БДС EN 12697-30
Юни 2012
ICS: 93.080.20 Заменя: БДС EN 12697-30:2004+A1:2008.
Асфалтови смеси. Методи за изпитване на горещи асфалтовисмеси. Част 30: Подготовка на пробни тела чрез ударенуплътнител
Bituminous mixtures - Test methods for hot mix asphalt - Part 30: Specimen preparation
by impact compactor
Европейският стандарт EN 12697-30:2012 има статут на български стандарт от2012-06-18.
Този стандарт е официалното издание на Българския институт за стандартизация наанглийски език на европейския стандарт EN 12697-30:2012.
27 стр.
Национален № за позоваване:БДС EN 12697-30:2012
За поръчка и закупуване на стандарти, стандартизационни материали и специализирани издания на БИС може да използвате един от посочените начини:
- В информационния център на БИС на адрес: София, кв. Изгрев, ул. “Лъчезар Станчев” №13, 1 етаж - On-line на нашата интернет страница: www.bds-bg.org - По факс +359 2 873-55-97 - По електронната поща: [email protected]
НАЦИОНАЛЕН ПРЕДГОВОР
Този стандарт е подготвен с участието на БИС/TK 68 "Пътно дело".
Следват 25 страници на EN 12697-30:2012.
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
EN 12697-30
April 2012
ICS 93.080.20 Supersedes EN 12697-30:2004+A1:2007
English Version
Bituminous mixtures - Test methods for hot mix asphalt - Part 30: Specimen preparation by impact compactor
Mélanges bitumineux - Méthodes d'essai pour mélange hydrocarboné à chaud - Partie 30: Confection d'éprouvettes
par compacteur à impact
Asphalt - Prüfverfahren für Heißasphalt - Teil 30: Probenvorbereitung, Marshall-Verdichtungsgerät
This European Standard was approved by CEN on 26 February 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 C O M I T É E U R O P É E N D E N O R M A LI S A T I O N EUR OP ÄIS C HES KOM ITEE FÜR NOR M UNG
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 12697-30:2012: E
EN 12697-30:2012 (E)
2
Contents Page
Foreword ..............................................................................................................................................................3�
1 Scope ......................................................................................................................................................7�
2 Normative references ............................................................................................................................7�
3 Terms and definitions ...........................................................................................................................7�
4 Principle ..................................................................................................................................................7�
5 Apparatus ...............................................................................................................................................7�5.1 Impact compactor with steel anvil .......................................................................................................7�5.1.1 General ....................................................................................................................................................7�5.1.2 Conditions of installation ................................................................................................................... 11�5.2 Impact compactor with wooden pedestal ........................................................................................ 12�5.2.1 General ................................................................................................................................................. 12�5.3 Compaction mould ............................................................................................................................. 12�5.4 Ovens or hot plates ............................................................................................................................ 13�5.5 Steel block ........................................................................................................................................... 13�5.6 Shields, baffle plates or sand baths ................................................................................................. 13�5.7 Plate ..................................................................................................................................................... 13�
6 Shape and dimensions of the specimens ........................................................................................ 19�
7 Specimen preparation ........................................................................................................................ 19�
8 Procedure ............................................................................................................................................ 19�
9 Report .................................................................................................................................................. 20�
Annex A (informative) Device for the measurement of the specimens thickness during compaction .......................................................................................................................................... 21�
Annex B (informative) Checking procedure for impact compaction devices ............................................ 22�B.1 Equipment ........................................................................................................................................... 22�B.2 Procedure ............................................................................................................................................ 22�B.3 Calculations and definition of impact dynamics: ............................................................................ 22�B.4 Validation ............................................................................................................................................. 23�B.5 Proposed process for validation of test equipment impact dynamics: ........................................ 23�B.6 Checklist .............................................................................................................................................. 24�
Bibliography ..................................................................................................................................................... 25�
EN 12697-30:2012 (E)
3
Foreword
This document (EN 12697-30:2012) 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 12697-30:2004+A1:2007.
The following is a list of significant technical changes since the previous edition:
⎯ allowance made for some oversize aggregate in the scope;
⎯ informative annex for a checking procedure for impact compaction devices added;
⎯ the tolerance on the angle of the sliding mass in reduced;
⎯ the requirement for inspections to establish that the safety requirements have been complied with has been deleted;
⎯ densities defined in Mg/m3 rather than kg/m3;
⎯ the requirement on the moisture content of wooden block pedestal is moved to a note;
⎯ the notes on the verification of the wooden block pedestal and the foot assembly have been clarified;
⎯ definition of the steel compaction hammer tightened up;
⎯ separate figure provided of typical compactor with wooden block;
⎯ steel block made optional;
⎯ the time that samples can be stored at elevated temperature reduced;
⎯ the uniform upper limit on the temperature of 130 °C removed, leaving just the reference temperature in EN 12697-35;
⎯ the limitations of heating of automatic compaction hammers is clarified in notes;
⎯ the timing of preparing multiple samples is specified;
⎯ requirements for filling the mould and reversing the specimen during compaction have been edited.
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 �: Soluble binder content
EN 12697-2, Bituminous mixtures — Test method for hot mix asphalt — Part 2: Determination of particle size distribution
EN 12697-30:2012 (E)
4
EN 12697-3, Bituminous mixtures — Test methods for hot mix asphalt — Part 3: Bitumen recovery: Rotary evaporator
EN 12697-4, Bituminous mixtures — Test methods for hot mix asphalt — Part 4: Bitumen recovery: Fractionating column
EN 12697-5, Bituminous mixtures — Test methods for hot mix asphalt — Part 5: Determination of the maximum density
EN 12697-6, Bituminous mixtures — Test methods for hot mix asphalt — Part 6: Determination of bulk density of bituminous specimens
EN 12697-7, Bituminous mixtures — Test methods for hot mix asphalt — Part 7: Determination of 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 �0: Compactibility
EN 12697-11, Bituminous mixtures — Test methods for hot mix asphalt — Part ��: Determination of the affinity between aggregate and bitumen
EN 12697-12, Bituminous mixtures — Test methods for hot mix asphalt — Part �2: Determination of the water sensitivity of bituminous specimens
EN 12697-13, Bituminous mixtures — Test methods for hot mix asphalt — Part �3: Temperature measurement
EN 12697-14, Bituminous mixtures — Test methods for hot mix asphalt — Part �4: Water content
EN 12697-15, Bituminous mixtures — Test methods for hot mix asphalt — Part �5: Determination of the segregation sensitivity
EN 12697-16, Bituminous mixtures — Test methods for hot mix asphalt — Part �6: Abrasion by studded tyres
EN 12697-17, Bituminous mixtures — Test methods for hot mix asphalt — Part �7: Particle loss of porous asphalt specimen
EN 12697-18, Bituminous mixtures — Test methods for hot mix asphalt — Part �8: Binder drainage
EN 12697-19, Bituminous mixtures — Test methods for hot mix asphalt — Part �9: Permeability of specimen
EN 12697-20, Bituminous mixtures — Test methods for hot mix asphalt — Part 20: Indentation using cube or cylindrical specimens
EN 12697-21, Bituminous mixtures — Test methods for hot mix asphalt — Part 2�: 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
EN 12697-30:2012 (E)
5
EN 12697-26, Bituminous mixtures — Test methods for hot mix asphalt — Part 26: Stiffness
EN 12697-27, Bituminous mixtures — Test methods for hot mix asphalt — Part 27: Sampling
EN 12697-28, Bituminous mixtures — Test methods for hot mix asphalt — Part 28: Preparation of samples for determining binder content, water content and grading
EN 12697-29, Bituminous mixtures — Test method for hot mix asphalt — Part 29: Determination of the dimensions of a bituminous specimen
EN 12697-30, Bituminous mixtures — Test methods for hot mix asphalt — Part 30: Specimen preparation by impact compactor
EN 12697-31, Bituminous mixtures — Test methods for hot mix asphalt — Part 3�: Specimen preparation by gyratory compactor
EN 12697-32, Bituminous mixtures — Test methods for hot mix asphalt — Part 32: Laboratory compaction of bituminous mixtures by vibratory compactor
EN 12697-33, Bituminous mixtures — Test methods for hot mix asphalt — Part 33: Specimen prepared by roller compactor
EN 12697-34, Bituminous mixtures — Test methods for hot mix asphalt — Part 34: Marshall test
EN 12697-35, Bituminous mixtures — Test methods for hot mix asphalt — Part 35: Laboratory mixing
EN 12697-36, Bituminous mixtures — Test methods for hot mix asphalt — Part 36: Determination of the thickness of a bituminous pavement
EN 12697-37, Bituminous mixtures — Test methods for hot mix asphalt — Part 37: Hot sand test for the adhesivity of binder on precoated chippings for HRA
EN 12697-38, Bituminous mixtures — Test methods for hot mix asphalt — Part 38: Common equipment and calibration
EN 12697-39, Bituminous mixtures — Test methods for hot mix asphalt — Part 39: Binder content by ignition
EN 12697-40, Bituminous mixtures — Test methods for hot mix asphalt — Part 40: In situ drainability
EN 12697-41, Bituminous mixtures — Test methods for hot mix asphalt — Part 4�: Resistance to de-icing fluids
EN 12697-42, Bituminous mixtures — Test methods for hot mix asphalt — Part 42: Amount of coarse foreign matters 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
prEN 12697-45, Bituminous mixtures — Test methods for hot mix asphalt — Part 45: Saturation ageing tensile stiffness (SATS) conditioning test
prEN 12697-46, Bituminous mixtures — Test methods for hot mix asphalt — Part 46: Low temperature cracking and properties by uniaxial tension tests.
EN 12697-47, Bituminous mixtures — Test methods for hot mix asphalt — Part 47: Determination of the ash content of natural asphalt
EN 12697-30:2012 (E)
6
prEN 12697-481), Bituminous mixtures — Test methods for hot mix asphalt — Part 48: Inter-layer bond strength
prEN 12697-491), Bituminous mixtures — Test methods for hot mix asphalt — Part 49: Determination of friction after polishing.
prEN 12697-501), Bituminous mixtures — Test methods for hot mix asphalt — Part 50: Scuffing resistance of surface course asphalt
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.
1) In preparation
EN 12697-30:2012 (E)
7
1 Scope
This European Standard specifies methods of moulding specimens from bituminous mixtures by impact compaction. Such specimens are primarily used to determine bulk density and other technological characteristics e.g. Marshall stability and flow according to EN 12697-34.
This European Standard applies to bituminous mixtures (both those made up in a laboratory and those resulting from work site sampling), with not more than 15 % by mass retained on the 22,4 mm sieve and none on the 31,5 mm sieve.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 12591, Bitumen and bituminous binders — Specifications for paving grade bitumens
EN 12697-10, Bituminous mixtures — Test methods for hot mix asphalt — Part �0: Compactibility
EN 12697-27, Bituminous mixtures — Test methods for hot mix asphalt — Part 27: Sampling
EN 12697-35:2004+A1, Bituminous mixtures — Test methods for hot mix asphalt — Part 35: Laboratory mixing
EN 13924, Bitumen and bituminous binders — Specifications for hard paving grade bitumens
EN 14023, Bitumen and bituminous binders — Specification framework for polymer modified bitumens
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 set number number of blows per side that is set for the test method for which the sample is intended to be used
Note 1 to entry: The number of blows is commonly 50 but can be 35 or 75.
4 Principle
To prepare the specimens, tempered asphalt mix, either freshly mixed according to EN 12697-35:2004+A1 or sampled on site or plant according to EN 12697-27 has to be transferred into a specified steel compaction mould. The mixture is then compacted into one of the specified impact compactors by the sliding mass falling from a specified height with a specified number of blows within a specified time onto the foot of the hammer, located on top of the asphalt specimen. The specimen is then allowed to cool down to room temperature.
5 Apparatus
5.1 Impact compactor with steel anvil
5.1.1 General
5.1.1.1 The impact compactor with steel anvil (see Figure 1), a machine-driven apparatus shall comprise the components listed in 5.1.1.2 to 5.1.1.9.
NOTE In Annex B, a guideline for possible checking based on self-composed equipment is described.
EN 12697-30:2012 (E)
8
5.1.1.2 Steel base plate, 15 mm thick and about 600 mm × 610 mm, set horizontally on a firm base.
5.1.1.3 Three feet of equal rigidity in the direction of both compression and shear, fitted with rubber buffers corresponding to the mass of the compaction pedestal.
5.1.1.4 Compaction pedestal (see Figure 2) made of cast iron having a mass of at least 100 kg.
5.1.1.5 Clamping device to hold the compaction mould.
NOTE Equipment with eccentric cam (see Figure 1) has been used successfully.
5.1.1.6 Compaction hammer, consisting of a cylindrical guide rod, a sliding mass (see Figure 3), weighing (4 550 ± 20) g, and a foot (see Figure 4), weighing (3 960 ± 20) g.
5.1.1.7 Chain-driven lifting gear, for the sliding mass, designed so that the length of the free fall is (460 ± 3) mm.
5.1.1.8 Device for counting and recording the number of blows.
NOTE The number of blows should be counted and added.
5.1.1.9 Linear variable differential transformer (optional), as described in Annex A, for measuring the specimen thickness during compaction for measuring compactibility in accordance with EN 12697-10.
EN 12697-30:2012 (E)
9
Key 1 basic apparatus with power-driven lifting gear for the sliding mass and impact counter (shown without shielding) 2 compaction hammer with guide rod for the sliding mass 3 eccentric cam for clamping device 4 mould base with compaction mould attached 5 compaction pedestal 6 feet 7 steel base plate 8 shielding
Figure 1 — Diagrammatic sketch of the impact compactor
NOTE See Annex A for optional linear variable differential transformer to measure the specimen thickness during compaction.
EN 12697-30:2012 (E)
10
Dimensions in millimetres
Key 1 lifting gear 2 base plate 3 foot
Figure 2 — Diagrammatic representation of compaction pedestal, supported on feet
EN 12697-30:2012 (E)
11
Dimensions in millimetres Dimensions in millimetres
Key a counter balance
Keya sphere
The tolerance on the diameter of the foot of the compaction hammer shall be ± 0,5 mm.
Figure 3 — Sliding mass of compaction hammer Figure 4 — Foot of compaction hammer
5.1.2 Conditions of installation
5.1.2.1 The impact compactor shall be set up in such a way that the base plate is horizontal. It shall be possible to insert the compaction hammer vertically and centrally into the compaction mould in order to ensure a virtually friction-free fall of the sliding mass along the guide rod. The compactor shall be set up in such a way so that the sliding mass is vertically + 2°.
The following safety and inspection requirements shall be applied:
5.1.2.2 During insertion and reversion of the mould cylinder in the compacting machine, the compaction hammer shall be secured in its upper rest position against accidental release. The compaction hammer shall be kept suspended at the top of the guide rod by means of a hoist.
NOTE This can be carried out by connecting the hoisting rope either to the clamping device on the eccentric cam or to a lever arrangement that is itself safeguarded against accidental release. Therefore, the compaction mould can only be inserted and removed when the hammer is suspended and securely fastened.
5.1.2.3 Measures shall be taken to prevent access to the danger zone when the lifting gear is in operation.
NOTE This can be achieved, for example, by the provision of a moveable shield fitted with an automatic locking device or by arranging for the sound-proof cubicle to be locked automatically when the apparatus is running.
EN 12697-30:2012 (E)
12
5.1.2.4 Requirements as to noise emission shall be met when operating an impact compactor, e.g. by erecting a soundproof cubicle.
5.2 Impact compactor with wooden pedestal
5.2.1 General
The impact compactor with wooden pedestal (see Figure 5), a machine-driven apparatus, shall comprise the components listed in 5.2.2 to 5.2.3.
NOTE In Annex B, a guideline for possible checking based on self-composed equipment is described. 5.2.2 Compaction pedestal (see Figure 5) shall consist of the components given in 5.2.2.1 to 5.2.2.3.
5.2.2.1 Vibrated concrete base, of minimum density 2,200 Mg/m3 and minimum dimensions of 450 mm × 450 mm × 200 mm with shoulder to receive a laminated hardwood block.
5.2.2.2 Laminated hardwood block (200 ± 4) mm in cross section and (450 ± 4) mm in height, made from dry straight-grained, seasoned timber (such as Sapele) free from shakes, splits and knots with a density of 0,67 Mg/m3 to 0,78 Mg/m3. The block shall be built up of between 6 and 10 approximately equal laminations of quarter sawn board bonded with waterproof resin glue. The ends shall be smooth and normal to the vertical axis and the block shall be treated with a water-resistant impregnate and varnished to minimise changes of moisture content.
NOTE 1 The dry mass of timber is based on an average moisture content of 15 %.
NOTE 2 The suitability of a block in terms of its density can be confirmed by comparative density measurements of compacted specimens compared to those compacted with an apparatus fitted with a block that is known to comply. The average of three specimen compacted with each block should not differ by more than 0,02 Mg/m³.
5.2.2.3 Mild steel plate, (300 ± 5) mm × (300 ± 5) mm × (25 ± 1) mm fitted with a positive location to receive the hardwood block and with a mould assembly holder to secure the mould assembly centrally on the pedestal during compaction and a guide to ensure that the hammer is maintained in a truly vertical position throughout compaction. The mild steel plate with assembly holder and guide shall be secured to the base with four rods each tensioned to the equivalent of a torque of (10 ± 1) Nm on a M10 thread.
5.2.3 Steel compaction hammer, of total mass (7 850 ± 50) g including a sliding weight of (4 535 ± 15) g, and a foot assembly (see Figure 6).
5.2.4 The foot assembly shall comprise a spring housing and a helical compression spring of hardened and tempered steel with a load rate of 10 N/mm to 18 N/mm and designed to exert a pre-load of 80 N to 150 N when confined within the foot assembly leaving a minimum movement of 20 mm. The foot of the hammer shall be machined flat and smooth and be securely fixed to the foot assembly.
NOTE The suitability of a foot assembly can be confirmed by comparative density measurements of specimens compared to those compacted with an apparatus fitted with a foot assembly that is known to comply.
5.2.5 The operating mechanism shall not be supported by the laminated hardwood block of the compaction pedestal. The free fall height shall be measured when the machine is in operation and be capable of being maintained with the specified tolerances throughout the compaction procedure.
5.3 Compaction mould
Compaction mould with an internal diameter of (101,6 ± 0,1) mm and consisting of an extension collar, a mould cylinder and a mould base. The mould base shall be made of a steel material stiff enough to be used without any deformation and hardened surfaces.
EN 12697-30:2012 (E)
13
NOTE Typical mould, extension collar, mould cylinder and mould base are shown in Figures 7, 8, 9 and 10, respectively for use with the impact compactor described in 5.1, and in Figure 11 for use with the impact compactor described in 5.2.
5.4 Ovens or hot plates
Ovens or hot plates for heating aggregates, bituminous material, specimen moulds, compaction hammers, and other equipment to obtain the required mixing and moulding temperatures.
NOTE Heating units are thermostatically controlled so as to maintain the required temperature within 5 °C.
5.5 Steel block
Steel block, of 100 mm diameter and height of at least 50 mm, for the initial heating of the compaction hammer (optional).
NOTE A steel block serves to heat up the hammer when the hammer cannot be disconnected for it to be heated up before the start of the compaction (optional).
5.6 Shields, baffle plates or sand baths
Suitable shields, baffle plates or sand baths for use on the surface of the hot plates to minimise localised overheating.
5.7 Plate
Plate fitted with cylindrical disc (optional) as shown in Figure 12.
EN 12697-30:2012 (E)
14
Dimensions in millimetres
Key 1 guide post 2 clamp ring 3 spring 4 hinge post 5 sample mould 6 steel plate 7 4 tie rods 8 wood block 9 concrete block 10 mould base locating pins
NOTE 1 A suitable framework is secured to the pedestal to ensure that the compaction is kept vertical.
NOTE 2 For the permanent centring of the timber block, either the concrete base is recessed (as shown) or an angle housing is bolted to the concrete base.
NOTE 3 The figure shows a suitable mould clamp system; other systems may be found equally satisfactory.
Figure 5 — Compaction pedestal
EN 12697-30:2012 (E)
15
Dimensions in millimetres
Key 1 guide rod 2 free fall 3 spring housing 4 sliding weight 5 foot assembly
Figure 6 — Typical compaction hammer
EN 12697-30:2012 (E)
16
Dimensions in millimetres Dimensions in millimetres
Key 1 extension collar 2 mould cylinder 3 mould base
Figure 7 — Typical compaction mould for impact compactor with steel anvil
Figure 8 — Typical extension collar for compaction mould
EN 12697-30:2012 (E)
17
Dimensions in millimetres Dimensions in millimetres
Figure 9 — Typical mould cylinder for compaction mould
Figure 10 — Typical mould base of compaction mould
EN 12697-30:2012 (E)
18
Key
1 extension/extraction collar 2 extraction plate 3 mould cylinder 4 mould base a symmetrical
Figure 11 — Typical set of equipment for compaction mould for impact compactor with wooden pedestal
EN 12697-30:2012 (E)
19
Dimensions in millimetres
Figure 12 — Diagrammatic representation of plate fitted with cylindrical discs
6 Shape and dimensions of the specimens
The specimen shall be a cylinder of diameter (101,6 ± 0,1) mm and height (63,5 ± 2,5) mm. The maximum aggregate size of the mixture shall not exceed 22,4 mm.
7 Specimen preparation
Prepare specimens using laboratory mixed asphalt or plant mixed asphalt. Because the amount of mixture needed for a specimen of specified height varies depending on the maximum density of the mixture, between 1 050 g and 1 400 g, the amount of mixture required for the specified height, shall be determined by carrying out a trial compaction. Specimens prepared from the same batch shall be, as far as possible, all of equal mass. The quantity of mixture prepared for compaction shall be not more than that required for 4 specimens.
8 Procedure
8.1 If required after mixing, the quantity of mixture required for 1 specimen shall be stored for not more than 1 h, without fresh air circulation, in an oven set at a maximum of the temperature given in 8.2.
8.2 The mixture shall be quickly brought up to the compacting temperature. For mixtures produced with paving grade bitumen in accordance with EN 12591, the compaction temperature is:
⎯ reference temperature given in EN 12697-35:2004+A1.
For mixtures produced with bitumen in accordance with EN 14023 or EN 13924, the compaction temperature shall be as defined by the supplier.
8.3 Heat the foot of the impact hammer (see Figure 6) and the complete mould prior to the preparation of the first specimen.
NOTE 1 The entire compaction hammer, complete with foot, is placed on a gently heated electric hotplate for about 10 min before the first specimen is prepared. With automatic hammers, it is not always practical to remove the foot to heat in an oven. In such cases alternative arrangements are needed.
NOTE 2 The first compacted sample is rejected when the hammer can only be heated by contact with the mixture.
If specimens are being prepared in batches, the foot and mould base shall only be heated prior to the preparation of the first specimen of the batch. If there is a gap of more than 10 min between finishing one specimen and starting compaction of the next in a batch, the heating shall be repeated.
8.4 Assemble the mould base, compaction mould and extension collar and heat up to the compaction temperature. Place a thin disc of tough, impermeable material, such as non-absorbent paper, slightly less than 100 mm diameter on the mould base prior to filling. Place the heated mixture in the mould assembly and distribute it evenly by spading with a heated spatula or knife. Care shall be taken that segregation does not occur. After filling, gently level the surface of the mixture with the spatula and cover with a second filter disc. The inside of the compaction mould shall not be coated with a parting agent.
EN 12697-30:2012 (E)
20
8.5 The compaction procedure shall then be commenced without delay. Fill the mould and compact the specimen within 4 min. The extension collar shall be set on the mould cylinder and connected to the compaction pedestal with the aid of the clamping device specified in 5.1.1.5. When the compaction hammer has been fitted, compact the specimen within 55 s to 60 s by applying the set number of blows, the sliding mass falling from a height of
⎯ (460 ± 3) mm for the impact compactor to 5.1;
⎯ (457 ± 5) mm for the impact compactor to 5.2.
The sliding mass shall not be kept back when it rebounds after impact. In accordance with the test purpose of the specimen to be compacted, a different number of blows can be fitted.
8.6 Remove the extension collar. Invert the mould, placing it on the base plate. Re-fit the extension collar and apply a further set number of blows in accordance with 8.5.
8.7 For further compaction (e.g. for refusal density) reverse the mould again for twice and compact the specimen in accordance with 8.6. The compaction procedure shall be completed within 7 min. Remove the filter discs and mark the specimen for identification purposes.
NOTE For other purposes the number of blows on each side may be changed.
8.8 Place the compaction mould containing the hot specimen on one of the cylindrical discs on the plate shown in Figure 12, in such a way that the specimen is directly supported by the disc. Cool the specimen in air or with the aid of a fan to approximately 40 °C and extract from the mould with the extruding device.
NOTE Water cooling may be used if quick results are needed.
If water cooling is used, the specimen shall remain in the mould and shall not have direct contact with the water. The water shall only have contact with the mould. After removal, place the specimen on a flat base and cool further to a temperature of between 18 °C and 28 °C.
9 Report
The test report shall make reference to this European Standard and shall include at least the following information:
a) identification of the mixture;
b) method of manufacture of the mixture, or if it was sampled from a compacted layer, size and location of the sample;
c) type of impact compactor;
d) test conditions;
e) compaction temperature;
f) number of blows.
EN 12697-30:2012 (E)
21
Annex A (informative)
Device for the measurement of the specimens thickness during
compaction
An inductive measurement of the specimen thickness during compaction is possible with the addition of a Linear Variable Differential Transformer (LVDT). The LVDT should have an accuracy of ± 0,02 mm. The device is added to the apparatus in the way shown in Figure A.1. The LVDT should be connected to a computer for data-registration.
Dimensions in millimetres
Key
1 LVDT
Figure A.1 — Linear Variable Differential Transformer (LVDT)
EN 12697-30:2012 (E)
22
Annex B (informative)
Checking procedure for impact compaction devices
B.1 Equipment
B.1.1 Load cell with a range of 500 % of the expected measured peak load.
B.1.2 Measuring amplifier with a measurement frequency of 20 000 Hz. The measuring amplifier has to be able to measure free from electromagnetic disturbances.
B.1.3 A specially designed device (in the shape of a Marshall mould), able to accommodate the load cell. It should be provided with an opening for the connection cord and a suitable fixation device, able to keep the load cell securely fixed under the compaction hammer, avoiding any displacement.
B.1.4 Data collection device, provided with software suitable for the acquisition/ filtering of the peak forces and peak durations.
B.2 Procedure
B.2.1 According to the checklist in B.6, verify items 1 to 9, so that the impact compactor is in the required condition.
B.2.2 Place and secure the impact meter (load cell and its container) centred under the compacting hammer of the impact compactor.
B.2.3 Connect the load cell to the measuring amplifier and data collection device. Set the amplifier at a measurement speed of 20 000 Hz.
B.2.4 Apply 20 consecutive blows and record their corresponding force versus time measurements.
B.3 Calculations and definition of impact dynamics:
B.3.1 the first three and last three measurements.
B.3.2 Determine the maximum force for each measurement i (Fmax,i) in kN.
B.3.3 Determine the duration (in ms) of each measured force peak value (Tpulse,i) as follows: Plot a straight line coincident with the (first) ascending straight segment of the force curve. Plot a second straight line coincident with the (last) descending straight segment of the curve. Plot a straight line down through the zero line. Determine the abscissa at the intersection points of both ascending and descending straight lines with the base line and measure the time interval between these points. This time interval is the peak duration.
B.3.4 Determine the average force peak value and peak duration. Determine also the standard deviation of the force peak values.
B.3.5 Calculate the product of the peak force Fmax,i and peak duration Tpulse,i for each blow i. Determine the mean value of Fmax,i × Tpulse,i. Calculate the ratio between the force-time product for each measurement i and the average Fmax,i × Tpulse,i.
B.3.6 Define the average impact pattern of the force curves obtained, by choosing from the following options, the one that fits best.
EN 12697-30:2012 (E)
23
a) The same ascent and descent angle of slope in the impact curve.
b) Ascent and descent angles of slope are significantly different from each other.
c) Compound curve. Several lower force peaks around a main one are registered.
B.4 Validation
B.4.1 According to results obtained in B.3.2 and B.3.3:
a) The differences with respect to the established optimum peak force and peak duration are less than 15 %: Adequate impact dynamics.
b) The differences with respect to the established optimum peak force and peak duration are between 15 % and 25 %: Questionable impact dynamics.
c) The differences with respect to the established optimum peak force and peak duration are more than 25 %: Significantly different impact dynamics. Compactor has to be revised or upgraded.
B.4.2 The standard deviation of the force peak values obtained in B.3.4 should not exceed 5 %.
B.4.3 If the ratio obtained in B.3.5 for each blow i is less than 20 % with respect to the average Fmax,i × Tpulse,i, then the impact compactor works correctly.
B.4.4 The shape of impact curve, defined as per B.3.6, is related to the state of maintenance of the compactor:
a) B.3.6.a) means an optimal operation.
b) B.3.6.b) indicates that an energy absorption by the compactor is taking place in each blow.
c) B.3.6.c) indicates severe wear or loose fitting in the falling weight/ guide rod contact area.
B.5 Proposed process for validation of test equipment impact dynamics:
Suitable ranges of values for the optimum peak force and peak duration should be proposed, according to those normally obtained by representative impact compactors of both steel anvil and wooden pedestal type.
The selected test equipment can be validated by comparing the measurement results to the standard test field in relation to a representative impact compactor. This allows different measurement setups in relation to the current measurement file.
The procedure and values to fill this matter have not been determined yet.
EN 12697-30:2012 (E)
24
B.6 Checklist
No. Item to be checked Correct?
1 Does the hammer stand perfectly vertical with respect to the specimen? Yes/No
2 Is the mould base and compaction mould properly attached to the pedestal? Yes/No
3 Is the steel base plate intact? Yes/No
4 Do the lifting gear and impact counter work properly? Yes/No
5 Does the sliding mass fall free of the chain? Yes/No
6 Is the guide rod free of rust and imperfections? Yes/No
7 Is the foot of the hammer clean and free of imperfections? Yes/No
8 Is the anvil clean and free of imperfections? Yes/No
9 Are the sliding weight and drop height calibrated? Yes/No
9a Is the difference between actual and desired drop height less than 3 mm? Yes/No
9b Is the difference between actual and desired drop weight less than 15 grams? Yes/No
If one of the items is answered with “NO”, then the impact compactor has to be upgraded.
EN 12697-30:2012 (E)
25
Bibliography
[1] EN 12697-34, Bituminous mixtures — Test methods for hot mix asphalt — Part 34: Marshall test