Tests for mechanical and physical properties of aggregates - Part 2: Methods for the determination of resistance to fragmentation

This European Standard describes the reference method, the Los Angeles test, used for type testing and in case of dispute (and an alternative method, the impact test) for determining the resistance to fragmentation of coarse aggregates and aggregates for railway ballast (Annex A). For other purposes, in particular factory production control, other methods may be used provided that an appropriate working relationship with the reference method has been established. This European Standard applies to natural, manufactured or recycled aggregates used in building and civil engineering.

Prüfverfahren für mechanische und physikalische Eigenschaften von Gesteinskörnungen - Teil 2: Verfahren zur Bestimmung des Widerstandes gegen Zertrümmerung

Diese Europäische Norm beschreibt ein Referenzverfahren, das Los Angeles Prüfverfahren, das für Baumusterprüfungen und im Schiedsfall (mit dem Schlagversuch als alternatives Verfahren) zur Bestimmung des Widerstandes gegen Zertrümmerung von groben Gesteinskörnungen (Haupttext) und Gesteinskörnungen für Gleisschotter (Anhang A) verwendet wird. Für andere Zwecke, insbesondere in der werkseigenen Produktionskontrolle, dürfen andere Verfahren angewendet werden, unter der Voraussetzung, dass eine entsprechende funktionierende Beziehung zum Referenzverfahren geschaffen wurde.
Diese Europäische Norm wird angewendet für natürliche oder künstlich hergestellte Gesteinskörnungen, die im Bauwesen eingesetzt werden.

Essais pour déterminer les caractéristiques mécaniques et physiques de granulats - Partie 2 : Méthodes pour la détermination de la résistance à la fragmentation

La présente Norme européenne décrit la méthode de référence, l'essai Los Angeles, utilisée pour les essais de type initiaux et en cas de litige (et une autre méthode, l'essai de fragmentation par impact) pour déterminer la résistance à la fragmentation d'un gravillon (texte principal) et des granulats pour ballast ferroviaire (Annexe A). Pour d'autres besoins, en particulier le contrôle de production en usine, d'autres méthodes peuvent être utilisées à condition que soit établie une relation de fonctionnement appropriée avec la méthode de référence.
La présente Norme européenne s’applique aux granulats naturels, artificiels ou recyclés utilisés dans le BTP.

Preskusi mehanskih in fizikalnih lastnosti agregatov - 2. del: Metode določevanja odpornosti proti drobljenju

Ta evropski standard opisuje referenčno metodo, preskus Los Angeles, ki se uporablja za tipsko preskušanje in v primerih spora (ter alternativno metodo, udarni preskus) za določevanje odpornosti proti drobljenju grobih agregatov in gramoza za železnice (Dodatek A). Za druge namene, zlasti za nadzor nad tovarniško proizvodnjo, se lahko uporabljajo druge metode, pod pogojem, da je vzpostavljen primeren delovni odnos z referenčno metodo. Ta evropski standard velja za naravne, proizvedene in reciklirane agregate, ki se uporabljajo pri gradnji in v gradbeništvu.

General Information

Status
Withdrawn
Public Enquiry End Date
19-Nov-2009
Publication Date
09-Jun-2010
Withdrawal Date
16-Jun-2020
Technical Committee
Current Stage
9900 - Withdrawal (Adopted Project)
Start Date
17-Jun-2020
Due Date
10-Jul-2020
Completion Date
17-Jun-2020

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Prüfverfahren für mechanische und physikalische Eigenschaften von Gesteinskörnungen - Teil 2: Verfahren zur Bestimmung des Widerstandes gegen ZertrümmerungEssais pour déterminer les caractéristiques mécaniques et physiques de granulats - Partie 2 : Méthodes pour la détermination de la résistance à la fragmentationTests for mechanical and physical properties of aggregates - Part 2: Methods for the determination of resistance to fragmentation91.100.15Mineralni materiali in izdelkiMineral materials and productsICS:Ta slovenski standard je istoveten z:EN 1097-2:2010SIST EN 1097-2:2010en,fr,de01-julij-2010SIST EN 1097-2:2010SLOVENSKI
STANDARDSIST EN 1097-2:1999/A1:2006SIST EN 1097-2:19991DGRPHãþD



SIST EN 1097-2:2010



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 1097-2
March 2010 ICS 91.100.15 Supersedes EN 1097-2:1998English Version
Tests for mechanical and physical properties of aggregates - Part 2: Methods for the determination of resistance to fragmentation
Essais pour déterminer les caractéristiques mécaniques et physiques de granulats - Partie 2 : Méthodes pour la détermination de la résistance à la fragmentation
Prüfverfahren für mechanische und physikalische Eigenschaften von Gesteinskörnungen - Teil 2: Verfahren zur Bestimmung des Widerstandes gegen ZertrümmerungThis European Standard was approved by CEN on 21 February 2010.
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 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 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 and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 1097-2:2010: ESIST EN 1097-2:2010



EN 1097-2:2010 (E) 2 Contents Page Foreword .41Scope .62Normative references .63Terms and definitions .64Apparatus .74.1General apparatus .74.2Additional apparatus required for the determination of resistance to fragmentation by the Los Angeles test method .74.3Additional apparatus required for the determination of resistance to fragmentation by the impact test method .95Determination of resistance to fragmentation by the Los Angeles test method .95.1Principle .95.2Preparation of test portion .95.3Test procedure . 105.4Calculation and expression of results . 105.5Test report . 106Determination of resistance to fragmentation by the impact test method . 106.1Principle . 106.2Preparation of test specimens . 116.3Test procedure . 116.4Calculation and expression of results . 126.5Test report . 12Annex A (normative)
Determination of the resistance to fragmentation of aggregates for railway ballast . 13Annex B (informative)
Alternative narrow range classifications for the Los Angeles test . 16Annex C (informative)
The impact tester: Construction, operation and safety requirements . 17C.1General . 17C.2Construction . 17C.3Lifting device . 17C.4Sample holder . 18C.5Anvil . 19C.6Base plate and dampers . 19C.7Safety requirements and testing . 20C.8Checking of impact tester . 20Annex D (informative)
Checking of the impact tester . 27D.1General . 27D.2Checklist . 27D.3Apparatus and test agents . 27D.4Procedure . 29Annex E (informative)
Precision . 31E.1General . 31E.2Los Angeles test . 31E.3Impact test . 31Annex F (informative)
Worked example of calculation of impact value SZ . 32SIST EN 1097-2:2010



EN 1097-2:2010 (E) 3 Annex G (informative)
Alternative narrow range classification for the Los Angeles test of 16/32 mm recycled aggregates . 33Bibliography . 34 SIST EN 1097-2:2010



EN 1097-2:2010 (E) 4 Foreword This document (EN 1097-2:2010) has been prepared by Technical Committee CEN/TC 154 “Aggregates”, the secretariat of which is held by BSI. 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 September 2010, and conflicting national standards shall be withdrawn at the latest by September 2010. 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 1097-2:1998. This standard forms part of a series of tests for mechanical and physical properties of aggregates. Test methods for other properties of aggregates are covered by the following European Standards:  EN 932 (all parts), Tests for general properties of aggregates
 EN 933 (all parts), Tests for geometrical properties of aggregates
 EN 1367 (all parts), Tests for thermal and weathering properties of aggregates
 EN 1744 (all parts), Tests for chemical properties of aggregates
 EN 13179 (all parts), Tests for filler aggregate used in bituminous mixtures
EN 1097, Tests for mechanical and physical properties of aggregates, consists of the following parts:
 Part 1: Determination of the resistance to wear (micro-Deval)
 Part 2: Methods for the determination of resistance to fragmentation  Part 3: Determination of loose bulk density and voids  Part 4: Determination of the voids of dry compacted filler
 Part 5: Determination of the water content by drying in a ventilated oven
 Part 6: Determination of particle density and water absorption
 Part 7: Determination of the particle density of filler
Pyknometer method
 Part 8: Determination of the polished stone value
 Part 9: Determination of the resistance to wear by abrasion from studded tyres — Nordic test
 Part 10: Determination of water suction height 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, SIST EN 1097-2:2010



EN 1097-2:2010 (E) 5 Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 1097-2:2010



EN 1097-2:2010 (E) 6 1 Scope This European Standard describes the reference method, the Los Angeles test, used for type testing and in case of dispute (and an alternative method, the impact test) for determining the resistance to fragmentation of coarse aggregates and aggregates for railway ballast (Annex A). For other purposes, in particular factory production control, other methods may be used provided that an appropriate working relationship with the reference method has been established. This European Standard applies to natural, manufactured or recycled aggregates used in building and civil engineering. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 932-1, Tests for general properties of aggregates — Part 1: Methods for sampling EN 932-2, Tests for general properties of aggregates — Part 2: Methods for reducing laboratory samples EN 932-5, Tests for general properties of aggregates — Part 5: Common equipment and calibration EN 933-1, Tests for geometrical properties of aggregates — Part 1: Determination of particle size distribution — Sieving method EN 933-2, Tests for geometrical properties of aggregates — Part 2: Determination of particle size distribution — Test sieves, nominal size of apertures
EN 1097-6:2000, Tests for mechanical and physical properties of aggregates — Part 6: Determination of particle density and water absorption EN 10025-2:2004, Hot rolled products of structural steels — Part 2: Technical delivery conditions for non-alloy structural steels 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 Los Angeles coefficient
LA percentage of the test portion passing a pre-determined sieve after completion of the test 3.2 impact value
SZ value SZ which gives a measure of the resistance of aggregates to dynamic crushing, and is equal to one fifth of the sum of the mass percentages of the tested sample passing through five specified test sieves when tested in accordance with Clause 6 3.3 test specimen sample used in a single determination when a test method requires more than one determination of a property SIST EN 1097-2:2010



EN 1097-2:2010 (E) 7 3.4 test portion sample used as a whole in a single test 3.5 laboratory sample reduced sample derived from a bulk sample for laboratory testing 3.6 constant mass successive weighings after drying at least 1 h apart not differing by more than 0,1 % NOTE In many cases constant mass can be achieved after a test portion has been dried for a pre-determined period in a specified oven (see 4.1.3) at (110 ± 5) °C. Test laboratories may determine the time required to achieve constant mass for specific types and sizes of sample dependent upon the drying capacity of the oven used. 4 Apparatus Unless otherwise stated, all apparatus shall conform to the general requirements of EN 932-5.
4.1 General apparatus 4.1.1 Test sieves, conforming to EN 933-2 with aperture sizes as specified in Table 1. Table 1 — Test sieves Test Aperture size
mm Los Angeles 1,6; 10; 11,2 (or 12,5); 14 Impact test a 0,2; 0,63; 2; 5; 8; 10; 11,2; 12,5 a For the impact test, because of the tolerances in the sieve openings, the same 8 mm test sieve used for the preparation of the test portion should again be used for the evaluation of the test.
4.1.2 Balance, capable of weighing the test portion to an accuracy of 0,1 % of the mass of the test portion. 4.1.3 Ventilated oven, controlled to maintain a temperature of (110 ± 5) °C. 4.2 Additional apparatus required for the determination of resistance to fragmentation by the Los Angeles test method 4.2.1 Equipment, for reducing the laboratory sample to a test portion, as described in EN 932-2. 4.2.2 Los Angeles test machine, comprising the following essential parts. NOTE An example of a machine that has been found to be satisfactory is shown in Figure 1.
SIST EN 1097-2:2010



EN 1097-2:2010 (E) 8
Key 1 internal length (508 ± 5) mm 2 internal diameter (711 ± 5) mm 3 shelf 4 cover and opening 5 rotation Figure 1 — Typical Los Angeles testing machine 4.2.2.1 Hollow drum, made of structural steel plate (120,15,0+−) mm thick conforming to grade S275 of EN 10025-2:2004 which has been selected to be formed without undue stress, and can be welded without significant distortion. The drum shall be closed at both ends. It shall have an internal diameter of (711 ± 5) mm and an internal length of (508 ± 5) mm. The drum shall be supported on two horizontal stub axles fixed to its two end walls but not penetrating inside the drum; the drum shall be mounted so that it rotates about a horizontal axis. An opening (150 ± 3) mm wide shall be provided, preferably over the whole length of the drum, to facilitate insertion and removal of the sample after the test. During the test, the opening shall be sealed so that it is dustproof, by using a removable cover which enables the inside surface to remain cylindrical. The cylindrical inner surface shall be interrupted by a projecting shelf, placed between 380 mm and 820 mm from the nearest edge of the opening. The distance shall be measured along the inside of the drum in the direction of rotation. The shelf shall have a rectangular cross section (length equal to that of the drum, width (90 ± 2) mm, thickness (25 ± 1) mm) and it shall be placed in a diametrical plane, along a generating line, and shall be rigidly fixed in place. The shelf shall be replaced when its width at any point wears to less than 86 mm and its thickness at any point along the front edge wears to less than 23 mm. The base of the machine shall be supported directly on a level concrete or stone block floor.
NOTE The removable cover should be made of the same steel as the drum. The projecting shelf should be made of the same steel or a harder grade.
4.2.2.2 Ball load, consisting of 11 spherical steel balls, each with a diameter of between 45 mm and 49 mm (see Annex B). Each ball shall weigh between 400 g and 445 g, and the total load shall weigh between 4 690 g and 4 860 g.
NOTE The nominal mass of the charge with new balls is 4 840 g. A positive tolerance of 20 g allows for manufacturing variation and a negative tolerance of 150 g allows for ball wear in use. SIST EN 1097-2:2010



EN 1097-2:2010 (E) 9 4.2.2.3 Motor, imparting a rotational speed to the drum of between 31 min-1 and 33 min-1. 4.2.2.4 Tray, for recovering the material and the ball load after testing. 4.2.2.5 Revolution counter, which will automatically stop the motor after the required number of revolutions. 4.3 Additional apparatus required for the determination of resistance to fragmentation by the impact test method 4.3.1 Impact tester, see Annex C. 4.3.2 Equipment for testing the accuracy of the impact tester, see Annex D. NOTE Annexes C and D are informative and do not contain any normative provisions for the application of this European Standard. However, it is strongly recommended that all the informative provisions of these annexes be observed when carrying out the test specified in Clause 6. 4.3.3 Brush and bowls. 5 Determination of resistance to fragmentation by the Los Angeles test method 5.1 Principle A sample of aggregate is rolled with steel balls in a rotating drum. After rolling is complete, the quantity of material retained on a 1,6 mm sieve is determined. 5.2 Preparation of test portion
The mass of the sample sent to the laboratory shall have at least 15 kg of particles in the 10 mm to 14 mm size range. The test shall be carried out on aggregate passing the 14 mm test sieve and retained on the 10 mm test sieve. In addition, the grading of the test portion shall comply with one of the following requirements: a) between 60 % and 70 % passing a 12,5 mm test sieve; or b) between 30 % and 40 % passing a 11,2 mm test sieve. NOTE 1 The additional grading requirements allow the test portion to be created from product sizes other than 10/14 (see Annex B). NOTE 2 For recycled aggregates, a test procedure for the 16/32 mm size fraction is described in Annex G. Sieve the laboratory sample using the 10 mm, 11,2 mm (or 12,5 mm) and 14 mm test sieves to give separate fractions in the ranges 10 mm to 11,2 mm (or 12,5 mm) and 11,2 mm (or 12,5 mm) to 14 mm. Wash each fraction separately, in accordance with EN 933-1, and dry them to constant mass. NOTE 3 For temperature-sensitive recycled aggregates, a drying temperature of (40 ± 5) °C should be used. Allow the fractions to cool to ambient temperature. Mix the two fractions to provide a modified 10 mm to 14 mm laboratory sample which complies with the appropriate additional grading requirement given above. Reduce the modified laboratory sample prepared from the mixed fractions to test portion size in accordance with EN 932-2. The test portion shall have a mass of (5 000 ± 5) g. SIST EN 1097-2:2010



EN 1097-2:2010 (E) 10 5.3 Test procedure Check that the drum is clean before loading the sample. Carefully place the balls in the machine, then the test portion. Replace the cover and rotate the machine for 500 revolutions at a constant speed between 31 min-1 and 33 min-1. Pour the aggregate into a tray placed under the apparatus, taking care that the opening is just above the tray in order to avoid losing any material. Clean out the drum, removing all fines, paying particular attention around the projecting shelf. Carefully remove the ball load from the tray, taking care not to lose any aggregate particles. Analyze the material from the tray in accordance with EN 933-1 by washing and sieving using a 1,6 mm sieve. Dry the portion retained on the 1,6 mm sieve at a temperature of (110 ± 5) °C (or lower, see Note 3 to 5.2) until a constant mass is achieved. 5.4 Calculation and expression of results Calculate the Los Angeles coefficient LA from the following equation: LA = 500005m− where
m is the mass retained on the 1,6 mm sieve, in grams.
Report the result to the nearest whole number. NOTE A statement on the precision of the Los Angeles test is given in Annex E. 5.5 Test report The test report shall include at least the following information: a) confirmation that the Los Angeles test was carried out in accordance with this standard; b) number of this standard; c) name and origin of sample; d) size fractions from which the test portion was obtained; e) Los Angeles coefficient LA. 6 Determination of resistance to fragmentation by the impact test method 6.1 Principle A test specimen is placed in a steel cylinder and subjected to ten impacts from a hammer of mass 50 kg, falling from a specified height. The amount of fragmentation caused by the ten impacts is measured by sieving the test specimen using five specified test sieves.
SIST EN 1097-2:2010



EN 1097-2:2010 (E) 11 6.2 Preparation of test specimens 6.2.1 A laboratory sample shall be obtained in accordance with EN 932-1. The sample shall contain at least 5 kg of the size fraction 8 mm to 10 mm and 2,5 kg of each of the size fractions 10 mm to 11,2 mm and 11,2 mm to 12,5 mm. 6.2.2 A quantity of the size fractions 8 mm to 10 mm, 10 mm to 11,2 mm and 11,2 mm to 12,5 mm sufficient for at least three test specimens (see 6.2.3 and 6.2.4) shall be prepared from the laboratory sample using the sieves 8 mm, 10 mm, 11,2 mm and 12,5 mm specified in 4.1.1. This quantity shall be washed in accordance with EN 933-1, dried to constant mass and left to cool to between 15 °C and 35 °C. NOTE For temperature-sensitive recycled aggregates, a drying temperature of (40 ± 5) °C should be used. 6.2.3 Material for at least three test specimens shall be recombined as follows and three test specimens shall be tested (see 6.2.4). The test specimens shall be composed of 50 % of the size fraction 8 mm to 10 mm, 25 % of the size fraction 10 mm to 11,2 mm and 25 % of the size fraction 11,2 mm to 12,5 mm and be weighed to the nearest 0,5 g. The three fractions shall be mixed thoroughly prior to weighing of the test specimen as described in 6.2.4. 6.2.4 The mass of the test specimen in kilograms shall be 0,5 times the value of the particle density in megagrams per cubic metre as determined in accordance with EN 1097-6 on a sample composed as specified in 6.2.3. If this particle density is known from previous tests, that result can be used.
For each test specimen the quantities, in kilograms, are: a) size fraction 8 mm to 10 mm: 0,25 times the particle density; b) size fraction 10 mm to 11,2 mm: 0,125 times the particle density; c) size fraction 11,2 mm to 12,5 mm: 0,125 times the particle density. The mass of a test specimen, referred to as M, prior to the testing shall not differ by more than 1 % from the nominal mass. 6.3 Test procedure 6.3.1 The test specimen shall be poured into the mortar of the impact test machine and its surface roughly evened by hand without jigging. The pestle shall be pressed by the corresponding device onto the test specimen and the hammer lifted up to a height of 370 mm. The test specimen shall then be subjected to ten blows by the hammer. 6.3.2 After the blows, lift up the pestle and take the mortar out of the apparatus. Then pass the crushed sample carefully into a bowl. Any fine particles adhering to the mortar shall be swept into the bowl with the brush and the test specimen shall subsequently be weighed. 6.3.3 The crushed test specimen shall be sieved in accordance with EN 933-1 on the following five test sieves specified in 4.1.1, starting with the 8 mm sieve: 0,2 mm; 0,63 mm; 2 mm; 5 mm; 8 mm. The fraction retained on the five test sieves and the pan shall be weighed to the nearest 0,5 g. 6.3.4 If the total mass of the test specimen after sieving differs from the original mass by more than 0,5 %, the impact test shall be carried out on a further test specimen. SIST EN 1097-2:2010



EN 1097-2:2010 (E) 12 6.4 Calculation and expression of results Calculate the mass retained on each of the five test sieves and on the pan, for each test specimen, as a percentage of the mass, M, of the test specimen before testing. Calculate from this the percentage masses passing the five sieves. Add up the percentage masses passing each of the five test sieves to give the sum of percentage masses M.
Calculate the impact value SZ, in percent, from the following formula: SZ = 5M (see Clause 3 and the worked example given in Annex F) where
M is the sum of the percentages of the mass passing each of the five test sieves. NOTE A statement on the precision of the impact test is given in Annex E. 6.5 Test report The test report shall include at least the following information: a) confirmation that the test was carried out in accordance with this Standard and number of this standard; b) name and origin of sample; c) size fractions from which the test portion was obtained; d) particle density of the size fraction 8 mm to 12,5 mm rounded to 0,01 Mg/m3 and determined in accordance with EN 1097-6; e) test result (impact value SZ, together with results of single test specimens rounded to 0,01 % and mean value rounded to 0,1 %).
SIST EN 1097-2:2010



EN 1097-2:2010 (E) 13 Annex A (normative)
Determination of the resistance to fragmentation of aggregates for railway ballast NOTE The following clause numbers refer to the corresponding clauses in the main document. These clauses express additions or modifications to main text clauses. 4 Apparatus 4.1 General apparatus 4.1.1 Test sieves, conforming to EN 933-2 with aperture sizes as specified in Table 1. Table 1 — Test sieves Test Aperture size
mm Los Angeles 31,5; 40; 50 Impact test 31,5; 40
4.2 Additional apparatus required for the determination of resistance to fragmentation by the Los Angeles test method 4.2.2.2 Ball load, consisting of 12 spherical steel balls instead of 11. The total load shall weigh (5 210 ± 90) g. 5 Determination of the resistance to fragmentation by the Los Angeles test method 5.2 Preparation of test portion The mass of the sample sent to the laboratory shall have at least 15 kg of particles in the 31,5 mm to 50 mm size range. The test shall be carried out on aggregates passing the 50 mm test sieve and retained on the 31,5 mm test sieve. Sieve the laboratory sample using the 31,5 mm, 40 mm and 50 mm test sieves to give separate fractions in the ranges 31,5 mm to 40 mm and 40 mm to 50 mm. Wash each fraction separately, in accordance with EN 933-1, and dry them in the oven at (110 ± 5) °C to constant mass. Allow the fractions to cool to ambient temperature.
Reduce the mass of the fractions in accordance with EN 932-2. Each fraction shall have a mass of (5 000 ± 50) g. Mix the two fractions to provide a 31,5 mm to 50 mm test portion. The test portion shall have a mass of (10 000 ± 100) g. SIST EN 1097-2:2010



EN 1097-2:2010 (E) 14 5.3 Test procedure Rotate the machine for 1 000 revolutions instead of 500. 5.4 Calculation and expression of results Calculate the Los Angeles coefficient LARB from the following equation: LARB =10000010m−
5.5 Test report The test report shall affirm that the Los Angeles test was carried out in accordance with Annex A of this standard. It shall include the following information: c) Los Angeles coefficient LARB. 6 Determination of the resistance to fragmentation by the impact test method 6.2 Preparation of test specimens 6.2.1 The sample shall contain at least 10 kg of the size fraction 31,5 mm to 40 mm. 6.2.2 A quantity of the size fraction 31,5 mm to 40 mm sufficient for at least three test specimens (see 6.2.3) shall be prepared from the laboratory sample using the sieves 31,5 mm and 40 mm specified in 4.1.1. This quantity shall be washed in accordance with EN 933-1, dried at (110 ± 5) °C to constant mass and left to cool to between 15 °C and 35 °C.
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