Bs En932!2!1999 - Test for General Properties of Aggregates

British Standard

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BRITISH STANDARD

Tests for general properties of aggregates Ð Part 2: Methods for reducing laboratory samples

I S B ) c ( , y p o C d e l l o r t n o c n U , 2 0 0 2 , 4 0 y r a u r b e F , m a h P a g N : y p o C d e s n e c i L

The European Standard EN 932-2:1998 has the status of a British Standard

ICS 91.100.15

NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW

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BS EN 932-2:1999

BS EN 932-2:1999

National foreword This British Standard is the English language version of EN 932-2:1998. It is included in a package of European Standards agreed by CEN/TC 154. The UK participation in its preparation was entrusted by Technical Committee B/502, Aggregates, to Subcommittee B/502/6, Methods of test, which has the responsibility to: Ð aid enquirers enquirers to understa understand nd the text; text; Ð present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; Ð monitor related international and European developments and promulgate them in the UK. A list of organiza organizations tions represen represented ted on this subcommi subcommittee ttee can be obtained obtained on request request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled ªInternational Standards Correspondence Indexº, or by using the ªFindº facility of the BSI Standards Electronic Catalogue. A British Standard Standard does not purport purport to include include all the necessary necessary provisions provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity I S from legal obligations. B ) c ( , y p o C d e l l o r t n o c n U , 2 0 0 2 Summary of pages , 4 0 This document comprises a front cover, an inside front cover, the EN title page, y r pages pages 2 to 10, an inside back cover and a back cover. cover. a u r b e Amendments Amendmen ts issued since publication F This British Standard, having , been prepared under the Amd. Amd. No. Date Text affected affected m direction of the Sector a Committee for Building and Civil h Engineering, was published under P the authority of the Standards a Committee and comes into effect g N on 15 May 1999 : y p © BSI 05-1999 o C d e s n e c ISBN 0 580 32099 5 i L

EN 932-2 932-2

EUROPEAN STANDARD Â ENNE NORME EUROPE È ISCHE NORM EUROPA

January 1999

ICS 91.100.15 Descriptors: aggregates, tests, samples, specimen preparation, preparation, reduction methods

English version

Tests ests for for gene genera rall prope propert rtie iess of aggr aggreg egat ates es Ð Part Part 2: Meth Method odss for for reducing laboratory samples

Essais pour deÂ terminer terminer les proprieÂ te teÂ neÂ rales des Â s geÂ Â ne Â rales granulats Ð Partie 2: MeÂ thodes thodes de reÂ duction duction d'un eÂ chantillon chantillon de laboratoire


Pru Pr È fverfahren uÈ fverfahren fu È r È r allgemeine Eigenschaften von Gesteinsko È rnungen È rnungen Ð Teil 2: Verfahren zum Einengen zum Laboratoriumsproben

This European Standard was approved by CEN on 26 December 1998. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which which stipul stipulate ate the condit condition ionss for giving giving this this Europe European an Standa Standard rd the status status of a nation national al standa standard rd withou withoutt any alter alterati ation. on. Up-toUp-to-dat date e lists lists and biblio bibliogr graph aphica icall references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version version in any other other language language made by translat translation ion under the responsib responsibility ility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN CEN memb member erss are are the the nati nation onal al stan standa dard rdss bodi bodies es of Aust Austri ria, a, Belg Belgiu ium, m, Czec Czech h Republ Republic, ic, Denma Denmark, rk, Finla Finland, nd, Franc France, e, Germa Germany ny,, Greec Greece, e, Icelan Iceland, d, Irela Ireland, nd, Italy Italy,, Luxem Luxembou bourg, rg, Nether Netherlan lands, ds, Norway Norway,, Portug Portugal, al, Spain, Spain, Sweden Sweden,, Switze Switzerla rland nd and United Kingdom.

CEN European Committee for Standardization ComiteÂ EuropeÂ en de Normalisation Europa È isches È isches Komitee fu È r È r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels © 1999

CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 932-2:1999 E

Page 2 EN 932-2:1999

Foreword This European Standard 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 July 1999, and conflicting national standards shall be withdrawn at the latest by 1 December 2003. This European Standard is one of a series of standards for tests for general properties of aggregates. Test methods for other properties of aggregates are covered by Parts of the following European Standards: EN 933, Tests for geometrical properties of aggregates. EN 1097, Tests for mechanical and physical properties of aggregates. EN 1367, Tests for thermal and weathering properties of aggregates. EN 1744, Tests for chemical properties of aggregates. prEN 13179, 13179, Tests for filler aggregate used in bituminous mixtures. The other parts of EN 932 will be: I Part 1: Methods Methods for samp samplin ling. g. S Part 3: Procedu Procedure re and term termino inology logy for simplif simplified ied B petrogra ographic phic descriptio description. n. ) petr c Part 5: Common Common equipme equipment nt and calibrat calibration ion.. ( , Part 6: Definiti Definitions ons of repe repeatab atabilit ility y and y p repr reproduc oducibi ibility lity. . o C Accordin According g to the CEN/CEN CEN/CENELEC ELEC Internal Regulatio Regulations, ns, d the national standards organizations of the following e l l countries are bound to implement this European o r Standard: Austria, Belgium, Czech Republic, Denmark, t n Finland, France, Germany, Greece, Iceland, Ireland, o c Italy, Luxembourg, Netherlands, Norway, Portugal, n U Spain, Sweden, Switzerland and the United Kingdom. , 2 0 0 2 , 4 0 y r a u r b e F , m a h P a g N : y p o C d e s n e c i L

Contents Page Foreword

2

1

Scope

3

2

Normative references

3

3

Definitions and symbols

3

4

Principle

3

5

Apparatus

3

6

Consideration before sample reduction

5

7

Sample Sample reduct reduction ion techni technique que using using a rotary sample divider

5

8

Sample reduction using a riffle box

5

9

Sample Sample reduct reduction ion using using fract fraction ional al shovelling

7

10

Sample reduction by quartering

7

11

Sample Sample reduct reduction ion to a test test porti portion on of of a specified mass within a small tolerance

8

Sample Sample reduct reduction ion with with crus crushin hing g to to reduce the particle size

8

Proce Procedur dures es for for obta obtaini ining ng dupl duplica icate te test test portions portions

8

12 13

Annex Annex A (informa (informative) tive) ¯, divisions by a riffle box



and

¾

9

Annex Annex B (informa (informative) tive) Worked Worked examples examples

10

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Page 3 EN 932-2:1999

1 Scope This European Standard specifies methods for reducing laboratory samples of aggregates to test portions portions,, when the test portion mass mass is: Ð specified by a lower limit on the mass; Ð specified by a tolerance around a target mass; Ð determined precisely by the requirements of a test method.

2 Normative references This European Standard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publicatio publications ns apply apply to this European European Standard Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 932-1, Tests for general properties of aggregates Ð Part Part 1: Methods Methods for samp sampling ling.. I S B ) c ( , y p o C d e l l o r t n o c n U , 2 0 0 2 , 4 0 y r a u r b e F , m a h P a g N : y p o C d e s n e c i L

prEN prEN 932-5, Tests for general properties of aggregates Ð Part 5: Common equipment and calibration.

3 Definitions and symbols 3.1 Definitions For the purposes of this European Standard, the following definitions apply: 3.1.1 laboratory sample sample intended for laboratory testing 3.1.2 subsam subsample ple sample obtained by means of a sample reduction procedur procedure e 3.1.3 subsample used as a whole in a single test

05-1999

3.1.6  divisi division on division of a sample into two subsamples, with masses approximately  and ï times the mass of the original sample (see Figure 2) 3.1.7 ¾ divisi division on division of a sample into two subsamples with masses approximately ¾ and ® times the mass of the original sample (see Figure 3). 3.2 Symbols mL

laboratory sample sample mass (in grams grams or kilograms). kilograms).

mS

subsample mass (in grams or kilograms). kilograms).

mT

specifie specified d test portion portion mass (in grams grams or kilograms).

4 Principle The procedures given in this European Standard are designed so that test portions are obtained by the minimum number of division steps, and so that, as far as possible, the operator is prevented from making small adjustments to the test portion and from choosing the particles that go into the test portion.

5 Apparatus Apparatu Apparatuss shall shall be as specifie specified d in EN 932-1 with the addition of suitable apparatus for crushing and grinding. All apparatus shall comply with the general requirements of prEN 932-5.

The dashed dashed lines lines denote denote dividing dividing of a sample sample into two subsam subsamples. ples.

Figur Figure e 1Ð

© BSI

3.1.5 ¯ divisi division on division of a sample into two subsamples of approximately equal mass (see Figure 1)

NOTE In all cases, cases, alternative alternative designs designs may be used so long long as the essential dimensions of width of opening and length are met, and the devices can be used to fulfil the sample reduction methods specified in clauses 7 clauses 7 to 13. 13.

test portion

NOTE

3.1.4 test specimen sample used in a single determination when a test method requires more than one determination of a property property

¯

division

Page 4 EN 932-2:1999

NOTE The dashed dashed lines denote denote dividing dividing of a sample sample into two subsampl subsamples. es. A dotted line line denotes the addition of a subsample retained from a previous division stage.

Figu Figure re 2 Ð




division

NOTE The dashed dashed lines denote denote dividin dividing g of a sample into into two subsamples. subsamples. A dotted dotted line denotes denotes the addition addition of a subsample subsample retained from a previous previous division stage

Figu Figure re 3 Ð

¾

division

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Page 5 EN 932-2:1999

6 Consideration before sample reduction 6.1 Moisture content and homogeneity of the sample When the moisture content of an aggregate is to be determined, one or more test portions shall be taken prior prior to drying. drying. A riffle riffle box or a mechanica mechanicall divider divider shall not be used. When test portions are required for other purposes than moisture content and a riffle box or mechanical divider is to be used, the laboratory sample shall be brought to a condition in which it is free-flowing. NOTE 1 For aggregates aggregates containing containing fines that segregate segregate when dry, or for aggregates containing lumps of clay visible to the naked eye, it is recommended that they are subjected to sample reduction in the condition in which they are received at the laboratory, not dried. NOTE 2 If on the basis of visual inspectio inspection, n, the laboratory laboratory sample needs mixing, then this should be performed on a sampling tray. For aggregate that contains a wide range of particle sizes it can be desirable to separate the laboratory sample into two (or more) fractions by sieving and to treat each fraction to sample reduction separately.

6.2 Test methods that specify only a lower limit to the test portion mass I S B ) c ( , y p o C d e l l o r t n o c n U , 2 0 0 2 , 4 0 y r a u r b e F , m a h P a g N : y p o C d e s n e c i L

For test methods that specify only a minimum mass ( mT) for the test portion or each of several test specimens one of the following procedures to yield yield 100 % to 150 % of the specifie specified d mass mass shall shall be used: used: a) sample reduction using a rotary sample divider (see clause 7); b) sample reduction using a riffle box (see clause 8); c) sample reduction using fractional shovelling (see clause 9); d) sample reduction by quartering (see clause 10). 10). NOTE a) above is the preferred preferred procedure procedure and d) is not recommended for wide gradings.

6.3 Test methods that allow a sizeable tolerance round a target mass For test methods, which require a test portion mass suited to the capacity of the equipment that is used, but can allow a sizeable tolerance around the test portion portion mass mass (for example, example, determin determination ation of water-soluble sulfates), one of the following procedur procedures es that gives gives a test portion mass within ± 15 % of the specified mass shall be used: a) sample reduction using a rotary sample divider (see clause 7); b) sample reduction using a riffle box (see clause 8); c) sample reduction using fractional shovelling (see clause 9). NOTE a) above is the the preferred preferred procedure. procedure.

6.4 Test methods that specify a test portion mass within a small tolerance For the following types of test methods, which require a test portion mass to be within a small tolerance of a specified mass, the procedure specified in clause 11 shall be used: a) test methods for which the test portion mass is determined by the capacity of a container used in the test (for example, bulk density); b) test methods that involve the manufacture of specimens (for example mortar or bituminous bound or hydraulically bound test specimens) from aggregate fractions that have to be weighed to the nearest 5 g or less; c) test methods where the test portion mass is specified with a very narrow tolerance.

7 Sample reduction technique using a rotary sample divider Select a configuration of the sample divider that will yield yield the test portions within 100 % to 150 % of the specified mass, or within 85 % to 115 % of the specified mass, as appropriate to the test method requirements. NOTE The calculations calculations and and schemes of sample sample reduction reduction divisions using a riffle box given in clause 8 clause 8 can also be applied to a rotary sample divider provided it can divide into a small and even number of subsamples.

Place the sample into the hopper and start the rotor. When the rotor is rotating at its operating speed start the vibrating feeder. Check that at least 35 revolutions are completed before the laboratory sample is exhausted. If this is not achieved, recombine the subsamples and repeat the sample reduction with a lower feed rate. If the mechanical sample divider is not equipped with a feeder and/or 35 revolutions cannot be achieved, the mass of each portion shall be checked and shall be within 100 % to 150 % of the specified mass, or within 85 % to 115 % of the specified mass as appropriate.

8 Sample reduction using a riffle box Put the sample into one of the riffle box receptacles. Spread the material out evenly over the full length of the receptacle. Place the other two receptacles in position. position. Pour the sample sample from the long side of the riffle box down the centre line of the riffle box. An example example of the division division steps steps using using a riffle riffle box is shown in annex A. 8.1 8.1 To provide provide a test test portio portion n mass within 100 100 % to 150 150 % of a specif specified ied mass mass 8.1.1 Calculations Obtain the value of the specified test portion mass mT from the test method and calculate 0,75 mT and 1,5 mT. NOTE If a test method method is performed performed frequently frequently then it may be convenient convenient to display display the pertinent pertinent informatio information n in the laboratory laboratory where the sample reduction is carried out, see Figure B.1.

Determine the mass of the laboratory sample, m L. Calculate m S = m L /2, m L /4, m L /8, m L /16, .... until until a mass mS is obtained that is less than 1,5 mT. © BSI

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Page 6 EN 932-2:1999

8.1.2 Sample reduction (see Figure 4)

8.2.2 Sample reduction (see Figure 5)

If m mS is between 0,75 mT to mT

If m mS is between 0,75 mT and 0,85 mT

reduce the laboratory sample by one ¾ division operation and then proceed using ¯ divisions to obtain the required test portion mass;

if m mS is between 0,85 mT and 1,15 mT

proceed proceed using ¯ divisions to obtain the required test portion portion mass; mass;

if m mS is between 1,15 mT and 1,5 mT

reduce the laboratory sample by one  division operation and then proceed using ¯ divisions to obtain the required test portion mass.

reduce the laboratory sample by one  division operation and then proceed using ¯ divisions to obtain the required test portion portion mass; mass;

if m proceed using using ¯ divisions to mS is between mT proceed to 1,5 mT obtain the required test portion mass. NOTE After three successive successive ¯ divisions it is advisable to determine determine the mass mS of the subsample and decide if a further  division is needed, using the same method as before, but with mS in place of m m L.

8.2 8.2 To provide provide a test test portio portion n mass within 85 85 % to 115 115 % of a specif specified ied mass mass 8.2.1 Calculations Obtain the value of the specified test portion mass mT from the test method and calculate 0,75 mT, 0,85 mT, 1,15 mT and 1,5 mT. NOTE If a test method method is performed performed frequently frequently then it can be convenient convenient to display display the pertinent pertinent information information in the laboratory laboratory where sample division is carried out (see Figure B.2).

NOTE After three successive successive ¯ divisions it is advisable to determine the mass m T of the subsample and decide if a further  or ¾ division is needed, using the same method as before, but with mS in place of m m L.

Determine the mass of the laboratory sample m L. Calculate mS = m L /2, m L /4, m L /8 ...... ...... until a mass mass mS is I obtained that is less than 1,5 mT. S B ) c ( , y p o C d e l l o r t n o c n U , 2 0 0 2 , 4 0 y r a u r b e F , m a h Figure 4 Ð Sample reduction reduction procedure procedure for 8.1 8.1 P a g N : y p o C d e s n e c i L © BSI

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Page 7 EN 932-2:1999


Figure 5 Ð Sample reduction reduction procedure procedure for 8.2 8.2

9 Sample reduction using fractional shovelling If an appropriate sample divider is not available, fractional shovelling can be used to divide a laboratory sample into a number of subsamples of approximately equal mass. Determine the mass of the laboratory sample, m L. Calculate the number n n of subsamples to be produced by fractional shovelling as: n = m L / mT If the test portion mass is to be within 100 % to 150 % of m mT, round ª nº down to the nearest whole number (the required tolerance can be achieved provided that n $ 2). If the test portion mass is to be within 85 % to 115 % of m mT, round ª nº to the nearest whole number (the required tolerance can be achieved provided that n $ 3). The shovel shall hold at most a mass (in kilograms) of mL /(10 n) of the aggregate, where m L is the mass of the laboratory sample and n the number of subsamples to which it is to be reduced. © BSI

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Take successively n shovelfuls from the laboratory sample and put them in n separate places on the working surface and number them from 1 to n. Proceed taking shovelfuls and add them to each of the n subsamples in turn, until the whole of the laboratory sample has been used. Using random numbers (see annexes B and D of EN 932-1:1996), randomly select the subsample, or subsamples, that are to be retained.

10 Sample reduction by quartering Place the laboratory sample on the working surface. Thoroughly mix the sample by heaping it up to form a cone, and turning it over with the shovel to form a new cone. Repeat this operation three times. When forming the cones, deposit each shovelful on the peak of the new cone in such a way that the aggregate runs down all sides of the cone and is evenly distributed so that the different sizes become well-mixed. Flatten the third cone by inserting the shovel repeatedly and vertically into the peak of the cone to form a flat heap which has a uniform thickness and diameter.

Page 8 EN 932-2:1999

Quarter the flat heap along two diagonals intersecting at right angles (see Figure 6). Discard one pair of opposite quarters and shovel the remainder into a stockpile.

When the subsample mass approaches the limiting value value specifie specified d in Table 1, the material material shall be crushed crushed or ground to a smaller size to enable further subdivision. This procedure shall be repeated until a test portion of the required mass is achieved. Table able 1 Ð Minimum Minimum mass of subsampl subsample e during sample division of chemical analysis

Figure 6 Ð Sample reduction by quartering

Repeat the process of mixing and quartering until the specified test portion is obtained. NOTE The use of a plate plate or a quartering quartering cross of wood wood or sheet metal, which can be forced down through the heap, often facilitates quartering in cases where the material tends to segregate.

11 Sample reduction to a test portion of I S a specified mass within a small tolerance

B 6.2 to obtain a ) Use a procedure as described in 6.2 to c subsample mass in excess of that required for the test ( , portion. y portion. p o Tip the subsample on to the working surface, mix C thoroughly and form a line of aggregate across the d working surface. Starting at one end of the line, and e l l using a flat bottomed scoop or a scraper, continue to o r withdraw aggregate from that end until a test portion t n of sufficient mass is obtained. Take care that smaller o c particle particless are not left behind. behind. n U , 2 12 Sample reduction with crushing to 0 0 reduce the particle size 2 , The reduction of laboratory samples to test portions 4 0 for chemical analysis shall be achieved by one or more y of the procedures specified in clauses 7 to 11 and 11 and r a crushing of subsamples at intermediate stages. u r b To ensure that the test portion is representative of the e original laboratory samples, the mass of the subsample F , at any intermediate stage shall not fall below the m limiting value in Table 1 appropriate for its particle a h size. P a g N : y p o C d e s n e c i L

Ma xi xi mu mum p ar ar ti ti cl cl e si ze ze

M in ini mu mu m m as ass o f subsample

mm

g

1

100

2

200

4

500

8

800

16

1 000

32

2 000

63

10 000

13 Procedures for obtaining duplicate test portions When two test portions are required for testing by the same method (for example, to check the repeatability of a test method), one of the procedures specified in 13.1, 13.1, 13.2 or 13.2 or 13.3 shall 13.3 shall be used. Divide the laboratory laboratory sample sample into two 13.1 Divide subsamples by ¯ division. Keep the two subsamples apart and produce a test portion of the specified mass from each subsample using the procedures specified in clauses 7 to 9. Produce one test portion portion of the required required mass as 13.2 Produce specified in clauses 7 to 9. Re-combine all the discard material, mix thoroughly, then follow the same procedur procedure e as before before to obtain obtain the second second test portion. portion. Produce a number of test portions portions of the 13.3 Produce required mass using the procedures specified in clauses 7 to 9. Choose two for testing using random numbers (see annexes B and D in EN 932-1:1996).

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Page 9 EN 932-2:1999

Annex Annex A (infor (informat mative ive) ) ¯, 

and ¾ divisions by a riffle box


Figure A.1

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Page 10 EN 932-2:1999

Annex Annex B (infor (informat mative ive) ) Worke Worked d exam exampl ples es B.1 Example 1: Preparation of a test portion for a sieving test from a laboratory sample with a maximum maximum grain size size of 32 32 mm The sieving method requires a test portion of at least 10 kg for the given particle size. A tolerance of 100 % to 150 % is acceptable, as specified in 6.2, 6.2, with m T = 10 kg. Following the procedures specified in 8.1.1, 8.1.1, calculate: a) 0,75 mT = 7,5 kg; b) 1,5 mT = 15,0 kg. Let the mass of the laboratory sample be m L = 75 kg. Calculate successive ¯ divisions of the laboratory sample mass as shown in Table B.1. This shows that a subsample of mass 9,4 kg would be obtained after three ¯ divisions. This would be less than the minimum test portion mass required. Therefore the first step should be a  division followed by two ¯ divisions as shown in Table B.2. A subsample of 14,1 kg is an acceptable test portion. Table B.1 Ð Calculation of successive ¯ divisions divisions of a laboratory sample of mass 75 75 kg

I S Number of ¯ divi si ons S ub s a m p l e m a s s B kg ) c ( 0 75,0 , y 1 37,5 p o 18,8 C 2 d 3 9,4 e l l o r t Table B.2 Ð  division followed by ¯ n divisions o c n Division step S u b sa m p l e m a s s U kg , 2 Ð 75,0 0 0 56,3 2  , 4 ¯ 28,1 0 y ¯ 14,1 r a u r b It can be helpful to display the following information e given in Figure B.1 in the laboratory where the sample F reduction is carried out. , m a SIEVE TEST, TEST, 32 mm AGGREGA AGGREGATE TE h P arget tes test por portion tion mass ass: 10 kg to 15 kg a Targ g N mS betwee between n 7,5 7,5 kg and 10,0 10,0 kg: one  division, then : ¯ divisions y p o C mS between 10,0 kg and 15,0 kg: ¯ divisions d Figure Figure B.1 Ð Sieve Sieve test of a 32 32 mm aggreg aggregate ate e s n e c i L

B.2 Example 2: Preparation of a test portion for the determination of lightweight contaminators in fine aggregates The test method requires a test portion of mass (350 ± 50) g, so m T = 350 g. Let the mass of the laboratory sample be m L = 8950 g. Following the procedures specified in 8.2.1, 8.2.1, calculate: a) 0,75 mT = 262,5 g; b) 0,85 mT = 297,5 g; c) 1,15 mT = 402,5 g; d) 1,5 mT = 525 g. Calculate successive ¯ divisions of the laboratory sample mass as shown in Table B.3. This shows that a subsample of mass 280 g would be obtained after five ¯ divisions. This would be less than the required test portion. Therefore the first step should be a ¾ division step followed by successive ¯ divisions, which would yield the required test portion mass as shown in Table B.4. Table B.3 Ð Calculation of successive divisions of a laboratory sample of mass 895 8950 0g Number of ¯ di visions

S ub sa m p l e m a ss g

0

8950

1

4475

2

2238

3

1119

4

559

5

280 Table B.4 Ð

¾

¯

division followed by ¯ divisions

D i v i si o n s t e p

Ð

Subsamp le ma ss g

8950

¾

5594

¯

2797

¯

1398

¯

699

¯

350

It can be helpful to display the following information given in Figure A.2 in the laboratory where the sample reduction is carried out. LIGHTWEIGHT CONTAMINATORS IN FINE AGGREGATE AGGREGATE Targe argett test test port portio ion n mas mass: s:

300 300 g to 400 400 g

between en 260 g and 300 g: One ¾ division, then mS betwe ¯ divisions mS between 300 g and 400 g:

¯

divisions

between en 400 g and 525 g: one  division, then mS betwe divisions

¯

Figure B.2 Ð Determination of lightweight contaminators in fine aggregate

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I S B ) c ( , y p o C d e l l o r t n o c n U , 2 0 0 2 , 4 0 y r a u r b e F , m a h P a g N : y p o C d e s n e c i L blank

I S B ) c ( , y p o C d e l l o r t n o c n U , 2 0 0 2 , 4 0 y r a u r b e F , m a h P a g N : BSI y p 389 Chiswick High Road o C London d W4 4AL e s n e c i L

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Bs En932!2!1999 - Test for General Properties of Aggregates

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