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BS 812 : Part 1 14 : 1989
UDC f625.07+691.221 : 620.191.392 + 543
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0 British Standards Institution. No part of this publication may be photooOpied or otherwise reproduced withwt the prior permission in writing of BSI

British Standard

I esting aggregates
Part I 14. Method for determination of
the polished-stone value

Essais des granulats

Partie 114. Méthode de détermination de l'indice de polissage

Prüfung von Zuschlagstoffen

Teil 114. Verfahren zur Bestimmung der Polierfähigkeit von Steinbaustoffenauf Straßenoberflächen

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 BSI BS*:BL2 P A R T * L L 4 49 W L b 2 4 b b î 0 0 2 2 4 b 7 b

BS 812 : Part 114 : 1989

Foreword a
This Part of BS 812 has been prepared under the direction
of the Cement, Gypsum, Aggregates and Quarry Products
Standards Policy Committee, It is a revision of clause 10 of
BS 812 : Part 3 : 1975, for the determination of the
polished-stonevalue of an aggregate. It is also a revision of
the alternative method for determining the polished-stone
value described in clause 11 of Amendment No. 2 to
BS 812 : Part 3 : 1975, which was published in March
1983. The method in this new Part 114 supersedes those
described in clause 10 and clause 11, both of which are
now withdrawn, The remainder of BS 812 : Part 3 is also
being revised and it is intended to issue further separate
Parts or Sections of the standard.
This t e s t method for determining the polished-stone
value i s basically that described in clause 11 of BS 812 :
Part 3 : 1975. The main changes are as follows.
(a) The procedure for mounting the aggregate in a sand
cement mortar is no longer described; only the resin
e
mounting method is to be used.
(b) The previous method determined an average value
from four specimens conditioned on one test run.
The revised method requires the conditioning of four
specimens in two pairs on two separate t e s t runs.
It is intended that other British Standards on aggregates
should call up BS 812 t e s t methods as the basis for
compliance. Nevertheless it is not intended that all
aggregates will be subjected regularly to all the listed
tests. Specifications in other standards should call up only
relevant t e s t methods. Some of the tests specified in other
Parts of this standard are of limited application and advice
on the use of simpler quantitative tests is given, for example,
when they can be used for a preliminary sorting of
aggregates to see whether more precise and expensive
testing is justified.
Reference should be made to BS 812 : Part 101 : 1984 for
general guidance on testing aggregates, precision of t e s t
methods and variance arising from sampling errors.
e
Compliance with a British Standard does not of itself
confer immunity from legal obligations.

a
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 Contents

Page
Foreword Inside front cover
Committees responsible Back cover

Method
1 Scope 2
2 Definitions 2
3 Principle 2
4 Sampling 2
5 Apparatus 2
6 Materials 6
7 Preparation of specimens 6
8 Conditioning of tyre 7
9 Accelerated polishing of specimens 7
1O Friction t e s t procedure 8
11 Calculations 8
12 Expression of results 9
13 Precision 9
14 Test report 9

Tables
1 Properties of the slider 5
2 Grading requirementsfor corn emery 6

Figures
1 Accelerated polishing machine 3
2 Roadstone specimen and mould 4
3 Friction tester 5

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 BS 812 : Part 114 : 1989

Method

1 scope to permit 14 of the specimens described in clause 7

to be clamped on the periphery so as to form a
This Part of BS 812 describes the method for determining continuous surface of stone particles 45 mm wide
the polished-stonevalue (PSV) of an aggregate. and 406 mm in diameter.
NOTE. The t i t l e s of the publications referred to in this standard (b) Means of rotating the road wheel about i t s own axis
are listed on page 9. a t a speed of 320 f 5 r/min.
(c) Two solid rubber-tyred wheels of 200 mm diameter
and with a width of 38 mm. These wheels shall be of
2 Definitions two colours. A dark-coloured wheel shall be used for
the corn emery and a light-coloured wheel for the
For the purposes of this Part of BS 812, the definitions
given in BS 812 : Parts 101 and 102 apply. emery flour. The rubber tyres shall be made according
to the Avon Tyre Ltd. compound code 4454 and shall
initially have a hardness of 69 +- 3 IRHD (see BS 2719).
NOTE. The rubber tyres are obtainable from the suppliers of
3 Principle the accelerated polishing machine.

The polished-stonevalue gives a measure of the resistance (d) Means of bringing the surface of the appropriate
of roadstone to the polishing action of vehicle tyres under solid rubber-tyred wheel to bear on the road wheel
conditions similar to those occurring on the surface of a with a total free force of 725 f 10 N. It shall be free
road. Where the surface of a road consists largely of road- to rotate about i t s own axis, which shall be parallel
stone the state of polish of the sample will be one of the with the axis of the road wheel, and the plane of
main factors affecting the resistance of the surface to rotation of the tyre shall be in line with that of the
skidding. The actual relationship between PSV and skidding road wheel.
resistance will vary with the traffic conditions, type of The machine shall be accurately aligned and both wheels
surfacing and other factors. All factors together with the shall be free to rotate without play in the bearings.
reproducibility of the test should be taken into account The following limits shall be applied:
when drawing up specifications for road-works which (1 ) the planes of rotation of the two wheels shall be
include t e s t limits for PSV. The t e s t is in two parts. not more than 20 min of arc out of parallel (1 rnm
(a) Firstpart. Samples of stone are subjected to a in 200 mm);
polishing action in an accelerated polishing machine. NOTE. This may be checked by means of a notched straight-
(b) Secondpart. The state of polish reached by each edge using the rim of the road wheel as a datum.
sample is measured by means of a friction t e s t and is (2) the planes through the centres of the two wheels
expressed as a laboratory-determinedPSV. shall be not more than 0.8 mm apart.
(e) Feed mechanism, dark-coloured for use with the
dark-coloured wheel (see (c)), t o feed the corn emery
4 Sampling" (see 6.1) and water at the specified rates (see 9.4).
It shall feed in such a way that the emery and water
The sample used in the laboratory for the t e s t shall be are continuously and uniformly spread over the surface
taken in accordance with clause 5 of BS 812 : Part 102 : of the tyre and the specimens where they are in contact.
1984. The sample shall be taken from the normal run of The emery and water shall be fed directly onto the road
production from the plant. wheel near the point of contact with the rubber-tyred
NOTE. Chippings that have been freshly crushed in the laboratory wheel,
or recovered from bituminous materials may give misleading
--

results. (f) Feed mechanism, light-coloured for use with the

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light-coloured wheel (see (c)), to feed the emery flour

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(see 6.2) and water a t the specified rates (see 9.5).

5 Apparatus It shall feed in such a way that the emery flour and
water are continuously and uniformly spread over the
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5.1 Acceleratedpolishing machine (figure 1), which shall surface of the tyre and the specimens where they are
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be rigidly mounted on a firm, level base of stone or in contact.

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concrete. It shall include the following. (9) A mearis of ensuring that the solid rubber-tyred
(a) A wheel, referred to as the 'road wheel', having a wheel is not left under load when not running, to prevent
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the risk of the tyre becoming deformed.

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flat periphery. It shall be of such a size and shape as

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5iourtes of supply of any of the apparatus or materials required for this t e s t can be obtained
necessary,, information on the current sources
*Where necescary,
from BSI Enquiry Section, BSI, Linford Wood, Milton Keynes MK14 6LE.
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 B S I BS*8L;! PART*L/4 84 = lb24bbî 0022470 b a
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Figure I. Accelerated polishing machine

5.2 Friction tester 5.2.1.2 The tester shall have the following features.
5.2.1 Design (a) A spring-loaded rubber slider of the mass, size and
shape specified in 5.2.1.3 to 5.2.1.6. It shall be
5.2.1.1 The friction test shall be made with a tester (see mounted on the end of a pendulum arm so that the
figure 3) manufactured to the design of the Transport sliding edge is approximately 510 mm from the axis
and Road Research Laboratory (TRRL)". All bearings of suspension.
and working parts of the instrument shall be enclosed
(b) Means for setting the column of the instrument
as far as possible, and all materials used shall be treated
vertical.
to prevent corrosion under wet conditions.

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 BSI B S * ô L 2 PART*lL4 89 3624669 0022473 ô =
BS812 : Part 114 : 1989

90.6 k 0.5mm
over a radius of
202.5 k 0.5mm

Dimensions of Test Specimen

All dimensions are shown in millimetres.

Figure 2. Roadstone specimen and mould

(c) Means for rigidly locating one of the curved 5.2.1.3 The mass of the swinging arm, including the slider,
specimens from the accelerated polishing machine with shall be 1.50 f 0.03kg. The centre of gravity shall lie on
i t s longer dimension in the track of the pendulum and the axis of the arm a t a distance of 410 f 5 mm from the
centrally with respect to the rubber slider and to the centre of suspension.
axis of suspension of the pendulum.
5.2.1.4 The slider shall consist of a rubber pad 31.75
(d) Means for raising and lowering the axis of suspension f 0.50 rnm wide, 25.4 f 1 .O mm long (in the direction of
of the pendulum so that the slider can: swing) and 6.35 f 0.50 mm thick. This shall be held on
(1) swing clear of the surface of the specimen; and a rigid base with a central pivoting axis and the combined
(2) be set t o slide over a fixed length of flat surface mass of slider and base shall be 20 f 5 g. The slider assembly
*
of 126.0 0.5 mm, as near as is visually possible. shall be mounted on the end of the swinging arm in such
a way that, when the arm is a t the lowest point of i t s swing
(e) Means of holding and releasing the pendulum arm so with the trailing edge of the slider in contact with the t e s t
that it falls freely from a horizontal position. surface, the plane of the slider is angled a t approximately
(f) A pointer balanced about the axis of suspension, 26 o to the horizontal. In this configuration the slider can
indicating the position of the pendulum arm throughout turn about i t s axis without obstruction to follow uneven-
i t s forward swing and moving over the circular scale. ness of the surface as the pendulum swings.
The mass of the pointer shall be not more than 85 g.
The friction in the pointer mechanism shall be adjust- 5.2.1.5 The slider shall be spring-loaded against the test
able so that, with the pendulum arm swinging freely surface. The nominal static force on the slider as set by
from a horizontal position, the outward tip of a the procedure defined in the equipment's calibration
nominal 300 mm long pointer may be brought to rest instructions shall be 22.2 f 0.5 N in i t s median position;
on the forward swing of the arm a t a point 10 mm below the change in the static force on the slider shall be not
the horizontal. greater than 0.2 N per millimetre deflection of the slider.
(9) A circular scale calibrated in unit F as described The resilience and hardness of the slider shall comply with
in 5.2.2.1 for curved specimens with 76 mm sliding table 1.
length. 5.2.1.6 The working edges of the slider shall be square
(h) A main scale as detailed in TRRL drawings for a and clean-cut, and the rubber free from contamination,
sliding length of 126 mm. by, for example, abrasive or oil. The rubber in the sheet
or slider form shall be stored in the dark a t a temperature
of 15 i75 'C.

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 BS 812 : Part 114 : 1989

Test specimen holder

Figure 3. Friction tester

I Table 1. Properties of the slider I

Property Temperature ( "Cl
O 10 20 30 40

Resilience (%) * 43 to 49 58 to 65 66 to 73 71 to 77 74 to 79
Hardness(1RHD)t 55f5 55I5 55+5 55+5 55I5

*LÜpke rebound test in accordance with BS 903 : Part A8.

tinternational rubber hardness degrees in accordance with BS 903 : Part A26.

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BSI B S X ä L 2 P A R T * L L 4 â7 W L b 2 4 b b î 0022473 L M
BS 812 : Part 114 : 1989

(f) Accurately machined metal moulds for preparing

5.2.2 Calibration of the tester
specimens of the dimensions shown in figure 2.
5.2.2.1 The calibration of the tester shall be checked a t (9) A pair of rigid metal covers having one face plane,
least once a year*. The scale of the instrument when used the other shaped t o the radius (189mm) of the polishing
for this test shall be the unit F , where F is a measure of the t e s t mould and slightly larger than the mould.
coefficient of friction (x IOO), drawn up by means of the (h) A clamp, such as a 200-mm G-clamp.
following equation:

F= (E) 100
(i)Two fine-haired brushes of about 3 mm diameter.
( j ) A stiff bristle brush.
(k) A spatula.
where
W is the force exerted by the swinging arm (in NI; 6 Materials
X i s the distance of the effective centre of gravity of 6.1 Fresh natural corn emery, complying with table 2.
the arm from the centre of oscillation (in mm); This shall be used only once.
Z.is the vertical distance of the edge of the scale below
the zero of the scale, which shall be 10 mm below
the horizontal when the arm is released to swing
I Table 2. Grading requirementsfor corn emery 1
freely from the horizontal (in mrn);
P is the nominal static force on the slider, as defined
in 5.2.1.5 (in N);
Nominal width
of sieve aperture

IJm
1Total passing

%
D i s the sliding distance (in mm);
600 98 to 100
p is the length of the pointer (in mm). 500 70 to 100
5.2.2.2 The instrument shall be cross-checked using the 425 , 30to 90
sliding length of 126 f 0.5 mm with the friction tester on 355 Oto 30
the following wetted surfaces using the main scale. 300. oto 5
(a) A glass plate.
(b) Five smooth-looking surfaces having a texture depth 6.2 Air-floated or water-washed emery flour, all of which
passes a 53 V t n test sieve.
less than 0.25 mm and covering a range of a t least
25 to 75 units. 6.3 PSV control stone, from a recognized supplier.
(c) Five rough-looking surfaces having a texture depth NOTE. To improve consistency of the material available, the control
greater than 0.50 mm and covering a range of a t least stone has been stockpiled. A t present the only recognized supplier
of material from this stockpile in Great Britain is Wessex Engineer-
25 t o 75 units. ing and Metalcraft Co. Ltd., Merchants Barton, Frome, Somerset
On these tests no pairs of results obtained with the two BA11 IPS.
instruments on any surface shall differ by more than
6.4 Stone for the calibration of the friction tester
3 units. The mean results for the 1 1 samples shall not (see 10.3).
differ by more than 1.5 units.
NOTE. This stone may be obtained from the suppliers of the PSV
5.4 Test sieves, consisting of a 10 mrn, square-holed, control stone or from Criggion Quarry, Ford, Powys.
perforated-plate sieve and woven-wire sieves, of sizes
600 pm, 500 pm, 425 pm, 355 pm, 300 pm, 212 pm.
The test sieves shall comply with BS 410. 7 Preparation of specimens
A 14 mm to 10 mm slotted flake sorting sieve complying
with BS 812 : Part 105 : Section 105.1,having a slot 7.1 Reduce the laboratory sample obtained in accordance
width of 7.2 k 0.1 mm, is also required. with clause 4,by the procedure described in clause 6 of
BS 812 : Part 102 : 1984 to produce a t e s t portion such
5.5 Equipment for preparing specimens, consisting of that when it is sieved in accordance with 7.2 a minimum
the following. of 2 kg is available for preparing the specimens.
(a) Release agent or liquid car polish.
7.2 Sieve the test portion so that all the aggregate particles
(b) Cleansing solvent or a mixture of 90 % acetone pass the 10 mm t e s t sieve and are retained on the 14 mm
and 10 %kerosene (by volume). to 10 mm flake sorting sieve. The particles shall not be
(c) Polyester resin and hardener. elongated and shall be clean and free from dust.
NOTE. Cryctic resin is suitable. NOTE. The surface texture of the particles which are t o be exposed
to the polishing action of the tyre should be representative of the
(d) Disposable paper or polypropylene cups for average surface texture of the stone. A few particles with a very
resin-mixing. smooth or very rough surface texture may occur in almost any
sample, but these are not to be used in preparing the t e s t specimen.
(e) Clear, flexible plastics sheet of materials, such as
acetate or polyethylene. 7.3 Obtain a minimum mass of 1 kg of the PSV control
I
stone by the procedures described in 7.1 and 7.2.
I
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BS 812 : Part 114 : 1989

7.4 Using the procedures described in 7.5 to 7.8 prepare 8.2 Following polishing (see clause 91, friction-test the
four specimens of each sample and four specimens of the control specimens in accordance with clause 10 and record
control stone. Each specimen shall consist of between 35 the mean result. If the mean result is greater than 55.5
and 50 particles, obtained as described in 7.2 and 7.3. make further preliminary runs using fresh specimens of
the control stone. If the result is less than 49.5 or if high
7.5 Prepare each specimen by carefully placing the selected
values persist, make appropriate corrections to the
particles in a single layer with their flattest surfaces lying
materials and procedure so as to ensure that the mean
on the bottom of the mould. Place them as closely as
value given by the following two specimens of control
possible and cover an area of 90.6 mm x 44.5 mm. Then
stone lies in the permitted range 49.5 to 55.5 (see note
fill the interstices between the particles to approximately
to 9.5).
threequarters of their depth with fine sand (all passing a
t e s t sieve of 212 pm aperture) and level with the second
fine-haired brush. Lightly coat the exposed internal faces
and top edges of the metal moulds with release agent using 9 Accelerated polishing of specimens
one of the fine-haired brushes.
9.1 Carry out the accelerated polishing a t a room
7.6 Mix the hardener with the resin in a disposable cup temperature of 20 f 5 OC.
(the exact proportion depends upon the resin used). 9.2 Fourteen specimens are polished during each run,
Fill the mould to overflowing with the mixed resin and numbered as follows:

| ---
float-off the surplus with the spatula without disturbing
the main body of the resin. two specimens of I s t sample numbered 1 and 2

| |
two specimens of 2nd sample numbered 3 and 4

|
NOTE 1. When using crystic resin (see note t o 5.5(c)), equal or

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nearly so proportions of the hardener and resin are suitable. two specimens of 3rd sample numbered 5 and 6
NOTE 2. As an alternative to floating-off, the surplus may be
two specimens of 4th sample numbered 7 and 8

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squeezed out by covering the mould with the plastics sheet and
pressing the metal cover on to the sheet. two specimens of 5th sample numbered 9 and 10

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7.7 When the resin begins io harden (after 5 min t o 10 min) two specimens of 6th sample numbered 11 and 12
trim any excess resin from the edges of the mould with a two specimens of PSV control stone numbered 13

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knife. Press the metal cover to the back of the specimen by and 14 and then arranged in the following order:

|
means of a clamp or weights t o prevent distortion during 13,9,3,7,5,1,11,14,10,4,8,6,2,12

--
setting. After the resin has completely set and cooled
(about 30 min from mixing), remove the specimen from 9.3 Clamp the 14 specimens in the specified order
the mould and remove the loose sand with the stiff bristle round the periphery of the road wheel of the polishing
brush. After a further 30 min it may be subjected to machine. Mark the specimens so that the direction of
polishing in accordance with clause 9. Clean moulds, rotation can be determined a t a later stage (see 10.4).
tools etc. as required with solvent, The outer surface of the specimens shall form a continuous
strip of particles with a periphery of 406 mm diameter,
7.8 Ensure that when the operations described in 7.4
upon which the rubber-tyred wheel can ride freely without
to 7.7 are completed, the surface of each specimen i s flat
bumping or slipping. Fill any gaps with a suitable packing
across the shorter dimension and is curved in the arc of a
piece level with the remainder of the specimen.
circle of 406 mm diameter along the longer dimension.
Also ensure that each finished specimen presents the 9.4 Bring the road wheel to a speed of 320 f 5 r/min
natural surface of the stone chipping, with no sharp and bring the dark-coloured wheel to bear on the surface of
projecting edges, to the polishing tyre and is not less than the specimens with a total force of 725 f 10 N. Feed the
12.5 mm thick. Ensure that the undersurface is the arc of corn emery (see 6.1) a t a rate of 27 f 7 g/min continuously
a circle of the same diameter as the periphery of the road with water on to the road wheel using the dark-coloured
wheel of the polishing machine. Reject any specimen with feed mechanism for a period of 3 h f 1 min. Feed the
resin exposed a t the surface or with disturbed particles. water at a rate just sufficient to carry the corn emery to
NOTE. The exposed surfaces of the specimens should stand proud the wheel; this is approximately the same rate as for the
of the backing resin. corn emery.
Interrupt the test run a t 1 hr +- 5 min and 2 hr f 5 min
to clean out any excess of corn emery which has collected
8 Conditioning of tyre in the base. On completion, ¡.e. after 3 h, thoroughly clean
the machine and specimens by washing so that all trace of
8.1 Before a new tyre i s used on a test, it shall be given a
the corn emery is removed.
preliminary run with the appropriate abrasive. Use the new
NOTE. It is important that the used corn emery is not allowed to
tyre as in an actual test but with 12 spare specimens and make contact with the road wheel.
two control specimens.
NOTE. I t is essential to use the correct wheel for each abrasive. 9.5 Fit the light-coloured wheel and feed mechanism for

-
It is also essential that the test includes the use of the other wheel emery flour. Then operate the machine continuously for
and appropriate abrasive to comply with the complete test a further 3 h t- 1 min (see 9.41, feeding the emery flour
procedure. Specimens from earlier tests are suitable as spare (see 6.2) a t a rate of 3 f 1 g/min continuously with water.
specimens in the preliminary run.
,
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BS 812 : Part 114': 1989

NOTE. I t is important that the solid rubber-tyred wheel is not left (c) Before measuring the set of specimens polished on
under load at any time other than when the wheel is running, each t e s t run, check the performance of the slider by
otherwise the tyre may become deformed. I t will be necessary to
replace the tyres periodically as indicated by excessive wear or testing a Criggion calibration specimen. Record the
by the control stone value moving below the range 49.5 to 55.5. resulting va Iue. Add itional polishing through repeated
It is essential that any tyre replacement be followed by r / r e testing yields progressively lower values and the control
conditioning in accordance with clause 8. Current experience shall be discarded when i t s value falls below 57. A new
indicates that replacement may be needed after 40 runs,
control shall then be drawn from the stock. If a check
particularly for the darkcoloured (coarse emery) wheel. Low
results in the early life of the tyre may suggest excessive polishing value is more than 2 units lower (or one unit higher)
due to misalignment of the wheels or the need to recalibrate the than the last recorded value for the control, discontinue
friction tester. testing and rectify any fault in the instrument or i t s
9.6 Remove the specimens from the machine and operation or due to changes in the slider. It is recom-
thoroughly wash them in running water to remove all trace mended that more than one slidfir be kept in use t o help
of emery flour. Clean the interstices between the stone differentiate between a faulty slider and a defective
particles by scrubbing with a bristle brush. instrument.
NOTE. Any trace of emery flour on or between the stone particles (d) Discard any slider that develops excessive burring
will lower the recut of the friction test. and scoring through prolonged use.
9.7 After washing, store the specimens face downwards 10.4 Rigidly locate the first t e s t specimen with i t s longer
under water a t a temperature of 18 O C to 22 O C for 30 min dimension lying in the track of the pendulum, and centrally
to 2 h. On removal from the water, immediately perform with respect to the rubber slider and to the axis of
the friction test in accordance with clause I O . At no time suspension of the pendulum. Locate it in such a way that
prior to this testing shall the specimen be allowed to dry the slider of the pendulum will traverse it in the same
out. direction as the specimen travelled in the polishing machine
9.8 Repeat the complete t e s t procedure (see 9.1 to 9.7) (see 9.3).
with two further specimens of each sample. NOTE. For this purpose it is advisable to mark one longitudinal
edge of each specimen. If this mark i$ on the side of the specimen
furthest from the operator during polishing, it should be nearest
to him during friction testing and vice versa.
I O Frictiontest procedure
10.5 Adjust the height of the axis of suspension of the
10.1 Keep the friction t e s t apparatus and slider in a room pendulum so that in traversing the specimen the rubber
where the temperature is controlled at 20 f 2 "C for a t slider is in contact with it over the whole width of the
least 2 h before the test begins and for the duration of the slider and over a length of 76.0 mm, as accurately as can
test. be visually gauged. Then wet the surfaces of the specimen
and the rubber slider with a copious supply of clean water,
10.2 Rest the tester upon a firm level surface and adjust
being careful not t o disturb the slider from i t s set position.
the levelling screws so that the column is vertical.
Release the pendulum and pointer from the horizontal
Then raise the axis of suspension of the pendulum so that
position and note the reading of the pointer to the nearest
the arm swings freely, and adjust the friction in the pointer
whole number. Perform this operation five times, rewetting
mechanism so that when the pendulum arm and pointer
the specimen each time, and record the mean of the last
are released from the right-hand horizontal position the
three readings to the nearest 0.1 unit.
pointer comes to rest a t zero position on the scale. Ensure
that the track of the slider is parallel to the long edge of Test the specimens in the following order:
the specimen across the sliding distance. 13,1,10,3,5,12,8,7,11,6,4,9,2,14
10.3 Use the following procedure to ensure that the rubber
slider is correctly conditioned.
NOTE. It is possible to reverse the slider to make use of both edges. 1 I Calculations
(a) Maintain a stock of Criggion specimens for calibra-
11.1 Calculate the mean of the recorded values of the two
tion purposes. These shall be made from stone from
PSV control stone specimens for each test run. Record to
Criggion Quarry and shall be made and polished as in
the nearest 0.1 unit providing two results for the complete
an actual determination. When tested they shall yield
duplicated test cycles.
a value in the range 58 to 66. Record the values and
air-dry the specimens and store them in a sealed 11.2 If the difference between the two mean values of
container for future use. the PSV control specimens for each test run is greater
than 4.7, the results for the t e s t shall be rejected. If the
(b) Before using a new slider, swing it five times over the
mean value of the two PSV control specimens for either
dry surface of a polished Criggion specimen fqllowing
t e s t run does not lie within the range 49.5 to 55.5 the t e s t
with a further 20 swings on i t s wetted surface! Keep the
results shall be rejected. The whole t e s t procedure shall

-
Criggion specimen used for this purpose apart from the
then be examined and modified as necessary to ensure
Criggion calibration specimens tested in (c); it may be
that these requirements for range and mean are satisfied.
used repeatedly provided i t s value (when wet) does not
fall below 55.
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11.3 For satisfactory test runs (see 11.2) the PSV of each I 3 Precision
sample shall be calculated as follows.
Calculate the mean value S of the recorded values of the Estimates of the repeatability ( r ) and reproducibility
four test specimens (two from each run) and record to the ( R I ) of the t e s t for determining the PSV are r = 3 and
nearest 0.1 unit. RI -5.
NOTE. Estimates are&, = 1.2, JVL = 1.I and JV specimens
Calculate the mean value C of the recorded values of the
= 1.2. These estimates are based on duplicate tests by 11 labora-
four control specimens (twofrom each run) and record to tories a t three levels of PSV (averaging 69,53 and 40).
the nearest 0.1 unit,
Uses of precision data are described in clause 5 of
Calculate the PSV from the following equation: BS812 : Part 101 : 1984.
PSV =s+52.5 -c
N O T E . This equation i s valid only for values of C between 49.5
a n d 55.5 14 Test report
The test report shall affirm that the PSV was determined in
12 Expression of results accordance with this Part of BS 812 and whether or not a
Certificate of Sampling is available. I f available, a copy of
Report the polished-stone value to the nearest whole
number together with the individual values and means of the Certificate of Sampling shall be provided. The test
the t e s t specimens and the control specimens. report shall contain the following additional information.
(a) Sample identification and sample description.
(b) The polished-stonevalue.
(c) The mean value recorded for the control stone.
(d) The values recorded for the four individual test
specimens and the four individual control stone
specimens, clearly indicating which specimens relate to
which test run.

Publications referred to
BS 410 Specification for test sieves
BS 812 Testing aggregates
Part 101 Guide-to sampling and testing aggregates
Part 102 Methods for sampling
Part 105 Methods for determination of particle shape
Section 105.2 Flakiness index
BS 903 Methods of testing vulcanized rubber
Part A8 Determination of rebound resilience
Part A26 Determination of hardness
BS 2719 Methods of use and calibration of pocket t y p e rubber hardness meters

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 BSI B S * 8 1 2 PART*LLL1 8 9 = 1624bb9 0022q77 7 '

BS812:Part 114:1989
This British Standard, having been prepared under the direction implenienting the standard, of necessary details such as symbols and
of the Cement, Gypsum, Aggregates and Quarry Products Standards size, type or grade designations. Enquiries should be addressed to
Policy Committee, was published under the authority of the Board the Publications Manager, BSI, Linford Wood, Milton Keynes
of BSI and comes into effect on 2 8 February 1990 MK14 6LE. The number for telephone enquiries is 0908 220022
O British Standards Institution, 1989 and for telex 825777.
Contract requirements. A British Standard does not purport to
ISBN O 580 17088 8 include all the necessary provisions of a contract. Users of British
The following BSI references relate to the work on this standard: Standards are responsible for their correct application,
Committee reference CAB/2 Draft for comment 86/10156 DC
Revision of British Standards. British Standards are revised, when
necessary, by the issue either of amendments or of revised editions.
British Standards Institution. Incorporated by Royal Charter, BSI i$ It is important that users of British Standards should ascertain that
the independent national body for the preparation of British they are in possession of the latest amendments or editions.
Standards. It is the UK member of the International Organization Automatic updating service. BSI provides an economic, individual
for Standardization and UK sponsor of the British National and automatic standards updating service called PLUS. Details are
Committee of the International Electrotechnical Commission. available from BSI Enquiry Section a t Milton Keynes, telephone
In addition to the preparation and promulgation of standards, BSI 0908 221 166, telex 825777.
offers specialist services including the provision of information
through the BSI Library and Standardline Database; Technical Help Information on all BSI publications is in the 6.9Catalogue,
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0908 221 166, telex 825777. revisions, amendments and withdrawn standards. Any person who,
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BSI. This does not preclude the free use, in the course of

Committees responsible for this British Standard

The preparation of this British Standard was entrusted by the Calcium Silicate Brick Association Ltd.
Cement, Gypsum, Aggregates and Quarry Products Standards Chartered Institute of Building
Policy Committee (CAB/-) to Technical Committee CAB/2, Concrete Society
upon which the following bodies were represented: County Surveyor's Society
Aggregate Concrete Block Association Department of the Environment (Property Services Agency)
Association of Consulting Engineers Department of the Environment (Building Research
Association of Consulting Scientists Establishment)
Association of Lightweight Aggregate Manufacturers Department of Transport (Highways)
Brick Development Association Department of Transport (Transport and Road Research
British Aggregate Construction Materials Industries Laboratory)
Electricity Supply Industry in England and Wales
British Cement Association
Federation of Civil Engineering Contractors
British Ceramic Research Ltd.
Institute of Concrete Technology
British Civil Engineering Test Equipment Manufacturers'
Institution of Civil Engineers
Association
Institution of Highways and Transportation
British Geological Sciences
Institution of Structural Engineers
British Precast Concrete Federation Ltd.
Institution of Water and Environmental Management (IWEM)
British Ready Mixed Concrete Association
Mortar Producers' Association Ltd.
British Steel Industry
Sand and Gravel Association Ltd.
Building Employers' Confederation
Society of Chemical Industry

Amendments issued since publication

Amd. No. Date of issue Text affected

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