BS 812-123

British Standard
A single copy of this British Standard is licensed to

Akin Koksal
Licensed Copy: Akin Koksal, Bechtel Ltd, 10 December 2002, Uncontrolled Copy, (c) BSI
10 December 2002
This is an uncontrolled copy. Ensure use of the most

current version of this document by searching British
Standards Online at bsonline.techindex.co.uk
| BS 812-123:1999
BRITISH STANDARD |
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Testing aggregates Ð |
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Part 123: Method for determination of |
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alkali-silica reactivity Ð Concrete prism |
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method |
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ICS 91.100.15 |
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NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW
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BS 812-123:1999
Committees responsible for this

British Standard
The preparation of this British Standard was entrusted by Technical Committee
B/502, Aggregates, to Subcommittee B/502/6, Test methods, upon which the
following bodies were represented:
British Civil Engineering Test Equipment Manufacturers Association

British Geological Survey
County Surveyors' Society
Department of the Environment, Transport and the Regions Ð Represented by the
Building Research Establishment
Department of the Environment, Transport and the Regions Ð Highways Agency
Quarry Products Association
UK Steel Association
United Kingdom Accreditation Service
This British Standard, having

been prepared under the
direction of the Sector
Committee for Building and Civil
Engineering, was published under
the authority of the Standards
Committee and comes into effect
on 15 June 1999
 BSI 08-1999 Amendments issued since publication

Amd. No. Date Comments
10613 August 1999 Indicated by a sideline

CorrigendumNo. 1
The following BSI references

relate to the work on this
standard:
Committee reference B/502/6
Draft for Comment 88/11922 DC
ISBN 0 580 28283 X

BS 812-123:1999
Contents
Page
Committees responsible Inside front cover
Foreword ii
1 Scope 1
2 Normative references 1
3 Terms and definitions 1
4 Principle 1
5 Sampling 1
6 Apparatus 1
7 Materials 2
8 Preparation of aggregate test portions 6
9 Mix design 6
10 Temperature and humidity conditions 7
11 Preparation of test prisms 7
12 Storage and measurement 8
13 Calculation and expression of results 9
14 Test report 9
Annex A (informative) Procedure for checking the uniformity of the

temperature within the room or cabinet used for storing the test prisms at
(38 ± 2) 8C 10
Annex B (normative) Proforma for calculating batch masses 10
Annex C (informative) Precision 11
Bibliography 12
Figure 1 Ð Example of stainless steel reference stud 3
Figure 2 Ð Example of reference stud providing hemispherical bearing 3
Figure 3 Ð Example of length comparator 4
Figure 4 Ð Container to provide humid environment around concrete prism 5
Table 1 Ð Mix proportions by volume for cement and dry aggregates 6
Table 2 Ð Temperature and humidity requirements 7
Table B.1 Ð Proforma for calculating batch masses for a 7 l concrete mix from
volume proportions 10
Table C.1 Ð Precision of the determination of the expansion of concrete prisms 11
 BSI 08-1999 i
BS 812-123:1999
Foreword
This British Standard has been prepared under the direction of Technical Committee
B/502. It specifies a method for the measurement of expansion of concrete produced
by alkali-silica reaction involving specific aggregate combinations, and is based on the
measurement of the length change of concrete prisms containing a high level of alkali
that are made from the aggregate under test.
| This test method was originally published as DD 218:1995, which is withdrawn.
Annex A is informative, annex B is normative and annex C is informative.
A British Standard does not purport to include all necessary 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
from legal obligations.
Summary of pages
This document comprises a front cover, an inside front cover, pages i and ii, pages
1 to 11, a blank page, an inside back cover and a back cover.
The BSI copyright notice displayed throughout this document indicates when the
document was last issued.
Sidelining in this document indicates the most recent changes by amendment.
ii  BSI 08-1999
BS 812-123:1999
1 Scope 4 Principle
This British Standard specifies a method of measuring Concrete test prisms are prepared from the aggregate
the expansion of concrete produced by alkali-silica combination under test, and stored for a period
reaction involving specific combinations of aggregates. of 52 weeks in conditions which would promote any
The method is designed as an accelerated laboratory potential alkali-silica reaction. During this time
test for a specific combination of aggregates and is not measurements are made at intervals to determine
considered to be a performance test for concrete. whether any expansion has occurred.
NOTE Aggregates are usually tested in the same combination as In order to promote the development of any expansive
when they are actually used. When the aggregate combination to forces and to ensure that slowly reacting aggregates
be used is not decided, however, the test sample of aggregate is are detected in the 52-week period, the test is
tested in combination with both an inert aggregate and an accelerated by:
aggregate geologically similar to itself in proportions specified in
the method. This procedure provides a generally satisfactory a) formulating the concrete to possess a higher than
assessment of the aggregate by accommodating any pessimum average cement and alkali content;
value which it may possess. b) storing the prisms at high humidity and a
comparatively high temperature (38 8C) to increase
2 Normative references the rate of the chemical reaction.
NOTE If expansion exceeding an agreed or specified limit is
The following normative documents contain provisions recorded in the test, or atypical expansion is obtained in routine
which, through reference in this text, constitute monitoring of an aggregate source, the individual test specimen
provisions of this part of this British Standard. For exhibiting the highest expansion may be examined to confirm that
dated references, subsequent amendments to, or alkali-silica reaction is the main cause of that expansion. Suitable
procedures are to be found in The Diagnosis of Alkali-Silica
revisions of, any of these publications do not apply. Reaction [1].
For undated references, the latest edition of the cited
publication referred to applies.
5 Sampling
BS 12, Specification for Portland cement.
The samples of coarse and fine aggregates used for the
BS 410, Specification for test sieves. test (the laboratory samples) shall be taken in
BS 812-2, Testing aggregates Ð Part 2: Methods for the accordance with the procedure specified in
determination of density. BS 812-102:1989, clause 5.
BS 812-100, Testing aggregates Ð Part 100: General NOTE The recommendations given in BS 812-102 are primarily
intended for sampling from a stockpile of aggregate. Where
requirements for apparatus and calibration. aggregate is being sampled from a quarry it is important to ensure
BS 812-101, Testing aggregates Ð Part 101: Guide to that the samples obtained for use in the test are satisfactorily
sampling and testing aggregates. representative of the sources concerned.
BS 812-102:1989, Testing aggregates Ð Part 102:

Methods for sampling. 6 Apparatus
BS 812-117, Testing aggregates Ð Part 117: Method for 6.1 General
determination of water-soluble chloride salts. All apparatus shall conform to the general
BS 882, Specification for aggregates from natural requirements of BS 812-100.
sources for concrete. 6.2 Sample divider, of size appropriate to the
BS 1881-108:1983, Testing concrete Ð Part 108: Method maximum particle size to be handled, or alternatively, a
for making test cubes from fresh concrete. flat shovel and a clean, flat, hard surface (e.g. a metal
tray), for use in quartering.
BS 1881-131, Testing concrete Ð Part 131: Methods for
NOTE A suitable divider is the riffle box illustrated in
testing cement in a reference concrete. BS 812-102:1989, Figure 2.
BS EN 196-6, Methods of testing cement Ð Part 6: 6.3 Test sieves, conforming to BS 410, of the size and
Determination of fineness. apertures appropriate to the nominal size of aggregates
BS EN 196-21:1992, Methods of testing cement Ð to be tested.
| Part 21: Determination of chloride, carbon dioxide 6.4 Balance, of minimum capacity 5 kg, readable
and alkali content of cement. to 1 g.
6.5 Balance, of minimum capacity 100 g, readable
3 Terms and definitions to 0.01 g.
For the purposes of this part of BS 812, the terms and 6.6 Four steel moulds, with cavities suitable for
definitions given in BS 812-100, BS 812-101 and casting concrete prisms of lengths (250 ± 50) mm. No
BS 812-102 apply. two cavities shall differ in length by more than 5 mm
and the cross-sections shall be (75 ± 2) mm by
(75 ± 2) mm. The moulds shall have the facility for
casting stainless steel reference studs into the
mid-points of the end faces of the prisms.
 BSI 08-1999 1
BS 812-123:1999
The reference studs shall be mounted inside the mould 6.10 Vibrating table, as specified in
before casting the prisms. The studs shall either have BS 1881-108:1983, 3.3.
smooth conical recesses into which a 6 mm ball may
be located, as shown in Figure 1, or shall provide 6.11 Containers, for maintaining a high relative
a 3 mm radius hemispherical bearing, as shown in humidity around the wrapped prisms during storage.
Figure 2. NOTE A suitable design of container is shown in Figure 4.
NOTE The use of stainless steel grade 316 S11, as specified in 6.12 Twill-weave cotton cloth, (240 ± 30) g/m2 dry, at
BS 970-1:1991, or a grade of similar quality, is recommended for least 10 mm wider, but not more than 20 mm wider,
the manufacture of reference studs.
than the length of the prisms.
6.7 Length comparator, incorporating a measuring
device with graduations not greater than 0.002 mm and 6.13 Polyethylene lay flat tubing, 500 gauge, 180 mm
having a maximum error of ±0.002 mm. The wide.
arrangement of the comparator and the range of 6.14 Polyethylene bags, 500 gauge, approximately
displacement of the gauge shall be such that specimens 500 mm 3 250 mm.
can be inserted and removed without damage or undue
pressure to the prisms, reference studs or measuring 6.15 Temperature-controlled room or cabinet, capable
device. of being maintained at a temperature of (38 ± 2) 8C
NOTE 1 To allow for typical variations of the prisms and the
throughout its storage space.
reference rod, a minimum range of displacement of the measuring 6.16 Temperature-recording equipment, capable of
device of 15 mm is recommended.
keeping a record of the temperature at one point
The gauge shall be mounted rigidly in a vertical within the storage facility (see 6.14).
orientation in a stoutly constructed measuring frame.

NOTE 2 An example of a measuring frame incorporating a 6.17 Temperature-controlled room, capable of being
mechanical gauge is shown in Figure 3. Similar devices utilizing maintained at a temperature of (20 ± 2) 8C and at a
digital or electronic gauges may be used. relative humidity of not less than 50 %.
Each stud locator of the comparator shall have a
6.18 Ventilated oven, thermostatically controlled at a
stainless steel hemisphere which can be placed into
temperature of (110 ± 5) 8C, for drying the aggregate.
the reference studs in the test prisms. Alternatively, if
reference studs which provide hemispherical bearings 6.19 Nine maximum/minimum thermometers.
are used, the comparator shall have recessed conical
cups which can be located onto the studs. 6.20 Steel rule, graduated in millimetres.
NOTE 3 Attention is drawn to the need to ensure the long term
stability and accuracy of comparators. In particular, mechanical 7 Materials
gauges should be checked for evidence of wear, and electrical
gauges for drift. 7.1 Potassium sulfate, of analytical reagent quality.
6.8 Reference length gauge rod, with ends machined 7.2 High-alkali Portland cement, with a certified
to match the shape of the reference studs in the alkali content1).
prisms. For example, for use with the recessed studs,
NOTE For testing other than reference and referee testing,
the rod shall have smooth conical recesses; for studs cement to the following specification may be used as an
with the hemispherical bearing, the rod shall have alternative to the certified reference cement. Portland cement
hemispherical ends of 3 mm radius. conforming to BS 12, having a total alkali content, expressed as
equivalent sodium oxide (the sum of the contents of Na2O
The rod shall be made from material which has a and 0.658 K2O), of not less than 0.8 % and not more than 1.0 % as
coefficient of linear thermal expansion, in the determined in accordance with BS EN 196-21:1992, clause 7
range 0 8C to 100 8C, of not more than 2 3 1024 % (see 9.3).
per 8C. WARNING Safety precautions should be taken when
NOTE 1 The material known as ªInvarº which is a nickel-iron preparing and handling test prisms made from mixes
alloy containing about 36 % nickel, has been found to be prepared from Portland cement. In particular, eyes
satisfactory.
should be protected during all mixing operations and
NOTE 2 The gauge length of the rod slowly diminishes with time
as the contact surfaces wear. It is therefore recommended that a gloves worn during mixing and whenever the test
second similar rod be stored for use as a primary standard for prisms are handled.
periodically checking the regular rod, or for use as a spare if
necessary. 7.3 Deionized water.
The gauge length of the rod shall not differ from the 7.4 Mixing water, of potable quality.
mean gauge length of the four prisms by more
than 5 mm.
6.9 Concrete mixing equipment, as specified in
BS 1881-131.
1) A reference cement with a certified alkali content can be obtained from Building Research Establishment, Garston, Watford, WD2 7JR.
2  BSI 08-1999
BS 812-123:1999
Dimensions in millimetres
9 5 Smooth conical recess
90 ± 5º
Ø6
10
7
6 B.A. thread
8 Circular grooves about

0.75 mm x 0.75 mm deep
or similar helical thread
Figure 1 Ð Example of stainless steel reference stud
22
3
R
Spherical end, smooth finish

Figure 2 Ð Example of reference stud providing hemispherical bearing
 BSI 08-1999 3
BS 812-123:1999
120
12
Rods
350
Figure 3 Ð Example of length comparator
4  BSI 08-1999
 BSI 08-1999
Measuring Insert
Section View
Container with air tight lid

Spacer
Top View
Concrete prism (nominal 75 x 75 x 250)
Prism wrapped in
damp cotton cloth
A and further double
wrapped in
polyethylene
Detail A
Clearance between prism
and plastic mesh not less
than 5 and not more than 20 Blotting paper held against
side of container by plastic
mesh
Measuring Insert
Support to hold prism

clear of Water
(Not less than 5 clearance)
BS 812-123:1999
Water
(minimum depth 20)
Figure 4 Ð Container to provide humid environment around concrete prism
5
BS 812-123:1999
8 Preparation of aggregate test portions 9 Mix design

8.1 If the chloride ion content of the aggregate, 9.1 Specific combinations of aggregates
determined in accordance with BS 812-117, If a specific combination of aggregates (see note 1) is
exceeds 0.01 %, wash the aggregate test portions twice, required for a mix design for a particular construction,
in each case using a fresh quantity of deionized water combine the aggregates in the proportions specified for
of twice the mass of the aggregate portion. Agitate the the construction mix.
aggregate with the first quantity of water for a few
minutes, and then decant the water; then soak the If the aggregate proportions are not yet established,
aggregate in the second quantity of water for 24 h use those given in Table 1.
before decanting and drying. Stir the aggregate at least In either case, the mix shall be prepared using the
twice during the soaking period. cement and water proportions given in Table 1.
NOTE 1 It is considered unlikely that minor adjustments to the
8.2 Oven-dry the laboratory samples of aggregate at a proportions of the fractions of aggregates from the same sources
temperature of (110 ± 5) 8C for (24 ± 2) h. will significantly influence the concrete prism test results.
Re-testing is not normally justified when the proportions of
8.3 Sieve the oven-dried laboratory sample of coarse aggregates are modified slightly from those originally designed and
aggregate into four fractions by means of sieves having tested.
apertures of 20 mm, 10 mm, and 5 mm. Weigh each of NOTE 2 Volume proportions are specified in order to maintain a
the four fractions and calculate the percentages of constant amount of cement (and hence alkali) per unit volume of
oversized and undersized materials which shall be aggregate when aggregates of different relative density are tested.
Allowance for the water absorption of the aggregate is made in
excluded from the test portions. order to achieve a constant free water content.
NOTE If a submitted aggregate sample contains oversized or

undersized materials in excess of the limits given in BS 882, it is Table 1 Ð Mix proportions by volume for
recommended that the suitability of the sample be reviewed with
the supplier or client, as appropriate, before proceeding with the
cement and dry aggregates
test. Material Proportion
% by volume
Reduce the four fractions by the procedure specified in
BS 812-102:1989, clause 6, to produce test portions of Cement 22.2
> 10 mm aggregate of approximate mass 5 kg, and of Coarse aggregates
< 10 mm aggregate of approximate mass 3.5 kg, plus < 10 mm 22.0
further portions of 2 kg and 1 kg respectively, for > 10 mm 16.5
density determination.
Fine aggregates 16.5
8.4 Sieve the oven-dry sample of fine aggregate into Water (free) 22.8
two fractions, using a sieve having 5 mm apertures.
Weigh each fraction and calculate the percentage 9.2 Other circumstances
oversize.
9.2.1 Fine aggregate
NOTE If a submitted aggregate sample contains oversized
material in excess of the limit given in BS 882, it is recommended If only a fine aggregate is supplied for test, test the
that the suitability of the sample as being representative be aggregate in the proportions set out in Table 1 in both
reviewed with the supplier or client, as appropriate, before the following combinations:
proceeding with the test.
Reduce the two fractions by the procedure specified in a) in combination with a coarse aggregate from the
BS 812-102:1989, clause 6, to produce a test portion of same or geologically similar source;
approximate mass 3.5 kg, plus a further portion of 500 g b) in combination with a non-reactive coarse
mass for density determination. aggregate2).
8.5 Determine the relative densities of the aggregates The grading of a fine aggregate shall be within the
in accordance with BS 812-2. Determine the water grading range appropriate to its normal production for
absorptions in accordance with BS 812-2, but for use as a concreting aggregate.
the 20 mm to 10 mm fractions and the 10 mm to 5 mm
fractions use a value for the water absorbed in 10 min. 9.2.2 Coarse aggregate
The particle densities and water absorptions are If only a coarse aggregate is supplied for test, test the
determined on aggregate portions which have had the aggregate in the proportions set out in Table 1 in both
< 63 mm fraction removed by washing. the following combinations:
a) in combination with a fine aggregate from the
same or geologically similar source;
b) in combination with a non-reactive fine
aggregate2).
2) Suitable non-reactive, coarse and fine aggregates are available from Building Research Establishment, Garston, Watford, WD2 7JR.
6  BSI 08-1999
BS 812-123:1999
9.3 Adjustment of the alkali content of the mix NOTE 1 Acceptable methods of keeping a record are:
a) a calibrated temperature probe linked to a chart recorder;
9.3.1 Adjust the alkali content of the mix, prepared as
b) a calibrated temperature probe linked to a data logger or
specified in clause 11, by adding potassium sulfate to personal computer that records the maximum and minimum
the mixing water to produce a mix having the same temperature each day;
alkalinity as a mix prepared from a cement having an c) a calibrated maximum/minimum thermometer that is read
alkali content of (1.00 ± 0.05) % sodium oxide and re-set on at least three days a week.
equivalent. Calculate the mass of potassium sulfate NOTE 2 Temperatures outside the tolerance of ±2 8C are allowed
required from the formula: for no more than a 48 h period, providing the temperature
tolerance is not exceeded by more than ±4 8C. These variations to
 1 2 s the procedure cannot be accepted more than four times during
M=C´ (1)
35. 56 a 52-week cycle.
where: 10.3 The temperature distribution of the room or
cabinet used for storing the test specimens at
M is the mass of potassium sulfate in grams (g), to (38 ± 2) 8C shall be verified at least once a year and
the nearest 0.01 g; after any major repair or replacement of heater
C is the cement content of the mix in grams (g); elements and/or thermostat. The room or cabinet shall
be filled with specimens to at least 50 % of capacity
s is the sodium oxide equivalent of the cement,
during the verification procedure.
expressed as a percentage.
NOTE A suitable procedure is given in annex A. Other
procedures may be used provided that it can be demonstrated that
9.3.2 Record the equivalent sodium oxide content of they give sufficiently accurate data.
the cement, and the mass of potassium sulfate added

to the mixing water per 100 g of cement.
11 Preparation of test prisms
10 Temperature and humidity conditions 11.1 Proportioning the concrete
Prepare the constituents in accordance with clause 9,
10.1 Use Table 2 to find the correct temperature and
using oven-dried aggregates. Calculate the batch
humidity of the laboratories and storage chambers
weights (see note) using the values for aggregate
used during the test.
relative density [oven-dried at (110 ± 5) 8C] and water
Table 2 Ð Temperature and humidity absorption determined in accordance with 8.5. If the
requirements relative density of the cement is not already known,
Stage Temperature Relative humidity
determine it by the method given in BS EN 196-6.
8C % NOTE For the preparation of four test prisms each
measuring 250 mm 3 75 mm 3 75 mm (see 11.3) a 7 l mix is
Mixing 20 ± 5 > 50 needed. A proforma for calculating the batch masses for a 7 l mix
First 24 h of storage is given in annex B.
in moulds 20 ± 2 > 90a 11.2 Mixing
Demoulding 20 ± 5 > 50
11.2.1 Add the required amount of potassium sulfate
The next 6 days after
to half the mixing water (see 9.3), ensuring that all the
demoulding 20 ± 2 > 96b
potassium sulfate is dissolved.
From 7 days age to
completion of test 38 ± 2 > 96b 11.2.2 Place the aggregates in the mixing pan, add
Length that half of the mixing water which does not contain
measurements 20 ± 2 > 50 the dissolved potassium sulfate, and mix the material
a To be achieved by the measures specified in 11.3. for 2 min. Allow the mix to stand for 8 min with the
b These values refer to the relative humidity immediately pan covered to minimize evaporation; then re-start the
around the prisms and may be achieved by the means specified mixer and add the cement gradually during the
in clause 12. next 30 s. Add the remainder of the mixing water
containing any dissolved potassium sulfate during the
10.2 Keep a record of the temperature at one point next 30 s and mix the concrete for a further 3 min.
within the room or cabinet used for storing the test
prisms at (38 ± 2) 8C. Use this record to set the 11.3 Casting
controls on the thermostat and heater so that, Cast four test prisms from each mix. Compact the
according to this record, the temperature varies within concrete into the moulds in two layers of
a range centred on 38 8C, i.e. so that the heater cuts in approximately equal depth, by the method specified in
when the temperature (in 8C) falls to (38 2 TA) and BS 1881-108 for compacting test cubes, using the
cuts out when the temperature (in 8C) rises to vibrating table.
(38 + TB). TA and TB are each no more than 2 8C, and
differ by no more than 0.5 8C.
 BSI 08-1999 7
BS 812-123:1999
After compacting the concrete, smooth the surfaces of Take this as the reading for the prism, a0. Similarly,
the prisms with a trowel and immediately cover the determine the gauge readings b0, c0, and d0
prisms with flat, impervious sheets (e.g. thin rubber, respectively for the other three prisms.
polyethylene, or steel) making contact with the upper Calculate the difference between the readings a0 and
edges of the moulds. Place the covered moulds inside r0 and take this as the initial measurement A0 of the
a polyethylene bag containing (10 ± 1) ml of water, and first prism. Similarly calculate the initial measurements
close the end of the bag. Cure the bagged prisms for B0, C0, and D0 of the other three prisms.
(24 ± 0.5) h in a place free from vibration and in
conditions which will prevent loss of moisture, either: 12.4 For each prism, cut a piece of the cotton
a) in a moist curing room or cabinet with a relative cloth 640 mm long and 10 mm wider than the length of
humidity greater than 90 %; the prism. Saturate each cloth with deionized water
(typically 80 ml is required for a cloth 260 mm wide)
b) wrapped completely with polyethylene or other and wrap one piece around the four large faces of
impervious sheeting, and placed under damp matting each prism in two layers. Place the wrapped prisms
or any other suitable material. into single pieces of the polyethylene tubing cut to the
NOTE 1 The preferred method of storing prisms during the same length as the prisms. Smooth each tube around
first 24 h of curing is that described in a). the cloth and secure with stout rubber bands.
NOTE 2 It is important to minimize loss of water during this NOTE No wrapping is applied to the end faces of the prisms.
initial hardening stage in order to reduce the risk of shrinkage
cracks forming in the specimens. Place the wrapped prisms in polyethylene bags.
Whichever method of moist air storage is used, Pour 5 ml of deionized water over the upper end face
of each prism and seal the bags. Place each bagged
maintain the temperature of the storage room or

cabinet at (20 ± 2) 8C. prism in a container (see 6.10) and ensure that it
contains water to a depth of at least 20 mm. Store at
(20 ± 2) 8C until the next measurement, which shall be
12 Storage and measurement at seven days after mixing.
12.1 On the day that the prisms are cast, place the 12.5 When the 7-day measurements are due, remove
comparator and its reference rod in the room, each prism from its polyethylene bag, but leave the
maintained at (20 ± 2) 8C, in which measurements are wrapping and rubber bands undisturbed. Clean the
to be made. For all subsequent measurements, place reference studs and take comparator readings on the
the comparator and its reference rod in the measuring reference rod and the four prisms by the procedures
room the day before measurements are to be made in given in 12.3. Record the readings r1 from the
order to allow the instruments to assume the reference rod, and a1, b1, c1 and d1 from the prisms
temperature of the room's atmosphere. Carry out all at 7 days. Calculate the 7-day measurements A1, B1, C1
measurements on the prisms at a temperature of and D1 from the difference between r1 and the four
(20 ± 2) 8C. prism readings.
12.2 Demould the prisms at (24 ± 0.5) h. Designate 12.6 Immediately after each measurement replace the
one end of each prism as the top and mark this end wrapped prism in its polyethylene bag. Pour 5 ml of
with a number for identification. Keep this end deionized water over the upper end of the prism
uppermost during all subsequent measurements. before sealing the bag. Check that there is at least
Immediately examine each prism and record any signs the 20 mm minimum depth of water in the containers
of plastic shrinkage cracks, or any other defects. and place the bagged prisms inside. Fit the caps. Store
Measure the length of each prism to the nearest 1 mm the containers in the cabinet or room maintained at
with a steel rule, and record these as the initial lengths (38 ± 2) 8C, until the prisms are required for further
la, lb, lc and ld. measurement.
12.3 Immediately after measuring the initial lengths of 12.7 24 h before making further measurements
the prisms, take a comparator reading on each prism (see 12.8), remove the prisms, inside their containers,
by the following method. from the room or cabinet and allow them to cool to
Clean the ends of the reference rod and the contact (20 ± 2) 8C.
surfaces of the comparator. Mark one end of the rod. When the prisms are returned to the storage room or
Place the rod in the comparator with the marked end cabinet, their positions shall be changed according to a
uppermost, slowly rotate the rod, and record the cycle that ensures that each prism is moved from top
minimum reading of the gauge to the nearest 0.002 mm. to bottom, from side to side, and from front to back of
Take this as the initial reference reading, r0. the room or cabinet during the 52 weeks of storage.
NOTE If a digital electronic device with a zeroing facility is used,
there is no need to record any reference readings, r0 etc.
Clean the prisms' reference studs and then place each
prism in turn in the comparator. Slowly rotate the
prism and record the minimum reading of the gauge to
the nearest 0.002 mm.
8  BSI 08-1999
BS 812-123:1999
12.8 At the end of periods two weeks, four Also calculate the mean length change of the four
weeks, 13 weeks, 26 weeks, 39 weeks and 52 weeks prisms for each measurement age. For example,
after mixing (see notes), remove the prisms from their at 4 weeks age the mean percentage length change m4
containers and take comparator readings on the is given by:
reference rod and the four prisms by the procedures
given in 12.3. Re-bag and store the prisms as described ha4 + hb4 + hc4 + hd4
m4 = (3)
in 12.6. Record the readings r2, a2, etc. and r4, a4, etc. 4
for 2 weeks and 4 weeks respectively, and so on.
Calculate the corresponding measurements A2, B2, etc. where ha4, hb4, hc4 and hd4 are the percentage length
and A4, B4, etc. changes of the four prisms at 4 weeks age.
NOTE 1 If measurements are to be continued beyond 52 weeks, Record this mean length change to the nearest 0.005 %.
intervals between successive measurements should not NOTE Estimates of the repeatability and reproducibility of this
exceed 13 weeks, except for the tolerance allowed in note 2. method and of the variability due to sampling are given in
NOTE 2 The casting day should be chosen so that readings can annex C.
be made precisely at 7 days and at 2 weeks after casting.
Subsequent readings can, exceptionally, vary from the set date by
up to 2 days. 14 Test report
NOTE 3 Maintenance of a consistently high humidity within each The report shall affirm that the test for measuring the
concrete specimen is critical to obtaining good reproducibility in
this test method. It is important therefore that the measurement
expansions produced by alkali-silica reaction was
of each prism is carried out without delay, so that the wrapped carried out in accordance with this British Standard
prisms are outside their sealed bags for the shortest possible time, and whether or not a certificate of sampling of the fine
thus avoiding excessive drying from the bare end faces. and/or coarse aggregates used is available. If available,
NOTE 4 If the mean expansion of the prisms between 39 weeks a copy of the certificate shall be provided. The test
and 52 weeks is greater than 0.010 % of initial measurement, they report shall contain the following additional
should continue to be stored under the stipulated conditions and
comparator readings should be taken after a further 13 weeks.
information:
This procedure should be repeated every 13 weeks until the mean a) the date of manufacture of specimens;
expansion between successive readings is less than 0.010 %, or
until an agreed mean cumulative expansion of the four prisms is b) the origin, identification and date of sampling (if
exceeded. available) of aggregates and cement;
12.9 Should any prism, when measured in the c) the aggregate combination tested and proportions
comparator, show a shrinkage relative to its initial by mass of aggregates;
reading at 24 h, that prism shall be discarded and all its d) details of the amounts, if any, of oversized or
readings disregarded. If two prisms show such undersized materials rejected;
shrinkage at any stage or stages, all four prisms shall e) the chloride content of the aggregate;
be discarded and the test repeated.
f) the equivalent alkali content of the cement and
the amount of potassium sulfate added per 100 g of
13 Calculation and expression of results cement;
Calculate the increase in length of each prism for each g) the percentage length change of each of the four
period of measurement, from the difference between specimens at each measuring age;
A0, B0, etc. and the appropriate values, An, Bn, etc. h) the mean length change for the set of four
where n is 1, 2, 4, 13, etc.. Calculate and report each specimens, to the nearest 0,005 %;
difference as a percentage of the initial length of the i) any noteworthy changes in the appearance of the
corresponding prism to the nearest 0.01 %. For specimens, such as cracking or surface deposits, and
example, at 4 weeks age the percentage length change the ages at which they were first observed.
ha4 of the first prism is given by:
If only a fine aggregate or only a coarse aggregate
A4 2 A0 has been tested, give the following information for
ha4 = 3 100 (2)
la items g) and h):
where: 1) the percentage length change of all eight
specimens at each measuring age;
A4 is the comparator measurement of the prism 2) the mean length change of the four specimens
at 4 weeks age; containing aggregate from the same or geologically
A0 is the initial comparator measurement of the similar source, to the nearest 0.005 %;
prism; 3) the mean length change of the four specimens
la is the initial length of the prism. containing the non-reactive aggregate, to the
nearest 0.005 %.
Record this length change to the nearest 0.01 %.
 BSI 08-1999 9
BS 812-123:1999
Annex A (informative) The room or cabinet should be considered to have a

satisfactory temperature profile if, after this period:
Procedure for checking the uniformity of a) no thermometer gives a minimum reading more
the temperature within the room or than 2 8C below the minimum reading on
cabinet used for storing the test prisms thermometer A;
at (38 ± 2) 8C b) no thermometer gives a maximum reading more
The procedure requires nine calibrated than 2 8C above the maximum reading on
maximum/minimum thermometers. thermometer A.
One of these (thermometer A) should be located close
to the sensor of the device used in 10.2 to keep a Annex B (normative)
temperature record.
Proforma for calculating batch masses
Four should be located in the upper one-third of the
usable space, and four in the lower one-third of the Table B.1 gives a proforma for calculating batch
usable space. Each should be at least 75 mm from the weights for a concrete mix from volume proportions.
sides of the room or cabinet. A 7 l mix is used as an example in this table.
Re-set the maximum/minimum indicators, then leave
the nine thermometers in position for 24 h.
Table B.1 Ð Proforma for calculating batch masses for a 7 l concrete mix from volume proportions
Material Volume of Volume Relative Batch masses for 7 l mix Water Absorbed water
material in for 7 l mix densitya absorption for 7 l mix
mix
% l G % g
Cement 22.2 1.554 Dc Mc = Dc 3 1 554
Aggregate: 22.0 1.540 D20 M20 = D20 3 1 540 A20 M20 3 A20
20 mm to10 mm W20 =
100
(nominal)
Aggregate: 16.5 1.155 D10 M10 = D10 3 1 155 A10 M10 3 A10
10 mm to 5 mm W10 =
100
(nominal)
Aggregate: 16.5 1.155 Ds Ms = Ds 3 1 155 As Ms 3 As
fine Ws =
100
Free water 22.8 1.596 1 596
Total absorbed W20 + W10 + Ws
water
Total added water 1 596 + W20 + W10 + Ws
Key
Dc is the density of the cement (g/cm3), determined in accordance with BS EN 196-6:1992;
D20 is the relative density on an oven-dry basis of 20 mm to 10 mm aggregate, determined in accordance with BS 812-2:1995;
D10 is the relative density on an oven-dry basis of 10 mm to 5 mm aggregate, determined in accordance with BS 812-2:1995;
Ds is the relative density on an oven-dry basis of fine aggregate, determined in accordance with BS 812-2:1995;
Mc is the total batch weight for the cement (g);
M20 is the total batch weight for 20 mm to10 mm aggregate (g);
M10 is the total batch weight for 10 mm to 5 mm aggregate (g);
Ms is the total batch weight for fine aggregate (g);
A20 is the percentage water absorption on a mass basis of 20 mm to 10 mm aggregate;
A10 is the percentage water absorption on a mass basis of 10 mm to 5 mm aggregate;
As is the percentage water absorption on a mass basis of fine aggregate;
W20 is the mass of absorbed water for 20 mm to 10 mm aggregate (g);
W10 is the mass of absorbed water for 10 mm to 5 mm aggregate (g);
Ws is the mass of absorbed water for fine aggregate (g).
a The density value used for cement is the particle density (g/cm3).
10  BSI 08-1999
BS 812-123:1999
Annex C (informative) C.2 The data for aggregate combination Z from two
laboratories contained outliers which were excluded
Precision from the calculation of repeatability and
C.1 The precision data given in Table C.1 were reproducibility.
determined from an experiment conducted C.3 The repeatability limits r0 and r1 (as defined in
in 1991 to 1992, involving 12 laboratories. Each Table C.1) which are to apply to expansion
laboratory was provided with two laboratory samples measurements (%) at ages earlier than 52 weeks may
of each aggregate fraction, and made two concrete be calculated from the following equations:
batches using each laboratory sample, and two prisms
from each concrete batch (i.e. they tested eight prisms
r0 = 0.40 E
for each aggregate combination). The aggregate
combinations tested were: r1 = 0.17 E + 0.003
X Chert fine aggregate from south-west England where

+ limestone coarse aggregate;
Y Trent Valley fine and coarse aggregates; E is the average of the percentage expansions to
which the limits are to be applied.
Z Thames Valley fine and coarse aggregates.
NOTE Modifications to the procedures have been made since
The reference cement specified in 7.2 was used for all these precision data were determined. The precision data given do
the tests. The prisms were stored at 38 8C and tested not apply to the modified test described in this British Standard,
after 52 weeks. which should yield significantly improved reproducibility.
Table C.1 Ð Precision of the determination of the expansion of concrete prisms

Aggregate Number of Average Repeatabilitya Reproducibilitya
combination laboratories expansion
% r0 r1 R1 R2
% % % %
X 12 0.278 0.097 0.054 0.155 0.155

Y 12 0.146 0.068 0.026 0.056 0.059
Z 10 0.039 0.017 0.007 0.057 0.059
Key
r0 is the value below which the range of test results for the percentage expansion of four individual prisms may be expected to
lie with a probability of 95 %, when individual prisms are made from the same concrete batch and tested over the same time
interval in the same laboratory by the same operator using the same equipment;
r1 is the value below which the absolute difference between two test results for the average percentage expansion of sets of
four prisms may be expected to lie with a probability of 95 %, when the prisms are made from different concrete batches and
tested over the same time interval in the same laboratory by the same operator using the same equipment, using the same
laboratory samples of the aggregate fractions;
R1 is the value below which the absolute difference between two test results for the average percentage expansion of pairs of
prisms may be expected to lie with a probability of 95 %, when the prisms are made from different concrete batches and
tested in different laboratories by different operators using different equipment, but using the same laboratory samples of
the aggregate fractions;
R2 is the value below which the absolute difference between two test results for the average percentage expansion of sets of
four prisms may be expected to lie with a probability of 95 %, when the prisms are made from different concrete batches and
tested in different laboratories by different operators using different equipment, and using different laboratory samples of the
aggregate fractions.
a For general definitions of these terms, see BS 5497-1.
 BSI 08-1999 11
blank
BS 812-123:1999
Bibliography
Standards publications
BS 970-1:1991, Specification for wrought steels for mechanical and allied engineering purposes Ð
Part 1: General inspection and testing procedures and specific requirements for carbon, carbon manganese,
alloy and stainless steels.
BS 5497-1, Precision of test methods Ð Part 1: Guide for the determination of repeatability and
reproducibility for a standard test method by inter-laboratory tests.
Other documents
[1] BRITISH CEMENT ASSOCIATION. The Diagnosis of Alkali-Silica Reaction. British Cement Association
Publication 45.042, 1992. (Publication available from the British Cement Association, Century House, Telford
Avenue, Crowthorne, Berkshire RG11 6YS.)
 BSI 08-1999
BS 812-123:1999 |
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British Standard

A single copy of this British Standard is licensed to

This is an uncontrolled copy. Ensure use of the most

Committees responsible for this

British Civil Engineering Test Equipment Manufacturers Association

This British Standard, having

 BSI 08-1999 Amendments issued since publication

10613 August 1999 Indicated by a sideline

The following BSI references

ISBN 0 580 28283 X

Annex A (informative) Procedure for checking the uniformity of the

BS 812-102:1989, Testing aggregates Ð Part 102:

orientation in a stoutly constructed measuring frame.

9 5 Smooth conical recess

8 Circular grooves about

Spherical end, smooth finish

Figure 3 Ð Example of length comparator

Container with air tight lid

Concrete prism (nominal 75 x 75 x 250)

Support to hold prism

8 Preparation of aggregate test portions 9 Mix design

NOTE If a submitted aggregate sample contains oversized or

the cement, and the mass of potassium sulfate added

maintain the temperature of the storage room or

Annex A (informative) The room or cabinet should be considered to have a

X Chert fine aggregate from south-west England where

Table C.1 Ð Precision of the determination of the expansion of concrete prisms

X 12 0.278 0.097 0.054 0.155 0.155

| implementation of those that have been published as British Standards, unless

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