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CONCRETE AND CONCRETING

1 Reference to British Standard

This Specification for concrete used in the Works is based uponthe following British Standards with the latest amendments:-

B.S. 12: 191 !ortland "ement #$rdinar% and &apid'ardening(

B.S. )1*: 19+9 Test sie,es

B.S. 12: 19+ ethods for the Sampling and Testing ofineral /ggregates0 Sands and illers

B.S. 2: 19+ /ggregates from 3atural sources forconcrete #including granolithic(

B.S. 11: 19* ethods of Testing "oncrete

B.S. 41): 199 Tests for Water for aking "oncrete.

B.S 42: 199* !art ) Specification for the proceduresto be used in sampling0 testing and assessingcompliance of concrete.

This Specification shall be interpreted0 and all sampling andtesting shall be carried out0 in accordance with the rele,antclauses in these Standards.

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3otwithstanding an% pre,ious acceptance an% bag of cementcontaining material which has hardened or otherwise

deteriorated shall be re;ected and remo,ed from the site b% the"ontractor forthwith and at his own e

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harmful 5uantities of cla%0 crusher dust0 organic impurities orother deleterious matter.

"oarse aggregate containing an e

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/ll reinforcement shall be cleaned from loose millscales0 loose

rust0 oil0 grease0 earth and other harmful matter before beingplaced in the forms and shall be free from these at the timethe concrete is placed.

1) Bending* +$acing and i,ing Reinforcement

/ll reinforcement shall be bent cold using bar bending machinesand appliances appro,ed b% the 7ngineer. 6nless otherwisespecified in the Crawings the bending dimensions and tolerances

and the dimensions of end anchorage0 hooks0 binders0 stirrupsand the like shall be in accordance with B.S. ))++0 8BendingCimensions and Scheduling of Bars for the &einforcement of"oncrete8.

The reinforcement shall be accuratel% assembled firml% securedb% wire ties made from 3o. 1+ S.W.D. soft annealed wire so thatthe whole assembl% is rigid and will not be displaced whileconcrete is being compacted around it. The ends of the wireties shall be turned inward awa% from the face of the forms andshall not be left pro;ecting be%ond the reinforcing bars.

Temporar% bracing shall be pro,ided to pre,ent mo,ement of allsteel pro;ecting from the concrete during the course ofconstruction.

The co,er shown on the Crawings shall be maintained b% precastspacing blocks securel% wired to the bars or b% other means

d b th 7 i S i Bl k f th i

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F-t%pe and two butt weld bend tests shall be carried out on aspecimen prepared to represent each form of butt welded ;oint.

The method of making weld tests shall be that laid down in B.S.*9: 19+).

12 orm-or.

The formwork shall be constructed with an% of the followingmaterials:-

#i( Sound softwood tongued and groo,ed boards not less than2* mm finished thickness0 wrought on one side and twoedges0 accuratel% formed and securel% fi

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surfaces within the forms shall be thoroughl% flushed withwater. The forms ma% with the appro,al of the 7ngineer be

treated with an appro,ed composition. "are should be taken toensure that such composition is kept out of contact with thereinforcement and concrete ;oint surfaces0 and that there is noe

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1" Sam#$ing and Testing Concrete and Concrete /ateria$s

/ll sampling and testing will be carried out in accordance withthe standard methods laid down in B.S. 110 19* unlessotherwise specified in the following clauses.

The "ontractor shall attend upon and pro,ide all assistance tothe 7ngineer when such sampling and tests are carried out0 andshall suppl% all concrete samples and other materials re5uired.

1% reenc0 of Sam#$ing and Testing

#i( "ompacting actor

The compacting factor of the mi< will be tested.

#a( dail% while concrete is being placed0

#b( Whene,er samples for test cubes are taken0

#c( Whene,er0 in the opinion of the 7ngineer0 thegrading or condition of an% of the aggregates haschanged since the last test was made.

#ii( Test "ubes

/ set of + concrete test cubes0 4 for testing at da%sd 4 f t ti t 2 d ft ti ill b d

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measures ha,e been taken to produce concrete which complieswith this Specification.

f the cube strengths at 2 da%s are less than those specified0the work from which the concrete for the test cubes was takenwill be re;ected b% the 7ngineer0 and will be broken out andrebuilt or otherwise made good as directed b% him at the"ontractor8s own e

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"oncrete ma% be con,e%ed b% chute onl% with the permission ofthe 7ngineer. /n% concrete which has attained its initial set

before being placed shall be discarded. !lacing concrete shallbe suspended during rain.

"oncreting shall be carried out continuousl% between and up tothe predetermined da%8s work or construction ;oints in onese5uence of operation.

/ll concrete shall be placed in the position in which it is tobe compacted and the material shall not be allowed to flow whileit is being placed and compacted. Fibrators shall be used solel%for compacting the concrete and not for distributing it intoplace. The concrete shall be pre,ented from flowing laterall% b%the use of ,ertical stopping off boards0 or other ,erticalfaces0 and the surface of the concrete shall be maintainedreasonabl% le,el during placing. "oncrete shall be placed in theformwork in la%ers not e

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the ad;oining area and the operation shall be repeated untilthe whole surface has been compacted. /lternati,el% a

,ibrator spanning the full width of the panel shall be used.

n all cases the placing of concrete shall be sufficientl%ahead of the ,ibrators so that the mass of concrete be%ond the,ibrators is sufficient to stand without flowing while,ibration is in progress. $n the other hand0 the concrete shallbe full% compacted before initial set is attained.

23 Constrction of Concrete Screed

/s soon as the e

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Where reinforcement is continuous across the ;oints0 notched,ertical stopping off boards shall be used for the

reinforcement to pass through.

The ;oints shall each ha,e a 6-groo,e formed at the top torecei,e sealing compound.

2! Constrction of 'a$$s of 'ater Retaining* 'ater Cone0ing* or

'ater E,c$ding Strctres

The walls are di,ided into segments b% ,ertical ;oints whichare continuous with the floor ;oints and e

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concreted. The indi,idual segments shall be cast in onecontinuous operation0 the concrete being placed and compacted

in regular strips across the full width of the segments. 7achstrip shall be placed against the pre,ious strip before theconcrete in the latter has attained its initial set. Wherereinforcement is continuous across the ;oints0 the ,erticalstopping off boards shall be notched to allow the reinforcementto pass through. The ;oint shall each ha,e a 6-groo,e formed onthe top to recei,e sealing compound.

2& 6oints

The "ontractor shall make the ;oints in the floors0 walls androofs strictl% in accordance with the Crawings. !articular careshall be taken to ensure that the waterstops where,er shown onthe Crawings are ade5uatel% secured so that the% will not bedisplaced while concrete is being placed. 6nder no circumstanceshall waterstops be nailed through. /n% water stop which hasbeen perforated shall be re;ected and replaced at the"ontractor8s e

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When concreting must be suspended at an% point because of

inclement weather0 or for an% unforeseen cause0 a da%8s work;oint shall be made.

When concrete at a da%8s work ;oint shall be allowed to hardenfor 2 hours. Before fresh concrete is placed against the da%8swork ;oint0 all loose and imperfect materials cement scums orlaitance shall be remo,ed from the ;oint surface0 which shallbe thoroughl% hacked until a completel% hacked0 roughened freshsurface is obtained. The fresh surface shall then be brushedclean0 and immediatel% before fresh concrete is placed againstit0 it shall be thoroughl% wetted and co,ered with a la%er of1:1-1@2 cement and sand mortar not less than )* mm thick. Themortar shall ha,e the consistenc% of condensed milk.

3) Sea$ing Com#onds

$nl% non-hardening sealing compounds appro,ed b% the 7ngineershall be used for sealing the groo,es pro,ided at ;oints.

/ll sealing compounds shall be applied in strict accordancewith the manufacturer8s instructions. The groo,es for recei,ingthe sealing compounds shall be thoroughl% brushed to remo,egrit0 soil and other loose particles. The groo,es and thesurrounding concrete shall be thoroughl% dried b% such means asthe 7ngineer shall direct0 and the sealing compounds or primersshall be applied before dampness returns to the surface of theconcrete.

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e

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programme agreed to b% the 7ngineer without such shock or,ibration as would damage the concrete and without interruptionto the curing of the concrete as herein before specified inthis Specification. 3ormall% formwork shall be struck after thefollowing periods ha,e elapsed.

rom sides of beams0 walls and columns

#unloaded( .. 4 da%s

rom bottom of slabs #props left under( .. da%s

rom soffits of beams #props left under( .. da%s

&emo,al of props under slabs #unloaded( .. 1) da%s

&emo,al of props under beams #unloaded( .. 1) da%s

"oncrete e

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float so that a uniform smooth and dense surfacethroughout is finall% presented.

/ll defects on concrete surfaces which will be permanentl%concealed in the finished structure shall be repaired and madegood as directed.

3" Testing for 'atertightness

The "ontractor shall0 at his own e

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Should an% leakage and@or percolation de,elop during the defectsliabilit% period specified in the "ontract0 remedial measuressimilar to those specified abo,e0 followed b% tests forwatertightness0 shall be carried out b% the "ontractor at hisown e

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41 Concrete +i#es

!lain or reinforced concrete pipes shall compl% with there5uirements of /ustralian Standards /.S. 14)2 and "/ 440 andshall be manufactured b% the centrifugal spinning process.The manufacturer8s certificates of test will be accepted asproof of the 5ualit% of the concrete pipes but the 7ngineerma%0 at his discretion0 re5uire for additional testing to bemade on samples of concrete pipes stored at the site. n thee,ent of an% concrete pipe being found to be not in accordancewith the rele,ant Standard under the additional tests or in thecourse of being worked0 the whole batch of pipes from which thefault% pipe comes ma% be re;ected b% the 7ngineernotwithstanding an% pre,ious acceptance on the strength of themanufacturer8s certificate. /n% pipe re;ected b% the 7ngineershall be remo,ed from the site at the "ontractor8s e

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Works test cubes to be made on Site b% the "ontractor inaccordance with the pro,ision of this Specification0irrespecti,e of an% sampling and@or testing which ma% becarried out b% the supplier.

43 To$erances and Defects

The permissible surface tolerances shall not e

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T/BA7 G/I

!&$!$&T$3S J ST&73DT'S $ "$3"&7T7

========================================================================================================================

3ominal i< Water Sie "ompacting inimum "ompressi,eCesig- Aocation in "ement@ine 7stimated !roportions of including of actor for Strength of Worksnation Works /ggregate@ ------------------------- Water in "oarse Fibrated "ubesof i< "oarse !ortland ine "oarse /ggregate /ggregate "oncrete --------------------- /ggregate "ement /ggregate /ggregate at da%s at 2 da%s========================================================================================================================

3@mm2 3@mm2

Drade 1:1:2 * kg ) kg 9 kg 22 litre 2* mm . 21 4* 4* to .9)=========================================================================================================================

Drade 1:1.:4 * kg * kg 1) kg 2 litre 2* mm .+ 1 2.*2 to

.9*=========================================================================================================================

Drade 1:2:) * kg 1* kg 19) kg 4* litre 2* mm .2 1) 2*2* to

.+=========================================================================================================================

ass 1:4:+ * kg 1* kg 4** kg as 2* mm - . ."oncrete directed=========================================================================================================================

3ote: #i( When concrete is compacted b% hand #and not ,ibrated( the compacting factor and the mi< shall be determined b% the 7ngineer when the preliminar% test mi