Site Sampling Testing Concrete

A practical guide for site personnel

Site sampling andtesting of concrete

Cubes have a vital role totest that the concretestrength meets thespecification requirement.

However, the cube resultswill be meaningless unlessthe sampling and testingprocedures given in thisbooklet are followedcarefully.

PART OF THE MINERAL PRODUCTS ASSOCIATION

Sampling amended booklet amended:Layout 1 4/8/09 14:14 Page 1

This practical guide for site personnel covers:

Sampling,

The slump test

The flow test

Making cubes

Storing cubes

it also gives guidance to Safety

This practical guide for site personnel isintended to be used in conjunction withthe poster ‘Site sampling and testingconcrete


SamplingThe standard compositesample

BS EN12350-1

To ensure it is representative of thewhole load a standard sampleconsists of scoopfuls taken fromfour different parts of the load andcollected in buckets.

Scoopfuls must be taken throughthe moving stream, as the load isdischarged, sampling the wholewidth and depth – not just the toppart. The size of sample taken shouldbe 11/2 times the estimated volumerequired for testing.

Slump test - 6 litresFlow test - 41/2 litresCube test - 1 litre for each cube

Let very first concrete goTake a scoopful from part 1Take a scoopful from part 2Take a scoopful from part 3Take a scoopful from part 4Let the last concrete go

Complete a sampling certificate andrecord which sampling method wasused.

The alternative spotsample

BS EN206-1:2000,clause 5.4.1

Do not use this method to makecubes

For an early check on theconsistence of concrete delivered ina truck mixer, this alternative methodof spot sampling from the initialdischarge may be used. Additionaltolerances will be applicable forconcrete sampled by this method.

Scoopfuls must be taken through themoving stream sampling the wholewidth and depth.

Let very first concrete go

Take six scoopfuls from the next0.3m3

Take six scoopfuls after the first0.3m3 has been discharged.

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The slump test BS EN 12350-2

Step 1• Empty the sampling buckets ontothe mixing tray

• Scrape each bucket cleanStep 2• Thoroughly remix the sample,shovelling into a heap

• Turn the heap over to formanother

• Do this three timesStep 3• Flatten the finalheap by repeated-ly digging-in theshovel vertically

• Lift the shovelclear each time

Step 4• Ensure the slump cone and baseplate are clean and damp

• Place the metal plate on solidlevel base away from vibration orother disturbance

• Place the cone on the plate andstand on the foot-pieces

Step 5• Fill the cone in three equal depthlayers

• Use the standardslump rod

• Rod each layer25 times

• Spread the blowsevenly

• Heap theconcrete above thetop of the cone before rodding thethird layer over the area

• Make sure the rod just penetratesthe layer below

Step 6• Top up if necessary• Use the rodwith a sawingand rollingmotion to strikethe concretelevel with thetop of the cone

Step 7• Carefully clean off spillagefrom sides and base plate whilstmaintaining foot pressure

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Step 8• Carefully liftthe cone straightup and clear, to acount of between2 and 5 seconds

Step 9• Lay the rodacross theupturned slumpcone

• Measurethe distancebetween theunderside ofthe rod and the highest point of theconcrete – the true slump

• Record the distance to thenearest 10mm

• Check and record the kind ofslump

• If the slump isn’t true, take anew sample and repeat the test

• If the second slump isn’t true,get advice

• Complete the sampling andtesting certificates

There are three kinds of slump

TrueShear

Collapse

Youwill need this equipment(always clean and dry the equipment

after use)

� Small scoop

� Slump rod

� Square-mouthed shovel

�Mixing tray

� Buckets or wheelbarrow

� Sampling and testing certificates

� Steel rule

� Damp cloth

� Sampling scoop

� Slump cone and rigid metal plate

3


The flow test BS EN 12350-5

First find a suitable location for aflow table. It must be placed on afirm, flat and level surface. It may benecessary to prepare an area for thetable.

Step 1• Empty the sampling buckets ontothe mixing tray

• Scrape each bucket cleanStep 2• Thoroughly remix the sample asdescribed for the slump test

Step 3• Ensure themould and tableare clean anddamp

• Place themould on thecentre of thetable and stand on the foot-pieces

• Fill the mould in two layers,tamping each layer ten times withthe tamping bar

• If necessary add more concrete tofill the top layer

• Use the tamping bar to strike thetop layer level with the top of themould

Step 4• Carefully clean off spillage fromaround the mould and table top

Step 5

• Wait 30 seconds from striking off

• Carefully lift themould straight upand clear to acount of between3 and 6 seconds

Step 6• Stabilise the flow table bystanding on the toe board at thefront of the table

Step 7• Slowly lift the table top by thehandle until it reaches the upperstop

• Allow the table to fall freely• Repeat this cycle to give a total of15 drops

• Each cycle should take about4 seconds

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Step 8• Measure the largest dimension ofconcrete spread in two directions,parallel to the table edges

• Record the flow value as d1 + d2divided by 2

• Report any segregation which mayhave occurred around the sampleedge

• Complete the sampling andtesting certificates


after use)

� Sampling scoop

� Small scoop

� Damp cloth


� Hardwood tamping bar

� Square mouth shovel

�Mixing tray

� Flow table

� 700mm rule

� Sampling and testingcertificates

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Making cubes BS EN 12390-2

Collect a composite sample to thestandard method described above.Concrete sampled using thealternative spot method must not beused to make cubes.

Step 1• Check thatthe mouldsare clean andlightly oiledwith all boltstightened sothat therewill be no leakage

• Ensure that the correct halves ofthe moulds are used and that thecorner lifting pins are correctlylocated

• Thoroughly remix the sample asdescribed for theslump test

Step 2• Fill the mouldwith concretein 50mm layersusing the tampingbar, compact theconcrete with nofewer than 25 tamps for each of thetwo layers in a 100mm mould and

no fewer than 35 tamps for for eachof the three layers in a 150mmmould

• For very high workability concreteyou may not need the minimumnumber of tamps

Step 3• After tampingof each layer, tapthe sides of themould with thehide hammer untillarge bubbles ofair cease toappear on the surface and the holesleft by the tamping bar are closed

Step 4

• Remove surplus concrete andsmooth over with a float

• Wipe clean themould edges

• Number themoulds foridentification andrecord details andimmediately placewhere they are tobe storedovernight

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Step 5• Cover each mould with a dampcloth and plastic sheet

• Store inside at room temperature(15-250C) e.g. on top of the curingtank

• Protect the cube moulds at alltimes from high and lowtemperature (especially sub-zerotemperatures) and drying winds

• Complete the sampling and cubemaking certificates


after use)

� Sampling scoop

� Small scoop

� Damp cloth and plastic sheeting


� Tamping bar

� Brush and mould oil

� Curing tank

�Hide hammer

�Maximum/minimum thermometer

� Square-mouthed shovel

� Felt tip pen or crayon

� Cube moulds

� Spanner

�Mixing tray

� Damp cloth

� Sampling. cube making and storagecertificates

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Storing cubes BS EN 12390-2

Having stored the moulds atbetween 15_250C the cubes shouldbe removed from the moulds noearlier than 16 hours and no laterthan 72 hours after casting.

Step 1• Record the maximum/minimumovernight storage temperatures onthe certificate

Step 2• Slacken all nuts• Part the sides of the mould,tapping gentlywith the hidehammer

• Lift offcarefully

• Remembernew cubes areeasily damagedunless handled carefully

Step 3• Mark each cube with itsidentification number on two of itscast sides

Step 4• Place thecubes in thecuring tankwith the watertemperaturecontrolled at200C ± 20C andthe cubes covered by water

Step 5• Clean and reassemble the moulds• Make sure the power supply is notswitched off day or night

• Check the temperature range dailyusing the maximum/minimumthermometer

• Keep a record of the readingsPlease note• If you have no curing tank,transport the cubes to the testinglaboratory within the 72 hour period

• For despatch to the testlaboratory, wrap the wet cubes indamp cloths, and then plastic bagsand pack in trays

• Attach the certificates forsampling, testing, cube making andstorage to the package – along withthe order for testing

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The first rule of working withconcrete is to be protected.

Ensure that the personnel arewearing adequate safetyequipment.

• If fresh, wet concrete touchesthe skin, it can cause cementburns - some of which don’tcause pain or dermatitis.

• The longer the skin is in contactwith the concrete, the worse theinjury will be. So it makes senseto protect yourself by wearingsafety goggles, waterproofgloves, a sturdy jacket,waterproof trousers and longboots.

• If wet concrete does contactyour skin, wash immediately andthoroughly with clean water.And if your eyes are affected, seekmedical help immediately.

• Remove and wash anyprotective clothes or boots thatbecome impregnated with freshconcrete, but making sure youwash yourself first.

• The water in the curing tank ishighly alkaline so ensure thatgloves are used when handlingcubes in the tank.

• Fresh concrete is heavy, with abarrow load weighing over 100kg.So carrying just a small volumemay cause physical injury.

Therefore organise enough help sothat you can place, compact andfinish the work before it setswithout straining yourself.

Safety

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Safety spectaclesor goggles

Wellington boots

Always wearlong trousers

Protect your handsat all times withwaterproof gloves

If you canʼt avoid kneelingin concrete, mortar orscreed, wear knee pads oruse an impervious mat


The other practical guide for site personnel inthis series is:‘Placing, compacting and curing concrete’.TCC/03/42

There are also A2 size posters of each of thesepublications.‘Placing, compacting and curing concrete’.TCC/03/41

‘Site sampling and testing of concrete’.TCC/03/39

All advice or information from Mineral Products Association is intended for use inthe UK only by those who will evaluate the significance and limitations of its con-tents and take responsibility for its use and application. No liability(including that for negligence) for any loss resulting from such advice orinformation is accepted by Mineral Products Association or its subcontractors,suppliers or advisors. Readers should note that the publications from MineralProducts Association are subject to revision from time to time and shouldtherefore ensure that they are in possession of the latest version.

Ref: TCC/03/40ISBN 978-1-904818-74-8Published May 2009

©Mineral Products Association

Produced and printed byThe Book on theWall Company.

Published byMineral Products AssociationGillingham House,38-44 Gillingham Street,London SW1V 1HUTel: +44 (0) 20 7963 8000

www.mineralproducts.org


Documents

Site Sampling Testing Concrete