Concrete Testing 1

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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 this

booklet are followedcarefully.

PARTOF THE MINERAL PRODUCTS ASSOCIATION

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


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This practical guide for site personnel covers:

Sampling,

The slump test

The flow test

Making cubes

Storing cubesit also gives guidance toSafety

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



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SamplingThe standard compositesample

BSEN12350-1

To ensure it is representative of thewhole load a standard sampleconsists of scoopfuls taken from

four 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 11/2times the estimated volume

required for testing.

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

Let very first concrete go

Take a scoopful from part 1Take a scoopful from part 2

Take 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 EN 206-1:2000,clause 5.4.1

Do not use this method to makecubes

For an early check on the

consistence 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 whole

width 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 EN12350-2Step 1

Empty the sampling buckets ontothe mixing tray

Scrape each bucket clean

Step 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 the

shovel 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 or

other 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 the

top of the coneStep 7

Carefullyclean off spillagefrom sides and base plate whilstmaintaining foot pressure

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Step 8 Carefullyliftthe cone straightup and clear, to acount of between2 and 5 seconds

Step 9

Lay the rodacross theupturned slumpcone

Measurethe distancebetween theunderside of

the 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 isnt true, take anew sample and repeat the test

If the second slump isnt true,

get advice

Complete the sampling andtesting certificates

There are threekinds of slump

TrueShear

Collapse

You will 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

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The flow test BS EN12350-5First 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 onto

the 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 the

mould straight upand clear to acount of between3 and 6 seconds

Step 6

Stabilise the flow table bystanding on the toe board at the

front 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 testing

certificates

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Making cubes BS EN12390-2Collect a composite sample to thestandard method described above.Concrete sampled using thealternative spot method must not beused to make cubes.

Step 1

Check that

the 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 low

temperature (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 EN12390-2Having 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/minimum

overnight storage temperatures onthe certificate

Step 2

Slacken all nuts Part the sides of the mould,tapping gentlywith the hide

hammer 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 at200C20C 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/minimum

thermometer Keep a record of the readings

Please 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 in

damp 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 safety

equipment.

If fresh, wet concrete touches

the skin, it can cause cementburns - some of which dontcause 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, waterproof

gloves, a sturdy jacket,waterproof trousers and long

boots.

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

medical 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 cant avoid kneelingin concrete, mortar orscreed, wear knee pads oruse an impervious mat



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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 these

publications.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 the Wall Company.

Published by

Mineral Products Association

Gillingham House,

38-44 Gillingham Street,

London SW1V 1HU

Tel: +44(0) 20 7963 8000

www.mineralproducts.org


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