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Guide to sampling concrete

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  • 1. &ite sampling testingof concreteA practical guide for site personnel
  • 2. FORENORDDuring the next few years, specifications will change An accompanying publication entitled Site samplingfrom using the as 1881 test methods to those given in and testing of concrete: a site managers guide hasthe series as 12350: Testing fresh concrete and the also been produced to assist site engineers andseries as 12390: Testing hardened concrete. managers to ensure that sampling and testing areFortunately the tests included on this poster are the carried out correctly. The guide highlights some of thesame and the only difference is in the reporting of the potential problems associated with using incorrectslump and flow values. However on the test certificate, procedures.it is necessary to report the standard used. Dont forget - The test results will be misleading if these procedures are not carried out. Get it right - Otherwise its a waste of time and could cost your company money. For fulldetailsof equipment,testsandrecords see:as 1881: Testing concrete, aSEN12350:Tesdngfreshconcret~and as EN 12390: Testing hardened concrete.
  • 3. SafetyWhen Portland cement is mixed with water, or even becomes damp, alkalis are released which can be harmful tothe skin. The effect depends on the length of contact, any abrasion, the individual, and the part of the bodyinvolved. Suitable protective clothing should be worn. If eyes are affected they should be washed out withoutdelay and medical attention sought.All advice or information in this publication is intended for those who will evaluate the significance and limitationsof its contents anCltake responsibility for its use and application. No liability (including that for negligence) for anyloss resulting from such advice or information is accepted. Readers should note that all publications are subject torevision from time to time and should therefore ensure that they are in possession of the latest version.
  • 4. SAMPLING BS1881:Part101or BSEN 12350-1The standard methodTo ensure it is representative of the whole load a Sample as the load is discharged.standard sample consists of scoopfuls taken from Scoopfuls must be taken through the moving stream,four different parts of the load and collected in sampling the whole width and depth - not just thebuckets. top part. let very first concrete go Take a scoopful from part 1 Take a scoopful from part 2 Take a scoopful from part 3 Take a scoopful from part 4 let the last concrete goComplete a Sampling certificate and record which sampling method was used.
  • 5. SafetyWhen Portland cement is mixed with water, or even becomes damp, alkalis are released which can be harmful tothe skin. The effect depends on the length of contact, any abrasion, the individual, and the part of the bodyinvolved. Suitable protective clothing should be worn. If eyes are affected they should be washed out withoutdelay and medical attention sought.All advice or information in this publication is intended for those who will evaluate the significance and limitationsof its contents and take responsibility for its use and application. No liability (including thatfor negligence) for anyloss resulting from such advice or information is accepted. Readers should note that all publications are subject torevision from time to time and should therefore ensure that they are in possession of the latest version.
  • 6. BS1881:Part 102orBSEN206-1: 2000, clause5.4. 1ThealternativemethodFor an early check on the workability of concrete Sample as the load is discharged.d€livered in a truckmixer this alternative method of Scoopfuls must be taken through the moving stream,sampling for the slump test may be used. Additional sampling the whole width and depth - not just thetolerances will be applicable for concrete sampled by top part.this alternative method. Let very first concrete go Take six scoopfuls from the next 0.3 m3 - Take six scoopfuls after the first 0.3m3 has been discharged.Do not use this sample to make cubes.BS 1881: Part 101 requires two slump tests when concrete is sampled by the alternative method.
  • 7. THE SLUMP TEST BS 1881: Part 102 or BS EN 12350-2 Empty the sampling Flatten the final heap by repeatedly buckets onto the mixing digging-in the shovel vertically tray Liftthe shovel clear each time. Scrape each bucket clean Ifthe alternative method of sampling has been used, divide this heap into two and test each part. Thoroughly remix the Ensure the slump cone is clean and sample shovelling into damp a heap Place the metal plate on a solid level. Turn the heap over to base away from vibration or other disturbance form another. Do this three times Place the cone on the plate and stand on the foot-pieces
  • 8. Fillthe cone in three equal depth Carefullycleanoff spillage layers from sideand baseplate Use the standard slump rod Rod each layer 2S times Spread the blows evenly over the area Make sure the rod just penetrates the layer below. Heap the concrete above the top of the cone before rodding the third layer. Top up if necessary . Carefully lift the cone Usethe rod with a sawingand straight up and clear, rolling motion to strikethe concrete to a count of between 5 levelwith the top of and 10 seconds the cone Complete steps 5 to 8 within 150 seconds
  • 9. Laythe rod across the upturned There are three kinds of slump slump cone Measure the distance between the underside of the rod and the highest - point of the concrete the true Slump i slump Recordthis distance to the nearest T Smm if using BS1881: Part 102 or 10 mm if using BSEN 123S0-2 In all cases record the kind of slump Checkthe type of slump Ifthe slump isnt true, take a new sample and repeat the test. Ifthe second slump isnt true, get advice 1.True. Complete the Sampling and testing certificates 2.Collapse 3.Shear
  • 10. Youwill need thisequipment or the SlumpTest fSmall scoop cf Sampling scoop cP Steel rule /Square-mouthedshovel Slump rod / Slump cone and rigidmetalplate i}Buckets orwheelbarrow 53 Mixing tray <> Sampling and testing certificates I!l "Cloth
  • 11. THE FLON TEST BS1881:Part 105or BSEN 12350-5First, find a suitable location for the flow table. It Sampling using the standard method ismust be placed on a firm flat surface. It may be recommendednecessary to prepare an area for the table.. Empty the sampling buckets Ensure the mould and table are clean onto the mixing tray and damp. Scrape each bucket clean Place the mould on the centre of the table and stand on the foot-pieces Fillthe mould in two layers, tamping each layer ten times with the tamping bar. Thoroughly remix the sample Ifnecessary, add more concrete to as described for the slump test fill the top layer Use the tamping bar to strike the concrete level with the top of the mould
  • 12. Carefullyclean off spillage from Carefully stand on the toe around the mould and table top board at the front of the table Wait 30 seconds from striking off Carefully lift the mould straight up and clear, to a count of between 3 and 6 seconds
  • 13. Slowly lift the table top by the handle until it reaches the upper stop. Allow the table to fall freely Repeat this cycle to give a total of 15 drops Each cycle should take about 4 seconds. Measure the largest dimension of concrete spread in two directions, parallel to the table edges. Record the two diameters to nearest 5mm if using BS 1881: Part 105 or 10mm if using BS EN 12350-5 If there is a ring of cement paste several mm beyond the coarse aggregate, report that segregation has occurred Complete the Sampling and testing certificates
  • 14. You will need this equipment for the Flow Test 1 .....r.""__.I :.r.8W:IU..-:i ......... (:.8::.l.L!1I818.1::.1.. i. ::.1_....,. d cJj !!lSmallscoop Sampling scoop Sampling and ,0:::...... , testingcertificates : "-Square-mouthedshovel 700mmrule / Mixing tray 0Buckets or FlowtablewheelbarrowMixing tray 53 Mould 13Cloth rQ9 Hardwood tamping bar
  • 15. MAKING CUBES BS 1881: Part 108 or BS EN 12390-2Sample the concrete in the standard manner. Concrete sampled using the alternative method cannotbe used for making cubes. Check that the . Fill the mould with moulds are clean and concrete in 50mm layers lightly oiled with all . Using the special tamping bolts tightened so bar. compact that there will be no the concrete with not less than:. leakage that the Ensure 25 tamps for each of correct halves of the the two layers in a mould are used and 100mm mould that the corner lining 35 tamps for each of pins are correctly the three layers in a located 150mm mould. Thoroughly remix the sample as described for the slump test
  • 16. . and smooth overconcrete Removesurplus with a Cover each mould with a damp cloth and plastic float sheet. Wipe the mould edges clean Store inside at normal room temperature (15C. Number the moulds for to 2SC) e.g. on top of the identification and record curing tank details Protect the cube moulds at all times from high and low temperatures (especially frost) and drying winds Complete the Sampling and cube making certificates
  • 17. Youwill need this equipment for Making CubesSmallscoop Sampling scoop SpannerSquare-mouthed Damp cloth and Hide hammershovel plastic sheet 8 Buckets or ClothTamping bar wheelbarrow
  • 18. Lightly re-oil the cube moulds with release oilCube moulds Mixing tray Sampling, cube making and storage certificatesMaximuml Steel float Curing tankminimumthermometer ; . -,Felt tip pen or Brush and I mouldoilcrayon
  • 19. STORING CUBES BS 1881: Part 111 or BS EN 12390-2The cubes should be taken from the moulds the day after making, numbered and put in a curing tank. Record the maximum/minimum . Part the sides of the mould, tapping gently with overnight storage the hide hammer temperatures on the lift off carefully certificate iMAX . Remember, new cubes are easily damaged unless handled carefully MIN lMJ. Slacken all nuts . Mark each cube with its identification number on two of its cast sides
  • 20. I . Place the cubes in the For despatch to test curing tank laboratory, wrap the wet . Clean and reassemble the cubes in damp cloths. and moulds then plastic bags and pack in trays . Attach the sampling. testing. cube making and storage certificates, plus the order for testing. to . Check that the water the package ...... temperature is controlled at 20.C :t 2.C and the cubes are covered by water . Make sure the power 20.C supply is not switched off day or night . Check the temperature range daily using the maximum/minimum thermometer . Keep a record of the readings
  • 21. - - Ql1ARRY PRODUCTS ASSOCJ AT IONo Quarry Products AssociationFirst published by the British Cement Associationfor the Ready-mixed Concrete Bureau National Helpline 07004 500 500Publication number 97. 334 (~First published 1993Revised 2002. 2004fS8N07210 14704Produced by Rudkin DesignTelephone: (01327) 301770 ) The Concrete Centre™ For further information contact: The Concrete Centre Riverside House, 4 Meadows Business Park Station Approach, Blackwater Camberley, Surrey GU17 9AB I.