Advance Concrete Technology Presentation.pdf

Factors affecting Concrete Workability ,Setting of Concrete ,Factors affecting Setting ,Manufacturing of Concrete ,Various stages of manufacture of concrete (Batching, Mixing, Transporting ,Placing ,Compacting ,Curing ,Finishing. )

1. Lecture # 5 (Advance
Concrete Technology)
Presented to
DR. Azmat Ali Shah

2. Group Members
Name Registration Number
Muhammad Bilal 16PWCIV4617
Tauseef Ahmad 16PWCIV4566
Jawad Hussain 15PWCIV4465
Farhad Hamid 2015/CUP/CIV-1429

3. Contents
•Factors affecting Concrete Workability
•Setting of Concrete
•Factors affecting Setting
•Manufacturing of Concrete
•Various stages of manufacture of concrete (Batching, Mixing,
Transporting ,Placing ,Compacting ,Curing ,Finishing. )

4. Factors affecting Concrete Workability
1.Water-Cement ratio
2. Amount and type of Aggregate
3. Aggregate Cement Ratio
4. Weather conditions a. Temperature b. Wind
5. Chemical Admixtures
6. Sand to Aggregate ratio

6. 1. Water content or Water Cement Ratio
•Morethewatercementratiomorewillbeworkabilityof
concrete
•Highwatercontentresultsinahigherfluidityandgreater
workabilitybutreducesthestrengthofconcrete
•Increasedwatercontentalsoresultsinbleeding,hence,
increasedwatercontentcanalsomeanthatcementslurrywill
escapethroughthejointsoftheformwork(Shuttering)

7. W/C ratio Vs Workability Graphically

8. Type of aggregate vs Workability

9. 2. Amount and type of Aggregate
•LargerAggregatesizeshaverelativelysmallersurfaceareas(for
thecementpastetocoat)andsincelesswaterisrequiredforit
soitresultsingreaterworkabilityandviceversa.
•GreatersizeofAggregate-lesswaterisrequiredtolubricateit,
theextrawaterisavailableforworkability.
•Usingsmoothandroundaggregateincreasestheworkability.
Workabilityreducesifangularandroughaggregateisused.
•Porousaggregatesrequiremorewatercomparedtonon
absorbentaggregatesforachievingsamedegreeofworkability

10. 3. Aggregate Cement Ratio
•More the ratio less the workability. Since less cement
mean less water, so the paste is stiff.

11. 4. Weather Conditions
(a)Temperature-Iftemperatureishigh,evaporationincreases,
thusworkabilitydecreases.
(b)Wind-Ifwindismovingwithgreatervelocity,therateof
evaporationalsoincreasereducestheamountofwaterand
ultimatelyreducingworkability.

12. 5. Admixtures
•Chemicaladmixturescanbeusedtoincreaseworkability.
•Useofairentrainingagentproducesairbubbleswhichactsas
asortofballbearingbetweenparticlesandincreases
mobility,workabilityanddecreasesbleeding.
•Theuseoffinepozzolanicmaterialsalsohasbetter
lubricatingeffectandmoreworkability.

13. 6. Sand to Aggregate ratio
•Iftheamountofsandismoretheworkabilitywillreduce
becausesandhasmoresurfaceareaandmorecontactarea
causingmoreresistance.

14. Setting of Concrete
•Thetransitionprocessofchangingofconcretefromplasticstateto
hardenedstateissettingORThehardeningofconcretebeforeitgains
strength.
•Settingofconcreteisbasedorrelatedtothesettingofcementpaste
Thuscementpropertiesgreatlyaffectthesettingtime.

15. Factors affecting Setting
Water Cement ratio
Suitable Temperature
Cement content
Type of Cement
Fineness of Cement
Relative Humidity
Admixtures
Type and amount of Aggregate

16. Batching and Mixing of
Concrete
Jawad Hussain(15PWCIV4465)

17. BATCHING OF CONCRETE
•Itistheprocessofmeasurementofdifferent
ingredients(Coarseaggregates,fine
aggregates,cementetc)ofconcreteinto
specifiedproportions.
•Types of Batching process
1.Batching by volume
2.Batching by weight

18. BATCHING OF CONCRETE
•BATCHING BY VOLUME:
•Volumetricbatchingofconcreteisamethod
usedtomeasurematerialsbyvolumeratherthan
weighttoproduceconcrete.Inthisprocess,the
componentsofconcrete-cement,aggregates,
andwater-aremeasuredbyvolumeratherthan
weight.
•Thismethodcanbeparticularlyusefulin
situationswheretheavailabilityofprecise
weighingequipmentislimitedorwhere
batchingbyweightisnotpractical.

19. BATCHING OF CONCRETE
•BATCHINGBYWEIGHT:
•Inthismethod,thecomponentsofconcrete
-cement,aggregates,andwater-are
measuredbyweight.
•Batchingbyweightoffersgreaterprecision
andcontroloverthemixproportions
comparedtovolumetricbatching,makingit
suitableforprojectsthatrequireconsistent
andpreciseconcretemixes.

20. COMPONENTS OF BATCHING PLANT
•Abatchingplant,alsoknownasaconcretebatchingplantorconcretemixingplant,is
afacilitywherevariousingredientsarecombinedtoproduceconcrete.
•Theprimarycomponentsofatypicalbatchingplantinclude:
•AggregateBins:Thesearestoragecontainersfordifferenttypesofaggregates,such
assand,gravel,orcrushedstone.Theaggregatesarestoredseparatelyandthenfed
intothemixingprocessasneeded.
•WeighingSystem:Batchingplantsareequippedwithweighingsystemstomeasure
thequantitiesofcement,aggregates,andsometimesothermaterialsaccurately.These
systemstypicallyincludeloadcellsandscalestoensureprecisemeasurements.
•CementSilos:Cementsilosarestoragecontainersforcementpowder.Theyare
designedtostorelargequantitiesofcementandoftenfeaturemechanismsfor
accuratemeteringanddispensingofthecementintothemixingprocess.
•WaterStorageandMetering:Batchingplantshavefacilitiesforstoringand
meteringwater,whichisacrucialcomponentofconcreteproduction.Wateris
typicallymeasuredandaddedtothemixingprocessincontrolledamountstoachieve
thedesiredconsistencyandworkabilityoftheconcrete.

21. COMPONENTS OF BATCHING PLANT
•MixingUnit:Themixingunitiswherethevariousingredientsarecombinedtoproduce
concrete.Itusuallyconsistsofamixer,whichthoroughlyblendsthecement,aggregates,
water,andanyadditivesoradmixturestoformahomogeneousmixture.
•ControlSystem:Batchingplantsareequippedwithcontrolsystemsthatoverseeand
regulatetheentiremixingprocess.Thesesystemscanbemanual,semi-automatic,or
fullyautomatic,dependingonthelevelofautomationandcontroldesired.Theyallow
operatorstomonitorparameterssuchasmaterialquantities,mixingtimes,anddischarge
rates,ensuringconsistentandaccurateproductionofconcrete.
•BatchingPlantStructure:Thebatchingplantishousedwithinastructurethatprovides
shelterandsupportforthevariouscomponents.Thisstructuremayincludeplatforms,
catwalks,andaccessstairsformaintenanceandoperation.
•AuxiliaryEquipment:Dependingonthespecificrequirementsofthebatchingplant
andthetypeofconcretebeingproduced,additionalauxiliaryequipmentmaybe
included.Thiscanincludeconveyorsfortransferringmaterials,storagetanksfor
admixtures,andheatingorcoolingsystemsforcontrollingthetemperatureofthe
concretemix.

22. CONCRETE BATCHING PLANT

23. MIXING OF CONCRETE
•Themixingofconcreteisacriticalstepin
theproductionprocess,wherevarious
ingredientsarecombinedtoforma
homogeneousmixturethatwillultimately
hardenintoastronganddurablematerial.
•Propermixingensuresthattheconcretehas
thedesiredproperties,includingstrength,
workability,durability,anduniformity.

24. TYPES OF MIXING OF CONCRETE
Hand Mixing:
•Thismethodinvolvesmanuallymixingthe
concreteingredientsusingshovels,hoes,or
otherhandtools.Itistypicallyusedfor
small-scaleprojectsorinsituationswhere
accesstomechanicalmixersislimited.
Whilehandmixingislabor-intensiveand
lessefficientthanmechanicalmethods,it
canbesuitableforsmallbatchesoron-site
repairs.

25. TYPES OF MIXING OF CONCRETE
•Machine Mixing:
•ContinuousMixers:Continuousmixersare
usedinlargerconcreteplantsandarecapable
ofproducingacontinuousflowofconcrete.
Theytypicallyfeaturerotatingbladesor
paddlesthatcontinuouslymixtheingredients
astheyarefedintothemixer.
•BatchMixers:Batchmixersarecommonly
usedinconcreteplantsandconstruction
sites.Theymixtheingredientstogetherin
batches.

26. TYPES OF BATCH MIXERS
•TiltingDrumMixers:Tiltingdrummixershave
arotatingdrumthattiltstoonesidetodischarge
theconcrete.Theyarecommonlyusedinsmallto
medium-sizedconcreteplantsandconstruction
sites.Tiltingdrummixersareversatileandcan
handleawiderangeofconcretemixes.
•Tiltingdrummixersconsistofacylindricaldrum
mountedonahorizontalaxis.Thedrumisopen
atthetopandhasbladesorpaddlesinsidefor
mixing.Thedrumissupportedbyaframeor
chassis,anditcantiltforwardorbackwardto
chargeanddischargetheingredients.

27. MIXING AND DISCHARGING OF TILTING
DRUM MIXER
•Mixing:Oncetheingredientsareloaded,thedrumistiltedbackinto
themixingposition,anditbeginstorotate.Therotationofthedrum
causesthebladesorpaddlesinsidetomixtheingredientsthoroughly,
ensuringahomogenousmixture.
•Discharging:Afterthemixingiscomplete,thedrumistiltedforward
againtodischargethemixedconcrete.Thedischargechuteoropening
atthebottomofthedrumallowstheconcretetobepouredout.

28. TYPES OF BATCH MIXERS
Non-TiltingDrumMixers:
•Non-tiltingdrummixershavearotatingdrum
thatdoesnottiltfordischarge.Instead,the
concreteisdischargedthroughachuteatthe
bottomofthedrum.Non-tiltingdrummixers
areoftenusedforlargerbatchesandhigher
productionrates.

29. TYPES OF BATCH MIXERS
•Reversingdrummixer(truckmixer)-The
reversibledrummixerissimilartothenontilting
mixerexceptthatthesameopeningisusedtoadd
theconstituentsandtodischargetheaggregate.
•Thedrumofthereversingdrummixerrotatesin
onedirectiontomixtheingredientsthoroughly.
Oncethemixingiscomplete,thedirectionof
rotationisreversed,causingthedrumtotiltinthe
oppositedirection.

30. TYPES OF REVERSING TRUCK MIXERS
REAR DISCHARGE TRUCKS
•Reardischargetrucksrequirebothadriveranda"chuteman"toguide
thetruckandchutebackandforthtoplaceconcreteinthemanner
suitabletothecontractor.

31. TYPES OF REVERSING TRUCK MIXERS
Advantages:
•Accessibility:Reardischargetruckmixersprovideeasyaccessto
thedrumforloadingandcleaning,reducingdowntimebetween
batches.
•Maneuverability:Thereardischargedesignallowsforprecise
placementofconcreteintightorcongestedconstructionsites.
•OperatorSafety:Operatorshavebettervisibilityandcontrolover
thedischargeprocessfromtherearofthetruck.

32. TYPES OF REVERSING TRUCK
MIXERS
Frontdischargetrucks-Newerfrontdischargetrucks
havecontrolsinsidethecabofthetrucktoallowthe
drivertomovethechuteinalldirections.
Advantages:
•EnhancedVisibility:Operatorshavebettervisibilityofthe
dischargeprocessfromthefrontofthetruck,allowingfor
improvedmaneuverabilityandcontrolduringconcrete
placement.
•Accessibility:Frontdischargetrucksprovideeasyaccess
tothedrumforloadingandcleaning,reducingdowntime
betweenbatches.
•PrecisePlacement:Thefrontdischargedesignallowsfor
preciseplacementofconcreteinvariousconstruction
scenarios,suchaspouringintoformsorstructureswith
limitedaccess.

33. TYPE OF BATCH MIXER
Pan Mixer
•Apantypemixerisaforced–actionmixer,as
distinctfromdrummixerwhichreliesonthe
freefalloftheconcreteinsidethedrum.The
panmixerconsistofacircularpanrotating
aboutits
•Axis with one or two stars paddles rotating
about vertical axis of pan.
•Components of a pan mixer are:
•Pan
•Shaft
•Scraper

34. Transporting and Placing
of Concrete
Farhad Hamid (2015/CUP/CIV-1429)

35. Methods of Concrete Transportation
•Concrete Mix Transportation
Defined as the process of transferring concrete from the mixing plant to
the construction site.
•Main Objective
To maintain the intended water-cement ratio, consistency, air content,
and homogeneity of the concrete mix during transportation

36. Important Factors in Choosing Transportation
•PreventSegregation
Ensurethatthemixdoesnotchangeitsstateasspecified
inthecontract.
•MaintainWorkability
Donotreducetheworkabilityofthemixduring
transportation.
•EfficientOrganization
Planandexecutethetransportationprocessinawell-
thought-outandefficientmanner.

37. •TimelyDelivery
Delivertheconcretewithintheacceptabletimelimitsto
preventdelaysandhoneycombing.
•ConsiderFactors
Takeintoconsiderationfactorslikemixtype,constructionsize,
weatherconditions,andcostwhenchoosingthemodeof
transport.
•AvoidSegregation
Choosetheappropriatemodeoftransportationtoprevent
segregationandmaintainthequalityoftheconcrete.

38. Categories of Transportation
a)Mortar Pan
Itisalaborintensivemethodand
generallyusedforsmallworks.
Therearenochancesof
segregationofconcrete.Inhot
weather,thereisasubstantialloss
ofwater
b) Wheelbarrow or Hand cart
Itisnormallyusedongroundlevel
i.e.roadconstructionandother
similarstructures.Segregationcan
occuriftransportationisdoneon
roughroads,howeverthisproblem
canbeminimizedifpneumatic
tyresareused

39. c) Belt Conveyor
•Haslimitedapplicationdueto
chancesofsegregationonsteep
slopes,rollerpoints,andchanges
indirectionofthebelt.Italso
involvesoverexposureof
concretetotheenvironment.
d) Concrete Pump
Pumpingisthemostsophisticated
methodforconcretetransportation.
It'sperfectforlimitedspacesor
largequantities.

40. e) Transit Mixer
Popularequipmentfor
transportingconcreteovera
longdistance,especiallyin
readymixconcreteplants.
Theyaretruck-mountedwith
acapacityof4to7cubic
meters

41. Concrete Placing
•PlacingProgram
Beforeanyconcreteisplaced,adetailedplanismadeforequipment,
layout,procedures,andmethods.
•FormworkInspection
Noconcreteisplaceduntiltheformworkisinspectedanddeemed
suitableforplacement.
•ContinuousFlow
Equipmentforconveyingconcreteshouldensureapractically
continuousflowofconcreteduringdepositing,withoutsegregationof
materials

42. •DirectPlacement
Concreteisplaceddirectlyinitsfinalpositionwithoutre
handlingorcausingsegregation.
•Confinement
Inlocationswheredirectplacementisnotpossible,suitable
dropandElephantTrunksareusedtoconfinethemovementof
concrete.
•SpecialCare
Concretedroppedfromaheight,especiallyifreinforcementis
intheway,ishandledwithspecialcaretoavoidsegregation.

43. Concrete Placement
Techniques
Concreteplacementisacrucialstepin
construction,requiringcarefulplanning
andexecution.Varioustechniquesare
employedtoensuretheconcreteis
properlydistributedandcompacted,
includingpouring,pumping,andhand-
placing.Eachmethodhasitsown
advantagesandconsiderationsfor
maximizingstrengthandquality.
Properconcreteplacementtechniquesare
essentialforachievingthedesired
structuralintegrity,surfacefinish,and
long-termdurabilityofthefinalproduct

44. Concrete Consolidation
Properconsolidationoffreshly
placedconcreteiscrucialto
removeairpocketsandensure
adense,uniformfinish.Thisis
typicallydoneusingvibrating
equipment,suchasinternal
vibratorsorsurfacevibrators,
tocompacttheconcreteand
eliminatevoids.

45. Factors Affecting Concrete Placement
•Concrete Mixture Design
The water-to cement ratio, aggregate gradation, and admixture content
all influence the pumpability, flowability, and finishing characteristics of
the concrete mix.
•Reinforcement Layout
The presence and spacing of steel reinforcement can create obstacles for
concrete placement, requiring careful planning and coordination to
ensure complete encapsulation and proper consolidation.

46. •Weather Conditions
Temperature,humidity,andwindcansignificantlyimpactthe
workabilityandcuringoffreshlyplacedconcrete.Monitoringthese
factorsiscrucialforoptimalplacementandstrengthdevelopment.
•Formwork Configuration
Thedesignandconstructionofformworkcanimpacttheeaseof
concreteplacement,particularlyinareaswithcomplexshapesorlimited
access.Properformworkpreparationisessential.

47. Safety Considerations in Concrete Placement
•Protective Equipment
Ensureallworkerswearhardhats,safetyglasses,steel-toedboots,andhigh-
visibilityveststopreventinjuriesduringconcreteplacement
•Site Preparation
Clearlymarkhazards,installbarricades,andestablishdesignatedworkzones
tominimizetheriskofaccidentsandmaintainasafeworkenvironment
•Handling Precautions
Trainworkersonpropertechniquesforliftingandmovingheavyconcrete
bucketsorhosestopreventbackinjuriesandothermusculoskeletalissues.

48. Conclusion and Key Takeaways
•Inconclusion,thetransportationandplacementofconcrete
requirecarefulplanning,specializedequipment,andattention
tosafety.
•Keytakeawaysincludethediverseconcretedelivery
methods,theimportanceofconcretepumpingsystems,and
bestpracticesforconsolidationandcuring.Bymastering
thesetechniques,constructionteamscanensuredurable,
high-qualityconcretestructuresthatstandthetestoftime.

49. Compaction, Curing and Finishing of
Concrete
Tauseef Ahmad (16PWCIV4566)

50. Compaction
•Theprocessofremovingentrappedairfromconcreteandmakingit
denseiscalledcompactionofconcrete.
•Ifairisnotremoved,itleadsto
1)Honeycombing
2)reducedstrength

51. Compaction Contd…
•Experiments show that 1% air reduces the strength of concrete by 6%.
Q: Why full compaction is important?
1)Air voids reduces strength
2)Air voids increases permeability
3)Air voids reduces durability
4)Due to air voids, moisture and air penetrates into concrete leads to
rusting of reinforcement

52. Compaction Contd…
•There are 2 methods of compaction:
1)Hand compaction
2)Mechanical compaction
1)HandCompaction:Doneforordinaryandunimportantstructures.
Canbefurtherdividedinto3methods.
a)Rodding:Theroddingmethodofcompactionismanualtechnique
usedtocompactconcreteinsmallmoldsorforms,typicallyfor
laboratoryspecimensorsmall-scaleconstructionprojects.Therod
havinglengthof2m,diameterof16mmisused.

53. Compaction Contd…
a)Rodding:Theroddingmethodofcompactionismanualtechnique
usedtocompactconcreteinsmallmoldsorforms,typicallyfor
laboratoryspecimensorsmall-scaleconstructionprojects.Therod
havinglengthof2m,diameterof16mmisused.

54. Compaction Contd…
b)Ramming:ThismethodisusedtocompactPCConground.Itisnot
usedforRCC.
c)Tamping:Thecompactionisdonebybeatingorapplyingpressureon
thesurfaceofconcrete.Tampingtoolisusedhavingcross-sectionof
10x10cm.

55. Compaction Contd…
2)MechanicalCompaction:Inthismethodvibrationisimpartedto
concretebymechanicalmeans.Duetothisvibrationairbubblescomes
tothetopandiseventuallyexpelled.Thiscanbeofvarioustypes.
a)InternalVibration:Mostcommontechniqueofcompactingconcrete
andresultsinhighqualityconcrete.Apokerorneedleisused,inserted
insideconcrete,havingdiameterof20to75mmandlengthof25to
90cm.Frequencyrangeis3500to5000rpm.

56. Compaction Contd…
a) Internal Vibration: Most common technique of compacting concrete
and results in high quality concrete. A poker or needle is used, inserted
inside concrete, having diameter of 20 to 75mm and length of 25 to
90cm. Frequency range is 3500 to 5000 rpm.
•Effective method of compaction as energy is uniformly distributed.

57. Compaction Contd…
b)ExternalVibration:Thisreferstotheprocessofcompactingconcrete
usingvibrationappliedexternallytotheformworkorsurfaceof
concrete.ItisusedwhereInternalVibrationcannotbeusedlikeinthin
sections,heavyreinforcement.
•Less effective
•Consumes more power
•Requires strong formwork

58. Compaction Contd…
c) Table Vibration: used to compact concrete in laboratory.
d) Platform Vibration: similar to table vibration
but on large scale

59. Compaction Contd…
e)SurfaceVibration:alsoknownasvibratingscreeds,isamethodused
tocompactandlevelthesurfaceoffreshlypouredconcrete.
•Not effective beyond 15cm depth.

60. Curing
•Itisaprocessofmaintainingadequatemoistureandtemperature
conditions,toallowconcretetoproperlyhydrateanddevelopstrength.
•Onceconcretehasbeenplacedandcompacteditmustbeallowedto
cureproperlytodevelopgoodfinalproperties.
•Strengthofconcretecomesfromhydrationofcement.
•Tocureproperly,thecementpastemustbefullysaturatedwithwater.
•Ifrelativehumidityreaches90%,hydrationslowsdown.
•Ifrelativehumidityreached80%,hydrationstops.

61. Curing Contd…
•Ifhydrationreactionstops,concretestrengthdevelopmentalsoget
affected.
•Notkeepingconcretesurfacemoistwillresultindevelopmentof
shrinkagecracks.
MethodsofCuring:
a)Waterissprayedovertheconcrete
b)Concreteiscoveredwithplasticordampfabrictostopevaporation

62. Curing Contd…
•Weather plays an important role in curing process.
•Hot windy weather, rapid evaporation, so frequency of curing required
will be high.
•Cold weather, rate of evaporation slow, so frequency of curing
required will be less.

63. Finishing
•Concrete that will be visible needs finishing.
•Screeding/strike off: Cutting off excess concrete to bring top surface to
a proper grade.

64. Finishing Contd…
•Bull Float: After screedingfloating is done. It eliminates high and low
spots and furthers levels the surface of concrete.

65. Finishing Contd…
•Contraction joints: done with hand grooveror by inserting strips of
plastic/wood/metal etcinto unhardened concrete.

66. Finishing Contd…
•Ifsmooth,hard,densesurfaceisdesired,floatingshouldbefollowed
bysteeltrowelling.
•If slip resistance surface is desired, broomingis done.

67. Thank
You