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ExpoStation&OverrunTunnelContract922DTL3ES007Panelsurfacerectificationprocedure

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DiaphragmWallRectificationWorkProposalforexposingofreinforcementbarandunsoundconcretesurfaceatPanelEN007

Location : ESSTunnel,PanelEN007 StructureElement : Diaphragmwall Elevation : BetweenB1andB2Diaphragmwallsurface TypeofDefect:Exposeofthereinforcementduetounsoundconcretesurface

1. ProposedrectificationmethodInaccordancetoourstandardrectificationmethod,abovementioneddefectshallbe

rectifiedbyusingflowgrout/pourgroutmethodwithnonshrinkcementmixorpressure

groutingmethodforthecaseofdeeperunsoundconcretecondition(defectextendbehind

themainreinforcementanddepthmorethan100mm).

Forthe

above

mention

case

,in

future

diaphragm

wall

surface

shall

be

hacked

and

shear

linksshallbeexposedforstraighteningpriortoinner/skinwallconstruction.

Thereforethose exposedreinforcementandunsoundconcreteareneededtobe

covered/repairedtemporarilybeforeskinwallconstructionstagetopreventcorrosionof

thereinforcementandpriortostrut/walerinstallation.

Thereforewewouldliketoproposefollowingrectificationworkforabovementionpanel

defects.

2. Procedureoftherectificationworka. Surfacecleaning

Hackandremoveallunsoundconcreteuntilexposesoundconcretesurface Removeanyintactlooseconcrete,loosescaleandrustfromthesteelbar,

anddegreasingthereinforcement ifnecessaryorifpresenceofoilor

grease.

Cleanthesurfacewithcleanwaterandcompressairblowforanylooseparticles.

b. ApplyingAntiCorrosivePaint Topreventthecorrosionorrusty,anticorrosivepaintsuchasNtitroprime

Zinrichorsimilarpaintshallbeappliedatleasttwocoatonthe

reinforcementsurfacebybrushuntilthesteelreinforcementfullcoverand

allowedforatleast1hourforcuring.

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ExpoStation&OverrunTunnelContract922DTL3ES007Panelsurfacerectificationprocedure

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c. ApplyingCementMortar Uponthecompletionofapplyinganticorrosivepaint,handmix

cement/sand/watermortarshallbeplasteredonthedefectsurfaceareaby

usingtrowel.Cementmortarthicknessshallbeatleast20mmcoveronthe

reinforcementsurface.

Cement:Sand:Waterratioshallbe1:3:3d. Removalofcementmortarsurface

PriortoconstructionofSkinwallandstraighteningofthediaphragmwallshearlinkstoconnecttotheskinwall, allthecementplastershallbetotally

removedfromthediaphragmwallsurface.

3. PhotoofthedefectsurfaceatthePanelEN007.

Photo.1

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ExpoStation&OverrunTunnelContract922DTL3ES007Panelsurfacerectificationprocedure

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Photo.2

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ExpoStation&OverrunTunnelContract922DTL3ES007Panelsurfacerectificationprocedure

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Photo.3