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Technical Notebook
WATERPROOFING STRUCTURES INSTALLED BELOW GROUND LEVEL
C.P.
MK
8387
30 -
(GB)
04/
11
Technical Notebook
WATERPROOFING STRUCTURES INSTALLED BELOW GROUND LEVEL
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Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
page 04 1. INTRODUCTION
page 05 2. GEOTECHNICSANDFOUNDATIONSpage 05 2.1 GEOTECHNICS
page 06 2.2 FOUNDATIONS
page 11 3. HYDROLOGYANDHYDROGEOLOGYpage 12 3.1 THEWATER-GROUNDRELATIONSHIP
page 12 3.2 WATERANDSUBSOIL
page 14 3.3 DRAINAGESYSTEMS
page 20 4. EXCAVATIONWORK
page 24 5. MAPEIWATERPROOFINGSYSTEMSFOR FOUNDATIONSTRUCTURESpage 24 5.1 WHYWATERPROOF?
page 26 5.2 MAPEPROOFANDBENTONITE
page 29 6. SPECIFICATIONSFORFOUNDATION CONCRETE
page 32 7. WATERPROOFINGNEWSTRUCTURES BELOWGROUNDLEVELpage 34 7.1 SEALINGCONSTRUCTIONJOINTS
page 34 7.2 WATERPROOFINGTHEBASEOFAJIBCRANE
page 35 7.3 WATERPROOFINGALIFTWELL
page 40 7.4 WATERPROOFINGHORIZONTALFOUNDATIONPADS
page 42 7.5 WATERPROOFINGPILEHEADS
page 47 7.6 WATERPROOFINGVERTICALSURFACESBEFORECASTING
page 54 7.7 WATERPROOFINGVERTICALSURFACESAFTERCASTING
03
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
page 55 7.7.1 WATERPROOFINGVERTICALSURFACESAFTER CASTINGWITHMAPEPROOFORMAPEPROOFLW
page 56 7.7.2 WATERPROOFINGVERTICALSURFACESAFTER CASTINGWITHMAPELASTICFOUNDATION
page 58 7.7.3 WATERPROOFINGVERTICALSURFACESAFTER CASTINGWITHPRODUCTSFROMTHEPLASTIMUL RANGE
page 61 7.8 WATERPROOFINGSTRUCTURALJOINTS
page 64 7.9 SEALINGTHROUGH-PIPESINVERTICALWALLS ANDFOUNDATIONPADS
page 66 7.10 SEALINGADRAINAGEWELL
page 67 7.11 WATERPROOFINGACCESSRAMPSTOAREAS BELOWGROUNDLEVEL
page 69 7.12 WATERPROOFINGDEPURATIONTANKS
page 71 7.13 WATERPROOFINGASEWAGEWASTEOUTLET ANDVENTCASTINPLACE
page 74 7.14 WATERPROOFINGCONSTRUCTIONSBUILTUSING THETOP-DOWNMETHOD
page 77 8. WATERPROOFINGEXISTING STRUCTURESBELOWGROUNDLEVELpage 78 8.1 LININGSURFACESINROOMSBELOWGROUNDLEVEL
page 78 8.1.1 WATERPROOFINGVERTICALSURFACES
page 80 8.1.2 WATERPROOFINGHORIZONTALANDVERTICAL SURFACESWITHMAPEPROOF
page 84 8.1.3 WATERPROOFINGHORIZONTALANDVERTICAL SURFACESWITHACOMBINEDBENTONITE- CEMENTITIOUSSYSTEM
page 89 8.2 WATERPROOFINGALIFTWELLAGAINST HYDRAULICLIFT
page 90 8.2.1 WATERPROOFINGWITHOSMOTICMORTAR
page 91 8.2.2 WATERPROOFINGWITHACOMBINEDOSMOTIC MORTAR-FLEXIBLECEMENTITIOUSMORTARSYSTEM
page 92 8.2.3 WATERPROOFINGWITHACOMBINEDBENTONITE- FLEXIBLECEMENTITIOUSMORTARSYSTEM
02
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2. GEOTECHNICS AND FOUNDATIONS
2.1 GEOTECHNICSGeotechnics is thestudyof themechanicalaspectsof thegroundand
itsapplication inengineeringworks.Thestratographicconformationof
thegroundanditsmechanicalbehaviourisanalysedtoidentifythemost
suitabletypeoffoundationstoguaranteethestabilityanddurabilityofa
structure.
Foundations are structural elements with the function of transferring
stressesand loads,bothpermanentandaccidental, fromthestructure
constructedonthefoundationstotheground.Thetypeof foundations
determines the “footprint” that a structure leaves on the ground. The
sizeofthefootprint(plinths,groundbeams,foundationpadsandribbed
foundationpads)isinverselyproportionaltotheresistanceoftheground
and proportional to the loads to be discharged onto it. The ground,
foundationsandtheoverallstructure,therefore,formasingleunitbody
whichmustbeconsideredasasinglesystem.
Thedesignofastructurestartswithapreliminaryanalysistodetermine
the type, stratographic conformation and physical and mechanical
characteristics of the ground. It is particularly important to determine
the safety load of the ground, known as its “load-bearing capacity”,
expressedinkg/cm2.
Apartfromtheeconomicaspectstobetakenintoconsideration,thereare
anumberofotherparameterswhichalsocontributeindefiningthetype
offoundationstouse,withthemainonesbeingasfollows:
• the construction system adopted for the structure built on the
foundations;
•restraintsandguidelinesoflocalbuildingregulations;
•thedepthatwhichthelayerwithsufficientload-bearingcapacityon
whichtheloadsactislocated.
1. INTRODUCTIONThe issuesdealtwith in thismanual regardwaterproofingmethods for
various types of structures below ground level (Fig. 1.1) according to
the type of ground and obviously the effect of water acting upon the
structure.Athoroughanalysisofthemorphologicalcharacteristicsofthe
groundandwaterflowduringvariousperiodsoftheyearallowforcorrect
analysisoftheconstructiontechniqueappliedforstructuresbelowground
level.Studying thecharacteristicsof theground (geotechnics)supplies
useful informationabout the load-bearingcapacityof theground itself
anditshydrogeologicalconformation.Itisalsoimportantthatanywater
present below ground level is carefully studied (hydrology) in order to
assessthecontextinwhichnewstructuresarebuilt,suchaswaterunder
pressure,waterpercolating frombelowor thepresenceofwidespread
damp. This will then influence the type of foundations system chosen
forthestructure,thetypeofwaterproofingusedand,clearly,thetypeof
temporarysupportsrequiredtoconstructthefinalstructure.
Fig.1.1–Phasesofanexcavationforconstructionworkcarriedoutbelowgroundlevelinabuilt-uparea
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
04
07
Fig.2.2-Truncated-pyramidplinth
Fig.2.1–Classificationoffoundationsaccordingtotheirloadtransfermechanismtotheground
2.2 FOUNDATIONSFoundations form a group of structural elements within a construction
system,withthefunctionoftransmittingloadstotheground.Sincethe
behaviouroftheground,thefoundationsandthestructurebuiltonthe
foundationsaredependentoneachother,thereisawidearrayofvariables
whichhave tobeconsideredwhencalculating thesizeof foundations.
Theparametersbelowmustbetakenintoconsiderationwhenchoosing
thetypeoffoundations:
•theloadsactinguponthefoundations;
•thefinaluseofthebuilding;
•typeandstratographicconformationoftheground;
•thepresenceandlevelofthestratum;
•theheightofthefoundations;
•economicimplications;
•presenceandtypeofsurroundingbuildings;
•frictionandslopeofthegroundonwhichthefoundationsareinstalled.
Theforcestransmittedfromthestructuretothefoundationsarethesum
ofthefollowing:
•loadsfromthestructure;
•permanentoverloads;
•accidentaloverloads(accordingtothefinaluseofthestructure);
•horizontalforcesduetowinds(generallybendingmoments);
•horizontalseismicloads(appliedeitherdynamicallyorstaticallytothecalculationmodel).
Foundationsmaybesub-dividedaccordingtotheirloadtransfermechanism
tothegroundoraccordingtotheTerzaghiclassificationsystem.Inthefirst
case,thefoundationsmaybeclassifiedasillustratedinFig.2.1.
With direct (or surface) foundations, the forces are transferred to the
groundbyenlarging the load-bearingelementsof the structureon the
foundations, while with indirect (or deep) foundations, the forces are
transferredmainlybyfrictionorlateraladhesionatthepile-groundinterface.
Themostsimpleformofintermittentdirectfoundationsarerepresented
by plinths, which basically consist of enlarging the pillars to distribute
the loads over a larger surface area. In certain cases, because of the
poor mechanical characteristics of the ground, restraints by seismic
regulationsor if the loadshave tobedistributedover largerareasand
theplinthsaretoolarge,foundationpadswhichcovertheentireareaof
thebuilding(continuousdirectfoundations)areamorefeasiblesolution.
Inothercases,indirectfoundationssuchaspileshavetobeused,sothat
theloadsfromthestructureonthefoundationsaretransferredtomore
compactandresistantgroundwhichmayonlybefounddeeperdown.
If theTerzaghiclassification is followed,ontheotherhand, thevarious
typesoffoundationsmaybesub-dividedaccordingtotheratioD/B(D:
depthofthefoundations,B:widthofthefoundationbase):
•directorsurfacefoundations(plinths,continuousbeams,foundationpads)D/B<4;
•semi-deepfoundations(shafts)<D/B<10;
•deepfoundations(piles)D/B>10.
Direct(orsurface)foundationsmaybeusedwhenitisnotnecessary
to excavate deep down to reach ground with good mechanical
characteristics.Accordingtotheformandsizeofthesupportbase,these
structuresmaythenbesub-dividedasfollows:
•intermittent(orisolated)foundationssuchasplinths;
•continuousfoundationssuchasgroundbeamsandfoundationpads.
Plinths (Fig. 2.2) are used to build framed structures (in reinforced
concrete or steel) for low stresses on ground with good geotechnical
characteristics.Theyaregenerallyquitepreciseelementswithatruncated
pyramidshapeandasquarebase,andformanenlargementatthebase
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
06
INDIRECT FOUNDATIONS
ON PILES WELL-TYPE
- FITTINGS
- CAST ON SITE
- IN WOOD (NO LONGER USED)- IN REINFORCED CONCRETE- IN IRON
DIRECT FOUNDATIONS
CONTINUOUS DISCONTINUOUS
- TRAVI ROVESCE
- GRIGLIATO DI TRAVI ROVESCE
- PLATEE
- GROUND BEAMS- NETWORK OF GRADE BEAMS- FOUNDATION PADS- RIBBED FOUNDATION PAD
- ISOLATED PLINTHS- PLINTHS FOR GROUPS OF PILLARS
Pillar
Truncated-pyramidplinthSubstrate
09
Fig.2.5–Ribbedfoundationpad
Fig.2.3–Schematicdiagramofstressesactingonafoundationbeam
ofthepillars.Iftheyarenottootall,theyarewithoutadoubtthemost
economical typeof foundation.Plinthsaremainlysubjected tovertical
forces,sothesizeoftheirsurfaceisgivenbytheverticalloadsandload-
bearingcapacityof theground,while theirheight isdeterminedby the
capacityofthematerialtoresistshearloads.Iftheplinthsarerectangular,
the longer side of the plinth is parallel to the longer side of the pillar.
Plinthsmaybedefinedasbeingeithersquatorslimaccordingtotheir
heighttolongersideratio.Accordingtoparameterscontainedinbuilding
regulationsforseismiczones,theplinthsmustbeconnectedtoabeam
andcurbnetworktoguaranteethatthebehaviouroftheentirestructure
ismorehomogenous.
Continuous direct foundations, on the other hand, are formed by
continuouselementssuchasgroundbeamsorfoundationpadsandare
usuallyusedinthefollowingcases:
•whentheresistantgrounddoesnothaveaveryhighsafetyload
(load-bearingcapacity);
•whentheresistantgroundisatashallowdepthcomparedwith
groundlevel;
•whentheresistantgroundisatsuchadepththatitismore
economicaltoreachitusingdeepfoundations;
•whenparticularlyhighloadsactuponthefoundations.
Groundbeams(Fig.2.3)arestructuralelementswhichfunctionmainlyin
alongitudinaldirectionand,unlikeinthecaseofstaticoverheadbeams,
theverticalloadsactinguponthemaregeneratedbytheirreactionwith
thegroundandactinanupwardsdirection.Groundbeamsareusedwhen
alargesupportsurfaceisrequiredtotransmittheloadstotheground,or
ifthegroundhasparticularlyirregularpointtopointresistance(therefore
with the riskofdifferential settling). In thecaseof networksof ground
beams (Fig.2.4), thebeamsthemselvesareplacedat rightanglesand
intersectincorrespondencewiththepillars.
Foundationpadsareusedwhenveryhighloadsneedtobetransferred
intogroundwithpoor load-bearingcapacity,orwhen it isnotpossible
to install deep foundations. This technique may be considered a
developmentofgroundbeamsand is formedbya reinforcedconcrete
floorslabwhichcoverstheentireareaofthegroundwherethebuildingis
constructedandinwhichthepillarsareinserted.
A foundationpad isaslabsubjected tovertical forcesconcentrated in
correspondencewiththepillars,bendingmomentsatthepillar/foundation
jointsandloadsdistributeduniformlyovertheentiresurfacegeneratedby
thereactionofthegroundintheoppositedirectiontotheverticalloads
fromthepillars.Therearetwotypesoffoundationpads:
•ribbedtypeformedbyasinglelowerpadandanetworkofmainand
secondarybeams(Fig.2.5);
•fulltype.
Whichtypetousedependsoneconomicalfactors,suchaslowercosts
for materials and labour, and technical considerations, in that ribbed
foundationpadsarestifferandweigh lesscomparedwith the full type
withthesamethickness.
Semi-deep foundations are shaft type, used in the 19th Century and
nowadayscompletely abandoned.This techniqueconsistedofdigging
adeepwellor shaftwithadefinedshapedown toa layerof resistant
ground.Itwasthenfilledwithdry,well-packedmaterialoracementitious
conglomerate with a low cement content, to form masonry pylons on
whichtheconstructionwasbuiltformedbyconnectingbeamsandarches
todischargetheloads.
Deep foundations are used when, because of the poor mechanical
Fig.2.4–Latticeofagroundbeam
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
08
Foundationbeam
Reactionfromtheground
Groundbeam
Substrate
Rib
RibFoundationpad
Foundationpad
SubstrateSubstrate
11
Fig.2.7–Phasesoftheconstructionofboredpiles
characteristicsof thesurfaceof theground,more resistant layerswith
suitableload-bearingcapacitytowithstandtheloadsfromthestructure
deep down in the ground need to be reached. Deep foundations are
formedbyfoundationpileswitharoundprofile.Theload-bearingcapacity
ofpiles(Fig.2.6)isgivenbytwodistinctcharacteristics:
•verticalload-bearingcapacity;
•lateralload-bearingcapacity.
Thefirstcharacteristicdependsonthesectionofthepileandthelayer
reachedbyitsbase(whichiswhywetrytoreachthemostresistantlayers
withthebaseofthepile).Thesecondcharacteristic,ontheotherhand,
isduetofrictionbetweenthesideofthepileandthegroundaroundthe
pileanddepends,therefore,onthetypeofpileandthetypeofground.
Veryoften,frictionisthepredominantphenomenonfortheload-bearing
capacity of piles. In fact, there is a particular category of piles, the
suspendedtype,inwhichthebaseofthepiledoesnotreachthemore
resistantlayersofthegroundanditsentireload-bearingcapacityisgiven
byfrictionalongitssides.
According to the installation technique used, piles are sub-divided as
follows:
•boredpiles (Fig.2.7): thefirststep is to remove thesoiland then
castacementitiousconglomerateinplacewhichisusuallyreinforced.
Theboredholemaybeformedbyperforation(usingrotatingorrotor-
percussionequipment)orbyexcavating(usingadiggerfittedwitha
roundtoothedbucket).Whenformingthehole,thesidewallsmaybe
mademorestablebyusingastabilisingfluidorbyinstallingatemporary
metallicliner(calledasleeve).Oncetheholehasbeencompleted,the
steel reinforcement cage is inserted and the concrete is poured in
throughatube.Oncethecastingoperationhasbeencompleted,the
temporarymetalliclinermayberemoved.
•drivenpiles(Fig.2.8):thesoilisnotremovedandthepilesaredriven
into the ground by hammering, vibrating, pressing, screwing or by
a combination of these techniques. Driven piles generate a lateral
compacting action upon the ground which increases their lateral
resistanceduetofriction.Anegativeaspectofthistechniqueisthat
thepilesmaybequitelongandahighamountofenergyisrequiredto
ramthemin.Rammedpilesmaybemadeusingthefollowingmaterials:
steel, reinforcedconcrete,wood (although thismaterial is no longer
used)oracombinationofmaterials.
Pilesusuallyhaveacircularsectionandtheirdiametervariesaccordingto
theirstructuralrequirements;smallerdiameters,between100and200mm,
areknownasmicro-piles.Thetransferofloadsfromthebuiltstructureto
eachsinglepile,whicharelevelledofftothesameheightafterinstallation,
isthroughconnectingstructuresonthesurfacesuchasplinths,ground
beamsandfoundationpads.Whenanalysingandconsideringthenature
of the ground for the foundations, its water content, one of the most
importantfactorsoftheground,mustbecarefullyassessed.Thisiswhy
it isuseful tobrieflydiscusshydrologicalandhydrogeologicalaspects,
thelatterofwhichisthestudyofundergroundwateranditsproperties.
3. HYDROLOGY AND HYDROGEOLOGYHydrologyisthesciencewhichstudieswaterontheearth,bothonthe
surfaceandbelowthesurface,howitisformed,howitcirculatesandhow
itisdistributedwithrespecttotimeandspace,itsbiological,physicaland
chemicalpropertiesandhowitinteractswiththeenvironment,including
withlivingbeings.Inbrief,hydrologyisthestudyoftheflowofwaterwhich
forms the so-called hydrological cycle. Hydrogeology is the branch of
geologywhichstudiesphreaticorundergroundwateranditsproperties.
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
Fig.2.6–Schematicdiagramofstrainsactingonafoundationpile
10
Peakload
Friction
Coherentground
1)Boringoperation 2)Insertionofreinforcement
3)Castingtheconcrete
4)Finishedpile
Pilehammer
Drive-head
Pile
Fig.2.8–Schematicdiagramofapilebeingrammedintotheground
13
3.1 THE WATER-GROUND RELATIONSHIPThegroundismadeupofvarioustypesofsolidmaterialofvariousorigin
andemptyspaces (Fig.3.1) in variousshapesandsizes.Thequantity
ofemptyspacesvaries,andtheymaycontaineitherairorwaterwhich
entersandthencirculates.
3.2 WATER AND SUBSOILThecapacityofthegroundtoletwaterpassthroughiscalledpermeability
anddependsonthepresenceofvoidsinthesolidmaterialwhichforms
thegrounditself.Ifthevoidsareformedbypores,itiscalledpermeability
byporosity.Ifthevoidsareformedbyfractures,ontheotherhand,itis
calledpermeabilityby fracturation. Inbothcases,only thevoidswhich
areconnectedtoeachotherallowwatertomove.
An example of a very porous rock with low permeability is pumice, in
whichonlyafewoftheporesintherockareconnectedtogether.Ground
formed by large-grained pieces is highly permeable. This means that
water infiltrates easily and does not tend to remain on the surface. In
ground formed by small-grained pieces, such as clayey ground, the
waterfiltersthroughmuchmoreslowly.Therefore,whereclayeyground
isfound,itismorelikelythatwaterwillbefoundonthesurface.Inground
formedbylayersofcompactrock,permeabilityvariesaccordingtothe
numberandsizeofthefracturesandhowthesefracturesareconnected
together.Therefore,tosumup,waterpassesthroughbothlayersofclay
(soil)andlayersofgravel(rock),buttheintensityofthephenomenonis
completelydifferent.Morethanacenturyago,Darcystudiedtheflowof
waterthroughhorizontalsandbeds,andestablishedthattheflowspeed
through porous matter is directly proportional to the loss in load and
inverselyproportionaltothelengthoftheroute.Darcyboundthevarious
rateswiththefollowingwell-knownequation:
v = k iwhere v is the discharge speed, k is the coefficient of permeability or
coefficient of hydraulic conductivity, and i is the hydraulic gradient
or slope of the piezometric line. Between 1915 and 1925 Terzaghi
demonstratedhowDarcy’slawcouldbeappliedtoalltypesofground.
Thecoefficientofpermeabilitykexpressesvelocityanddependsonthe
porosityofthematerialandthefluid.Variousfactorshaveaninfluenceon
thecoefficient,especiallykwhichisdirectlyproportionaltothesizeofthe
granules.Infact,gravellygroundhasahighrateofpermeability,whereas
clayeygroundismoreorlessimpermeable.Inthefollowingsection,the
term“impermeable”willbeusedanumberoftimes,whileinnature
completelyimpermeablegrounddoesnotactuallyexist.
Waterwhich infiltrates into thegroundandmoves in thesubsoil forms
underground “groundwater”. The term “aquifer” will be used in this
section, which indicates ground (compact or less compact, and either
stratifiedornon-stratified)whichhasthecapacityofstoringwater,making
itcirculateandthenreturningitinlargequantities.Anaquiferisdelimited
inthelowerpartbyalayerofimpermeablegroundandthewatermoves
aroundslowlyintheaquifer.
In general, aquifers fed directly by rainwater which infiltrates from the
surface and penetrates into permeable ground, until it runs into an
impermeablelayerofmaterial(forexampleclay)whichslowsitdown(or
whichcompletelyblocksit)andstopsitgoingdeeper,areknownaswater
tablesorfreestrata.Thislayerformsthebaseor“bed”ofthewatertable.
Theupperlimitofthewatertableisbasicallyformedbyafinersaturated
zone(the“phreaticsurface”)andthepressureofthewatercontainedinit
isthesameastheatmosphericpressure.
Therearealsostrataunderpressureknownasartesianstrata (Fig.3.3)
whicharedelimitedinboththelowerandupperpartsbyanimpermeable
layer. The water which feeds these strata is the same which infiltrates
where thepermeableground,which forms the stratum itself, ison the
surfaceandmaythereforereceivethewater.Thus,theareawhichfeeds
a stratum under pressure may be quite a distance from the stratum
itself.Strata“underpressure”areknownbythistermbecausethewater
inside the stratum is subjected to a pressure which is higher than the
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
Fig.3.3-Sectionalviewofaportionofgroundandanartesianstratum
Fig.3.2–Sectionalviewofaportionofgroundanditswatertable
Fig.3.1–Schematicsectionalviewofaportionofground
12
Aria
Granuliditerreno Acqua
Air
Grainsofearth Water
Phreaticsurface
Groundwater
Impermeablestratum
Piezometricsurface
Impermeablestratum
Artesianstratum
Impermeablestratum
15
Fig.3.5–Schematicdiagramofhowthelevelofthewatertableisloweredusingawellpointsystem
Fig.3.6–Drillingoperationstoinsertwellpoints
atmosphericpressure,andwhichhelpsitrisespontaneouslyinsideahole
drilledintheground.Thewatercontainedinbothtypesofaquifermaybe
extractedbymakingawell.
Thewatercontainedinthegroundmaybeclassifieddifferentlyaccording
tothewayitbondswiththegrainsofearth:
•retainedwaterwhichadherestothegrainsofearthandisnotpartof
thehydrologiccycle;
•freewaterwhichinfiltratesintothegroundduetotheforceofgravity.
Freewater isthemost importanttyperegardingtheproblemofground
drainage.
Undergroundwatermaybeconductedtotwodifferentzones:saturated
andnon-saturated.Thenon-saturatedzonemaybe found immediately
below the surface of the ground and the empty spaces contain both
waterandair,whilethesaturatedzoneformstheactualstratum.
3.3 DRAINAGE SYSTEMSIfthereisanareaofasitewithgroundwater,asuitabledrainagesystem
mustbeinstalledinordertocarryoutconstructionoperations.Thetypeof
drainagesystemusedishighlydependentonathoroughunderstanding
ofthelithologicnatureoftheareaofgroundinquestionandtheneedto
lowerthelevelofthegroundwater.
Drainingoffthegroundwaterusingawellpointsystemallowsconstruction
worktobecarriedout,evenwhenthereiswaterpresent.Therelatively
lowcostofthissystemcomparedwiththeresultsobtainedisthemain
advantageofthissolution,anditisthequickestandmostcost-effective
methodtotemporarilyorpermanentlydrainoffgroundwater.Thewellpoint
system, which has been used for a number of years in industrial and
constructionapplications,hasbeendevelopedover the last fewyears
andisnowoftenusedforreclaimingland.
Thewellpointsystem(Fig.3.4)isjustoneofthetechniquesapplied,and
consistsinforminganumberofminiwells(wellpoints)intheareaaround
thegroundwherethelevelofgroundwaterneedstobelowered,andis
mainly used in sandyground. It is alsoused to dry off muddyground
afterformingdrainagesleevesinwhichthewellpointsarepositioned.Itis
importanttopointoutthatawellpointsystemtemporarilylowersthelevel
ofthegroundwater(Fig.3.5).
Awellpointsystem(Fig.3.6)comprisesthefollowing:
•anelectricordieselcentrifugalpump(Fig.3.7)withahighvacuum
capacitytopumpthewatertoahigherlevel;
• an intakemanifold (flexiblehoses) to connect thewellpoint to the
pump;
•wellpointswithaseriesofmetallicorplasticfilterstodrawoutthe
waterwithoutdrawingsolidparticlesfromtheground;
•dischargepipestocarrythewaterawayfromtheexcavatedarea.
If thewaterneedstobecarriedovera longdistanceawayfromthe
excavated area, supplementary booster pumps will also have to be
employed.
Inidealconditions,themaximumsuctionliftofawellpointsystemwould
be8.7m.Inrealsiteconditions,however,theperformanceofthepumps
isdrasticallyreduced,andforparticularlydeepexcavationstolowerthe
levelofthegroundwaterbymorethan4metres,wellpointsareinstalled
insteps.Insodoing,thewaterheadisreducedinsuccessivestepsby
installingwellpointsatdifferentlevels.Awellpointsystemallowsanarea
ofasitetobedriedoffsoconstructionworkmaybecarriedoutbelowthe
levelofthegroundwater.
Please note: the drainage system must not be switched until the
reinforcedconcretestructurehascuredsufficientlytowithstandthe
buoyancyforceexertedonthesite.
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
14
Intakemanifold
Initiallevelofgroundwater Heightofsuctionpumpinlet
PumpSuctionpipe
Loweredgroundwater
Fig.3.4–Flexiblehouseusedtoconnectwellpointstoanintakemanifold
17
Thetypeofgroundinfluencesthechoiceofthemostsuitabledrainage
system. According to the various types of ground and their grain
distribution, various drainage systems may be adopted as described
below.
•Pebbles(diameter>60mm):todrainoffgroundformedbypebbles,
oneoftwowellsystemsmaybeused.Thefirstsysteminvolvesdrilling
awellatground levelusingacontinuouscoringauger.Thesecond
technique involves positioning a series of perforated concrete rings
usinganexcavator.Althoughthis techniquehasamuch lowercost,
eachsiteneedstobecarefullyassessedtoverifyifsuchasystemis
feasible.Bothsystemsuseanopenairpumpingsystemwitheithera
surfacemountpumporasubmergedpump.
• Gravel (20 mm < diameter < 60 mm): the most suitable drainage
systems are formed by a system of wells or a wellpoint system for
gravel.Thewellsystemissimilartotheonedescribedforpebblesand
isusedwhenitisnotpossibletodriveinwellpointrods.Regardingthe
wellpointtechnique,itisverysimilartothetraditionalsystembydriving
inrodswithahighpressurepump,whilethesandfilterisreplacedwith
aspecialtipforgravelcalledaprobe.Dryingoffgroundwithagravel
wellpointisasystemwhich,unlikedrainingoffwaterwithawell,works
by creating a cone of depression in the water table which forcedly
drawsthewaterfromthesubsoilandincreasesitsvelocity.Withthe
welldrainagesystem,noconeofdepression is formed in thewater
table and the water is drained off by gravitational force, that is, by
runningintothewell.Itsvelocityislowercomparedwiththevelocity
inducedbyawellpointsystemandasaresult,thewaterrequiresmore
time to reach the well and the flow rate is lower. In fact, according
tothesizeofthesiteandthepiezometric leveltobereached, ifthe
drainage capacity of a gravel matrix aquifer is interpreted correctly,
thenumberofpumpsrequiredand, therefore, theoverallcostsmay
bereduced.
•Sandwithagravelmatrix(0.6mm<diameter<20mm):sandysoil
withagravelmatrixisbasicallydrainedoffwithawellpointsystemfitted
withanti-sandfiltersorgravelprobes,accordingtothepercentageof
gravelintheground.Incertaincases,itmaybenecessarytoinstalla
mixedsystemtogetthebestresults.Thewellpointrods,witheither
anti-sand filters or gravel probes, are driven into the ground under
pressure.
•Cleansand(0.2mm<diameter<0.6mm):cleansandistheideal
groundforinstallingawellpointsystemwithmicro-porefilters.Although
it is unlikely that this type of ground is homogenous with uniform
isotropy and grain size distribution, a wellpoint system is almost
alwaysaguaranteethatthedepthtoexcavatemaybereachedindry
conditions,withanacceptablebalancebetweentheresultsobtained
andtheoverallcostofthesystem.Thesystemisalsorelativelyeasyto
install,inthattherodsaresimplydriveninunderpressure.
•Sandwithamuddymatrix(0.02mm<diameter<0.2mm):sandwith
amuddymatrixmaybedrainedoffusingatraditionalwellpointsystem
withanti-sandfilters.Ifthemuddymatrixdoesnothaveaneffecton
thepumps,therodsmaybedriveninunderpressure.If,however,the
muddymatrixtendstoclogthefilters,apre-filteringsystemmustalso
beinstalledbyboringaholeintheground.
•Silt (0.006mm<diameter<0.02mm): themostsuitabledrainage
systemforsiltyground isonewithapre-filter, that is,byboring the
ground,insertingadrainagesleeveandthenbleedingandrinsingthe
wellpointwithasuitablepump.
•Siltwithaclaymatrix(0.002mm<diam.<0.006mm):clayeysiltmay
bedrainedoffusingoneofthefollowingsystems:
-wellpointsystemwithapre-filter;
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
16
Fig.3.7–Centrifugalpumpusedinawellpointsystem
19
- installationofperforatedconcreteringsusinganexcavator.The
useofthistypeofsystem(muchmoreeconomicalafterassessing
itsfeasibilityonsite)dependsonthestabilityofthesidewallsofthe
excavations.
-layingadrainagepipeafterformingadrainagetrench.
•Clay(diameter<0,002):whenthegroundisclayey,therearebasically
twotypesofdrainagesystemsavailable:
-wellpointsystemwithapre-filter;
-layingadrainagepipeafterformingadrainagetrench.
Inrockyground,thewatercirculatesthroughchannelswhicharedifficult
to trace during the preliminary phase. In such conditions, therefore, it
is impossible to get good results with a wellpoint system. A wellpoint
systemmaynotbeabletocontrolthelevelofthegroundwaterinlarge-
grained ground or ground with high hydraulic conductivity. In these
cases,drainagewellswithelectricimmersionpumpsareused.Thewells
aredesignedaccordingtothegeologyofthesubsoilandtheamountand
chemicalandphysicalcharacteristicsofthewatertobedrainedoff.The
designofthewellsmustinclude:
•theboringmethod(percussionorrotating);
•thetypeand lengthofthefilterrequiredandthedepthatwhich it
mustbeinstalled;
•thegraindistributionifdrainagelayersareused.
Wellsaremadeaccordingtothefollowingsteps:
•verticalholesareboredinthegroundusingapercussionorrotating
(direct rotation or inverse rotation) boring machine, with the core
pulverisedbyacrushingcone.Linersarerecommendedtoprotectthe
verticalsidewallsofthebore.Thedepthoftheboremustbesuchthat
itreachesthelowesttheoreticallevelrequiredforthegroundwaterplus
3mmore,toformapermanentbuffer.
•filtersanddrainagepipeswitha1mmfilteringcapacityareinserted
intothebore;
•gaugedinertmaterialisusedtofillanygapsbetweenthedrainage
pipesandtheverticalsidesofthebore;
•thewelliscementedoffandisolated.
Afterinsertingthefiltersandpipesandselectingthegrainsizeandmineral
typefordraining,thewellmustbecementedtoisolatethewaterfromthe
surfaceandbetweeneachwell.Thefinaloperationsistofinishoffthewell
sothatitisasefficientaspossibleandtoavoidsandorimpuritiesbeing
draggedfromthewaterdrainedoff.
If the groundwater is on the surface and there is only a small amount
ofwatertobecontrolled,horizontalgravitationaldrainagesystemsmay
beused (Fig.3.8).Trenchesaredugat90° to theflowof thewater to
channelthewatertowardsdefinedcollectionpoints.FlexiblePVCpipes
linedwithperforatednon-wovenfabrictostopthewaterreleasingfiner
particlesintothegroundarepositionedinthecollectionpoints.Inorder
toincreasethedrainagecapacityofthesystem,thePVCpipesmayalso
beconnectedtoabatteryofsuctionpumps.Thedrainagepipesarelaid
byaspecialmachinewhichoperates inacontinuouscycleandwhich
mayreachdepthsofupto5m.Onceallconstructionoperationshave
beencompleted, thePVCpipesare leftburied intheground.Withthis
system,thetimerequiredtodrainoffthewaterisconsiderablyreduced
andtheareaistotallyaccessible.However,largespacesarerequiredfor
thelayingequipmenttocarryoutmanoeuvresandtherearenoutilities
availableunderground.
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
18
21
Fig.3.8–Schematicviewofahorizontalgravitationaldrainagesystem,withandwithoutadrainagepipe
Aftertakingalookatthevariousdrainagesystemsavailable,according
to the type of ground where the groundwater needs to be lowered, it
is quite clear that, before designing the drainage system, an in-depth
analysismustbecarriedouttoobtainallthedatarequiredtocalculate
anddeterminethemostsuitabledrainagesystem.
Andonlyafterobtainingacompleteunderstandingofthetypeofground,
itsstratographiccompositionandthepresenceofgroundwatermaythe
nextphaseofidentifyingthemostsuitabletypeofexcavationbetackled.
4. EXCAVATION WORKInthebuildingsector,excavationworkreferstotheremovalofrockand/
orgroundfromitsoriginallocationtoformcavitieswithvariousshapes
anddimensionstocarryoutengineeringandconstructionwork.
Excavationworkmaybedividedasfollows:
•openairexcavations;
•excavationsintunnelsandpassages.
Open air excavations may then be further divided into fixed section
(or trenching) and stripping (or open section) types. Fixed section
excavations are the same width, or narrower, than the depth of the
excavationandstartsfromthesurfaceofthegroundorthebottomofa
previousstrippingexcavation.
Goingfurtherintodetail:
• fixed section excavations are those in which the length of the
horizontal sides is less than the depth. They are generally used for
foundationplinthsorgroundbeams.
•trenchingexcavations are continuouswithanarrowsection.Theyare
generallyusedforlayingpipe-lines,buriedutilities,etc.
Stripping(oropensection)excavations(Fig.4.1)arethoseinwhichthe
horizontalsurface ismuch larger than thedepthof theexcavationand
the section is sufficiently large toallowaccess for vehicles right up to
thefrontoftheexcavation(directaccessusingtemporaryramps)sothat
thematerialdugoutmaybe loadeddirectlyon trucks.Stripping is the
most simple, economical andnatural formof excavationwork tobuild
structuresbelowgroundlevel,andbasicallyusesthefrictionangleinthe
groundtostabilisethesidesoftheexcavation.Ifwaterorrainarepresent,
apartfromthefrictionangleoftheground,thepermeabilityoftheground
isalso important. In fact, thestabilityof thesidesof theexcavation is
heavily influencedby theseparameters,since there isnovegetation to
holdthegroundtogether,asnormallyoccursonnaturalslopes.Generally
speaking, theconditionsdescribedabovearenot thereal limits to this
system. In certain cases, there are other insurmountable problems for
thissystem,suchasthelargespacesrequired,whichincreasedrastically
according to thedepthof theexcavationand thepermanent loadson
theadjacentarea.Infact,whenconstructionworkiscarriedoutinbuilt-
up areas or close to transport networks, apart from the density of the
saturatedground,theloadsofthesestructuresmustalsobetakeninto
consideration.Whentheseconditionsarepresent,theexcavationmustbe
confinedbyinsertingsupportstructures,whichhaveadoubleadvantage:
thesidesoftheexcavationmaybeverticalwhichconsiderablyreduces
theoverallareatoonlywhatisreallynecessaryfortheconstructionwork,
and theyalsosupport thegroundadjacent to theexcavationareaand
guaranteethestabilityofthesurroundingbuildings.
Thesupportstructuresusedtocontainthesidewallsoftheexcavation
aregenerallysimilartobulkheads:relativelythin,verticalstructuresdriven
intothegroundatacertaindepthbelowthe leveloftheexcavation,to
form a support which is sufficiently robust to contrast the thrust from
theembankment,thewaterandanyother loads.Thesestructuresmay
beinstalledwithorwithoutanchoringsystems.Inthefirstcase,stability
isguaranteedbythepassiveresistanceofthegroundontheembedded
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
20
Fig.4.1–Strippedgroundwithoutconfinement
Fillermaterial
PVCdrainagepipeGeofabric
Drainagematerial
HORIZONTALDRAINAGEBYGRAVITY
23
Fig.4.3–Strippedgroundconfinedbyboredpiles
Fig.4.2–Strippedgroundconfinedbydiaphragms
partofthestructureandthebehaviourofthebulkheadismoreorlesslike
thatofabracket.Inthesecondcase,stabilityisalsoguaranteedbystays
clampedinthegroundusingspecialmortarmadefromgroutmixedwith
CABLEJETplasticising,expansiveadditive.Thebulkheadsmaybemade
frompre-fabricatedsheetpiling(overlappedanddrivenintotheground),
reinforcedconcretediaphragmsbuiltdirectlyonsite,bypilesboredinto
theground(sidebysideoratangles)orbymicro-piles.
Thesheetpilingismadefromsteelandisavailablewithvariousprofiles
toobtainwhatevermodulusofresistanceisrequired.
Diaphgrams(Fig.4.2)arebuiltdirectlyonsite,bydiggingatrenchinwhich
theconcreteisthenpoured.Theyareformedbypanelsgenerallybetween
50and120mmthick,atleast200cmwideandmaybeextremelylong,
muchlongerthanpre-fabricatedpanelswhichareusuallyuptoonly15-
20minlength.
Piles (Fig. 4.3) are straight elements made from reinforced concrete,
and their size depends on the cohesion of the ground and the depth
towhich theyaredriven.Thepitchbetweeneachpiledependson the
characteristicsoftheground,theamountofwaterinthegroundandthe
sizeofeachpile.
Micro-pilesarepileswithadiameterlessthan300mmifboredintothe
groundand150mmifdriven in.Micro-pilesarereinforcedwithasteel
tubeorprofileorasteelcagemadefromrebar,whilethefillermaterialis
madefromeithercementitiousmortarorbeton.
Steelsheetpilingbulkheadsaregenerallymoreflexiblethandiaphragms.
This fact must be considered during the design phase because the
evolution,distributionandthefinalactionofthegroundalsodependon
howthesupportstructuresdeformandhowmuchtheydeflect.
Bulkheads are generally constructed before excavating the ground to
the depth required. The vertical bulkhead is usually installed around
theperimeterof theexcavationbeforeplacingthetoppingbeams.The
groundisthenexcavatedinsidetheperimetertothedepthofthefirstrow
ofstays(ifused),thestaysareinsertedandthentightened.Excavation
workisthencarriedoutlevelbylevel,followingthesameprocedureas
describedaboveuntilreachingthedepthrequired.
Bulkheadswithoutanchoragepointsaregenerallyacceptableforshallow
excavations,sincethemoduleofresistancerequiredincreasesquicklyas
thedepthofthegroundtobesupportedincreasesandbecausetheyare
subjecttoconsiderablelateralflexure.Bulkheadswithanchoragepoints
areusedfordeeperexcavationsandespeciallywhentheareaexcavated
is particularly widespread. The use of anchorage points reduces the
lateralmovements, themaximumbendingmomentand thedepth they
aredrivenin.Thepositionoftheanchoragepoints(Fig.4.4)forthestays
must be such that the active thrust prism (ground lift) acting on the
bulkheaddoesnotinterferewiththepassiveresistanceduetotheaction
oftheanchoragepoints.Anchoragestaysfixedinplacebyaribinjected
underpressurearegenerallybuttedtothebulkheadwithananchorplate
orothersuchanchoringmeans,whichisusedtotransmitthepullingforce
ofthestaytothestructure.
If there are constructions below ground level in the vicinity of the
excavation,itisimpossibletoanchorthebulkheads.Inthesecases,the
Top-Downsystemwillhavetobeadopted (Fig.4.5),whichalsoallows
the surface at ground level to be prepared much more quickly than
with conventional systems. The Top-Down system means building the
constructionstartingfromthetopandworkingdownwards,theopposite
ofthetraditionalmethod.Aftercompletingthetemporarystructure,the
ground is excavated to the depth required for the floor slab, which is
thenpoureddirectlyontheground(oftenwiththeuseofplasticsheets
to improve itsfinalappearance).Afterwaiting thestandard timebefore
strippingthefloorslab,excavateunderthefloorslabbypassingthrough
holespreviouslymadeorfromanaccessramp.Withthismethod,afterjust
afewmonths,theroads,squaresandgardensonwhichtheworkisbeing
carriedoutareavailableforpublicuse.Fromthismomenton,theonlyarea
occupiedbythesiteistheaccessramp.Thefloorslabsareanchoredto
thetemporarysidestructuresandbecomeself-bearingwithoutbuilding
thewallsbelow.Thereinforcementtierodsforthepouredconcreteare
theninserteddownwardsandbenttoshape.Aftercompletingallthefloor
slabs,theuprightsarethendugoutandtheconcreteispouredin,with
spacesinthefloorslabswheretheconcreteispouredin.Reinforcement
tierodsandconstructionjointsarehandledexactlytheoppositewayto
traditionalmethods.Insodoing,constructionworkiscarriedoutworking
downwardsuntilthefoundationsarereached.
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
22
25
In certain cases, the need to exploit areas below ground level derives
fromthe lackofnewbuilding landandspacesandthehighdensityof
thebuilt-upareasinsomecities.Constructionworkbelowgroundlevel
alsorepresentsachancetobeexploitedforbuildingauxiliaryandservice
structures (such as car-parks and production units). Structures below
groundlevelcomeintocontactwiththedampintheground,withwater
whichpercolatesupwardsandwithgroundwaterand,therefore,needto
bewaterproofedtoavoid infiltrationscompromising the functionalityof
theroomsinsidesuchstructures.Structuresalsoneedtobewaterproofed
to protect the construction from deteriorating due to the presence of
chemicalagentsinthegroundorcarriedbywaterintotheconstruction
materials,toguaranteealongerservicelifeofthestructure.
5. MAPEI WATERPROOFING SYSTEMS FOR FOUNDATION STRUCTURES
5.1 WHY WATERPROOF?Fromatheoreticalpointofview,goodconcretehasaverylowcoefficient
of permeability k (see Section 3.2), so it may be considered more or
less impermeable to water under pressure. UNI 9858 : 1991 (replaced
by EN 206-1 : 2001) established that for a concrete to be considered
impermeable, itswater/cementratiomustbe<0.55.Inrealconditions,
inspiteofthemostmodernproductiontechniquesbeingemployed,itis
extremelydifficulttomakeconcretewhichisperfectthroughoutitsentire
bulk.Infact,eventhesmallestimperfection(cracks,honeycombs,etc.)
and construction and structural joints form a preferential passage for
water.Therearevariousphenomenawhichgeneratecracksinconcrete,
suchasshrinkageduringcuring,seismicactivity,settlingoffoundations
and vibrations caused by traffic. It is obviously impossible to keep all
thesephenomenaundercontrolandbecertainthattherearenocracks
in theconcreteafter ithasbeenpoured.Also,waterwhichpenetrates
into the concrete is acid, and therefore aggressive for both the base
componentsoftheconcreteandforthereinforcementrods.Considering
theabove,theonlysolutiontoadopttostopwaterpenetratingintothe
concreteand infiltrating into the roomsbelowground level, is tousea
waterproofingsystem.
When a waterproofing system needs to be installed, the highest point
of the groundwater must be considered, whether the level is constant
or influenced by temporary events and by the type of ground. In fact,
thecharacteristicofgroundwithgooddrainage,comprisingmainlysand
andgravel, isthat itreleasesthewaterveryquickly,buttransfers large
amountsofwater justasquicklyaround thestructure, thusgenerating
high pressure. With compact, impermeable ground on the other hand,
suchasclayeyground,thewaterisreleasedveryslowlywiththeriskof
watercollectingandgeneratinginfiltrationsinroomsbelowgroundlevel.
Evenwhenthereisnogroundwater,theinfiltrationofrainwaterprovokes
aggressionactiononthestructurewiththepossibilityofwaterpermeating
intoroomsbelowgroundlevel.
Therefore,fromapracticalpointofview,waterproofingmaybeinstalled
tosolvethreedifferenttypesofproblem:
• damp present in drainage ground which does not cause water to
accumulateduringexcavationwork;
• non-draining ground in excavations which causes water to
accumulate;
•groundwithwaterunderpressure.
Inthefirstcase,thewaterproofinglayerisnotsubjecttohighhydrostatic
loads.Thisismainlyduetotheformationoftheground,generallyformed
by sand and gravel, which have good drainage characteristics and,
therefore, are able to release the water which percolates quite quickly
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
24
Fig.4.4–Anchoragepointsforstaysinsertedoutoftheground’sactivethrustzone
Fig.4.5–ExampleofaTop-Downconstruction.Excavationworkcarriedoutunderthereinforcedconcretefoundationpadcastbeforeexcavating
Bulkhead
Plate
Groundlevel
Tie-rod
Anchoragezone
ActivethrustprismofthegroundLowestpointofexcavation
27
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
withoutitcollecting.Thisconditionmayalsobeachievedongroundwith
poordrainagebyapplyingasuitabledrainagesystematthebaseofthe
foundationsandonalltheverticalsurfaces.
Inthesecondcase,thepresenceofcompactgroundorclayeyground
withnodrainagesystemcauseswatertocollect.Excavationoperations
modify the intrinsic balance between the ground and the water. After
completingtheconstructionworkandfillingintheexcavatedareas,the
groundwillbeconsiderably lesscompactandmoreporous, therefore,
compared with the adjacent ground. This will form a drainage area
towardswhichthewater fromtheadjacentgroundwill tendtomigrate
and generate temporary, high pressures, also due to the fact that the
waterisreleasedveryslowly.Itisworthrememberingthatawaterhead
ofonemetreisequaltoapressureof1000kg/m2(Fig.5.1).
In the third case the water under pressure, due to the presence of
groundwater, is indirectcontactwith thestructureandwillhave tobe
consideredwhenchoosingboththewaterproofingsystemandthetype
ofstructure itself.Therefore,whengroundwater ispresent,even ifonly
duringcertainperiodsoftheyear,afoundationstructurewillhavetobe
installedwhichhasthecapacityofcontrastingtheliftfromwaterunder
pressure.Theonlyfoundationstructurewiththiscapacityisafoundation
pad.
5.2 MAPEPROOF AND BENTONITEMAPEI offers a wide range of products for waterproofing structures
belowgroundlevel(refertotheWaterproofingProductscatalogue)which
aresuitable forbothnewconstructionsandforrepairworkonexisting
structures. Below is a brief description of MAPEI MAPEPROOF and
MAPEPROOF LW bentonite sheets, which completes the information
available on the Technical Data Sheets for each product and in the
WaterproofingProductscatalogue.
MAPEPROOF and MAPEPROOF LW are composed of two layers of
polypropylenegeo-textilefabric.Theupper layer isanon-wovenfabric
whilethelowerlayerisawovenfabric.Theyareneedle-punchedtogether
with a layer of natural sodium bentonite sandwiched between the two
layers.Theneedle-punchprocess(Fig.5.2)involvestheuseofthousands
ofneedleswithahookedtip,whichforcepartofthefibresoftheupper
layerofnon-wovenfabricthroughthemiddlelayerofbentonite,andstitch
ittothelowersupport layerofgeo-textilefabric.Thankstothisspecial
weavingsystem,thenaturalsodiumbentonitecontainedinMAPEPROOF
remains fixed in place, even after hydration. The special grain size of
the bentonite, together with the type of non-woven geo-textile fabric,
guarantee saturation of the non-woven fabric which is in contact with
thepouredconcrete.Thischaracteristicgivestheproductanimportant
technicaladvantage:thefabricmaybeappliedafterpouringtheconcrete
(Fig.5.3).Thedifferencebetweenthetwosheetsistheamountofnatural
sodium bentonite each one contains: MAPEPROOF contains 5.1 g/m2,
whileMAPEPROOFLWcontains4.1g/m2.
Forthisreason,MAPEPROOFLWisonlyrecommendedforwaterproofing
concrete structures below ground level with a hydraulic head of less
than5m.AccordingtoASTMD5887,MAPEIbentonitesheetshavea
permeabilitycoefficientk<1E-11m/s.Thus,onthebasisoftheequation
v=ki(Section3.2),thevelocityvatwhichthewaterpassesthroughthe
sheetissolowthatitispracticallyzero.
The basis of the waterproofing capacity of MAPEPROOF sheets is
bentonite,aclaymineralcomposedmainlyofmontmorilloniteandsodium.
Bentonite originates from the alteration of volcanic ash. It devitrifies in
awatery environmentwith removal of apart of the silica content. The
montmorilloniteisthencrystallised,anditschemicalcontentdependson
thechemicalcontentofthewaterinwhichthevolcanicashprecipitated.
Bentonite is generally divided into two types: sodium bentonite and
calciumbentonite.Sodiumbentoniteexpandswhenitcomesintocontact
withmoisturewhichmakes itparticularly suitable for sealingpurposes
andtocreatewaterproofbarriers.
Calciumbentoniteisausefulabsorbentofionsinsolutionaswellasfats
andoil,whichiswhyitwasprobablyoneofthefirstcleaningagentsused
onanindustrialscale.
26
Fig.5.2–Aschematicviewoftheneedle-punchprocess
Needle
Whitenon-wovenfabric
Sodiumbentonite
Dark-colouredfabric
Fig.5.1–Aonemeterheadofwatergeneratesaloadof1000kg
29
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
Bentoniteisusedinvarioussectors.Becauseofitsviscosisingproperties,
it is used in cement, adhesives, and ceramics and as a binder in the
productionofpelletsforthesteelindustry.Itisalsousedincosmetics
fortreatingacneandoilyskinbecauseofitscapacitytoabsorbexcess
sebumandcleanporesintheskin.Anotherinterestingcharacteristicof
bentoniteisitscapacitytoabsorblargequantitiesofproteinmolecules
fromwaterysolutions,whichmakesitanexcellentagenttoreducethe
levelofproteinscontainedinwhitewine.
Montmorillonite, from which bentonite is made, has a special lamellar
crystalline structure and is non-toxic and chemically inert. The high
specificsurfaceareaofbentoniteandthenegativechargeofthelamellas
which form the structure give this mineral the property to absorb and
adsorbvariouselements.
Themechanismthroughwhichbentoniteisabletoholdwaterwithinits
molecularstructureisbasedonitscapacitytoswell inthepresenceof
waterandmoisture.Confined,swollenbentoniteblocksthepassageof
waterbetween theparticles (Fig. 5.4). This isdue toboth an increase
in the length of the route of the water molecules and the formation
of a stable structure which maintains the energy bond between the
sodiumionsandthewateratahighlevel.Thisstopsthewaterpassing
through thebentonite and it is trapped inside thecrystalline structure.
Whatactuallyhappensisthat,inthepresenceofwaterormoisture,the
bentonite forms a waterproof, water-repellent gel. Hydration rates and
timesvaryaccordingtoanumberoffactors,includingthegrainsizeofthe
mineralandthesurroundingtemperaturewherethephenomenonoccurs.
Thewaterproofing propertiesof bentonite laidon site isdemonstrated
whenexpansionofthebentoniteisblockedbythefoundationstructure.
Thebentonitehydratesandincreasesinvolumeaccordingtothespace
available.Thisincreaseinvolume,asmaybeeasilyimagined,allowsthe
materialtoblockthepassageofthewaterthroughitsstructureandstops
itmigratinglaterally.
Expandedbentoniteobstructsthecavitiesandsaturatescracksupto3
mmwidecausedbyhygrometricshrinkageorsettlingafterpouringthe
concrete.
6. SPECIFICATIONS FOR FOUNDATION CONCRETE
Before analysing typical site conditions and problems and suitable
technical solutions to be adopted, a brief overview of foundation
structuresandtheconcreteusedforsuchstructureswouldbeveryuseful.
Asdiscussedpreviously,withconstructionworkbelowgroundlevelinthe
presenceofgroundwater,whetheritiscontinuousorduetotemporary
events,theonlytypeofstructurecapableofwithstandinghydrostaticlift
isacontinuousfoundation.Asfarasdurabilityisconcerned,theconcrete
must be designed according to EN 206-1 : 2001, which defines the
environmentalexpositionclasses(Table1a-b),onthebasisofwhichthe
limitvaluesaredefined (Table2) for thecompositionandpropertiesof
concrete:themaximumwater/cementratio,theminimumstrengthclass
andtheminimumcementcontent.
Concretemustbewellvibratedtoeliminategravelclusters,andsuitable
admixesmustbe includedso itfillsall thespacesandgapsandflows
freely around the steel reinforcement. In this case, we recommend
using a super-plasticising admix from the DYNAMON range, produced
by MAPEI S.p.A. The DYNAMON system is based on DPP (Designed
Performance Polymer) technology, a new chemical process which,
through total monomer design (exclusive know-how of MAPEI), allows
thecharacteristicsoftheadmixtobemodulatedaccordingtothespecific
performance requirements of the concrete employed. Concrete made
withproductsfromtheDYNAMONrangeiseasytoapplywhilefreshand
offersveryhighmechanicalperformancewhenhardened.
Fig.5.3–AnexampleofMAPEPROOFappliedaftercasting
Fig.5.4–HydrationprocessofsodiumbentonitecontainedinMAPEPROOFandMAPEPROOFLW.
Ifthebentoniteisconfined,whenitswellsitblocksporosityandimpedesthepassageofwater
Porosityof concrete
Bentonite sheet
28
31
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
30
EXPOSURE CLASSESClass
denominationType of conditions and surroundings Examples of conditions and surroundings when the exposure
classes may be applied1 No risk of corrosion or attack
XO Concrete with no metallic reinforcement or inserts: all exposures except freeze/thaw cycles and chemical attack. Concrete with metallic reinforcement or inserts: in very dry surroundings.
In buildings with a relatively low level of damp.Concrete without reinforcement inside buildings.Concrete without reinforcement embedded in non-aggressive ground or water.Concrete without reinforcement subjected to wet/dry cycles but not subjected to abrasion, freezing weather or chemical attack.
2 Corrosion induced by carbonatationNote – The levels of humidity refer to those present in the concrete or material used to cover steel reinforcement or metal inserts. In many cases, such levels may be considered as the same as the surrounding environment. in such cases, classification of the surrounding may be considered sufficient. This may not necessarily be the case if there is a barrier between the concrete and the surroundings.
XC1 Dry or permanently wet In buildings with a relatively low level of damp.Conventional reinforced concrete or pre-compressed concrete with the exposed surface in the building, apart from the areas exposed to condensation or immersed in water.
XC2 Wet, rarely dry Parts of structures for containing liquids and foundations.Conventional reinforced concrete or pre-compressed concrete usually immersed in water or non-aggressive ground.
XC3 Moderately damp Conventional reinforced concrete or pre-compressed concrete with external surfaces protected from the rain, or inside areas with a moderate to high level of humidity.
XC4 Cyclically wet and dry Conventional reinforced concrete or pre-compressed concrete cast outside with surfaces subjected to dry/wet cycles.Natural-finish concrete in urban environments.Surfaces in contact with water not included In class XC2.
3 Corrosion induced by chlorides excluding chlorides from seawater
XD1 Moderately damp Conventional reinforced concrete or pre-compressed concrete on surfaces or parts of bridges and viaducts exposed to sprayed water containing chlorides.
XD2 Wet, rarely dry Conventional reinforced concrete or pre-compressed concrete in structural elements completely immersed in water, including industrial water, containing chlorides (swimming pools).
XD3 Cyclically wet and dry Conventional reinforced concrete or pre-compressed concrete for structural elements directly subjected to de-icing agents or sprayed water containing de-icing agents.Conventional reinforced concrete or pre-compressed concrete for elements with one surface immersed in water containing chlorides and the other surface exposed to the air.Parts of bridges and floors in carparks.
4 Corrosion induced by chlorides except chlorides from seawater
XS1 Exposed to salty seawater but not directly in contact with seawater
Conventional reinforced concrete or pre-compressed concrete with structural elements on or near to the coast.
XS2 Permanently submerged Conventional reinforced concrete or pre-compressed concrete for marine structures completely immersed in water.
XS3 Zones exposed to sea-spray or high tides. Conventional reinforced concrete or pre-compressed concrete with structural elements exposed to tidal areas or for zones exposed to sea-spray or waves.
5 Attack from freeze/thaw cycles with or without de-icing agents
XF1 Moderate saturation of water without de-icing agents Vertical concrete surfaces, such as façades of columns exposed to the rain and freezing weather. Non-vertical surfaces whichh are not completely saturated but exposed to freezing weather, rain or water.
XF2 Moderate saturation of water with de-icing agents Elements such as parts of bridges whichh would otherwise be classified as XF1, but whichh are directly or indirectly exposed to de-icing agents.
XF3 High saturation of water without de-icing agents Horizontal surfaces in buildings where water may accumulate and whichh may be subjected to freezing weather and elements subjected to frequent wetting and exposed to freezing weather.
XF4 High saturation of water with de-icing agents or with seawater
Horizontal surfaces, such as roads and floors exposed to freezing weather and indirectly or directly to de-icing salts, and elements exposed to freezing weather and subjected to frequent wetting with de-icing agents or seawater.
LIMIT VALUES FOR THE COMPOSITION AND PROPERTIES OF CONCRETE
EXPOSURE CLASSESNo risk of corrosion to steel
reinforcement
Corrosion of steel reinforcement induced by
carbonatation
Corrosion of steel reinforcement inducedby chlorides
Environment with freeze/thaw cycles
Aggressive environment due to
chemical attackSeawater Chloride fromother sources
XO XC1 XC2 XC3 XC4 XS1 XS2 XS3 XD1 XD2 XD3 XF1 XF2 XF3 XF4 XA1 XA2 XA3
Maximum water/cement ratio - 0,60 0,55 0,50 0,50 0,45 0,55 0,50 0,45 0,50 0,50 0,45 0,55 0,50 0,45
Minimum strength class C12/15 C25/30 C28/35 C32/40 C32/40 C35/45 C28/35 C32/40 C35/45 32/40 25/30 28/35 28,35 32/40 35/45
Minimum cement content (kg/m3) - 300 320 340 340 360 320 340 360 320 340 360 320 340 360
Minimum air content (%) 3,0a)
Other requirements Aggregates in compliance with UNI EN 12620 for sufficient resistance to freeze/thaw cycles
Cement resistant to sulphatesb) is required
*) Table 7 from EN 206-1 mentions class C8/10 which corresponds to specific concrete for substrates and for covering purposes. For this class, durability regarding water and aggressive ground must be defined.a) When the concrete does not contain added air, its performance must be checked compared with aerated concrete with a proven value for resistance to freeze/thaw cycles determined according to UNI 7087 for respective exposure class.b) If the presence of sulphates leads to exposure classes XA2 and XA3, it is essential that cement resistant to sulphates according to UNI 9156 is used
Class denomination
Type of conditions and surroundings Examples of conditions and surroundings when the exposure classes may be applied
6 Attacco chimico**)
XA1 Weak chemically aggressive environment according toTable 2 from EN 206-1
Sludge basins and decantation basins.Containers and basins for waste water.
XA2 Moderate chemically aggressive environment according to Table 2 from EN 206-1
Structural elements or walls in contact with aggressive ground.
XA3 High chemically aggressive environment according toTable 2 from EN 206-1
Structural elements or walls in contact with highly aggressive industrial water.Containers for forage, animal feed and sewage.Cooling towers for industrial fumes and discharge gases.
*) the level of saturation in the second column reflects the frequency at which freezing occurs in saturated conditions: - moderate: occasional freezing in saturated conditions; - high: high frequency of freezing in saturated conditions.**) By water from the ground and flowing water
Tab2–Table4fromEN206-1:2001withindicationsoflimitvaluesforthecompositionandpropertiesofconcrete.
Tab1a-b–Table1fromEN206-1:2001withindicationsofenvironmentalexposureclasses.
33
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
7. WATERPROOFING NEW STRUCTURES BELOW GROUND LEVEL
This section will discuss the problem of waterproofing new structures
below ground level, and will offer a series of technical solutions to be
adopted, theproducts requiredandmethodsand techniques to install
and apply the products. All the information will be accompanied by
specifictechnicaldetails.
When excavation work is carried out, an artificial space is created
in which the part of the structure below ground level will be installed.
The hydrogeological balance of the site is modified and, even if there
is no groundwater present, after stripping the ground, rainwater and
precipitationswillcollectintheartificialspaceandformanartificialpond.
Insuchconditions, thestructuresof thebuildingwillhave tobemade
waterprooftoprotectthemfromlargequantitiesofwaterwhichcollects
intheareabelowgroundlevelaroundtheconstruction.
Inviewof theabove, it isclear thatastructuremustbewaterproofed
correctlyusingtheso-called“basin”or“pouch”methodwhichissuitable
to contrast the lift from the water, especially from groundwater. The
waterproofingsystemisappliedbystickingittothestructure(foundations
andwalls)withnopointleftuncovered.
Therenowfollowsadescriptionofaseriesofwaterproofinginterventions
tobecarriedoutonsitetoguaranteethatstructuresbelowgroundlevel
arewatertight.
Thefirstinterventionwhichmaybenecessarytocarryoutonsite,butwhich
isoftenoverlooked,istowaterproofthebaseofjibcraneswhentheyare
positionedinthefoundationstructure,whichshouldthenbefollowedby
waterproofingtheliftwells.Waterproofingofliftwellsisoftenoverlooked,
andmustbecarriedoutbeforewaterproofing theplinth.Thisshouldbe
carriedoutbecause,aswewillseelater,thebaseoftheliftwellisusually
thelowestpointoftheentireconstruction.Inthecaseoffoundationpads
restingonpiles,beforepreparingtheareaforlayingthebentonitesheetsto
waterproofthestructure,theheadsofthepilesmustbesealed.
ThemethodappliedtolayMAPEPROOFwillbedifferentaccordingtothe
typeofexcavation.Inthecaseofexcavationswithoutconfinement(see
Section4),thebentonitesheetsmustbehemmeduponformwork.With
confinedexcavations,ontheotherhand,thesheetsmustbeappliedon
thecontainmentbulkheadsonthesidewallsoftheexcavationwithone
ofthefollowingfourdistinctlayingsituations:onsheetpiling,piles,micro-
pilesanddiaphragms.
In excavations without confinement, waterproofing of the reinforced
concrete facing walls is carried out after pouring the concrete. MAPEI
offersarangeofproductswithdifferentcharacteristicsandperformance
levelsforthistypeofapplication:
•MAPEPROOF(seeSection5.2);
•MAPEPROOFLW(seeSection5.2);
• MAPELASTIC FOUNDATION two-component, flexible cementitious
mortar for waterproofing surfaces subject to negative and positive
hydrauliclift;
•PLASTIMULbitumenwaterproofingemulsion;
•PLASTIMUL1KSUPERPLUS solvent-free,one-component,quick-
drying,low-shrinkage,high-yield,high-flexibilitybitumenwaterproofing
emulsioncontainingpolystyrenebeadsandrubbergranules;
• PLASTIMUL 2K PLUS solvent-free, one-component, quick-drying,
low-shrinkage, high-flexibility bitumen waterproofing emulsion
containingcellulosefibres;
•PLASTIMUL2KSUPERsolvent-free,two-component,quick-drying,
low-shrinkage, high-flexibility bitumen waterproofing emulsion
containingpolystyrenespheres.
Special care must be taken when sealing around structural joints,
elementswhichpassthroughthefoundationpadandsidewalls,drainage
wellsandwellpoint rods.Waterproofing interventionsonaccess ramps
belowgroundlevelanddepurationtankswillbeillustratedlater.
32
35
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
7.1 SEALING CONSTRUCTION JOINTSConstructionjointsrepresentapointofdiscontinuityinthepouredconcrete
onbothhorizontalandverticalfaces.Theymustbemadewatertightto
avoid thepointsofdiscontinuity formingapreferential route forwater.
MAPEIoffersaproductdevelopedspecifically for sealingconstruction
jointscalledIDROSTOPB25(Fig.7.1-2).Itformsahydro-expanding,self-
sealingjointandhasasectionof20x25mm.itismadefromamixtureof
naturalsodiumbentoniteandpolymers,whichgivetheproductexcellent
characteristics of compactness, flexibility and stability. The swelling
processtakesplaceinacontrolled,uniformandgradualmannerwithout
the riskofaltering theequilibriumof themixture.Afterswelling,which
occurswhentheproductcomesintocontactwithwater,IDROSTOPB25
adaptsperfectlytothevolumedefinedbytheconfinementand,thanks
tothisspecialcharacteristic,perfectlysealsbothconstructionjointsand
localisedgravelclustersinthecastconcrete.BeforeapplyingIDROSTOP
B25, carefully clean the surface to eliminate all traces of debris, and
especiallytheslurrywhichbleedsfromthesurfaceandusuallyformswhen
compactingthecementitiousconglomerate.Thennailarib(1nailevery25
cm)alongthemiddleoftheverticalwallbetweenthesteelreinforcement.
Jointheendstogetherbysimplylayingthepiecesalongsideeachother
foratleast6cm(Fig.7.3).AsanalternativetoIDROSTOPB25,IDROSTOP
pre-formed, hydro-expanding, acrylic polymer tape may be used. This
productwasdevelopedtomakejointsintheconstructionindustrywhich
remainwaterproofuptoapressureof5atm.
The following paragraphs illustrate specific cases in which IDROSTOP
B25mustbeusedandhowtolaytheproduct.
7.2 WATERPROOFING THE BASE OF A JIB CRANEThebaseofajibcrane(Fig.7.4)ismadebyexcavatingaholewhichis
then linedwithawaterproofingsystembeforepouring in theconcrete.
Belowisadescriptionofthephasestobecarriedouttowaterproofthe
excavation.
- To form a suitable laying surface and make application of the
waterproofing system easier, the bottom of the excavation must be
evenedoutbyapplyingalayerofleanconcreteabout10cmthick.
-Tolaytheverticalpartofthewaterproofingsystem,installformwork
onwhichtheMAPEPROOFwillthenbeapplied.Positiontheunderside
(thedarkside)ofthegeo-textilepolypropylenefabriconthesubstrate
and overlap the edges of the sheets by at least 10 cm. Fasten the
sheetsinplacewithnailsandMAPEPROOFCDpolyethylenewashers
approximatelyevery30cm.
-Afterlayingthesystemontheverticalsurfaces,laytheMAPEPROOF
onthehorizontalsurfacebypositioningtheunderside(thedarkside)
of the geo-textile polypropylene fabric on the surface of the lean
concreteandtheuppersideofthefabric(thewhiteside)onthevertical
surfaces.Overlaptheedgesofthesheetsbyatleast10cm.Fastenthe
sheetsinplaceonthehorizontalsurfacewithnailsandMAPEPROOF
CDpolyethylenewashersapproximatelyevery50cm.Avoid forming
creaseswhenlayingthefabricontheleanconcrete.
-Afterlayingthebentonitesheets,thesteelreinforcementforthebase
mustbeplaced inposition,withspacersbetweenthereinforcement
andtheMAPEPROOFsheetstoguaranteethattheconcreteflowsfreely
betweenthereinforcementandthebentonitesheetsandcompletely
coversthereinforcement.Thenpourintheconcretetoformthebase
forthecranesothattheheightofthetopfaceofthebasecoincides
withtheheightofthefoundationpadinwhichitwillbeincorporated.
7.3 WATERPROOFING A LIFT WELLAliftwelliswithoutadoubtthepartofaconstructionwhichismostlikely
tocomeintocontactwithgroundwater.Infact,itoftenhappensthatlift
wellsarewaterproofedafterconstructiontoeliminateproblemsofwater
infiltrationandtomaketheelectricalequipmentoftheliftsafe.Thispart
Fig.7.1-IDROSTOPB25appliedtosealhorizontalandverticalconstructionjoints
Fig.7.2–TheminimumdistanceswhichmustbemaintainedbetweenIDROSTOPB25andthebladesinformwork,andbetweenIDROSTOPB25andtheoutersurfaceofconcrete,toguaranteecorrectconfinement
Fig.7.3–JointbetweentheendsoftwostripsofIDROSTOPB25bysimplylayingthemalongsideeach
otherforatleast6cm
34
been applied), which also help the concrete to flow under the steel
reinforcementandguaranteethatitiswellcovered.
-Pourintheconcretefortheliftwellfoundationpadwhichmustbe
calculatedtowithstandthein-serviceloadsandthehydraulicliftfrom
thegroundwater.
-Oncetheconcretehascuredcorrectly,sealtheconstructionjoints
between the foundationpadand theverticalwallsusing IDROSTOP
B25 hydro-expanding, self-sealing bentonite jointing material with a
sectionof20x25mm.BeforeapplyingIDROSTOPB25,carefullyclean
thesurfacetoeliminatealltracesofdebris,andespeciallytheslurry
whichbleedsfromthesurface,whichusuallyformswhencompacting
thecementitiousconglomerate.
37
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
ofthestructure,therefore,isthefirstonetoconsiderwhendesigninga
waterproofingsystemtoprotectitagainsttheaggressiveactionofwater.
Excavationsforliftwellsmaybecarriedoutusingthefollowingmethods:
a)withadeterminedshape(Fig.7.5);
b)bystripping.
Inthecaseofanexcavationwithadeterminedshape,waterproofingof
theliftwell(Fig.7.6)iscarriedoutasfollows.
- To form a suitable laying surface and make application of the
waterproofing system easier, the bottom of the excavation must be
evenedoutbyapplyingalayerofleanconcreteabout10cmthick.
- To lay the waterproofing system on the vertical surfaces, form a
relativelyevensurfaceonwhichtheMAPEPROOFisappliedandfold
the geo-textile over onto the laying surface of the foundation pad.
Positiontheunderside(thedarkside)oftheMAPEPROOFgeo-textile
polypropylene fabricon the substrate andoverlap the edgesof the
sheetsbyat least10cm.Fasten thesheets inplacewithnailsand
MAPEPROOFCDpolyethylenewashersapproximatelyevery30cm.
-SpreadMAPEPROOFonthehorizontalsurfaceandfastenitinplace
every50cmwithnailsandMAPEPROOFCDpolyethylenewashers.
Avoidformingcreaseswhenlayingthefabricontheleanconcrete.
-Inordertoprotectthesheetswhenpositioningthesteelreinforcement
before pouring on the concrete for the lift well foundation pad, a
5-10cmthickprotective layerof thesameconcreteasusedforthe
foundationpadmayberequiredontheMAPEPROOF.Thisoperation
is not absolutely necessary because the bentonite sheets are able
toresistdamagefromboththespacersandthesteelreinforcement.
Specialplasticspacersmustbeusedtokeepthereinforcementcage
for the lift well away from the sheets (if a protective layer has not
Fig.7.5c–Positioningthesteelreinforcement
Fig.7.5d–CastingthefoundationpadforaliftwellFig.7.5a–Oneofthephasesofwaterproofingandcastingaliftwell:applicationofMAPEPROOFonthesidewallsoftheexcavation
36
Fig.7.6–Detailedlayoutofwaterproofingaliftwell
Reinforced concrete foundation pad
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
4 Regulating layer of lean concrete
1
2
3
4
Ground
Reinforced concrete structure
IDROSTOP B25
Fixing rods
5
6
7
8
Fig.7.4–WaterproofingthebaseofajibcranewithMAPEPROOFbentonitesheets
Fig.7.5e–Positioningwoodenformworkbeforesealingconstructionjointsbetweenafoundationpadandthe
wallsusingIDROSTOPB25
Fig.7.5b–LiftwelllinedwithMAPEPROOF
39
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
Thennail a rib (1nail every25cm)along themiddleof the vertical
wallbetweenthesteelreinforcement.Jointheendstogetherbysimply
layingthepiecesalongsideeachother,andneverontopofeachother,
foratleast6cm.
-Afterinstallingtheinternalformwork,pourintheconcretetoformthe
verticalwallsoftheliftwell.Toachievethecorrectdurability,itmustbe
designedaccordingtothespecificationsinSection6.
Whencreatingaliftwellbythestrippingmethod(Fig.7.7)thestructure
mustbewaterproofedasfollows.
- To form a suitable laying surface and make application of the
waterproofing system easier, the bottom of the excavation must be
evenedoutbyapplyingalayerofleanconcreteabout10cmthick.
-Installtheouterformworktocastthefoundationpad.Thenlaythe
MAPEPROOF with the polypropylene underside of the geo-textile
polypropylene fabric (the dark side) on the sides of the formwork
(Fig.7.8)andthenfolditoveratleast20cmontotheleanconcrete.
Theuppersideofthegeo-textilefabric(thewhiteside)willbeturned
towardstheinsidesoitisvisible.
- Overlap the edges of the sheets by at least 10 cm. Fasten the
sheetsinplacewithnailsandMAPEPROOFCDpolyethylenewashers
approximately every 30 cm. Avoid forming creases when laying the
fabricontheformwork.Whenlayingneartopipe-workwhichpasses
throughthesurface(seeSection7.9)thesheetsmustbecuttoshape
tosuittheshapeofsuchelements.
-SpreadMAPEPROOFonthehorizontalsurfaceandfastenitinplace
every50cmwithnailsandMAPEPROOFCDpolyethylenewashers.
Avoid forming creases when laying the fabric on the lean concrete.
Whenlayingneartoelementswhichpassesthroughthesurface
(drains,pipe-work,etc.)thesheetsmustbecuttoshapetosuitthe
shapeofsuchelements.
-Inordertoprotectthesheetsduringnormalsiteactivitiesandwhile
positioning the steel reinforcement for the poured concrete for the
foundationpad,itmaybenecessarytocovertheMAPEPROOFwitha
5-10cmthicklayerofthesametypeofconcreteaswillbeusedforthe
foundations.7.9).Thisoperationisnotabsolutelynecessarybecause
thebentonitesheetsareabletoresistdamagefromboththespacers
andthesteelreinforcement.Inthiscase,specialplasticspacersmust
beusedtokeepthereinforcementcagefortheliftwellawayfromthe
MAPEPROOFsheets,whichalsohelptheconcretetoflowunderthe
steelreinforcementandguaranteethatitiswellcovered.
Fig.7.5f–Castingverticalwalls
38
Fig.7.7–Waterproofingaliftwellbuiltinastripped-typeexcavation
Fig.7.8–DetailedlayoutofMAPEPROOFappliedonwoodenformwork
Reinforced concrete foundation pad
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
Regulating layer of lean concrete
Ground
Wooden formwork
1
2
3
4
5
6
41
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
-Pourintheconcretefortheliftwellfoundationpadwhichmustbe
calculatedtowithstandthein-serviceloadsandthehydraulicliftfrom
thegroundwater.
-Oncetheconcretehascuredcorrectly,sealtheconstructionjoints
between the foundationpadand theverticalwallsusing IDROSTOP
B25 hydro-expanding, self-sealing bentonite jointing material with a
sectionof20x25mm.Beforeapplying the IDROSTOPB25, carefully
cleanthesurfaceandfastenthebentonitejointasdescribedpreviously.
-Installthedoubleformworkfortheverticalconcretewalls,andmakesure
thatthefirstrowoflowerspacersis5-10cmfromtheIDROSTOPB25.
- Pour in the concrete for the walls of the lift well. Use concrete
designedaccordingtothespecificationsinSection6.
- Once the walls have cured correctly, strip the formwork and
waterproof the walls by applying MAPEPROOF (see Section 7.7.1).
Sealthefilletjointsbetweenthefoundationpadandtheverticalwalls
usingIDROSTOPB25hydro-expanding,self-sealingbentonitejointing
materialwithasectionof20x25mm.
- After completing the waterproofing operations of the lift well, lay
theMAPEPROOFon the leanconcreteas illustrated in the following
Section.It isabsolutelyessentialtoguaranteethattheMAPEPROOF
sheetsbetweentheverticalwallsandthehorizontalsheetsunderthe
foundationpadarecontinuous,andoverlapbyatleast10cm.
7.4 WATERPROOFING HORIZONTALFOUNDATION PADS
Tomakeapplicationofthewaterproofingsystemeasier,thelayingsurface
mustbeevenwithnobulges,largegapsand/orsharpprotuberancesso
thesystemmaybe laidcorrectly.Evenover thesurfaceof theground
withalayerofleanconcretewithanaveragethicknessofaround10cm.
Werecommendformingthelayerofleanconcreteinacontinuous,single
layer.
Inthecaseofexcavationswithoutconfinement(seeSection4)applythe
waterproofingsystemasindicatedbelow:
- Install theouterformworktocastthefoundationpad.Thenlaythe
MAPEPROOF with the underside (the dark side) of the geo-textile
polypropylenefabricontheinnersidesoftheformwork(Fig.7.7andFig.
7.10)andthenfolditoverby20cmontotheleanconcrete.Theupper
sideofthegeo-textilefabric(thewhiteside)willbeturnedtowardsthe
insidesoitisvisible.Theedgesofthesheetsmustoverlapbyatleast
10 cm. Fasten the sheets in place with nails and MAPEPROOF CD
polyethylenewashersapproximatelyevery30cm.
Inthecaseofexcavationswithoutconfinement(seeSection4)applythe
waterproofingsystemasindicatedbelow:
-laytherollsofMAPEPROOFbypositioningtheunderside(thedark
side) of the geo-textile polypropylene fabric on the surface of the
leanconcreteandtheuppersideofthefabric(thewhiteside)facing
upwardsso it isvisible.Theedgesmustoverlapbyat least10cm.
FastenthesheetsinplaceonthesubstratewithnailsandMAPEPROOF
CDpolyethylenewashersapproximatelyevery50cm.
-ApplyMAPEPROOFinthelowerpartofthecontainmentbulkheads
of the excavation, and fold a strip at least 20 cm wide on the lean
concrete. The underside of the geo-textile polypropylene fabric (the
darkside)mustbeplacedonthesubstrateandtheuppersideofthe
geo-textilefabric(thewhiteside)mustfaceupwardssoitisvisible.
After laying thegeo-textile fabricon the formworkor the lowerpartof
40
Fig.7.9–OneofthephasesofcastingtheprotectivelayerofconcreteonMAPEPROOF,usingconcretewiththesameRckasthatofthefoundationpad
Fig.7.10–NailingMAPEPROOFtowoodenformwork Fig.7.12–LayingMAPEPROOFusingametalliftingrig
43
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
the bulkheads, lay the rolls of MAPEPROOF on the lean concrete as
describedbelow.
-Lay(Fig.7.12)therollsofMAPEPROOFbypositioningtheunderside
(thedarkside)ofthegeo-textilepolypropylenefabriconthesurface
oftheleanconcreteandtheuppersideofthefabric(thewhiteside)
facing upwards so it is visible. The edges must overlap by at least
10 cm. Fasten the sheets in place on the substrate with nails and
MAPEPROOFCDpolyethylenewashersapproximatelyevery50cm.
-Inordertoprotectthesheetsduringnormalsiteactivitiesandwhile
positioning the steel reinforcement for the poured concrete for the
foundationpad,itmaybenecessarytocovertheMAPEPROOFwitha
5-10cmthicklayerofthesametypeofconcreteaswillbeusedforthe
foundations.Thisoperation isnotabsolutelynecessarybecausethe
bentonitesheetsareabletoresistdamagefromboththespacersand
thesteelreinforcement.Inthiscase,thesteelreinforcementmustbe
positionedatacertaindistancefromtheMAPEPROOFusingspecial
plasticspacers(Fig.7.13)whichalsohelptheconcretetoflowunder
thesteelreinforcementandguaranteethatitiswellcovered.
- Position the steel reinforcement and pour in the concrete for the
foundationpad,calculatedtowithstandthein-serviceloadsandthe
hydraulicliftofthegroundwater.Useconcretedesignedwithdurability
characteristicsaccordingtothespecificationsinSection6.
7.5 WATERPROOFING PILE HEADSDesignersoftenhavetodesignfoundationstructuresongroundwithpoor
load-bearingcapacity,andarethereforeobligedtousedeepfoundation
systemssuchasreinforcedconcretepiles.Thepilesworkinconjunction
withthefoundationpadtocomplywiththerequirementsoftheproject.
Whenwaterproofingafoundationpadrestingonpiles,itisnecessaryto
differentiatebetween twodifferentapplicationmethods.Thedifference
liesinthewaytheMAPEPROOFislaid,inthatitmayhavetheheadsof
thepilespassingthroughit.
Inthecaseoftheheadsofthepilespassingthroughthebentonitesheets
(Fig.7.14)applythewaterproofingsystemasindicatedbelow:
-croptheheadofthepileuntilthescarifiedsurfaceisatleast10cm
belowtheleveloftheouterfaceoftheleanconcrete.
Thepileshouldbecropped(Fig.7.15)byscarifyingwithalightweight
pneumatic hammer to leave a rough surface. Carefully clean the
scarified surface using high-pressure water jets (120-180 atm) to
completelyremovealltracesofdustoranyothertypeofmaterialwhich
couldcompromisethebondofthesuccessivelayerofrepairmortar.
-Positionacylindricalmetalmould(Fig.7.16)15cmhighwithawidth
suitable for the section of the pile. Then, to guarantee a monolithic
bond between the head of the pile and the new repair mortar, we
recommend applying EPORIP solvent-free, two-component epoxy
adhesiveonthesurfaces.
42
Fig.7.11–WaterproofingaribbedfoundationpadbyapplyingMAPEPROOF
Fig.7.13–MetallicreinforcementpositionedonMAPEPROOFandseparatedfromthesheetswithspacers
Fig.7.14–Detailedlayoutofwaterproofingtheheadsofpileswhichworktogetherwiththefoundationpadandpassthroughthebentonitesheet
Reinforced concrete foundation pad
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
Regulating layer of lean concrete
Ground
MAPEPROOF MASTIC
1
2
3
4
Steel rebar or round bar
Foundation pile
MAPEGROUT HI-FLOW
IDROSTOP B25
MAPEPROOF SEAL
7
8
9
10
5
6
11
45
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
ApplyEPORIPonthesubstrate,whichshouldbedryoronlyslightly
damp,makingsureitpenetratesintotheparticularlyroughandporous
areastoguaranteeaperfectbondoverthewholesurface;
- Pour (Fig. 7.17-18) MAPEGROUT HI-FLOW controlled-shrinkage,
fibre-reinforcedmortarforrepairingconcretewith30%ofgravelwitha
grainsizebetween5and8-10mmand0.25%MAPECURESRAcuring
compoundtoreducehygrometricandplasticshrinkageintothemould
whiletheEPORIPisstillfresh.MAPEGROUTHI-FLOWguaranteesboth
aperfectwatertight jointandhighcompressivestrengthatthehead
ofthepile.
-Afterremovingthemould,theperimeteroftheheadofthepilewill
needtobesealed(Fig.7.19)byinserting300gpermetreofpowdered
MAPEPROOFSEAL.
- Lay on the MAPEPROOF andcut the sheets to shapearound the
heads of the piles (Fig. 7.20) positioning the underside of the geo-
textilepolypropylenefabric(thedarkside)ontheleanconcrete.The
edgesofthesheetsmustoverlapbyatleast10cm.Fastenthesheets
tothesubstratewithnailsandMAPEPROOFCDpolyethylenewashers
approximately every 50 cm. Take care when unrolling the fabric to
avoidformingcreaseswhenlayingthefabricontheleanconcrete.
-Aroundtheheadsofthepiles,nailtheIDROSTOPB25inposition(Fig.
7.21)hydro-expanding,self-sealingbentonitewithasectionof20x25
cm.Jointheendsbysimplylayingthemalongsideforatleast6cm.
- Finish off the waterproofing system by grouting all the steel
reinforcement in the heads of the piles by trowelling around each
rod with MAPEPROOF MASTIC natural sodium bentonite grout with
plasticisingadditives(Fig.7.22).
Iftheheadsofthepilesdonotpassthroughthebentonitesheets(Fig.
7.23)applythewaterproofingsystemasindicatedbelow:
-LayontheMAPEPROOFandmakeholesinittoallowthereinforcement
rodsintheheadofthepilestopassthrough(Fig.7.24)andpositionthe
underside(thedarkside)ofthegeo-textilepolypropylenefabriconthe
surfaceoftheleanconcretewiththeuppersideofthefabric(thewhite
side) facing upwards so it is visible. The edges must overlap by at
least10cm.Fastenthesheetsinplaceonthesubstratewithnailsand
MAPEPROOFCDpolyethylenewashersapproximatelyevery50cm.
-AftergroutingallthereinforcementrodswithMAPEPROOFMASTIC
applyapieceofbentonitesheetovereachrod.
Thefilletbetweenthepiecesofsheetandthereinforcementrodsmust
alsobegroutedwithMAPEPROOFMASTIC(Fig.7.25-27).
Fig.7.13–MetallicreinforcementpositionedonMAPEPROOFandseparatedfromthesheetswithspacers
44
Fig.7.16–MetalliccylindricalmouldinplacebeforecastingMAPEGROUTHI-FLOW
Fig.7.15–Croppingtheheadofapile Fig.7.17–TheheadofapilerebuiltwithMAPEGROUTHI-FLOW
Fig.7.18–Anoverallviewofaseriesofpilesduringtherebuildingoftheheads
Fig.7.23–Detailedlayoutofwaterproofingtheheadsofpileswhichworktogetherwiththefoundationpadwithoutpassingthroughthebentonitesheet
Reinforced concrete foundation pad
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
Regulating layer of lean concrete
1
2
3
4
Ground
MAPEPROOF MASTIC
Steel rebar or round bar
Foundation pile
5
6
7
8
47
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
Towaterproofthefoundationpad,thetechniqueusedtolaythebentonite
sheetsisthesameasdescribedinSection7.4.
InordertoprotecttheMAPEPROOFfrombeingdamagedduringnormal
siteactivitiesandwhilepositioningthesteelreinforcementforthepoured
concreteforthefoundationpad,itmaybenecessarytocoverthesheets
witha5-10cmthicklayerofthesametypeofconcreteaswillbeused
forthefoundations.Thisoperationisnotabsolutelynecessarybecause
the bentonite sheets are able to resist damage from both the spacers
andthesteelreinforcement.Inthiscase,specialplasticspacersmustbe
usedtokeepthesteelreinforcementawayfromtheMAPEPROOFsheets,
whichalsohelptheconcretetoflowunderthesteelreinforcementand
guaranteethatitiswellcovered.
After positioning the steel reinforcement, pour on the concrete for the
foundationpadaccordingtothespecificationsfortheconcreteinSection
6.Iftheconcreteneedstobepouredindifferentsteps,thejointsbetween
each cast must be sealed (Fig. 7.28-29) using IDROSTOP B25 hydro-
expandingbentonitejointingmaterialwithasectionof20x25mmmade
fromnaturalsodiumbentoniteandpolymers.Theribmustbefastened
onthefoundationpadatthemid-pointoftheperimeterwallswithnails
(1nailevery25cm).Theendsarejoinedbysimplylayingthemalongside
eachother(andneverbyoverlapping)foratleast6cm.TheIDROSTOP
B25usedtosealtheconstructionjointsinthefoundationpadandtoseal
theconstructionjointsintheverticalwallsmustalsobejoinedtogether
bylayingthestripsalongsideeachother(Fig.7.30).
After completing casting of the foundation pad, there will be one of
two situations: if the excavation is confined, the waterproofing system
maybe laidontheverticalsurfacesbeforecasting (Section7.6). If the
excavationisnotconfined,theverticalconcretewallsmaybecastbefore
waterproofingthem(Section7.7).
7.6 WATERPROOFING VERTICAL SURFACESBEFORE CASTING
The laying of MAPEPROOF on the containment bulkheads of the side
wallsofexcavationsmaybedividedintofourdifferentcases,accordingto
thetypeofstructuralelementusedtoconfinetheexcavation:sheetpiling,
piles,micro-pilesanddiaphragms.
Sheetpiling
MAPEPROOF may be applied directly on sheetpiling if the sheetpiling
doesnothavetoberecoveredafterconstruction,oronOSB(Oriented
StrandBoard)attachedtothesheetpiling(Fig.7.31).
Bentonitesheetsmaybecuttoshapesotheymaybelaiddirectlyonthe
sheetpilingandperfectlyadapttoitsshape.Thefirstoperationtocarry
outistocleantheentiresurfacewithhighpressurewaterjets(150-180
Fig.7.19–SealingaroundtheperimeteroftheheadofapilewithMAPEPROOFSEAL
Fig.7.20-MAPEPROOFcuttoshapearoundtheheadofapile
46
Fig.7.22–GroutingthereinforcementinapilewithMAPEPROOFMASTIC
Fig.7.24-MAPEPROOFwiththesteelreinforcementofapilepassingthroughit
Fig.7.25–LocalisedreinforcementofthewaterproofingwithapieceofMAPEPROOFgrouted
withMAPEPROOFMASTIC
Fig.7.28–Detailedlayoutofsealingaconstructionjointonafoundationpad
Ground
Regulating layer of lean concrete
MAPEPROOF
Protective concrete layer with the same Rck value as the concrete for the foundation pad
1
2
3
4
Reinforced concrete foundation pad
Adjacent reinforced concrete foundation pad
IDROSTOP B25
Fixing rods
5
6
7
8
Fig.7.21-ApplicationofIDROSTOPB25aroundtheheadofapile
applywaterproofingsheetsonalltheverticalsurfaces,startingfromthe
top.Overlapthesheetsbyatleast10cmandfastentheminplacewith
nailsandMAPEPROOFCDpolypropylenewashersapproximatelyevery30
cm.Thetoppingbeamonthebulkheadmustalsobewaterproofed.Clean
thesurfaceswithhighpressurewaterjets(180-300atm)andthensmooth
offthesurfacewithPLANITOP400quick-setting,compensated-shrinkage,
thixotropicmortar forquick repairson thesurfaceofconcrete,orwith
PLANITOP 430 fine-grained, fibre-reinforced, compensated-shrinkage
thixotropic mortar for repairing deteriorated concrete or products from
theMAPEGROUTrange.Oncethesurfacehasbeensmoothedoff,apply
twocoatsofMAPELASTICFOUNDATIONwithabrush,arollerorbyspray
toformalayeratleast2mmthick.Approximately4hoursafterapplying
thefirstlayeringoodweather,andinallcasesonlywhenthefirstlayer
hasdried,thesecondlayermaybeapplied.MAPELASTICFOUNDATION
Fig.7.34–DetailedlayoutofapplyingMapeproofagainstapilebulwarkwithasurfacewhichhasbeenlevelledoff
49
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
atm)toeliminatelooseparts.TheMAPEPROOFisthenapplied,starting
fromthetopandunrollingtherollsofgeo-textilefabricwiththeunderside
(thedarkerside)against thesheetpiling,withanoverlapofat least10
cmbetweeneachsheet.Thesheetsarethenfixedtothesubstratewith
nails insertedwithanailgunapproximatelyevery30cm.Thissolution
avoidstheoverlapsopeningupundertheweightoftheconcretewhich
couldoccurwhenitispoured.Ifthesheetpilingneedstoberecovered
when construction work has been completed, OSB (Oriented Strand
Board)panelsmustbeplacedagainstthesheetpiling.Thissolutionmay
be adopted even if just a flat laying surface needs to be prepared to
guarantee a suitable support so the bentonite sheets may be fixed to
thepanelsusingadenseseriesofstaples.Beforecastingtheconcrete
walls, the gaps between the OSB panels and the sheetpiling must be
filledwithsandtomakesurethepanelshaveasolidsupportalongthe
entirestretch.
The techniques used to lay MAPEPROOF on piles, micro-piles and
diaphragms are very similar to each other, but each technique will be
describedseparatelytohighlighttheirdifferences.
Piles
Ifparticularlylargepilesareused,thebentonitesheetsmaybelaiddirectly
onthepilesthemselves(Fig.7.32)aspreviously illustratedwhenlaying
MAPEPROOFonsheetpiling.AvalidalternativeistoapplyMAPEPROOF
onOSBpanels (Fig.7.33-34)placedagainst thepiles, like thesystem
usedforsheetpiling.Ifsmallpilesareinserted,firstofallthesurfacemust
be cleaned with high pressure water jets, followed by levelling off the
layingsurfaceandtheheadsofthetie-rods(ifpresent)withMAPEGROUT
T60 sulphate-resistant, fibre-reinforced thixotropic mortar mixed with
025%ofMAPECURESRAcuringagenttoreducehygrometricandplastic
shrinkage.
Oncetheconcretehashardened,applypiecesofMAPEPROOFonthe
heads of the tie-rods to locally reinforce thewaterproofing layer. Then
48
Fig.7.29–SealingaconstructionjointonafoundationpadwithIDROSTOPB25.TheprotectivePEsheetonthe
stripofMAPEPROOFmaybeseenprotrudingfromthefoundation,whichisthenoverlappedwiththeadjacent
sheetlaidbeforecastingthenextlayerofconcrete
Fig.7.30–StripsofIDROSTOPB25usedtosealconstructionjointsinthefoundationpadalongsideastripusedtosealconstructionjointsbetweenthe
foundationpadandthewallsandbetweenthewalls
Reinforced concrete foundation pad
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
Regulating layer of lean concrete
1
2
3
Ground
Reinforced concrete wall
IDROSTOP B25
Pile bulkhead
Smoothing and levelling layer on pile bulkhead
Fixing rods
5
6
7
84 9
10
Fig.7.26–Apieceofsheetnailedtothesubstrate Fig.7.27–Anoverallviewofthewaterproofinglayerontheheadofaseriesofpiles
51
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
must be applied on all the front face of the topping beam (Fig. 7.35),
on the inner faceof thebeamandon theupperpartof thebulkhead,
and thenoverlap itbyat least30cmwithMAPEPROOF tocompletely
sealthewaterproofingsystem.ThefilletjointbetweenMAPEPROOFand
MAPELASTICFOUNDATIONmustbesealedbyapplyingIDROSTOPB25.
Micro-piles
Bulkheadsmadefrommicro-pileshaveanunevensurfaceandsoaflat
laying surface suitable for applying MAPEPROOF must be created. As
analternative,asuitablemeansofsupporttofixtheverticaloverlapsof
thebentonitesheetsinplacemaybeused.Therearethreemainstepsto
applythewaterproofingsystem:
-layacontinuousrowofOSB(OrientedStrandBoard)panelsagainst
themicro-piles;
-cleanthesurfacewithwaterjetsandevenoutthesurface(Fig.7.36)
by applying MAPEGROUT T60 sulphate-resistant, fibre-reinforced
thixotropicmortarmixedwith0.25%ofMAPECURESRA;
-fastenplanksofwoodtothemicro-pilesatapitchequaltothewidth
ofthebentonitesheetstofixtheverticaloverlapsoftheMAPEPROOF
inplace.
Aftercarryingouttheaboveoperations,laytheMAPEPROOFstartingfrom
thetopandoverlapthesheetsbyatleast10cm.Fixthesheetsinplace
with nails and MAPEPROOF CD polyethylene washers approximately
every30cm.
Diaphragms
ThesurfaceofdiaphragmsissmoothenoughtolayMAPEPROOFsheets
directly(Fig.7.37-39).Thelayingprocedureisidenticaltotheprocedure
used for sheetpiling, so the first operation to carry out is to clean the
surface with high pressure water jets (150-180 atm) to eliminate loose
parts.Leveloff theheadsof the tie-rods (ifpresent)withMAPEGROUT
T60 sulphate-resistant, fibre-reinforced thixotropic mortar mixed with
025%ofMAPECURESRAcuringagentwhichreduceshygrometricand
plasticshrinkage.
Oncethemortarhashardened,applypiecesofbentonitesheetonthe
heads of the tie-rods to locally reinforce the waterproofing layer. Then
laytheMAPEPROOFstartingfromthetopwiththeunderside (thedark
side)ofthegeo-textilefabriconthesubstrate,overlappingthesheetsby
atleast10cm.Fixthesheetsinplacewithnailsapproximatelyevery30
cm.Thissolutionavoidstheoverlapsopeningupundertheweightofthe
concretewhichcouldoccurwhenitispoured.Ifseepingwaterispresent,
includingwaterunderpressure,beforelayingtheMAPEPROOFsealthe
leaks by applying LAMPOSILEX ultra quick-hardening hydraulic binder
manually,aproductusedtoblockinfiltrationsofwater.
Fig.7.31–MAPEPROOFapplieddirectlyonsheetpiling
50
Fig.7.33–ApplicationofMAPEPROOFonOSBpanelslaidagainstpiles
Fig.7.35–Waterproofingthetoppingbeamonabulwark
1
2
3
4
Pile bulkhead
Smoothing and levelling layer
MAPEPROOF
Reinforced concrete wall
5 IDROSTOP B25
MAPELASTIC FOUNDATION
Topping beam
Ground
5
6
7
8
Fig.7.32–MAPEPROOFapplieddirectlyonapilebulkhead
In all four examples described above, the bentonite sheets applied
verticallymustoverlapthesheetlaidbeforecastingthefoundationpad.
This will guarantee structural continuity between the horizontal and
verticalwaterproofinglayers.
In certain cases, to reduce the thickness of the reinforced concrete
structures to be built, insert reinforcement connectors between the
bulkhead and the structure to be cast to form a static union between
the two structural elements (Fig. 7.40). In correspondence with the
reinforcementconnectors,holesmustbemadeintheMAPEPROOF for
theconnectorspassthrough.AfterlayingtheMAPEPROOF,theymustbe
sealedinthreestepsasfollows:grouttheconnectorswithMAPEPROOF
MASTIC natural sodiumbentonitegroutwithplasticisingagents; apply
piecesofbentonitesheetandnailtheminplace;groutthefilletaround
thetie-rodwithMAPEPROOFMASTIC.
53
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
After applying the MAPEPROOF, seal the construction joints between
the foundation pad and the reinforced concrete vertical walls with
IDROSTOPB25hydro-expandingbentonitejoint,nailedinplaceevery25
cmatthemid-pointofthesectionoftheverticalwallsbetweenthesteel
reinforcementrods.
BeforeapplyingIDROSTOPB25,carefullycleanthesurfacetoeliminateall
tracesofdebris,andespeciallytheslurrywhichusuallybleedsfromthe
surfacewhencompactingthecementitiousconglomerate.Thensealthe
formworkandcasttheverticalreinforcedconcretewallswithreinforced
concrete according to the specifications in Section 6. The sealing
operationwith IDROSTOPB25mustbe repeated foreachconstruction
jointintheverticalwalls,makingsurethattheriblaidverticallybetween
thewallsislaidalongsidetheribonthehorizontalsurfaceforatleast6
cm(Fig.7.41).
Fig.7.37-LayingMAPEPROOFagainstadiaphragm
52
Fig.7.36–Bulkheadinmicro-pileslevelledoffwithMAPEGROUTT60
Fig.7.39–DetailedlayoutofapplyingMAPEPROOFagainstadiaphragm
1
2
3
4
Reinforced concrete foundation pad
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
Regulating layer of lean concrete
Ground
Reinforced concrete wall
IDROSTOP B25
Diaphragm
Fixing rods
5
6
7
8
9
Fig.7.40–DetailedlayoutofapplyingMAPEPROOFagainstadiaphragmwhichworkstogetherwiththestructure
1
2
3
4
Reinforced concrete foundation pad
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
Regulating layer of lean concrete
Ground
Reinforced concrete wall
IDROSTOP B25
Diaphragm
Fixing rods
5
6
7
8
9
55
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
7.7 WATERPROOFING VERTICAL SURFACESAFTER CASTING
As previously discussed, if an excavation has no confinement, it is
possibletooperateontheexternalsideoftheverticalwallsandinstall
the waterproofing system after casting. In these cases, after casting
the foundation pad and once the foundation pad has cured, seal the
constructionjointsbetweenthefoundationpadandthereinforcedconcrete
verticalwallswithIDROSTOPB25hydro-expandingbentonitejoint,nailed
inplaceevery25cmatthemid-pointofthesectionoftheverticalwalls
between thesteel reinforcement rods.Beforeapplying IDROSTOPB25,
carefullycleanthesurfacetoeliminatealltracesofdebris,andespecially
theslurrywhichusuallybleeds fromthesurfacewhencompacting the
cementitiousconglomerate.Thensealtheformworkandcastthevertical
reinforced concrete walls with reinforced concrete according to the
specifications inSection6).Thesealingoperationwith IDROSTOPB25
mustberepeatedforeachconstructionjointintheverticalwalls,making
surethattheriblaidverticallybetweenthewallsislaidalongsidetherib
onthehorizontalsurfaceforatleast6cm.AsanalternativetoIDROSTOP
B25,IDROSTOPmaybeappliedaspreviouslyillustratedinSection7.1.
MAPEI offers a wide range of technical solutions and products for
waterproofing vertical surfaces after casting, which will be described
below.
Continuity between waterproofing layers applied before casting
(foundationpad)andaftercasting(walls)isguaranteedbyoverlappingthe
sheetsby10cm,andonverticalsurfacesMAPEPROOForMAPEPROOF
LW isalsoused. If thewaterproofing layerappliedonverticalsurfaces
aftercastingismadeusingMAPELASTICFOUNDATIONorwithaproduct
fromthePLASTIMULrange,theymustbeappliedinsuchawaythatthey
jointotheMAPEPROOFappliedbeforecasting.Therefore,toguarantee
continuityinthewaterproofinglayer,applyastripofMAPEPROOFstarting
from the wall-foundation pad fillet joint, grouted with MAPEPROOF
MASTIC,until itoverlapsthewaterproofinglayerappliedbeforecasting
byatleast10cm.
7.7.1 WATERPROOFING VERTICAL SURFACES AFTER CASTING WITH MAPEPROOF OR MAPEPROOF LW
TheMAPEPROOFandMAPEPROOFLWsheetsmayalsobeappliedafter
casting(Fig.7.42).BeforeapplyingtheMAPEPROOFthespacersmustbe
eitherremovedorsealed(Fig.7.43-44)accordingtowhetherthespacers
aremetallic(forwoodenformwork)orplastic(formetallicformwork).Then
eliminateallirregularitiesinthesubstratesandsmoothovergravelclusters
in thesurfacewithMAPEGROUTFAST-SETfibre-reinforced,controlled-
shrinkage,quicksettingandhardeningmortar for repairingconcreteor
PLANITOP400quick-setting,controlled-shrinkagethixotropicmortarfor
repairingthesurfaceofconcrete.
Inthevicinityofthe90°jointbetweenthewallandthefoundationpad,we
recommendformingabeadtosupportthefilletbetweenthehorizontal
andverticalsurfacesusingMAPEGROUTFAST-SETorPLANITOP400,or
withmortarmadeusingsandandcementwithPLANICRETEsynthetic
latexrubberadmixforcementitiousmixesataratioof1to3.
Astripatleast50cmwideatthetopofthewallmustbewaterproofed
withMAPELASTICFOUNDATIONappliedintwocoatstoformalayerat
least2mmthick.ThenlaytheMAPEPROOFstartingfromthetop,making
surethatitoverlapstheMAPELASTICFOUNDATIONbyatleast20cm.
Inthefilletbetweenthetwosystems,applyMAPEPROOFMASTICon
topof theMAPELASTICFOUNDATION.Fasten thesheets inplacewith
nailsandMAPEPROOFCDpolyethylenewashersapproximatelyevery30
cm.Whenappliedaftercasting(Fig.7.45),thebentonitesheetsarelaid
withtheuppersideofthegeo-textilefabric(thewhiteside)againstthe
reinforcedconcretewall,whiletheundersideofthegeo-textilefabric(the
darkerside)facestheoutside,thatis,incontactwiththeground.Please
note that thewhite non-woven fabricof MAPEPROOF must alwaysbe
laidincontactwiththesurfacetobewaterproofed.Whenlayingnearto
pipe-workwhichpassesthroughthesurface,thesheetsmustbecutto
shapetosuittheshapeofsuchelements,whichmustthenbesealedas
describedinSection7.9.
54
Fig.7.38–ApplicationofMAPEPROOFonthelowerpartofdiaphragms
57
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
AfterlayingtheMAPEPROOF,lay250g/m2non-wovenfabrictoprotect
thewaterproofinglayerwhenfillinginexcavations.Fillwithhomogenous
fineandmixedlooseearthinwell-compactedlayers40to50cmthick,to
guaranteethat,oncethefillingoperationshavebeencompleted,thereare
nogapsorvoidsandthereisbetterconfinementofthesystem.
7.7.2 WATERPROOFING VERTICAL SURFACES AFTER CASTING WITH MAPELASTIC FOUNDATION
MAPELASTIC FOUNDATION is a two-component, flexible cementitious
mortarspecificallyforwaterproofingconcretesurfacessubjecttopositive
hydrauliclift(Fig.7.46)andnegativehydrauliclift(upto1.5atm,equalto
a15mheadofwater).Thesurfacestobetreatedmustbecleanandfree
ofstrippingcompound,greaseandalltracesofdirtoranyothermaterial
which could potentially compromise the bond of the waterproofing
material. The surfaces, therefore, must be thoroughly cleaned by dry
sandblasting at a controlled pressure or with high pressure water jets
(150-180atm).
Eliminateallirregularitiesinthesubstratesandsmoothovergravelclusters
with MAPEGROUT FAST-SET fibre-reinforced, controlled-shrinkage,
quicksettingandhardeningmortar for repairingconcreteorPLANITOP
400quick-setting,controlled-shrinkagethixotropicmortarforrepairingthe
surfaceofconcrete.
MAPELASTICFOUNDATIONmustbeappliedbybrush (Fig.7.48),with
a rollerorbyspray to formacoatat least2mmthick.Approximately4
hoursafterapplyingthefirst layer ingoodweather,andinallcasesonly
when the first layer has dried, the second layer may be applied. Apply
MAPEBAND TPE (Thermoplastic Elastomer) high-flexibility, waterproof
tapeincorrespondencewiththestructuraljoints,aproductrecommended
forflexiblesealingandwaterproofingofexpansionjointsupto10mmwide
56
Fig.7.44–Levellingofftheconcretesurfaceafterremovingthebladesoftheformwork
Fig.7.43–Thebladesoftheformworkstickingthroughareinforcedconcretewallbeforebeingremoved
Fig.7.41–StripsofIDROSTOPB25usedtosealconstructionjointsbetweenafoundationpadandthewallsandconstructionjointsbetweenadjacentwalls
FIG.7.42–DETAILEDLAYOUTOFWATERPROOFINGAFTERCASTINGWITHMAPEPROOF
Fig.7.46–DetailedlayoutofwaterproofingafoundationpadwithMAPEPROOFandMAPELASTICFOUNDATIONappliedonthewall
1
2
3
4
Reinforced concrete foundation pad
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
Regulating layer of lean concrete
Ground
Reinforced concrete wall
IDROSTOP B25
MAPEPROOF MASTIC
MAPELASTIC FOUNDATION
Continuous-yarn NWF (non-woven fabric) (weight ≥250 g/m2)
Fixing rods
5
6
7
8
9
10
11
Reinforced concrete foundation pad
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
Regulating layer of lean concrete
Ground
Reinforced concrete wall
IDROSTOP B25
Bead of MAPEGROUT RAPIDO/PLANITOP 400
Continuous-yarn NWF (non-woven fabric) (weight ≥250 g/m2)
Fixing rods
4
5
6
7
8
9
10
1
2
3
59
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
subjecttomovement.Thetapeis1mmthickwithedgesreinforcedwith
polyesterfabric,andmustbebondedinplacewithADESILEXPG4two-
component,thixotropicepoxyadhesiveasfollows(Fig.7.48):
-applyaneven1-2mmthicklayerofADESILEXPG4withasmooth
trowelontheclean,drysubstrate.Trytoavoidtheadhesiverunning
into the joint.Lay theMAPEBANDTPEbypressingalong thesides,
makingsuretherearenocreasesorairbubbles.
-ApplyasecondlayerofADESILEXPG4freshonfresh,andcompletely
coverthesidesofthetapewiththesecondlayer.Smoothoverwith
aflattroweland,whiletheproductisstillfresh,sprinkleonalayerof
0.5 spheroid quartz to form a rough layer to help the MAPELASTIC
FOUNDATIONformagoodbond.
- Once the reticulation process of the ADESILEX PG4 has been
completed, remove any loose quartz and lay the MAPELASTIC
FOUNDATION.Whenthemortarhashardened,applyalayerof250g/
m²non-wovenfabrictoprotectthewaterproofingsystemwhenfilling
in(Fig.7.49).
7.7.3 WATERPROOFING VERTICAL SURFACES AFTER CASTING WITH PRODUCTS FROM THE PLASTIMUL RANGEVerticalsurfacesmaybewaterproofedaftercastingwithproductsfrom
thePLASTIMULrange,bituminousemulsionwaterproofingproductswith
differenttechnicalpropertiesandfinalperformancecharacteristics.
Before applying one of the products from the PLASTIMUL range, the
surfacetobetreatedmustbecleanandfreeofalltracesofdirtorany
other material which could potentially compromise the bond of the
waterproofingmaterial.Concretesurfacesmustalsobefreeofallrough
edgesandhoneycombs.Sealcracksandimperfectionsinthesubstrate
with PLANITOP 400 quick-setting, compensated-shrinkage thixotropic
mortarusedforrepairingthesurfaceofconcrete,orwithproductsfrom
theMAPEGROUTrange.
PLASTIMUL is a solvent-free bitumen emulsion which may be used to
protect rendered, brickwork structures or concrete structures against
risingdampfromthegroundoraccumulatedwater.Thesurfacestobe
treatedmustbedampenedbeforeapplyingtwolayersofPLASTIMULas
follows:
- first layer (primer). Dilute PLASTIMUL with approximately 45-50%
ofwaterandmixuntilcompletelyblended.Applythesolutionwitha
brush.When it iscompletelydry,whichnormally requires3-6hours
according to the surrounding temperature and the ventilation, apply
thesecondlayer.
-Second layer.Applya1mmthickcoatofneatPLASTIMULwitha
trowel(Fig.7.50)orwithaflatbrush.Oncecompletelydry,PLASTIMUL
forms a waterproof plastic dressing coat which is resistant to re-
emulsification after long periods of immersion in water, including
waterwhichisslightlyacidicoralkaline,andwhichisalsoresistantto
aggressiveagentsintheground.
PLASTIMUL1KSUPERPLUS is aone-component, solvent-free, quick-
drying, low-shrinkage, high-yield, high-flexibility bitumen waterproofing
emulsion containing polystyrene beads and rubber granules. The
polystyrene beads guarantee the minimum thickness while the rubber
increases the product’s flexibility. Thanks to these components, the
productiseasytoapplywithaflatornotchedtrowelorbyspraywitha
peristalticpump.PLASTIMUL1KSUPERPLUS isresistanttothealkalis
intheconcreteandaggressivesubstancesusuallyfoundintheground.
Itisusedtoformathickbitumenwaterproofinglayeronhorizontaland
vertical concrete and brick surfaces subject to high dynamic stresses.
Thethicknessof thedry layermustbeat least3mmwhendryandat
least4mmifthereiswaterinpressure.Inthiscase,insertMAPENET150
alkali-resistant glass fibre mesh between the two layers. Before laying
58
Fig.7.45b–AverticalwallwaterproofedwithMAPEPROOFaftercasting
Fig.7.47–ApplicationofMAPELASTICFOUNDATIONwithabrushontheupperpartofawallbeforeapplyingMAPEPROOF
Fig.7.48a–Phasesofwaterproofinganexpansionjointsubjecttomovementsofupto10mmwith
MAPEBANDTPE:toavoidtheepoxyadhesiveleavingaroughedge,applymaskingtapealongthesidesof
thejoint
Fig.7.45A–NailingMAPEPROOFtothesubstrateaftercasting
61
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
the product, apply an even coat of PLASTIMUL PRIMER (solvent-free,
ready-to-use,low-viscosity,quick-dryingbitumenemulsion)witharoller,
bybrushorbysprayonthesubstrate(Fig.7.51).
PLASTIMUL1KSUPERPLUS(Fig.7.52)mustbelaidinanevenlayerover
theentiresurface.Ifworkneedstobeinterrupted,spreadthePLASTIMUL
1KSUPERPLUSdowntoafeatheredgeandthenoverlapwiththenew
materialby10cmwhenworkrecommences.
PLASTIMUL 2K PLUS (Fig. 7.53) is a two-component, solvent-free,
highly-flexible,quick-drying,low-shrinkagebitumenemulsionwithadded
cellulosefibressuitableforwaterproofinghorizontalandverticalconcrete
andbrickworksurfaces.PLASTIMUL2KPLUSiseasytoapplywithaflat
ornotchedtrowelorbyspraywithaperistalticpumpandisresistantto
thealkalis in theconcreteandaggressivesubstancesusually found in
theground.Itisparticularlyrecommendedwhenthewaterproofinglayer
isappliedatlowtemperaturesorwithhighlevelsofdamporifthelayer
isappliedonsmoothsurfaces.Thethicknessofthedrylayermustbeat
least3mmwhendryandatleast4mmifthereiswaterinpressure.Inthis
case,insertMAPENET150alkali-resistantglassfibremeshbetweenthe
twolayers.Beforelayingtheproduct,applyanevencoatofPLASTIMUL
PRIMER(solvent-free,ready-to-use,low-viscosity,quick-dryingbitumen
emulsion)witharoller,bybrushorbyspraytoevenoutthesubstrate.
PLASTIMUL2KPLUSmustbeappliedinaneventhicknessoverthewhole
surface.Ifworkneedstobeinterrupted,spreadthePLASTIMUL2KPLUS
downtoafeatheredgeandthenoverlapwiththenewmaterialby10cm
whenwork recommences.PLASTIMUL2KSUPER (Fig. 7.54) is a two-
component, solvent-free, quick-drying, low-shrinkage, high-flexibility
bitumenwaterproofingemulsioncontainingpolystyrenespheres.These
characteristics make the product easy to apply with a flat or notched
trowel on bricks or reinforced concrete. PLASTIMUL 2K SUPER is
resistant toalkalis in theconcreteandaggressivesubstancesnormally
containedintheground.Thethicknessofthedrylayermustbeatleast
3mmwhendryandat least4mmif there iswater inpressure. In this
case,insertMAPENET150alkali-resistantglassfibremeshbetweenthe
twolayers.Beforelayingtheproduct,applyanevencoatofPLASTIMUL
PRIMER(solvent-free,ready-to-use,low-viscosity,quick-dryingbitumen
emulsion)witharoller,bybrushorbysprayonthesubstrate.PLASTIMUL
2KSUPERmustbeappliedinaneventhicknessoverthewholesurface.
Ifworkneedstobeinterrupted,spreadthePLASTIMUL2KSUPERdown
toafeatheredgeandthenoverlapwiththenewmaterialby10cmwhen
work recommences. Once dry, a process which is accelerated by the
hydraulicfillingbindercontainedintheproduct,PLASTIMUL2KSUPER
formsahighly-flexiblewaterproofdressingcoat.
ThestrongpointofPLASTIMUL1KSUPERPLUS,PLASTIMUL2KPLUS
andPLASTIMUL2KSUPERistheirversatilitywhichmakesthemsuitable
forapplicationonawiderangeofsubstrates,suchas:limestonemasonry,
cellular concrete, pumice stone, lightweight bricks and breeze blocks.
These substrates do not need to be rendered, but the joints between
thebricksorblocksmustbegroutedwithPLANITOP400quick-drying,
controlled-shrinkagethixotropicmortar.ThenapplyacoatofPLASTIMUL
PRIMERwitharoller,bybrushorbysprayand,whenthisproducthas
cured,spreadonPLASTIMUL1KSUPERPLUS,PLASTIMUL2KPLUSor
PLASTIMUL 2K SUPER, with MAPENET 150 alkali-resistant glass fibre
meshbetweenthefirstandsecondcoat.
After applying theproduct, check that it is completelydry and,before
filling in the trenches, protect the waterproofing layer with a suitable
perforation-proofsystemtoensureitisnotdamagedandthatitremains
water-tight.
7.8 WATERPROOFING STRUCTURAL JOINTSIncivilengineering,astructuraljointisaninterruptioninthecontinuityof
aconstruction.Thisinterruptionisindispensable:
-toavoidtemperaturevariationsprovokingco-actionstates;inthese
cases,theyallowforfreeexpansionofastructuretensofmetreslong
withoutdamagingorcrackingthestructure.
60
Fig.7.48b–SpreadingonADESILEXPG4withatrowel
Fig.7.48c–PositioningMAPEBANDTPE Fig.7.48e–BeforereticulationofADESILEXPG4,sprinklequartzsandonthesurfaceandremovethe
maskingtape
Fig.7.48d–SpreadingonthesecondlayerofADESILEXPG4withatrowel
63
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
- To avoid damage by seismic activity; during seismic activity, two
adjacentareasofthesamestructurewithdifferentseismicbehaviour
riskbeingdamaged in thepointwhere theyare joined togetherand
hittingeachother (hammeringphenomenon) if the jointbetweenthe
twostructuresisnotwideenoughallowforfreemovements.
To overcome such phenomenon, the Italian Construction Techniques
Norms & Regulations (Ministerial Decree 14th January 2008, article
7.2.2GeneralConstructionCharacteristics)establishedthatthedistance
between two adjacent constructions must be at least the sum of the
maximumcalculatedhorizontalmovementsaccordingtotheSafeguard
LimitState(SLS)and,inallcases,neverlessthanthevalueestablished
bytheNorms&Regulations.
Therefore,awell-designedstructuraljointallowsforenoughmovementof
theoscillatingcomponentssothatthestructureremainsundamagedby
seismicbehaviourbut,asfarashydraulicsealingisconcerned,thejoint
representsapointwhichmustbetreatedwithparticularcare.Thewater
tightnessofajointisguaranteedbytheuseofspecialPVCwaterstops
insertedinthecastconcrete:IDROSTOPPVCBEandIDROSTOPPVCBI.
IDROSTOP PVC BE is a pre-formed, flexible external waterstop made
by extruding high quality PVC designed for sealing construction and
expansion joints in reinforced concrete structures. In correspondence
withthejoint,werecommendapplyingafurtherstripofMAPEPROOF1
mwidetoformadoublelayerofbentonitesheetbetweenthetwosides
ofthejoint.IDROSTOPPVCBEisthennailedontopofthisstrip,whichis
embeddedinthecastconcrete(Fig.7.55).
DROSTOP PVC BI is a pre-formed, flexible external waterstop made
by extruding high quality PVC designed for sealing construction and
expansionjointsinreinforcedconcretestructures.Thejointispositioned
at themid-pointof the foundationpadorwall (Fig.7.56)andmustbe
stretchedandheldinpositionwithwire.Oneendofthewireisattached
tothereinforcementrodswhiletheotherendisattachedtothewaterstop.
62
Fig.7.49–Protectionofthewaterproofingmaterialwhenre-fillingbyapplying250g/m2nonwovenfabricinacontinuousthread
Fig.7.55–DetailedlayoutofsealingastructuraljointwithIDROSTOPPVCBE
1
2
3
4
Ground
Regulating layer of lean concrete
MAPEPROOF
Protective concrete layer with the same Rck value as the concrete for the foundation pad
IDROSTOP PVC BE
Reinforced concrete structure
Separation element
Adjacent reinforced concrete
structure
5
6
7
8
Fig.7.57–DetailedlayoutofsealingastructuraljointwithIDROSTOPPVCBI
1
2
3
4
Ground
Continuous-yarn NWF (non-woven fabric) (weight ≥250 g/m2)
MAPEPROOF
MAPEPROOF MASTIC
Rods bent to hold IDROSTOP PVC BI in place
Reinforced concrete structure
Separation element
Idrostop PVC BI
Adjacent reinforced concrete structure
5
6
7
8
9
Fig.7.50–UsingatroweltoapplyPLASTIMULonaverticalretainingwall
65
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
Also in thiscase,we recommendapplyinga further1mwidebandof
bentonitesheetontheouterface,tobeinsertedinthejointandbentto
formaΩshape(Fig.7.57).
7.9 SEALING THROUGH-PIPES IN VERTICAL WALLS AND FOUNDATION PADS
AsindicatedinthedescriptionforlayingMAPEPROOF,incorrespondence
with elements which pass through vertical walls and foundation pads,
thebentonitesheetmustbecuttoshapesoitfitsperfectlyaroundthe
elements.Theinterfacebetweendifferentmaterialsformsapreferential
route for water and, therefore, it is good practice to take the right
precautions toguarantee that it isperfectlywatertight.Apipepassing
throughaverticalwallmustbesealedbyadoptingtwoprecautions.
ThefirstoneistoapplyIDROSTOPB25hydro-expandingbentonitejointing
materialaroundthepipe(atthemid-pointofthewall)beforecastingthe
concrete. The second precaution is to apply a piece of MAPEPROOF
bentonitesheetaroundthethroughelementandover the layeralready
applied, and to seal the edges of the piece of sheet by grouting with
MAPEPROOFMASTIC(Fig.7.58).
In the case of through-pipes in the foundation pad (Fig. 7.59), the
MAPEPROOFsheetmustbecuttoshapearoundthepipeandtheouter
partofthethroughelementmustbesealedasfollows(Fig.7.60):
-applyMAPEPROOFSEALnaturalsodiumbentoniteinpowderform
onthesheet.
- Apply IDROSTOP B25 hydro-expanding bentonite joint around the
throughelementandovertheMAPEPROOF.
-SealoverthebentoniteribwithMAPEPROOFMASTICnaturalsodium
bentonitegroutwithplasticisingadditives.
64
Fig.7.54–ApplicationofPLASTIMUL2KSUPER
Fig.7.53–ApplicationofPLASTIMUL2KPLUSFig.7.51–UsingarollertoapplyPLASTIMULPRIMER
Fig.7.52–ApplicationofPLASTIMUL1KSUPERPLUS
Fig.7.56b–Demolitiontoadepthof15cmfromtheupperpartofthefoundationpad
Fig.7.59–Detailedlayoutofsealingapipewhichpassesthroughafoundationpad
1
2
3
4
Reinforced concrete foundation pad
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
Regulating layer of lean concrete
Ground
MAPEPROOF SEAL
IDROSTOP B25
MAPEPROOF MASTIC
Through pipe
5
6
7
8
9
Fig.7.58–Detailedlayoutofsealingapipewhichpassesthroughafacingwall
1
2
3
Reinforced concrete structure
IDROSTOP B25
MAPEPROOF
Through pipe
MAPEPROOF MASTIC
4
5
EXTERNAL INTERNAL
Fig.7.56a–AnexampleoflayingIDROSTOPPVCBIalongthecentreofawallwhenthewaterstophasnotbeenclampedinthecastconcrete:twolengthsofrebarfastenedinplacewithmetalwireattheendsofthewaterstop
67
7.10 SEALING A DRAINAGE WELLIfdrainagewellshavebeenusedwithin theareawhere the foundation
pad is tobe laid, theywill have tobesealedoff (Fig.7.61-62).Please
note that thepipingmusthaveanti-slipclampsconnectedto thesteel
reinforcementofthefoundationpad.AfterlayingtheMAPEPROOFsheet
cuttoshapearoundthewell,theouterpartofthethroughelementmust
besealedasfollows:
-applyMAPEPROOFSEALnaturalsodiumbentoniteinpowderformon
thesheet.
-ApplyIDROSTOPB25hydro-expandingbentonitejointaroundthewell
andovertheMAPEPROOF.
-SealoverthebentoniteribwithMAPEPROOFMASTICnaturalsodium
bentonitegroutwithplasticisingadditives.
Afterthesesteps,placeformworkaroundtheheadofthewelltoprotect
itwhencastingthefoundationslab.
Whentheconcreteforthefoundationslabhascured,place IDROSTOP
B25bentonitecordaroundthewellandthenblockthewellwithmasses
of MAPEPROOF SEAL natural sodium bentonite in powder form, and
thencompletelyfillthewellwithcastconcrete.Beforesealingoffthewell
withametalliccoverfixedto theheadof thewellwithstudbolts,seal
thejointbetweenthewellcoverandthewellwithMAPEPROOFSWELL
one-component,hydro-expandingpaste.Thegapleft inthefoundation
slabtoseal thewellmustthenbefilledbycasting inMAPEGROUTHI-
FLOWcontrolled-shrinkage,fibre-reinforcedmortarforrepairingconcrete
with30%ofgravelwithagrainsizebetween5and8-10mmand0.25%
MAPECURESRAcuringcompound.
7.11 WATERPROOFING ACCESS RAMPS TO AREAS BELOW GROUND LEVEL
Fromastructuralpointofview,accessrampstoareasbelowgroundlevel
maybemadeinoneoftwoways:
a)withareinforcedconcretefloorslabstructurallyindependentfromthe
restofthebuilding,laiddirectlyontheground;
b)withafoundationpadandsidewallstoformabox-likestructurewhich
runspartlyunder the rampandonwhich the reinforcedconcretefloor
slaboftherampisthenplaced.
In the first case, the waterproofing (Fig. 7.63) is installed in various
steps,inthatthelayingsurfacesoftherampandofthefoundationpad
aredifferent. In the jointbetween the twostructures,adouble layerof
bentonitesheetmustbeapplied.Theprocedureisasfollows:
-laytwolayersofMAPEPROOF,withtheunderside(thedarkside)of
thegeo-textilepolypropylenefabricontheinnerfacesoftheformwork
and overlap the edges of the sheets by at least 10 cm. Fasten the
sheets inplaceonthe leanconcretewithnailsandMAPEPROOFCD
66
Fig.7.56c–PositioningandfasteningIDROSTOPPVCBItothesteelreinforcement
Fig.7.56d–SealingwithMAPEPROOFSWELL
Fig.7.56e–RepairingfoundationswithMAPEGROUTCOLABILE
Fig.7.60a–Oneofthephasesofsealingapipewhichpassesthroughthefoundationpad:applicationof
MAPEPROOFSEALaroundthepipe
Fig.7.60b–ApplicationofMAPEPROOFMASTIConthesheet
Fig.7.60c–LayingIDROSTOPB25Fig.7.62–Detailedlayoutofsealingadrainagewellembeddedinthefoundationpad
1
2
3
4
Reinforced concrete foundation pad
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
Regulating layer of lean concrete
Ground
MAPEPROOF SEAL
IDROSTOP B25
Cast-iron manhole cover
MAPEPROOF MASTIC
5
6
7
8
9
MAPEGROUT HI-FLOW
Concrete
MAPEPROOF SWELL
Embedded fixing clamps
Tie-rod
10
11
12
13
14
69
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
plastic washers approximately every 50 cm. Avoid forming creases
whenlayingthefabricontheleanconcrete.
- When casting the concrete, protect the ends of the two layers of
MAPEPROOFwithpolyethylenesheet.
-ApplyIDROSTOPPVCBIpre-formedwaterstop,madebyextruding
highqualityPVC,atthemid-pointofthefoundationpad,andtighten
itwithmetalwireconnectedtothewaterstopatoneendandthesteel
reinforcementinthewallattheotherend.
-Castthefoundationpad.
- Lay MAPEPROOF on the lean concrete on the ramp and overlap
it on the two layers previously laid after removing the protective
polyethylenesheet.Beforecastingtheramp,placemetalgutteringto
collectrainwaterandfixittothesteelreinforcementintherampwith
clamps.
In the second case, the box-like structure must be waterproofed as
illustrated previously for waterproofing vertical surfaces after casting
(Section7.7.1),foldingtheMAPEPROOFundertherampwhichmustthen
bewaterproofedasfollows:
- thesurfaces tobe treatedmustbecleanand freeofoil, stripping
compound, grease and all traces of dirt or any other material
which could potentially compromise the bond of the waterproofing
material.Thesurfaces,therefore,mustbethoroughlycleanedbydry
sandblastingatacontrolledpressureorwithhighpressurewaterjets
(150-180atm).
- Eliminate all irregularities in the substrate and smooth over gravel
clusters with MAPEGROUT FAST-SET fibre-reinforced, controlled-
shrinkage,quicksettingandhardeningmortarforrepairingconcreteor
PLANITOP400quick-setting,controlled-shrinkagethixotropicmortar
forrepairingthesurfaceofconcrete.
- Apply MAPELASTIC FOUNDATION two-component, flexible
cementitious mortar for waterproofing concrete surfaces subject to
positiveandnegativehydrauliclift(upto1.5atm,theequivalentofa
15mheadofwater).Theproductmaybeappliedbybrush,witharoller
orbyspraytoformacoatatleast2mmthick.Approximately4hours
afterapplyingthefirstlayeringoodweather,andinallcasesonlywhen
thefirstlayerhasdried,thesecondlayermaybeapplied.
7.12 WATERPROOFING DEPURATION TANKSFor collection basins for waste water (Fig. 7.64) the basins must be
preparedbeforeapplyingthewaterproofingsystemasfollows:
68
Fig.7.60d–FasteningIDROSTOPB25inplacewithmetalwire
Fig.7.60e–FurthergroutingwithMAPEPROOFMASTIC
Fig.7.61–ExtrusionofMAPEPROOFSWELLtosealthejointbetweenamanholecoverandawell
Fig.7.63–Detailedlayoutofwaterproofinganaccessramptoanundergroundgaragewhichisstructurallyindependentfromtherestofthebuilding
1
2
3
4
Reinforced concrete foundation pad
Steel connector rods
Protective concrete layer with the same Rck value as the concrete for the foundation pad
MAPEPROOF
Regulating layer of lean concrete
Ground
IDROSTOP PVC BI
Access ramp
Rainwater channel
MAPEFLEX PU45 with MAPEFOAM cord
5
6
7
8
9
10
71
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
-theinnerfacesofthebasin(floorandwalls)mustbeclean,freeof
strippingcompound,grease,dirtandanyothermaterialwhichcould
compromise the bond of the waterproofing system. The surfaces,
therefore, must be thoroughly cleaned by dry sandblasting at a
controlledpressureorwithhighpressurewaterjets(150-180atm).
-Form5x5cmtriangularfilletsbetweenthefloorof thebasinand
theverticalwallsandbetweentheadjacentwallsbyapplyingEPORIP
two-component, solvent-free epoxy adhesive mortar with a trowel
orbrush,andthen,while it isstill fresh,PLANITOP430fine-grained,
fibre-reinforced, controlled-shrinkage, medium-strength (30 MPa)
thixotropicmortarforrepairingconcrete.
-RoughareasinthesubstratemustbesmoothedoverwithMAPEFINISH
two-componentcementitiousmortarforfinishingoffconcrete,applied
by trowel at a thickness of up to 2-3 mm. After the MAPEFINISH
has cured, apply TRIBLOCK P three-component epoxy primer, with
the capacity of reticulating on damp surfaces, including particularly
smoothones(suchasporcelainandceramictiles,marble,etc.),onthe
floorandwallsofthebasintocreateanefficientbarrieragainstrising
damptoguaranteeagoodbond,includinginconditionsofpositivelift,
ofthewaterproofinglayer.TRIBLOCKPdilutedaccordinglyisapplied
intwocoatsbybrush,witharollerorbyairlesssprayonthesurfaces
tobetreated.Thetwocoatsshouldbeappliedcriss-crossed,making
surethattheyarealsoappliedevenly.Thesecondcoatmaybeapplied
4-6hoursafterthefirstone.
-Approximately24hoursafterapplyingthesecondcoatofTRIBLOCK
P,coverallthesurfacesofthebasinwithDURESILEBprotectiveanti-
acidtreatmentmadefromtwo-componentepoxypaintmodifiedwith
hydrocarbonresinandspecialadditives,resistanttofreezingweather
anddirectsunlight.Applytheproductintwocoatsusingconventional
methods,suchasbybrushwitharollerorbyairlessspray.Waitfrom
6 to 24 hours between the first and second coat, according to the
surroundingconditions.
-Onceithascompletelyhardened,DURESILEBmaycomeintocontact
withsewagewasteand,therefore,maybeusedforcoatingdepuration
basinsandbasinsforrun-offwaterfromdrains.Itisresistanttoacids,
dilutedalkalis,basematerials,salts,mineraloilandhydrocarbons,as
wellasthemainaggressivechemicalproductscarriedinsewagewaste
suchaschloridesandsulphates,andprotectsagainsttheaggressive
actionofcarbonatationandfreeze/thawcycles.
7.13 WATERPROOFING A SEWAGE WASTE OUTLET AND VENT CAST IN PLACE
Waterproofingofasewagewasteoutletandventcastinplaceiscarried
outby takingspecialcarewhen foldingover theMAPEPROOF (laidon
theverticalwall)insidetheholeinthewallforthestructure.The250g/m2
non-wovenfabricusedtoprotect thewaterproofing layermustalsobe
folded into thehole in thewall forwhen thestructure is filled inup to
thebaseofthesewagewasteoutletandvent.Fillintrenchesandgaps
withhomogenousfineandmixed looseearth inwell-compacted layers
40to50cmthick,toguaranteethat,oncethefillingoperationshavebeen
completed,therearenogapsorvoidsandthereisbetterconfinementof
thesystem.Thencastalayerof leanconcrete10cmthicktoevenout
thehorizontallayingsurface,onwhichtheMAPEPROOFfoldedintothe
holeforthestructureisthenoverlapped,thensealtheconstructionjoints
betweenthewallsofthebuildingandthebaseofthesewagewasteoutlet
andventbyapplyingIDROSTOPB25inbetweenthesteelreinforcement.
MAPEPROOFisthanappliedintheformworkwherethefoundationpad
ofthesewagewasteoutletandventistobecast,andthenfoldedover
onto the lean concrete to guarantee that it overlaps with the sheet on
thehorizontalsurface.TherollsofMAPEPROOFmustbepositionedwith
the underside (the darker side) of the geo-textile polypropylene fabric
70
Fig.7.64–Sedimentationtankinanadvancedstateofdeterioration
73
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
aroundtheformwork,whiletheupperside(thelighterside)isfoldedon
the inside so it is visible. Theedgesof the sheetsmustoverlapbyat
least10cm.Fasten thesheets inplace to the leanconcretewithnails
andMAPEPROOFCDpolyethylenewashersapproximatelyevery50cm.
Thesteelreinforcementforthefoundationpadmustbeplacedonspecial
plasticspacerstohelptheconcretetoflowunderthereinforcementand
guaranteethatitiswellcovered.Afterpositioningthesteelreinforcement,
pourontheconcreteforthebaseofthesewagewasteoutletandvent
according to the specifications for the concrete in Section 6. After
casting the base for the sewage waste outlet and vent and once the
basehascured,sealtheconstructionjointsbetweenthebaseandside
wallsof thesewagewasteoutletandventwith IDROSTOPB25hydro-
expandingbentonitejoint,nailedinplaceevery25cmatthemid-point
ofthesectionoftheverticalwallsbetweenthesteelreinforcementrods.
Thenseal the formworkandcast thevertical reinforcedconcretewalls
withconcreteaccordingtothespecificationsinSection6).Thesealing
operationwithIDROSTOPB25mustberepeatedforeachconstruction
jointintheverticalwalls,makingsurethattheriblaidverticallybetween
thewalls is laidalongside the ribon thehorizontalsurface forat least
6cm.Asanalternative, IDROSTOP hydro-expanding rubberprofile for
waterproofingworkingjointsuptoapressureof5atmmayalsobeused.
Oncethecastwallshavecured,thesurfaceofthereinforcedconcrete
mustbe smoothedover as follows: remove the spacers to adepthof
1-2cm,smoothovertheroughareasandgravelclusterswithPLANITOP
400quick-setting,compensated-shrinkage, thixotropicmortar forquick
repairson thesurfaceofconcrete,orwithPLANITOP430fine-grained,
fibre-reinforced,compensated-shrinkagethixotropicmortarforrepairing
deterioratedconcreteorproductsfromtheMAPEGROUTrange.
Astripat least50cmwideat thetopof thewallof thesewagewaste
outletandventmustbewaterproofedwithMAPELASTICFOUNDATION
appliedintwocoatstoformalayeratleast2mmthick.
Then lay the MAPEPROOF starting from the top, making sure that it
overlapstheMAPELASTICFOUNDATIONbyat least20cm. In thefillet
between the two systems, apply MAPEPROOF MASTIC on top of the
MAPELASTICFOUNDATION (Fig.7.65).Whenappliedaftercasting, the
bentonite sheets are laid with the upper side of the geo-textile fabric
(thewhiteside)againstthereinforcedconcretewall,whiletheunderside
ofthegeo-textilefabric(thedarkerside)facestheoutside.Pleasenote
thatthewhitenon-wovenfabricofMAPEPROOFmustalwaysbelaidin
contactwiththesurfacetobewaterproofed.Avoidformingcreaseswhen
layingthe fabric.When layingnear topipe-workwhichpassesthrough
thesurface,thesheetsmustbecuttoshapetosuittheshapeofsuch
elements,whichmustthenbesealedasdescribedinSection7.9.After
laying the MAPEPROOF, lay 250g/m2non-woven fabric toprotect the
waterproofinglayerwhenfillinginexcavations.
Fillwithhomogenousfineandmixedlooseearthinwell-compactedlayers
40to50cmthick,toguaranteethat,oncethefillingoperationshavebeen
72
Fig.7.65–SchematiclayoutofsealingafilletjointbetweenMAPEPROOFandMAPELASTICFOUNDATIONusingMAPEPROOFMASTIC
Concretewall
Fig.7.64–Detailedlayoutofwaterproofinganaerationoutletcastinplace
1
2
3
4
Reinforced concrete wall
Window or door fitting
MAPELASTIC FOUNDATION
Wall of sewage waste outlet
Continuous-yarn NWF (non-woven fabric) (weight ≥250 g/m2)
Ground
Fixing rods
IDROSTOP B25
MAPEBAND
MAPEFLEX PU45
5
6
7
8
9
10
11 Waste outlet
Foundation pad of sewage waste outlet
MAPEPROOF MASTIC
Manifold for run-off water
MAPEPROOF
Regulating layer of lean concrete
Screed to create slope
12
13
14
15
16
17
75
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
completed, therearenogapsorvoidsandthere isbetterconfinement
of thesystem.Thesewagewasteoutletandvent isalsowaterproofed
(Fig. 7.64) on the inside to avoid rainwater seeping into the reinforced
structure,otherwiseitmaydeteriorateprematurelyandreduceitsservice
life.Thesurfacetobetreatedmustbesolidandperfectlyclean.Remove
anycementlaitancepresentonthesurface,aswellaslooseandcrumbly
partsandtracesofdust,strippingcompoundandgreasebysandblasting
or with high pressure water jets. Even out the surface as described
previouslyfortheouterfaceofthewallsofthesewagewasteoutletand
vent,andthenwaterproof thesurfacewithMAPELASTICFOUNDATION
two-component,flexiblecementitiousmortarforwaterproofingconcrete
surfacessubjecttopositiveandnegativehydrauliclift.Incorrespondence
withtheholeforthefloordrain,applyaspecialshapedpieceofMAPEBAND
rubbertapewithafeltbackingresistanttoalkalisbondedtothesubstrate
withMAPELASTICFOUNDATION.MAPELASTICFOUNDATIONisapplied
bybrushorwitharollertoformalayeratleast2mmthick.Approximately
4hoursafterapplyingthefirstlayer,andinallcasesonlywhenthefirst
layerhasdried,thesecondlayermaybeapplied.
7.14 WATERPROOFING STRUCTURES BUILT USING THE TOP-DOWN METHOD
Thetop-downmethodwasdescribedbrieflyattheendofSection4.The
waterproofing(Fig.7.65)ofaconstructionbuiltusingthismethodmust
bemadestartingfromthetopworkingdownwards.Infact,afterpreparing
thetemporarystructures,aholeisexcavatedforthefirstfloorslab,which
iscastonthegroundwherepolyethylenesheetshavebeenplaced(Fig.
7.66)to improveitsfinalappearance.Whenithascured,thegroundis
dugoutunder thefloor slab throughspecialpassagesor accesses to
the future ramp. Special attention must be paid to guarantee that the
waterproofinglayeriscontinuousincorrespondencewiththeanchorage
pointsfortheendsofthefloorslabinthebulkheadsfortheexcavation.In
fact,ifcareistakenwiththeseconstructionfeatures,itwillguaranteethat
thebasementiswaterproof.Wheninstallingtheintermediatefloorslabs,
oncethegroundhasbeendugouttotheexternalfaceofthefloorslab,the
surfaceofthecontainmentwallsmustbecleanedwithhighpressurewater
jets(180-300atm)andlevelledoffwithMAPEGROUTT60sulphate-resistant,
fibre-reinforcedthixotropicmortarwith0.25%ofMAPECURESRA.
ThenlayontheMAPEPROOFstartingatleast1m(Fig.7.67)fromthebottom
oftheexcavationandoverlapthesheetsbyatleast10cm.Fixthesheetsin
placewithnailsandMAPEPROOFCDpolyethylenewashersapproximately
every30cm.MAPEPROOFmustbefoldedover(Fig.7.68)ontotheground,
makingsurethatitisprotectedbyasheetofpolyethylenetoguaranteethat
theconcretedoesnotattachtotheMAPEPROOFandthatitisprotectedand
undamageduntilallworkiscompleted.Thebentonitesheetandbulkheads
must thenbeperforatedso that themetalconnectorsused toanchor the
floorslabmaybecastfirmlyinplace.Theseanchorpointsarethensealedby
applyingMAPEPROOFMASTIC (Fig.7.69)naturalsodiumbentonitegrout
withplasticisingadditives.Thecycledescribedabovemustberepeatedfor
eachintermediatefloorslabuntilthelevelofthefoundationpadisreached
where,unlikeotherfloorslabs,thehemoftheMAPEPROOFisnotprotected
byasheetofpolyethylene,butoverlapsthebentonitesheetappliedallover
thesurfaceoftheleanconcrete.Onthesurface,toguaranteecontinuityofthe
waterproofinglayer,MAPEPROOF isoverlappedwiththesheetlaidbefore
castingthefloorslab.
The toppingbeamon thebulkheadmustalsobewaterproofed.Clean the
surfaceswithhighpressurewater jets (180-300atm)and thensmoothoff
the surface with PLANITOP 400 quick-setting, compensated-shrinkage,
thixotropic mortar for quick repairs on the surface of concrete, or with
PLANITOP 430 fine-grained, fibre-reinforced, compensated-shrinkage
thixotropic mortar for repairing deteriorated concrete or products from
the MAPEGROUT range. Once the surface has been evened off, apply
MAPELASTIC FOUNDATION (Fig. 7.70) in two coats one after the
otherusingaroller,brushorbysprayto forma layerat least2mmthick.
Approximately4hoursafterapplyingthefirstlayeringoodweather,and
inallcasesonlywhenthefirstlayerhasdried,thesecondlayermaybe
74
Fig.7.69–GroutingmetallicconnectorswithMAPEPROOFMASTIC
Fig.7.70–ApplicationofMAPELASTICFOUNDATIONonthetoppingbeamsonthebulkhead
Fig.7.71–SealingafilletjointbetweenMAPELASTICFOUNDATIONandMAPEPROOFwithMAPEPROOF
MASTICandthennailingIDROSTOPB25inplace
Fig.7.66–ApplicationofasheetofPEtoformafloorslabwitharegularinnerside
Fig.7.68–Bentonitesheetlaidontheverticalsurfaceandthenhemmedoverontothehorizontalsurface
Fig.7.67–TakingmeasurementsbeforecuttingMAPEPROOFsheets:startlayingthesheetsatleast1mfromthebottomoftheexcavation
8. WATERPROOFING EXISTING STRUCTURES BELOW GROUND LEVEL
Upuntilthispoint,wehavediscussedwaterproofinginterventionscarried
out on new constructions. Very often, however, the water tightness
of existing structures must also be guaranteed, and for which no
waterproofingsystemhadbeenconsideredduringthedesignphase.
Also,itisquitecommontocarryoutinterventionsonexistingwaterproofing
systemswhicharenolongercapableofcarryingouttheiroriginalfunction.
Belowwewilldiscussandanalyseanumberofconditionswhichoften
occuronexistingstructures,andsupplysuitable technicalsolutions to
be adopted, the products to be used and the methods for laying and
applying these products. All the information will be accompanied by
specifictechnicaldetails.
applied. MAPELASTIC FOUNDATION must be spread over all the front
face of the topping beam, on the inner face of the beam and on the
upperfaceofthebulkhead,soitmaybeoverlappedwithMAPEPROOF
for at least 30 cm to form a completely water-tight system. The fillet
joint between MAPEPROOF and MAPELASTIC FOUNDATION must be
sealed by applying IDROSTOP B25. In certain cases, this seal may be
reinforced by grouting with MAPEPROOF MASTIC (Fig. 7.71) between
the MAPELASTIC and MAPELASTIC FOUNDATION before applying
IDROSTOPB25,andthenextrudedMAPEPROOFSWELL(Fig.7.72)
77
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
76
Fig.7.73-Excavationworkcarriedoutunderthereinforcedconcretefoundationpadcastbefore
excavating
Fig.7.75–Aholeleftinthefloorslabtopourconcreteintotheverticalwalls
Fig.7.72–ExtrusionofMAPEPROOFSWELLontoIDROSTOPB25inthefilletjointbetweenMAPELASTICFOUNDATIONandMAPEPROOF
Fig.7.74–MAPEPROOF,appliedbeforecastingthefloorslab,ishemmedovertoguaranteethatitoverlapswiththenextsheetlaidontheverticalsurface
Fig.7.65–Detailedlayoutofwaterproofingtheendofanintermediatefloorslabinatop-downconstruction
1
2
3
4
Ground
Protective PE sheet
Intermediate floor slab
Pieces of MAPEPROOF
MAPEPROOF MASTIC
Rods for anchoring to the bulkhead
Bulkhead
IDROSTOP B25
Fixing rods
Reinforced concrete counter-wall
Smoothing and levelling layer on bulkhead
MAPEPROOF
6
7
8
9
10
11
5
12
Fig.7.76–Waterproofingthetoppingbeamonabulkhead
1
2
3
4
Pile bulkhead
Smoothing and levelling layer
MAPEPROOF
Reinforced concrete wall
IDROSTOP B25
MAPELASTIC FOUNDATION
Topping beam
Ground
5
6
7
8
79
8.1 LINING SURFACES IN ROOMS BELOWGROUND LEVEL
Ifwaterseepsintoroomsbelowgroundlevel,therearevariouswaysto
intervene:
•waterprooftheverticalsurfaces(MAPELASTICFOUNDATION);
•waterproofboththehorizontalandverticalsurfaces(MAPEPROOFor
MAPEPROOFinconjunctionwithMAPELASTICFOUNDATION).
Below, for each type of intervention mentioned above, there is a
descriptionoftheapplicationcycleofthewaterproofingsystem.
8.1.1 WATERPROOFING VERTICAL SURFACES AFTER CASTING
This typeof intervention iscarriedoutwhenwater fromvertical facing
wallsseepsintotheroom,mainlyduetopercolatingwaterpresentinthe
ground.Inthiscase,onlytheretainingwallswillbeinvolved,andconsists
intreatingthesurfaceswithMAPELASTICFOUNDATIONtwo-component,
flexible cementitious mortar specially developed for waterproofing
surfaces subjected to negative and positive hydraulic lift. The various
phasesforthistypeofapplicationaredescribedbelow.
Concrete walls
-Removetherenderdowntotheleveloftheunderlyingmasonry.
-Remove thegravelclustersand leveloff theverticalsurfaceswith
PLANITOP 400 quick-setting, compensated-shrinkage, thixotropic
mortarforquickrepairsonthesurfaceofconcrete,orwithPLANITOP
430fine-grained,fibre-reinforced,compensated-shrinkagethixotropic
mortar for repairing deteriorated concrete or products from the
MAPEGROUTrange.
-Constructionjoints(Fig.8.1),cracksinthesubstrateandpipe-work
(Fig.8.2)andotherelementswhichpassthroughtheconcretewalls
must be sealed with MAPEPROOF SWELL one-component, hydro-
expanding paste for waterproof seals. Carefully demolish the area
around the through elements, cracks and construction joints with
suitabletoolstoadepthofatleast6cm.Tosealconstructionjoints
between old substrates and repairs, extrude MAPEPROOF SWELL
andthenrepairthesubstratewithMAPEGROUTT40orMAPEGROUT
BMmortar.Whendemolishing theareas, ifwatercontinues toseep
through,stoptheflowwithLAMPOSILEXquick-settingandhardening
hydraulicbinderforstoppinginfiltrationofwater(Fig.8.3).
- Once the surface has been smoothed off, apply two coats of
MAPELASTICFOUNDATIONwithabrush,arollerorbyspraytoform
alayeratleast2mmthick.Approximately4hoursafterapplyingthe
first layer ingoodweather,and inallcasesonlywhenthefirst layer
hasdried, thesecond layermaybeapplied.OncetheMAPELASTIC
FOUNDATION is completely cured, spread a layer of POROMAP
INTONACO macro-porous, de-humidifying render which acts as an
anti-condensationbufferonthenewwaterproofingsystem(following
thecycleindicatedontheTechnicalDataSheet).
Brick walls
-Removethedeterioratedrenderdowntotheleveloftheunderlying
brickwork.
-Pipe-workandotherelementswhichpassthroughtheconcretewalls
must be sealed with MAPEPROOF SWELL one-component, hydro-
expandingpasteforwaterproofseals.Carefullydemolishtheareaaround
thethroughelements,cracksandconstructionjointswithsuitabletools
toadepthofatleast6cm.ExtrudeMAPEPROOFSWELLaroundthe
through elements and then repair the substrate with MAPEGROUT
78
Fig.8.2–SealingapipepassingthroughthesurfacebyextrudingMAPEPROOFSWELLandthenconfining
thepipewithMAPEGROUTBM
Fig.8.1e–Asealed,repairedconstructionjoint
Fig.8.1a–Oneofthephasesofsealingaconstructionjoint:mechanicaldemolitionaroundaconstructionjointtoadepthofapproximately6cm
Fig.8.1b–ExtrusionofMAPEPROOFSWELL
Fig.8.1d–ConfinementofMAPEPROOFSWELLbyapplyingMAPEGROUTT40
Fig.8.1c–ConstructionjointsealedwithMAPEPROOFSWELL
81
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
BMmortar.Whendemolishing theareas, ifwatercontinues toseep
through,stoptheflowwithLAMPOSILEXquick-settingandhardening
hydraulicbinderforstoppinginfiltrationofwater.
- Smooth over the surfaces with a new layer of render 2 cm thick,
reinforcedwithmetalmeshfastenedtothesubstratewithplugs.Forthe
newlayerofrender,applyMAPEGROUTT60sulphate-resistant,fibre-
reinforced thixotropic mortar or MAPEGROUT BM two-component
mortar with a low modulus of elasticity. As a substitute for the
reinforcedrender,thesurfacemaybesmoothedoverwithPLANITOP
HDM MAXI two-component, fibre-reinforced, high-ductile mortar
madefrompozzolan-reactionbindersinconjunctionwithMAPEGRID
G120orMAPEGRIDG220alkali-resistant,primedglassfibremesh.
- When the render is cured, apply two coats of MAPELASTIC
FOUNDATIONwithabrush,arollerorbyspraytoformalayeratleast
2 mm thick. Approximately 4 hours after applying the first layer in
goodweather,andinallcasesonlywhenthefirstlayerhasdried,the
second layermaybeapplied.Once theMAPELASTICFOUNDATION
iscompletelycured,spreadalayerofPOROMAPINTONACOmacro-
porous, de-humidifying render which acts as an anti-condensation
bufferonthenewwaterproofingsystem(followingthecycleindicated
ontheTechnicalDataSheet).
8.1.2 WATERPROOFING HORIZONTAL AND VERTICAL SURFACES WITH MAPEPROOF
Thistypeofinterventioniscarriedoutwheneverthestoreybelowground
levelisinfiltratedwithwaterfromthefloorandverticalretainingwallsdue
tothepresenceofgroundwaterunderpressure.Inthesecases,various
techniques and products may be used according to the construction
characteristicsofthestructureandthehydrostaticpressurewhichacts
onthesubstrates.Thevariousstepsarelistedbelow.
-Demolishthefirst3or4stepsofanystairwayspresentinthearea
belowgroundlevel.Allthepartitionwalls,floorsandsubstratesmust
alsoberemoved.
- Level off the vertical surfaces with PLANITOP 400 quick-setting,
compensated-shrinkage, thixotropic mortar for quick repairs on
the surface of concrete, or with PLANITOP 430 fine-grained, fibre-
reinforced, compensated-shrinkage thixotropic mortar for repairing
deterioratedconcreteorproductsfromtheMAPEGROUTrange.
- Construction joints, cracks in the substrate and pipe-work and
other elements which pass through the substrates must be sealed
with MAPEPROOF SWELL one-component, hydro-expanding paste
forwaterproofseals.Carefullydemolishtheareaaroundthethrough
elements,cracksandconstructionjointswithsuitabletoolstoadepth
ofat least6cm.Tosealconstruction jointsbetweenoldsubstrates
and repairs, extrude MAPEPROOF SWELL and then repair the
substrate with MAPEGROUT T40 or MAPEGROUT BM mortar. When
demolishing the areas, if water continues to seep through, stop the
flowwithLAMPOSILEXquick-settingandhardeninghydraulicbinder
forstoppinginfiltrationofwater.
-Line the inner facesof the roombyapplyingMAPEPROOFsheets
on thehorizontalandverticalsurfaces (Fig.8.4-5)bypositioning the
underside(thedarkside)ofthegeo-textilefabriconthesurfaceofthe
leanconcreteandtheverticalwallsandtheuppersideofthefabric(the
whiteside)facingupwardssoitisvisible.Theedgesmustoverlapbyat
least10cm.Fastenthesheetsinplacetothesubstratewithnailsand
MAPEPROOFCDpolyethylenewashersapproximatelyevery50cmon
horizontalsurfacesandevery30cmonverticalsurfaces.Whenlaying
theproductaroundthroughelements(pillars,pipe-work,etc.)thesheets
mustbecuttoshapesotheyfitperfectlyaroundtheelements,which
80
Fig.8.3–ExtrusionofMAPEPROOFSWELLonazonedamagedbyseepingwaterblockedbeforehandwithLAMPOSILEX
83
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
mustalsobesealedwithIDROSTOPB25(incertaincases,itmaybe
necessarytoextrudeMAPEPROOFSWELLovertheIDROSTOPB25).
Makesurethereareabsolutelynocreaseswhenlayingthesheets.
-Ifthereisahorizontalstructuretowhichthenewfoundationsmay
be anchored, the MAPEPROOF must be perforated so that metallic
connectors may be cast in place. This operation means that the
thicknessofthenewfoundationsmaybelower,inthattheoldstructure
willactasballastforthenewone.MAPEPROOFmustbeperforated
according to the results of structural calculations. Apart from the
thicknessofthenewfloorslabandwalls,thestructuralanalysismust
alsoindicatethenumberpersquaremetreanddiameterofthemetallic
connectorswhichmustbeusedonthehorizontalsurfaces(foundation
pad)andverticalsurfaces(walls).Anchorageoftheconnectorstothe
horizontal surfaces must be carried out by casting EPOJET super-
fluid epoxy resin, while ADESILEX PG1 two-component, thixotropic
epoxyadhesivemustbeusedfortheverticalsurfaces.Thepointsin
whichtheconnectorspassthroughthesheetsmustbegroutedwith
MAPEPROOFMASTIC.
- After carrying out the operations described above, position the
steelreinforcementforthenewreinforcedconcretefloorslabonthe
horizontal surfaces, at a suitable distance from the MAPEPROOF
sheetsusingplasticspacers.Thesespacersallowtheconcretetoflow
freelyunderandaroundthesteelreinforcementandguaranteethatthe
reinforcementiswellcovered.Thencastthereinforcedconcrete,the
thicknessofwhichmustbesufficient toresist thehydraulic lift from
thegroundwater.
-Aftercastingandcuring theconcrete for thenew foundationpad,
positionIDROSTOPB25hydro-expandingbentonitecordbetweenthe
steel reinforcement for the walls and cast the concrete to form the
verticalstructures,whichmustalsobeconnectedtotheexistingwalls
of the area below ground level with new anchored, sealed metallic
connectors. The 20x25 mm jointing material must be nailed to the
substrateevery25cm.ThesealingoperationwithIDROSTOPB25must
berepeatedforeachconstructionjointintheverticalwalls,makingsure
thattheriblaidverticallybetweenthewallsislaidalongsidetheribon
thehorizontalsurfaceforatleast6cm.Asanalternative,IDROSTOP
hydro-expandingrubberprofileforwaterproofingworkingjointsupto
a pressure of 5 atm may also be used. Before applying IDROSTOP
B25,carefullycleanthesurfacetoeliminateall tracesofdebris,and
especially the slurry which usually bleeds from the surface when
compacting the cementitious conglomerate used for the foundation
pad.
82
Fig.8.5a–OneofthephasesofliningtheinsideofaroomwithMAPEPROOFonthehorizontalandverticalsurfaces:applicationofMAPEPROOFonthelowerpartoftheverticalwallswiththesheethemmedoverontotheleanconcrete
Fig.8.5b–Afterlayingthesheetonthehorizontalsurface,thesteelreinforcementforcastingthereinforcedconcretefloorslabandcounter-wallisplacedinposition
Fig.8.4–DetailedlayoutofreliningtheinsideofaroombyapplyingMapeproofonthehorizontalandverticalsurfacesandthencastingthereinforcedconcretefloorslabandretainingwalls
1
2
3
4
Old reinforced concrete structure
MAPEPROOF
MAPEPROOF MASTIC
Connectors
IDROSTOP B25
Regulating layer of lean concrete
Ground
New reinforced concrete structure sized to resist against hydraulic lift
5
6
7
8
85
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
-Thensealalltheformworkandcastthereinforcedconcretecounter-
walls. The thickness of the walls must be calculated to resist the
hydraulic lift from thegroundwater.Theconcretecounter-wallsmay
alsobemadetoformasinglebodywiththeexistingstructurefollowing
theindicationsdescribedpreviously.
8.1.3 WATERPROOFING HORIZONTAL AND VERTICAL SURFACES WITH A COMBINED BENTONITE-CEMENTITIOUS SYSTEM
Thechoiceofwhichsystemtouseforthistypeofinterventiondoesnot
dependonthehydrostaticpressureactingonthestructure(bearinmind
thatMAPELASTICFOUNDATIONishighlyresistanttonegativelift,upto
1.5baror a 15mheadofwater), but ratheron twomain factors: the
spaceavailableintheroombelowgroundlevelandthetimerequiredto
carryoutthework.Itisquiteobviousthatliningtheinnersurfaceswith
MAPEPROOFreducestheareaavailableintheroombelowgroundlevel,
inthatthecounter-wallmustbethickenoughtoresistthehydraulicliftof
thegroundwater.Theuseofacementitioussystem,ontheotherhand,
doesnotreducethespaceavailablebutmayleadtolongdelayswhen
carryingouttheworkifithastobeappliedonareinforcedrenderlevelling
layer. Therefore, when choosing which system to use in rooms below
groundlevel,theanalysismusttakeintoconsiderationboththetechnique
andtimeaspectsandtheoverallcostoftheintervention.
Concrete walls
-Demolishthefirst3or4stepsofanystairwayspresentinthearea
belowgroundlevel.Allthepartitionwalls,floorsandsubstratesmust
alsoberemoved.
- Level off the vertical surfaces with PLANITOP 400 quick-setting,
compensated-shrinkage, thixotropic mortar for quick repairs on
the surface of concrete, or with PLANITOP 430 fine-grained, fibre-
reinforced, compensated-shrinkage thixotropic mortar for repairing
deterioratedconcreteorproductsfromtheMAPEGROUTrange.
- Construction joints, cracks in the substrate and pipe-work and
other elements which pass through the substrates must be sealed
with MAPEPROOF SWELL one-component, hydro-expanding paste
forwaterproofseals.Carefullydemolishtheareaaroundthethrough
elements,cracksandconstructionjointswithsuitabletoolstoadepth
ofat least6cm.Tosealconstruction jointsbetweenoldsubstrates
and repairs, extrude MAPEPROOF SWELL and then repair the
substrate with MAPEGROUT T40 or MAPEGROUT BM mortar. When
demolishing the areas, if water continues to seep through, stop the
flowwithLAMPOSILEXquick-settingandhardeninghydraulicbinder
forstoppinginfiltrationofwater.
84
Fig.8.5c–ReinforcedconcretefloorslabcastontheMAPEPROOFatathicknesscalculatedtowithstandhydraulicliftfromthegroundwater
Fig.8.5d–SealingafilletjointbetweenMAPEPROOFandMAPELASTICFOUNDATIONwithIDROSTOPB25
Fig.8.6d–Metalconnectorsarerequiredtomakethenewstructurepartoftheexistingone
Fig.8.6a–OneofthephasesofreliningtheinsideofaroomwithMAPELASTICFOUNDATIONontheverticalwallsandMAPEPROOFonthehorizontalsurfaces:applicationofMAPELASTICFOUNDATIONontheverticalwallsandonthenewleanconcreteatawidthofatleast50cm
Fig.8.7a–DetailedlayoutofreliningtheinsideofaroombyapplyingMAPEPROOFonthehorizontalsurfacesandMAPELASTICFOUNDATIONontheverticalsurfaces:filletjointbetweenthefloorslabandretainingwall
1
2
3
4
Old reinforced concrete structure
MAPELASTIC FOUNDATION
MAPEPROOF MASTIC
Connectors
New reinforced concrete structure sized to resist against hydraulic lift
IDROSTOP B25
MAPEPROOF
Regulating layer of lean concrete
Ground
6
7
8
9
5
87
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
-Ontheverticalwalls(Fig.8.6-7)andhorizontalsurfaces,applytwo
coatsofMAPELASTICFOUNDATIONoneaftertheothertoformastrip
atleast50cmwidewithabrush,arollerorbyspraytoformalayerat
least2mmthick.Approximately4hoursafterapplyingthefirstlayerin
goodweather,andinallcasesonlywhenthefirstlayerhasdried,the
secondlayermaybeapplied.
- When applying the waterproofing system on horizontal surfaces,
referalsototheindicationsattheendofthisSection.
Brick walls
-Demolishthefirst3or4stepsofanystairwayspresentinthearea
belowgroundlevel.Allthepartitionwalls,floorsandsubstratesmust
alsoberemoved.
-Removethedeterioratedrenderdowntotheleveloftheunderlying
masonry.
-Smoothovertheverticalwallswithanewlayerofrender4cmthick,
reinforcedwithmetalmeshfastenedtothesubstratewithplugs.Forthe
newlayerofrender,applyMAPEGROUTT60sulphate-resistant,fibre-
reinforced thixotropic mortar or MAPEGROUT BM two-component
mortar with a low modulus of elasticity. As a substitute for the
reinforcedrender,thesurfacemaybesmoothedoverwithPLANITOP
HDMMAXItwo-component,fibre-reinforced,high-ductilemortarmade
frompozzolan-reactionbindersinconjunctionwithMAPEGRIDG120
orMAPEGRIDG220alkali-resistant,primedglassfibremesh.
-Pipe-workandotherelementswhichpassthroughthewallsmustbe
sealed with MAPEPROOF SWELL one-component, hydro-expanding
paste for waterproof seals. Carefully demolish the area around the
throughelements, cracksandconstruction jointswith suitable tools
toadepthofat least6cm.Tosealconstruction jointsbetweenold
substrates and repairs, extrude MAPEPROOF SWELL around the
through elements and then repair the substrate with MAPEGROUT
BMmortar.Whendemolishing theareas, ifwatercontinues toseep
through,stoptheflowwithLAMPOSILEXquick-settingandhardening
hydraulicbinderforstoppinginfiltrationofwater.
- On vertical walls and horizontal surfaces, apply two coats of
MAPELASTICFOUNDATIONoneaftertheothertoformastripatleast
50cmwidewithabrush,arollerorbyspraytoformalayeratleast2
mmthick.Approximately4hoursafterapplyingthefirstlayeringood
weather,andinallcasesonlywhenthefirstlayerhasdried,thesecond
layermaybeapplied.
86
Fig.8.6e-LayIDROSTOPB25incorrespondencewiththejointsbetweenMAPELASTICFOUNDATIONand
MAPEPROOF
Fig.8.6f–GroutingthemetalconnectorswithMAPEPROOFMASTIC
Fig.8.6c–AfterlayingMAPEPROOFontheleanconcrete,makeholestoinsertthemetalconnectors
Fig.8.6b–MAPELASTICFOUNDATIONisalsoappliedalsoonthepillars
Fig.8.6g–Metalconnectorsgroutedbeforepositioningthesteelreinforcementforthenewfloorslabtobeinstalled
Fig.8.7b–DetailedlayoutofreliningtheinsideofaroombyapplyingMAPEPROOFonthehorizontalsurfacesandMAPELASTICFOUNDATIONontheverticalsurfaces:filletjointbetweenthefloorslabandapillarorpartingwall
1
2
3
4
Old reinforced concrete structure
MAPELASTIC FOUNDATION
MAPEPROOF MASTIC
Connectors
New reinforced concrete structure sized to resist against hydraulic lift
IDROSTOP B25
MAPEPROOF
Regulating layer of lean concrete
Ground
6
7
8
9
5
89
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
Horizontal surfaces
WhentheMAPELASTICFOUNDATIONiscompletelycured,applythe
MAPEPROOFonthehorizontalsurfacesbypositioningtheunderside
(thedarkside)ofthegeo-textilefabriconthesubstrateandtheupper
sideofthefabric(thewhiteside)facingupwardssoit isvisible.The
edgesmustoverlapbyatleast10cm.Fastenthesheetsinplaceto
thesubstratewithnailsandMAPEPROOFCDpolyethylenewashers
approximatelyevery50cm.Whenlayingtheproductaroundthrough
elements (pillars, pipe-work, etc.) the sheets must be cut to shape
sotheyfitperfectlyaroundtheelements,whichmustalsobesealed
withIDROSTOPB25(incertaincases,itmaybenecessarytoextrude
MAPEPROOFSWELLover the IDROSTOPB25).Makesure thereare
absolutelynocreaseswhenlayingthesheets.
-JointsbetweenMAPEPROOFandMAPELASTICFOUNDATIONmust
be sealed with IDROSTOP B25 hydro-expanding bentonite jointing
material,fixedtothesurfacewithnailsevery25cm.Asanalternative,
IDROSTOPhydro-expandingrubberprofileforwaterproofingworking
jointsuptoapressureof5atmmayalsobeused.
-Ifthereisahorizontalstructuretowhichthenewfoundationsmay
be anchored, the MAPEPROOF must be perforated so that metallic
connectors may be cast in place. This operation means that the
thicknessofthenewfoundationsmaybelower,inthattheoldstructure
willactasballastforthenewone.MAPEPROOFmustbeperforated
according to the results of structural calculations. Apart from the
thicknessofthenewfloorslabandwalls,thestructuralanalysismust
alsoindicatethenumberpersquaremetreanddiameterofthemetallic
connectorswhichmustbeusedonthehorizontalsurfaces(foundation
pad)andverticalsurfaces(walls).Anchorageoftheconnectorstothe
horizontal surfaces must be carried out by casting EPOJET super-
fluid epoxy resin, while ADESILEX PG1 two-component, thixotropic
epoxyadhesivemustbeusedfortheverticalsurfaces.Thepointsin
whichtheconnectorspassthroughthesheetsmustbegroutedwith
MAPEPROOFMASTIC.
- After carrying out the operations described above, position the
steelreinforcementforthenewreinforcedconcretefloorslabonthe
horizontal surfaces, at a suitable distance from the MAPEPROOF
sheetsusingplasticspacers.Thesespacersallowtheconcretetoflow
freelyunderandaroundthesteelreinforcementandguaranteethatthe
reinforcementiswellcovered.Thencastthereinforcedconcrete,the
thicknessofwhichmustbesufficienttoresistthehydraulicliftfromthe
groundwater.
8.2 WATERPROOFING A LIFT WELL AGAINST HYDRAULIC LIFT
Waterproofingaliftwellagainsthydrauliclift(Fig.8.7)maybecarriedout
inoneofthreeways:
1. by applying a layer ofwater-repellentmortarmadewith IDROSILEX
andIDROSILEXPRONTOontheverticalwalls;
2. applicationofawaterproofcoatingwithwater-repellentmortarmade
withIDROSILEXonthehorizontalsurfaceandMAPELASTICFOUNDATION
ontheverticalandhorizontalsurfaces;
3. applicationofMAPEPROOFon thehorizontal surface inconjunction
withMAPELASTICFOUNDATIONontheverticalsurfaces.
With all three solutions, the construction joints, cracks and pipe-work
andelementswhichpassthroughtheconcretemustfirstlybesealedby
applyingMAPEPROOFSWELLone-component,hydro-expandingpaste
for waterproof seals. Carefully demolish the area around the through
elements,cracksandconstructionjointswithsuitabletoolstoadepthof
atleast6cm.ExtrudeMAPEPROOFSWELLaroundthethroughelements
andthenrepairthesubstratewithMAPEGROUTT40orMAPEGROUTBM
mortar.Whendemolishingtheareas,ifwatercontinuestoseepthrough,
stop the flowwith LAMPOSILEX quick-setting andhardeninghydraulic
binderforstoppinginfiltrationofwater.
88
Fig.8.6h–Castingofthereinforcedconcretefloorslab,calculatedtowithstandthehydraulicliftfromthegroundwater
Fig.8.7–Infiltrationsincorrespondencewiththeconstructionjointsinthereinforcedconcretestructureforaliftwell
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
The surfaces to be waterproofed must be perfectly clean and solid.
Anygravelclustersmustberemovedandtheverticalsurfacesmustbe
levelled off with PLANITOP 400 quick-setting, compensated-shrinkage,
thixotropicmortar forquick repairson thesurfaceofconcrete,orwith
PLANITOP 430 fine-grained, fibre-reinforced, compensated-shrinkage
thixotropic mortar for repairing deteriorated concrete or products from
theMAPEGROUTrange.Thenremovealldustandresiduesofprevious
operations with a mechanical brush, by sand-blasting or with high
pressurewaterjets.
After preparing the substrate as described above, the waterproofing
productmaybeappliedasdescribedbelow.
8.2.1 WATERPROOFING WITH OSMOTIC MORTAR
-Afterpreparingthesubstrateasdescribedabove,wetthesubstrate
untilitissaturatedwithadrysurface,thenapplyIDROSILEXPRONTO
waterproof osmotic cementitious mortar with a brush, trowel or by
spray.Payparticularattentionwhenapplyingtheproductonthefillet
jointbetweenthewallsandhorizontalsurfaceandbetweenadjacent
walls, and make sure it penetrates into the substrate. Spread the
IDROSILEXPRONTOontheverticalsurfacesandformanoverlapon
thehorizontalsurfaceatleast30cmwide.Theproductmustforma
layer at least 2-3mm thick and thecharacteristicsof thehardened
layermakeitsuitableonlyforformingrigidwaterproofinglayers.
- Complete the waterproofing system by applying several layers of
water-repellentmortarmadewithIDROSILEXinpowderorliquidform,
as described above. On the surface, spread bonding slurry made
from PLANICRETE, synthetic latex rubber for cementitious mixes
andthesameamountofwater,blendedwiththecementataratioof
1:3.Using the freshon fresh technique,applya7-8mmthick layer
of mortar with a plastic consistency made from sand, cement and
IDROSILEXaccordingtotheproportionsintheTechnicalDataSheet.
After approximately one hour, before the substrate has completely
91
hardened,installa40mmthickscreedmadefromsand,cementand
IDROSILEXaccordingtotheproportionsintheTechnicalDataSheet.
-Thescreedmustbewellcompactedandsmoothedoverandmust
be cured for at least two days. Then apply a layer of EPORIP two-
component, solvent-freeepoxyadhesiveon thefillet jointsbetween
thehorizontalandverticalsurfacesandbetweentheadjacentwalls.On
thefreshEPORIP,formfilletswithMAPEGROUTBMtwo-component
mortarwithalowmodulusofelasticity.
8.2.2 WATERPROOFING WITH A COMBINED OSMOTIC MORTAR-FLEXIBLE CEMENTITIOUS MORTAR SYSTEM
- After preparing the substrate as described above, apply several
layers of water-repellent mortar made with IDROSILEX in powder or
liquid form,asdescribedbelow.Spreada layerofbondingslurryon
thesurface(Fig.8.8)madefromPLANICRETEsyntheticlatexrubberfor
cementitiousmixesandthesameamountofwater,blendedwiththe
cementataratioof1:3.Usingthefreshonfreshtechnique,applya7-8
mmthicklayerofmortarwithaplasticconsistencymadefromsand,
cementandIDROSILEXaccordingtotheproportionsintheTechnical
Data Sheet. After approximately one hour, before the substrate has
completelyhardened, installa40mmthickscreedmade fromsand,
cementandIDROSILEXaccordingtotheproportionsintheTechnical
DataSheet.
-Thescreedmustbewellcompactedandsmoothedoverandmust
be cured for at least two days. Then apply a layer of EPORIP two-
component,solvent-freeepoxyadhesiveonthefilletjointsbetweenthe
horizontalandverticalsurfacesandbetweentheadjacentwalls.Onthe
freshEPORIP,formfilletswithMAPEGROUTBMtwo-componentmortar
withalowmodulusofelasticity.Aftercompletingthecycle,applytwo
coatsofMAPELASTICFOUNDATIONwithabrushor rolleronall the
vertical and horizontal surfaces to form a layer at least 2 mm thick.
90
Fig.8.8c–ApplicationofEPORIPinthefilletjointsbetweenhorizontalandverticalsurfacesandbetweenadjacentwalls
Fig.8.8a–Oneofthephasesoftheinstallationofwaterproofcoatingwithwater-repellentIDROSILEXmortaronthehorizontalsurfaceandMAPELASTICFOUNDATIONontheverticalandhorizontalsurfaces:spreadingonbondingslurry
Fig.8.8b–Screedmadefromsand,cementandIDROSILEX
Fig.8.8e–VerticalwallsandhorizontalsurfaceswaterproofedwithMAPELASTICFOUNDATION
Fig.8.8e–ApplicationofMAPELASTICFOUNDATION
Fig.8.8d–MakingfilletsontheEPORIPwhilestillfreshwithMAPEGROUTBM
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
Approximately4hoursafterapplyingthefirstlayer,andinallcasesonly
whenthefirstlayerhasdried,thesecondlayermaybeapplied.
8.2.3 WATERPROOFING WITH A COMBINED BENTONITE-FLEXIBLE CEMENTITIOUS MORTAR SYSTEM
-Afterpreparingthesubstrateasdescribedabove,applytwocoats
of MAPELASTICFOUNDATION on thehorizontal surfaceanda strip
at least30cmwideontheverticalsurfaceswithabrushorrollerto
formalayeratleast2mmthick.Approximately4hoursafterapplying
thefirstlayer,andinallcasesonlywhenthefirstlayerhasdried,the
secondlayermaybeapplied.
- Line the horizontal surfaces with MAPEPROOF by positioning the
underside (the dark side) of the geo-textile fabric on the substrate
andon theverticalwallsand theuppersideof the fabric (thewhite
side) facing upwards so it is visible. The edges must overlap by at
least10cm.Fastenthesheetsinplacetothesubstratewithnailsand
MAPEPROOFCDpolyethylenewashersapproximatelyevery50cmon
horizontalsurfacesandevery30cmonverticalsurfaces.Whenlaying
theproductaroundthroughelements,thesheetsmustbecuttoshape
sotheyfitperfectlyaroundtheelements,whichmustalsobesealed
withIDROSTOPB25(incertaincases,itmaybenecessarytoextrude
MAPEPROOFSWELLover the IDROSTOPB25).Makesure thereare
absolutelynocreaseswhenlayingthesheets.
-JointsbetweenMAPEPROOFandMAPELASTICFOUNDATIONmust
be sealed with IDROSTOP B25 hydro-expanding bentonite jointing
material,fixedtothesurfacewithnailsevery25cm.Asanalternative,
IDROSTOPhydro-expandingrubberprofileforwaterproofingworking
jointsuptoapressureof5atmmayalsobeused.
-Tojointhesteelreinforcementinthenewreinforcedconcretefloor
slabwith the reinforcement in theoldone, theMAPEPROOF sheets
93
mustbeperforatedaccordingtotheresultsofstructuralcalculations.
Apartfromthethicknessofthenewfloorslab,thestructuralanalysis
mustalsoindicatethenumberpersquaremetreanddiameterofthe
metallicconnectorswhichmustbeusedon thehorizontalsurfaces.
Theconnectorsmust thenbecast inplacewithEPOJETsuper-fluid
epoxy resin. The points in which the connectors pass through the
sheetsmustbegroutedwithMAPEPROOFMASTIC.
- After carrying out the operations described above, position the
steelreinforcementforthenewreinforcedconcretefloorslabonthe
horizontal surfaces, at a suitable distance from the MAPEPROOF
sheetsusingplasticspacers.Thesespacersallowtheconcretetoflow
freelyunderandaroundthesteelreinforcementandguaranteethatthe
reinforcementiswellcovered.Thencastthereinforcedconcrete,the
thicknessofwhichmustbesufficienttoresistthehydraulicliftfromthe
groundwater.
Bibliography1. P. Colombo, F. Colleselli: "Elements of Geotechnics". Third edition. 2004. Printed by Zanichelli.
2. Varisco Wellpoint, "Draining ground with the wellpoint system".
92
Fig.8.9-DetailedlayoutofreliningtheinsideofaliftwellbyapplyingMAPEPROOFonthehorizontalsurfaceandMAPELASTICFOUNDATIONontheverticalsurface:filletjointbetweenthefloorslabandretainingwall
1
2
3
4
Old reinforced concrete structure
MAPELASTIC FOUNDATION
MAPEPROOF MASTIC
Connectors
New reinforced concrete structure sized to resist against hydraulic lift
IDROSTOP B25
MAPEPROOF
Regulating layer of lean concrete
Ground
6
7
8
9
5
CENTRAL STATIONMilan - Italy
Waterproofingtheformerundergroundcar-parkarea,nowusedasanarchive,withMAPEPROOFandIDROSTOPB25
NIKE STORESan Benedetto del Tronto
Italy
WaterproofingstructuresbelowgroundlevelwithMAPEPROOF,
MAPELASTICFOUNDATION,IDROSTOPB25,MAPEPROOF
SWELLandLAMPOSILEX
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
9594
Technical Notebook
WATERPROOFING STRUCTURESINSTALLED BELOW GROUND LEVEL
96
NOTES