donald meinheit durability presentation 3-3-10

7/28/2019 Donald Meinheit Durability Presentation 3-3-10

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Concrete Durability Design

Minnesota Concrete CouncilMinnesota Concrete Council

ConcreteConcrete A Changing IndustryA Changing Industry

ByBy

,,


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Acknowled ements Design and Control of Concrete MixturesDesign and Control of Concrete Mixtures,,

thth

,, ,,

20022002

,,

Committee Report, 2008Committee Report, 2008

StructuresStructures, ACI 362, Committee Report 1997, ACI 362, Committee Report 1997

u uu u Photos from archives of WJEPhotos from archives of WJE


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Outline DurabilityDurability DefinitionsDefinitions

What structures require durabilityWhat structures require durability

durabilitydurability a concre e m x ure an cur nga concre e m x ure an cur ng

conditions affect durabilityconditions affect durability

How can concrete be designed forHow can concrete be designed for


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Concrete


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Ob ective

Describe issues that cause concreteDescribe issues that cause concrete

durability problemsdurability problems

taken to provide durability to concretetaken to provide durability to concrete


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Definition of Concrete Durabilit Concrete DurabilityConcrete Durability

Concrete fit for the purpose for which itConcrete fit for the purpose for which itwas intended, under the conditions towas intended, under the conditions to

w c e concre e s expec e o ew c e concre e s expec e o e

exposed, and for the expected life duringexposed, and for the expected life during ..

Adam Neville CI July 2000Adam Neville CI July 2000


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Definition of Concrete DurabilitACI 201.2RACI 201.2R Guide to DurableGuide to Durable

oncre eoncre eDurability of hydraulic cement concrete isDurability of hydraulic cement concrete is

determined by its ability to resistdetermined by its ability to resist

weathering action, chemical attack,weathering action, chemical attack,a ras on, or any ot er process oa ras on, or any ot er process o

deteriorationdeterioration


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CI 201 Deterioration Modes Freezing and thawingFreezing and thawing

AlkaliAlkali--aggregate reaction (AAR)aggregate reaction (AAR)

Corrosion of embedded metalsCorrosion of embedded metalsAbrasionAbrasion


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Steel Reinforcin


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Structure T es Structure types needing to be durableStructure types needing to be durable

Bridge decksBridge decks Bridge piers, especially when in salt waterBridge piers, especially when in salt water

Parking structuresParking structures

PavementsPavements


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Service Life Ex ectationsAspects having direct bearing onAspects having direct bearing on

ura yura y Nature of the projectNature of the project

Type of structureType of structure

Expected service lifeExpected service life

Exposure conditionsExposure conditions

Consider as ects concurrentl to assessConsider as ects concurrentl to assess

levellevel ofof durabilitydurability


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Attack Mechanisms Freezin and thawinFreezin and thawin

CarbonationCarbonation

CrackingCracking LeakingLeaking

A re atesA re ates

Chemical attackChemical attack


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Makin Concrete Durable There are two fundamental ways toThere are two fundamental ways to

ma e concre e ura ema e concre e ura eAddress the properties of the concreteAddress the properties of the concrete

Provide protective systems external to theProvide protective systems external to the

concreteconcrete


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Concrete Mixture Pro erties BasicBasic Admixture andAdmixture and

emenemen

Coarse aggregateCoarse aggregate Air entrainingAir entraining

Fine aggregateFine aggregate

WaterWater

a er re ucersa er re ucers

Other cementitiousOther cementitious

Mixing/PlacingMixing/Placing ma er a sma er a s

Corrosion inhibitorsCorrosion inhibitors

ur ng reg mesur ng reg mes


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Water to Cementitious Ratio w/cm plays defining role for concretew/cm plays defining role for concrete

ura yura y Generall the lower the w/cm ratio theGenerall the lower the w/cm ratio the

better the performancebetter the performance


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Water to Cementitious Ratio

precast / prestressed concrete

ive

Strengt

cast-in-place concrete

Compress

. . . . . . . . .Water - Cementitious Ratio


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Mixin Extended mixingExtended mixing

Higher concrete temperaturesHigher concrete temperatures

Add water to restore slumpAdd water to restore slump

Impacts air void pore size distributionImpacts air void pore size distribution

Reduces concrete strengthReduces concrete strength


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Placin and Consolidation Excessive free fallExcessive free fall

Reduces the entrained air contentReduces the entrained air content Pum in chan es air contentPum in chan es air content

Vibration durationVibration duration

ncrease v ra on re uces a r con enncrease v ra on re uces a r con en

Reduced vibration leaves voidsReduced vibration leaves voids

Good vibration reduces permeabilityGood vibration reduces permeability


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Inade uate Vibration - Hone combin


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A re ates - Po out


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A re atesAlkaliAlkali--silica reaction (ASR)silica reaction (ASR)

Involves chemical reaction between alkaliInvolves chemical reaction between alkalisource (cement) and reactive silicasource (cement) and reactive silica

s ceous aggrega ess ceous aggrega es

Can manifest itself in 5 to 20 yearsCan manifest itself in 5 to 20 years

nterna tear ng crac ng o t e concretenterna tear ng crac ng o t e concrete

matrix)matrix)


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Alkali-silica Reaction ASR


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Silica gel in microcrack


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A re atesAlkaliAlkali--carbonate reaction (ACR)carbonate reaction (ACR)

Involves certain argillaceous dolomiticInvolves certain argillaceous dolomitic

limestoneslimestones

Chemical reaction between alkali sourceChemical reaction between alkali source

(cement) and certain calcium(cement) and certain calcium--magnesiummagnesiumcar onate roc s o om tescar onate roc s o om tes

Not a significant issue in U.S. exceptNot a significant issue in U.S. except

VirginiaVirginia


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A re ate Evaluation Petrographic examination ASTMPetrographic examination ASTM

Laborator testinLaborator testin

Mortar Bar Test ASTM C 227Mortar Bar Test ASTM C 227

Quick Chemical Test ASTM C 289Quick Chemical Test ASTM C 289

oncre e r sm es soncre e r sm es s

Essentially, measure expansionEssentially, measure expansion


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Prism Tests


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Reducin ASR in Concrete Use nonreactive aggregatesUse nonreactive aggregates

Use low alkali cementUse low alkali cement, ,, ,

Use lithium compoundsUse lithium compounds


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Concrete Mixture Pro erties BasicBasic Admixture andAdmixture and

emenemen

Coarse aggregateCoarse aggregate Air entrainingAir entraining

Fine aggregateFine aggregate

WaterWater

a er re ucersa er re ucers

Other cementitiousOther cementitious Mixing/PlacingMixing/Placing ma er a sma er a s

Corrosion inhibitorsCorrosion inhibitors

ur ng reg mesur ng reg mes


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Air EntraininAir entraining is the most importantAir entraining is the most important

aspec , nex o w cm, or en anceaspec , nex o w cm, or en ance

durability in concretedurability in concrete

Air entraining essential in freezingAir entraining essential in freezing


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Freezing and Thawing


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Air Entrainment

No air entrainment


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D-Crackin


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D-Crackin


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Concrete Scalin


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Good Deicer Rapid ice melting rateRapid ice melting rate

Minimal scalingMinimal scaling

crackingcracking

n ma me a corros on po en an ma me a corros on po en a


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Deicin or Anti-icin DeicingDeicing -- an effort to remove ice froman effort to remove ice from

sur aces a er ce ex s ssur aces a er ce ex s s

AntiAnti--icinicin -- a surface treatmenta surface treatment

applied prior to ice formation;applied prior to ice formation;

bond between ice and surfacebond between ice and surface


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Deicin Chemicals Chloride saltsChloride salts

Sodium chlorideSodium chloride -- NaClNaCl

Calcium chlorideCalcium chloride -- CaClCaCl22

Magnesium chlorideMagnesium chloride -- MgClMgCl22

Potassium chloridePotassium chloride -- KClKCl

Phosphate saltsPhosphate salts

ono so um p osp a eono so um p osp a e -- aa 22 44

Mono calcium phosphateMono calcium phosphate Ca(HCa(H22POPO44)H)H22OO

Mono potassium phosphateMono potassium phosphate -- KHKH22POPO44


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Deicin ChemicalsAcetatesAcetates

Calcium magnesium acetateCalcium magnesium acetate -- CMACMA

Potassium acetatePotassium acetate -- KCKC22HH33OO22

BenzeneBenzene

,,

Synthetic ureaSynthetic urea


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Deicin Chemicals Concentrations in concrete of 2Concentrations in concrete of 2 4 %4 %

cause mos amagecause mos amage

Lower percentages not as damagingLower percentages not as damaging

Higher percentages of some deicersHigher percentages of some deicers --

damagingdamaging ConversionConversion

--

equivalent to 0.5equivalent to 0.5 1.0 molality1.0 molality


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Scalin Mechanism

Water freezes in capillary poresWater freezes in capillary pores

ce crys a s ormce crys a s orm

Develop hydraulic pressuresDevelop hydraulic pressures

If available pore space is less thanIf available pore space is less than

required for all the water (criticalrequired for all the water (criticalsaturation), excess is driven off bysaturation), excess is driven off by

pressure of expansionpressure of expansion

If pressure exceed tensile strength ofIf pressure exceed tensile strength ofconcrete, local cracking occursconcrete, local cracking occurs


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Scalin Mechanism - Deicers

Concrete is further damaged by deicingConcrete is further damaged by deicing

Increase in the osmotic pressureIncrease in the osmotic pressure

Deicing agent magnifies the pressures inDeicing agent magnifies the pressures in

the concretethe concrete Increases the potential for surface scalingIncreases the potential for surface scaling

Deicer salt scaling generally thought to beDeicer salt scaling generally thought to be

physical rather than chemicalphysical rather than chemical


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Salt Scalin


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Deicin Rate


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Summar

Very low concentrationsVery low concentrations small effect onsmall effect on

Very high concentrationsVery high concentrations cause longcause long--

erm sca ngerm sca ng

ObjectiveObjective keep water and salt (chlorides)keep water and salt (chlorides)outout

Make concrete tighterMake concrete tighter

Low w/cm not the answerLow w/cm not the answer Add supplementary cementitious materialsAdd supplementary cementitious materials


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Summar

NaClNaCl -- least expensiveleast expensive

os amag ng o re n orc ng s eeos amag ng o re n orc ng s ee

CMACMA -- more expensivemore expensive Can chemically damage concreteCan chemically damage concrete

Does not induce corrosion of reinforcing steelDoes not induce corrosion of reinforcing steel

Use beet juice?Use beet juice?


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Water Reducers

w/cm concrete workablew/cm concrete workable

reduces the effectiveness of airreduces the effectiveness of air

entrainin a ents AEAentrainin a ents AEA Water reducers can cause slight increaseWater reducers can cause slight increase

Water reducers have no detrimentalWater reducers have no detrimental


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Su lemental Cementitious Materials

Fly ash (Type C)Fly ash (Type C)

Fly ash (Type F)Fly ash (Type F)

Silica fumeSilica fume Ground granulated blast furnace slagGround granulated blast furnace slag

(GGBFS)(GGBFS)

Natural pozzolansNatural pozzolansMetakaolin Calcined claMetakaolin Calcined cla

Calcined shaleCalcined shale


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Fly ash Class FMetakaolin

Silica fume

Metakaolin

SlagSlag

Fly ash - Class CFly ash - Class CCalcined shale


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, ,, ,

GGBFS)GGBFS)Adds a material that has cementingAdds a material that has cementing

ro ertiesro erties Reduces permeabilityReduces permeability

Fills the voids between cement particlesFills the voids between cement particles


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1,000X


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2,100X


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20,000X


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2,000X

C t P bilit


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Concrete Permeabilit

140

)

100

120

m/sec

x101

Maximum w/cm exposed to water

Maximum w/cm exposed

to freezin and thawin

80

m

eability(c

Maximum w/cm

exposed to deicing

40

cientofPer sa s, c em ca s,

salt water, seawater,

or salt spray

0

20

0.20 0.30 0.40 0.50 0.60 0.70 0.80

Coeffi

Water - Cementitious Ratio

P bilit M t


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Permeabilit Measurements

Two methods exist to assessTwo methods exist to assess

ASTM C 1202,ASTM C 1202, Electrical Indication ofElectrical Indication of

PenetrationPenetration -- Rapid Chloride PenetrationRapid Chloride Penetration

Test RCPTTest RCPTAASHTO T259,AASHTO T259, Resistance of Concrete toResistance of Concrete to

Chloride Ion PenetrationChloride Ion Penetration 9090--day pondingday ponding

testtest

R id Chl id P bilit T t


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Ra id Chloride Permeabilit Test

90 Da Pondin Test


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90 Da Pondin Test

Permeabilit Measurement


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Permeabilit Measurement

Chemical Attack


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Chemical Attack

CarbonationCarbonation

Acid attackAcid attack

Corrosion of embedded steelCorrosion of embedded steel

Carbonation


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Carbonation

Hardened concrete exposed to COHardened concrete exposed to CO22

COCO22

penetrates concrete and reactspenetrates concrete and reacts

with h droxideswith h droxides

Sulfate Attack


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Sulfate Attack

Sulfates in soil, usually, react with hydratedSulfates in soil, usually, react with hydrated

Chemical reactions cause internal pressureChemical reactions cause internal pressure srup s e cemen pas esrup s e cemen pas e

Internal compounds formedInternal compounds formed

r ng er ng e

GypsumGypsum

ruc e magnes um y rox eruc e magnes um y rox e

Thaumasite (forms in moist conditions)Thaumasite (forms in moist conditions)

Sulfate Attack


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Sulfate Attack

Sulfate Attack


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Sulfate Attack

Dela ed Ettrin ite Formation


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Dela ed Ettrin ite Formation

DEFDEF -- Deleterious formation of ettringiteDeleterious formation of ettringite

orm o su a e a acorm o su a e a ac

Ettringite is normal component of cementEttringite is normal component of cementhydrationhydration

Late formation causes expansion distressLate formation causes expansion distress Expansion causes crackingExpansion causes cracking prematurepremature

deteriorationdeterioration

Found in many precast productsFound in many precast products

Delayed Ettringite Formation


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y g

Ettringite is compoundEttringite is compound

that naturally formsthat naturally forms

when portland cementwhen portland cementse s upse s up

Formation delayed byFormation delayed by

high initialhigh initial

temperaturestemperatures

Requires moistureRequires moisture



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y g

Examples



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u u

microcrack

aggregate



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About 160 oF is critical



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Acid Attack


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Acid Attack

Some acids dissolve cement paste andSome acids dissolve cement paste and

Protection for portland cement concrete isProtection for portland cement concrete isno eas e w a m x uresno eas e w a m x ures

Need a protection system (coating/surfaceNeed a protection system (coating/surface

treatment)treatment)

ACI code does not cover externalACI code does not cover external

protection systemsprotection systems

Paste erosion by acid


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Corrosion of Embedded Steel


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ObjectiveObjective -- limit the ingress of chemicals thatlimit the ingress of chemicals that

Methodologies to limit corrosion by modifyingMethodologies to limit corrosion by modifying

Decrease diffusion rate into concreteDecrease diffusion rate into concrete

se c or e n or a m x uresse c or e n or a m x ures

Cathodic protectionCathodic protection

m na e crac ngm na e crac ng

Increase coverIncrease cover

Reduce the w/cm ratioReduce the w/cm ratio

rr i n f n l


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2+ -

Anode

Chloride and moisture ingress

Ch

2Fe(OH)2 +1/2O2 Fe2O3 + 2H2O

Fe2+ + 2OH- Fe(OH)2Fe3O4

Fe2O3

2OH- Fe3O42e -

Cathode area >> anode area

1/2O

2+ H

2O + 2e - 2OH-

Cathode

Diffusion


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Use supplemental cementitiousUse supplemental cementitious

ma er a sma er a s

Fly ashFly ash

Silica fumeSilica fume

GGBFSGGBFS

Natural pozzolans (Metakaolin)Natural pozzolans (Metakaolin)

Diffusion - Fl Ash


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Diffusion - SF & GGBSF


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Corrosion Inhibitor T es


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Calcium NitriteCalcium Nitrite

Organic Esters and aminesOrganic Esters and amines

AlkenlyAlkenly--succinic acidssuccinic acids

Corrosion Inhibitors


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Consequences of using inhibitorsConsequences of using inhibitors

Influence on freezin and thawinInfluence on freezin and thawin

resistanceresistance

Influence on inhibitin corrosionInfluence on inhibitin corrosion uncracked concreteuncracked concrete



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z w



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Corrosion and Chloride In ress


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Corrosion and Chloride In ress


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Crackin


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Cracking exists in reinforced concreteCracking exists in reinforced concrete

s ruc uress ruc ures

Crackin - Width


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ACI 318 Code


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ACI 318 Chapter 4ACI 318 Chapter 4 DurabilityDurability

equ remen sequ remen s

Exposure Categories and ClassesExposure Categories and Classes

Freezing and thawing (F)Freezing and thawing (F)

Sulfate (S)Sulfate (S)

Low permeability (P)Low permeability (P)

Corrosion rotection of steel reinforcin CCorrosion rotection of steel reinforcin C

Exposure Categories and Classes


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- z w Exposure category FExposure category F x er or concre ex er or concre e

Exposed to freezing and thawingExposed to freezing and thawing oss e exposure o e c ng c em ca soss e exposure o e c ng c em ca s

Four ClassesFour Classes

F0F0 Not exposed to freezing and thawing (fNot exposed to freezing and thawing (f--t)t)

F1F1 Occasionally exposed to moisture and fOccasionally exposed to moisture and f--tt

F2F2 Exposed to fExposed to f--t and continuous contact witht and continuous contact with

moisture before freezingmoisture before freezing

-- ont nuous contact w t mo sture,ont nuous contact w t mo sture, --t, ant, an

deicing chemicalsdeicing chemicals



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- u Exposure category SExposure category S

deleterious amounts of soluble sulfatedeleterious amounts of soluble sulfate

S0S0 Very low exposureVery low exposure

sulfate (moderate) [seawater]sulfate (moderate) [seawater]

sulfate (severe)sulfate (severe) S3S3 -- Structural member in contact with solubleStructural member in contact with soluble

sulfate : high sulfate content (very severe)sulfate : high sulfate content (very severe)



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- y Exposure category PExposure category P Concrete in contact with water where lowConcrete in contact with water where low

permeability is neededpermeability is needed

Two ClassesTwo Classes

P0P0 No s ecific ermeabilit neededNo s ecific ermeabilit needed

P1P1 Needed where water permeation intoNeeded where water permeation into

tank]tank]



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- Exposure category CExposure category C

and prestressing steel requiring protectionand prestressing steel requiring protection

Three ClassesThree Classes

C1C1 Exposed to moisture but no chloridesExposed to moisture but no chlorides

chlorides (deicing chemicals, brackish water,chlorides (deicing chemicals, brackish water,seawater, seawater spray) [parking decks,seawater, seawater spray) [parking decks,

bridge decks, piers]bridge decks, piers]

ACI 318 Re uirements


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Select concreteSelect concrete

exposure classexposure class

Cate or F

M i / 0 45M i / 0 45


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Maximum w/cm 4500 n ra ne a r con enn ra ne a r con en

or useor usesupplementalsupplemental

materialsmaterials

Cate or S

U lf t i t tU lf t i t t


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Use sulfate resistantUse sulfate resistant

Type IIType II

T e VT e V

Maximum w/cm ratioMaximum w/cm ratio

Minimum fMinimum f No chlorides allowedNo chlorides allowed

for S2 and S3for S2 and S3

Cate or P

Mi i l i tMi i l i t


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Minimal requirementsMinimal requirements

< 0.50< 0.50cc

Cate or C

Minim mMinim m ff > 5000 psi> 5000 psi


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MinimumMinimum ffcc> 5000 psi> 5000 psi

Maximum w/cm


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u u Low w/cm concrete effective in controllingLow w/cm concrete effective in controlling

Supplementary cementitious can reduceSupplementary cementitious can reducec or e ngress ra ec or e ngress ra e

Corrosion inhibitors can extend service lifeCorrosion inhibitors can extend service life

Heat curing below 160Heat curing below 160ooF can reduceF can reduce

ermeabilitermeabilit

Air entrainment necessary in freezingAir entrainment necessary in freezing


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External Protection Schemes

FHWA sponsored research 1992FHWA sponsored research 1992


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FHWA sponsored research 1992FHWA sponsored research 1992

ObjectiveObjective

Find costFind cost--effective coatin s or alternateeffective coatin s or alternate

materialsmaterials

Desi n life for infrastructure facilities: 75 toDesi n life for infrastructure facilities: 75 to100 years100 years

Corrosion of Reinforcin Bars


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Delaminations

lternate Reinforcin Bar T es

ASTM A 615 / A 706 blackASTM A 615 / A 706 black


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ASTM A 615 / A 706 blackASTM A 615 / A 706 black

poxy coa e arspoxy coa e ars

BendableBendable NonbendableNonbendable

Galvanized barsGalvanized bars

MetallicMetallic--clad barsclad bars

ZincZinc

CopperCopper

StainlessStainless

Metallic corrosion resistant bars (stainless)Metallic corrosion resistant bars (stainless)

Wettin and Dr in Re imes


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Effectiveness Rankin


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Zone Ma for Parkin Structures


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ACI 362 Precast


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Parkin Structure Desi n

Effective use of protective measuresEffective use of protective measures


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Good design measuresGood design measures

DrainageDrainageDetailing for crack controlDetailing for crack control

Proper coverProper cover

Proper finishingProper finishing

Proper curingProper curing




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Internal measuresInternal measures

Air entrainmentAir entrainmentCorrosion inhibitorsCorrosion inhibitors

Reduced permeabilityReduced permeability

Coated or special reinforcing barsCoated or special reinforcing bars




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External measuresExternal measures

SealersSealersProtective coatings (membranes)Protective coatings (membranes)

Traffic Bearin Membranes


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Summary Durable Concrete

u uAlternate reinforcing bar schemes canAlternate reinforcing bar schemes can


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gg

ex en serv ce eex en serv ce e

Need same type bar throughoutNeed same type bar throughout Epoxy coating effectiveEpoxy coating effective

Stainless for lon service life in crackedStainless for lon service life in cracked

concreteconcrete

in.)in.)


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Questions

donald meinheit durability presentation 3-3-10

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