QUALITY ASSURANCE & QUALITY ASSURANCE & TRANSPORTATION OF TRANSPORTATION OF CCP’sCCP’s

Dave Dave DiedrickDiedrickLafargeLafarge

May 2, 2008May 2, 2008

Our Goals:Our Goals:

Basics of Fly Ash as a Cementitious Basics of Fly Ash as a Cementitious MaterialMaterial

ClassificationClassificationQuality AssuranceQuality AssurancePerformancePerformanceMarkets & Transportation of Markets & Transportation of CCP’sCCP’s

Our Goals:Our Goals:

Basics of Fly Ash ProductionBasics of Fly Ash ProductionCoalCoalCombustionCombustionCollectionCollection

Where Does Fly Ash Come From?Where Does Fly Ash Come From?

Coal Pulverizer Boiler Precipitator Silo

•Type of coal•Fineness of pulverization

•Type of boiler

Factors that effect fly ash quality:

Coal CombustionCoal Combustion

Coal Coal –– stored chemical energystored chemical energyProcessing Processing –– pulverizingpulverizingCombustion Combustion –– release of energyrelease of energyCombustion byCombustion by--products products –– flue gases, flue gases, mineral residuemineral residue

Fly Ash CollectionFly Ash Collection

Electrostatic PrecipitatorsElectrostatic PrecipitatorsBaghouses Baghouses –– Fabric FiltersFabric FiltersHoppersHoppersStorage SilosStorage Silos

What is Fly Ash?What is Fly Ash?

Fly AshFly Ash

PozzolanPozzolan

Coal Combustion ProductCoal Combustion Product

Supplementary Cementitious MaterialSupplementary Cementitious Material

Mineral AdmixtureMineral Admixture

Finely Divided MaterialFinely Divided Material

Fly AshFly Ash

Finely divided residue Finely divided residue resulting from the burning of resulting from the burning of coal at coal fired power plants.coal at coal fired power plants.

Cement & Cementitious MaterialsCement & Cementitious Materials

Cement Cement –– ManufacturedManufactured

Slag Slag –– ByBy--product/Manufacturedproduct/Manufactured

Fly Ash Fly Ash –– ByBy--productproduct

Standards for Fly Ash in Standards for Fly Ash in ConcreteConcrete

ASTM C311ASTM C311Standard test method for sampling and testing fly Standard test method for sampling and testing fly ash or natural pozzolans for use as a mineral ash or natural pozzolans for use as a mineral admixture in Portland Cement Concreteadmixture in Portland Cement Concrete

ASTM C618ASTM C618Standard specification for coal fly ash and raw or Standard specification for coal fly ash and raw or calcined natural pozzolan for use as a mineral calcined natural pozzolan for use as a mineral admixture in concreteadmixture in concrete

ASTM C 618 ClassificationASTM C 618 Classification

Class FClass FASTM C 618 requires: ASTM C 618 requires: sum of SiOsum of SiO22 + Al+ Al22OO33 + FeO+ FeO33, min % = 70.0, min % = 70.0

Technically class F also meets class CTechnically class F also meets class C

Class CClass CASTM C 618 requires: ASTM C 618 requires: sum of SiOsum of SiO22 + Al+ Al22OO33 + FeO+ FeO33, min % = 50.0, min % = 50.0

Some consider class C if over 10% CaOSome consider class C if over 10% CaO

Class C Fly AshClass C Fly AshNormally produced from burning lignite Normally produced from burning lignite or subbituminous (western) coalor subbituminous (western) coalHigher calcium oxide content, lower Higher calcium oxide content, lower silicate contentsilicate contentNot only pozzolanic, but has Not only pozzolanic, but has cementitious properties as wellcementitious properties as wellLight grayish buff to buff in colorLight grayish buff to buff in colorHigher density (specific gravity) 2.5 to Higher density (specific gravity) 2.5 to 2.82.8

Class F Fly AshClass F Fly Ash

Normally produced from burning Normally produced from burning bituminous (eastern) coalbituminous (eastern) coalLower calcium oxide content, higher Lower calcium oxide content, higher silicate contentsilicate contentHas pozzolanic, but no cementitious Has pozzolanic, but no cementitious propertiespropertiesLight gray to dark gray in colorLight gray to dark gray in colorLower density (specific gravity) 2.2 to 2.5 Lower density (specific gravity) 2.2 to 2.5

PozzolanicPozzolanicFinely divided siliceous or siliceous and Finely divided siliceous or siliceous and aluminus material which by itself aluminus material which by itself posses little or no cementitious value. posses little or no cementitious value. However, in the presence of moisture, However, in the presence of moisture, it will chemically react with calcium it will chemically react with calcium hydroxide at ordinary temperatures to hydroxide at ordinary temperatures to form cementitious compounds. form cementitious compounds.

Cement + Water = CSH (Glue) + Cement + Water = CSH (Glue) + CaOHCaOHCaOHCaOH + Fly Ash = CSH+ Fly Ash = CSH

CementitiousCementitious

Finely divided material that in the Finely divided material that in the presence of water will harden and gain presence of water will harden and gain strength over time.strength over time.

Portland Class F Class C Class CCement Slag Fly Ash Fly Ash Fly Ash

SiO2 (silicon dioxide) 21.1 40.6 52.3 40.6 32.4Al2O3 (aluminum oxide) 4.8 11.8 20.4 18.7 17.8Fe2O3 (iron oxide) 2.2 1.4 7.2 6.4 6.1

CaO (calcium oxide) 63.8 38.6 3.4 16.9 25.6MgO (magnesium oxide) 4.2 4.6 0.98 4.2 4.9SO3 (sulfur trioxide) 2.9 0.2 0.92 2.7 3.2

Na2O (sodium oxide) 0.61 0.11 0.96 1.68 2.2K2O (potassium oxide) 0.14 0.08 2.11 0.33 0.41

Quality AssuranceQuality Assurance

No control over the burning of the coal No control over the burning of the coal or over the type of coal burnedor over the type of coal burnedCan be selective of fly ash used for Can be selective of fly ash used for concreteconcrete

Must meet ASTM C 618, State DOT, and Must meet ASTM C 618, State DOT, and applicable project specapplicable project specMust meet fly ash suppliers internal Must meet fly ash suppliers internal specificationsspecificationsMust be consistentMust be consistent

Sampling Fly AshSampling Fly Ash

Grab: Grab: a sample that is taken in a single a sample that is taken in a single operation from a conveyor delivering to bulk operation from a conveyor delivering to bulk storage, from bags or from a bulk shipmentstorage, from bags or from a bulk shipmentRegular: Regular: a sample that is constructed by a sample that is constructed by combining equal portions of grab samples that combining equal portions of grab samples that were taken at predetermined times or locations were taken at predetermined times or locations from any single lotfrom any single lotComposite: Composite: a sample that is constructed by a sample that is constructed by combining equal portions of grab or regular combining equal portions of grab or regular samplessamples

Minimum Sampling and Minimum Sampling and Testing FrequencyTesting Frequency

Daily or every 400 tons:Daily or every 400 tons:moisture content, LOI, fineness (retained on moisture content, LOI, fineness (retained on #325 sieve)#325 sieve)

Monthly or every 3200 tons (C 618 Monthly or every 3200 tons (C 618 Report):Report):

composite samplecomposite sampleSiOSiO22, Al, Al22OO33, FeO, FeO33, SO, SO33, moisture content, LOI, , moisture content, LOI, fineness, strength activity, water requirement, fineness, strength activity, water requirement, soundness (autoclave expansion) soundness (autoclave expansion)

Daily TestsDaily Tests

Moisture Content: percent of moisture Moisture Content: percent of moisture based on mass lost during drying at 105 based on mass lost during drying at 105 to 110to 110°° CCLoss On Ignition (LOI): percent of material Loss On Ignition (LOI): percent of material lost on ignition at 750 +/lost on ignition at 750 +/-- 5050°° C (using C (using material remaining from moisture content material remaining from moisture content determination)determination)Fineness: amount retained when wetFineness: amount retained when wet--sieved on a 45sieved on a 45--µµm (No. 325) sievem (No. 325) sieve

LOI (Loss on Ignition)LOI (Loss on Ignition)

Small sample of fly ash is ignited at 750 ± 50 Small sample of fly ash is ignited at 750 ± 50 degrees Cdegrees CThe loss in mass is expressed as a percentage The loss in mass is expressed as a percentage of the total initial massof the total initial massLOI is an indication of the carbon contentLOI is an indication of the carbon contentASTM C 618:ASTM C 618: 6.0% max6.0% max12% for class F based on acceptable service records 12% for class F based on acceptable service records

or lab testing (don’t recommend) *or lab testing (don’t recommend) *

FinenessFineness

Amount retained on #325 sieveAmount retained on #325 sieveAmount retained considered too coarse to Amount retained considered too coarse to reactreactASTM C 618:ASTM C 618: 34% maximum retained34% maximum retainedCoarser = Less ReactiveCoarser = Less Reactive

Foam IndexFoam Index

The Foam Index test is used as an The Foam Index test is used as an indicator of changes in the surface indicator of changes in the surface

area (adsorption capacity) of area (adsorption capacity) of carbon present in fly ash. These carbon present in fly ash. These changes may adversely affect the changes may adversely affect the entrained air content of concrete entrained air content of concrete

productsproducts

Foam Index Testing MethodFoam Index Testing Method

Set amount of cement, fly ash and water or fly Set amount of cement, fly ash and water or fly ash and water are introduced into a jar, capped ash and water are introduced into a jar, capped and shakenand shakenDiluted drops of AE admix are added in small Diluted drops of AE admix are added in small increments and shaken after each additionincrements and shaken after each additionDetermine how many drops are required to Determine how many drops are required to produce a stable foam on the surfaceproduce a stable foam on the surfaceThe number of drops is the foam indexThe number of drops is the foam index

Foam IndexFoam Index

Each ash source has a foam index Each ash source has a foam index baseline baseline LOI may not change but foam index could LOI may not change but foam index could fluctuatefluctuateConsistency is keyConsistency is key

Foam Index Over TimeFoam Index Over TimePleasant Prairie Unit 1 Foam Index versus time

0

5

10

15

20

25

30

35

40

12/24/07 01/13/08 02/02/08 02/22/08 03/13/08 04/02/08 04/22/08 05/12/08

Date

Foam

Inde

x in

Dro

ps

ASTM C 618, Table 1ASTM C 618, Table 1Chemical RequirementsChemical Requirements

F CS um of S iO 2, A l2O 3, andF e2O 3, m in , % 70 .0 50 .0

S O 3, m ax , % 5 .0 5 .0

M oistu re C on ten t, m ax , % 3 .0 3 .0

L O I, m ax , % 6 .0 6 .0

ASTM C 618, Table 2ASTM C 618, Table 2Physical RequirementsPhysical Requirements

F C

Fineness, max, % 34 34

Strength Activity Index, percent ofcontrolAt 7 days, min 75 75

At 28 days, min 75 75

Water Requirement, max 105 105

Soundness, Autoclave expansion or contraction, max, % 0.8 0.8

Uniformity requirements:

Density, max variation from average, % 5 5

Fineness, max variation percentage points from average 5 5

Strength Activity & Water Strength Activity & Water RequirementRequirement

Mortar cubes vs. cement controlMortar cubes vs. cement control20% fly ash by weight, equal flow20% fly ash by weight, equal flowwater requirement as a percent of the control water requirement as a percent of the control calculatedcalculated

ASTM C618ASTM C618Strength Activity, min. % of control: 75% of Strength Activity, min. % of control: 75% of control at 7 or 28 days (meeting 7 days satisfies control at 7 or 28 days (meeting 7 days satisfies C618)C618)Water Requirement, max. % of control:Water Requirement, max. % of control: 105105

Autoclave SoundnessAutoclave Soundness

Hardened paste bars subjected to 420F at Hardened paste bars subjected to 420F at 300psi300psiLow w/c ratio: 0.23Low w/c ratio: 0.23Measurement of expansion or contractionMeasurement of expansion or contractionExcessive expansion may result from free Excessive expansion may result from free lime, free magnesium or cement/fly ash lime, free magnesium or cement/fly ash incompatibilityincompatibility

Fly Ash Performance in ConcreteFly Ash Performance in Concrete

Strength Development Strength Development Air EntrainmentAir EntrainmentWater DemandWater DemandTime of SetTime of SetHeat of HydrationHeat of HydrationASR MitigationASR MitigationSulfate ResistanceSulfate Resistance

SummarySummary

Fly Ash is a coal combustion product that Fly Ash is a coal combustion product that has pozzolanic or pozzolanic/cementitious has pozzolanic or pozzolanic/cementitious properties that complement the properties properties that complement the properties of cement enhancing the durability and of cement enhancing the durability and performance of concreteperformance of concrete

SummarySummary

Consistency Consistency –– High quality fly ash is a High quality fly ash is a uniform material with consistent chemical uniform material with consistent chemical and physical propertiesand physical properties

Different fly ashes have different Different fly ashes have different properties: difficult to make general properties: difficult to make general statements about the properties of fly statements about the properties of fly ashesashes

CHALLENGE CHALLENGE -- Distributing the Distributing the Product to the MarketProduct to the Market

•• Once the material has been classified and Once the material has been classified and QA has been performed the key is to then QA has been performed the key is to then insure adequate supply to the marketinsure adequate supply to the market•• ConcreteConcrete•• NonNon--Traditional (nonTraditional (non--concrete)concrete)•• Raw FeedRaw Feed•• Etc Etc

Fly Ash Production vs. Sales Fly Ash Production vs. Sales Demand CurveDemand Curve

Demand

Production

DEC

TONS

SHORTAGE

EXCESS

JAN

ImplicationsImplicationsStorageStorageMarket development (Non Traditional, Exports)Market development (Non Traditional, Exports)StockoutsStockouts

TransportationTransportation

Fly ash application with Lafarge vane feeder

Ash Storage OperationsAsh Storage Operations

Traditional Silo Storage

Questions?Questions?