MINERAL ADMIXTURES

IN CONCRETE

by

Dr J D BAPAT

Seminar on Admixtures in Concrete

28 June 2011

Institution of Engineers, Shivajinagar

Pune, Maharashtra, India

FOREWORD

� THIS PRESENTATION GIVES BRIEF VIEW

ON SOME MINERAL ADMIXTURES TO

OBTAIN MORE WORKABLE & DURABLE

CONCRETE

� APPROVED BY IS 456: 2000 BUT NOT

COMMONLY USED

DURABLE CONCRETE

� DURABLE CONCRETE MEANS CONCRETE WITHFEWER MICRO-CRACKS (10-100 µm)

� MICRO-CRACKS IN CONCRETE ALLOW INGRESS OFEXTERNAL DETERIORATING AGENTS: WATER,EXTERNAL DETERIORATING AGENTS: WATER,CARBON DIOXIDE, CHLORIDES, SULPHATES & SOON, LEADING TO DETERIORATION, DISTRESS ANDDESTRUCTION OF STRUCTURE

� MICRO-CRACKS IN CONCRETE CAN BE REDUCEDUSING POZZOLANIC OR CEMENTITIOUSMATERIALS, COLLECTIVELY CALLED MINERALADMIXTURES, TO REPLACE CEMENT IN CONCRETE.

MINERAL ADMIXTURES

THE TERM INCLUDES ALL SILICEOUS &ALUMINOUS MATERIALS, WHICH IN FINELYDIVIDED FORM AND IN PRESENCE OF WATERCHEMICALLY REACT WITH CALCIUMHYDROXIDE GENERATED DURING CEMENTHYDRATION TO FORM ADDITIONALCOMPOUNDS POSSESSING CEMENTITIOUSCOMPOUNDS POSSESSING CEMENTITIOUSPROPERTIES

THEY MAY BE NATURALLY OCCURRINGMATERIALS, INDUSTRIAL, AGRICULTURALWASTES OR BYPRODUCTS OR THE ONESREQUIRING LESS ENERGY TOMANUFACTURE

MINERAL ADMIXURES MINERAL ADMIXURES PERMITTED BY IS 456: 2000PERMITTED BY IS 456: 2000�� FLYFLY ASHASH OROR PULVERISEDPULVERISED FUELFUEL ASHASH (IS(IS 38123812,, GRADEGRADE I)I)

�� GGBSGGBS OROR GROUNDGROUND GRANULATEDGRANULATED BLASTBLAST FURNACEFURNACE SLAGSLAG(IS(IS 1208912089))

�� SFSF OROR SILICASILICA FUMEFUME (IS(IS 1538815388:: 20032003))�� SFSF OROR SILICASILICA FUMEFUME (IS(IS 1538815388:: 20032003))

�� METAKAOLIN (MK)METAKAOLIN (MK)

�� RICE HUSK ASH (RHA)RICE HUSK ASH (RHA)

�� CARRY SUFFICIENT LAB TESTS WHEN THERE IS NO CARRY SUFFICIENT LAB TESTS WHEN THERE IS NO STANDARDSTANDARD

SILICA FUME (SF)SILICA FUME (SF)

SILICA FUME (SF)

� BYPRODUCT OF SMELTING PROCESS

IN PRODUCTION OF SILICON METAL &

FERROSILICON ALLOYS

MOSTLY COMPOSED OF SUBMICRON� MOSTLY COMPOSED OF SUBMICRON

PARTICLES OF AMORPHOUS SILICON

DIOXIDE (SiO2).

� POZZOLANIC

COMMERCIAL SF

�UNDENSIFIED SF (BULK DENSITY 350 kg/m3 ):

�AVAILABLE IN BULK/BAGS NEARSMELTERS (.) MAINLY USED INSMELTERS (.) MAINLY USED INMAKING PRE-BAGGED PRODUCTS:GROUTS OR REPAIR MORTARS

� INCONVENIENT TO HANDLE: DUSTY,SELF-AGGLOMERATING & DIFFICULTTO TRANSPORT

COMMERCIAL SF

� DENSIFIED SF (480-720 kg/m3):

� PARTICLES LOOK LIKE SMALL BEADS, FLOW LIKEWATER & PRODUCE VERY LITTLE DUST

� CAN BE SHIPPED IN BULK IN PNEUMATIC TRUCKS,JUMBO BAGS, IN SMALL (USUALLY 25 kg) PAPERBAGS

� HIGH BULK DENSITY REDUCES COST OFTRANSPORTATION

COMMERCIAL SF

� PELLETISED (10-25 mm) SF (about 1000

kg/m3 ):

� NOT SUITABLE FOR DIRECT USE IN� NOT SUITABLE FOR DIRECT USE IN

CONCRETE, AS THE HARD PALLETS DO

NOT BREAK AND DISPERSE IN A CONCRETE

MIXER (.) CAN BE INTERGROUND WITH

PORTLAND CEMENT CLINKER TO PRODUCE

BLENDED SF CEMENT

PHYSICAL CHARACTERISTICSPHYSICAL CHARACTERISTICS

•• IT IS AMORPHOUS SILICA (85IT IS AMORPHOUS SILICA (85--98%) & GLASSY. ALSO DECIDES QUALITY98%) & GLASSY. ALSO DECIDES QUALITY

•• SPHERICALSPHERICAL PARTICLESPARTICLES WITHWITH AVERAGEAVERAGE 00..0202--00..2525 MICRONMICRON DIAMETER,DIAMETER,NEARLYNEARLY 100100 TIMESTIMES SMALLERSMALLER THANTHAN CEMENTCEMENT PARTICLEPARTICLE..

•• AS A RESULT OF AGGLOMERATION, ACTUAL SIZE: 1AS A RESULT OF AGGLOMERATION, ACTUAL SIZE: 1--50 MICRON50 MICRON

•• TOTO MAKEMAKE ULTRAULTRA--HIGHHIGH STRENGTHSTRENGTH CONCRETE,CONCRETE, ULTRASONICULTRASONICDISPERSIVITYDISPERSIVITY SHOULDSHOULD BEBE MEASUREDMEASURED && ACCEPTEDACCEPTED WHENWHEN PARTICLEPARTICLESIZESIZE << 11 MICRONMICRON OBTAINEDOBTAINED

•• WELLWELL DISPERSED,DISPERSED, SUPERFINESUPERFINE SFSF PARTICLESPARTICLES ACTACT ASAS FILLERFILLER ((..)) FILLFILLVOIDVOID SPACESPACE BETWEENBETWEEN THETHE IRREGULARIRREGULAR SHAPEDSHAPED CEMENTCEMENT PARTICLESPARTICLESTOTO BRINGBRING ININ REFINEMENTREFINEMENT OFOF THETHE POREPORE STRUCTURESTRUCTURE ININ HARDENEDHARDENEDCONCRETECONCRETE..

•• DENSIFIED SF SOMETIMES DIFFICULT TO DISPERSE DENSIFIED SF SOMETIMES DIFFICULT TO DISPERSE

•• REFERREFER USERUSER MANUALMANUAL BYBY USUS FederalFederal HighwayHighway AdministrationAdministration andand SilicaSilicaFumeFume AssociationAssociation

SF QUALITYSF QUALITY

•• SILICA (> 85%)SILICA (> 85%)

•• CARBONCARBON CONTENTCONTENT OROR LOSSLOSS ONONIGNITIONIGNITION (<(< 44 –– 66%%))

•• CONTENTCONTENT OFOF CRYSTALLINECRYSTALLINE &&•• CONTENTCONTENT OFOF CRYSTALLINECRYSTALLINE &&AMORPHOUSAMORPHOUS SILICASILICA

•• SPECIFIC SURFACE AREA (> 15 m2/g)SPECIFIC SURFACE AREA (> 15 m2/g)

•• POZZOLANICITYPOZZOLANICITY OROR POZZOLANICPOZZOLANICACTIVITYACTIVITY (ASTM(ASTM 100100 –– 105105%%))

SF IN CONCRETESF IN CONCRETE

�� FRESH: FRESH:

�� LOWERLOWER DENSITYDENSITY ((22..22<<33..22)) INCREASESINCREASES

PASTEPASTE VOLUMEVOLUME && MAYMAY SHRINKSHRINK MOREMORE ((..))

HIGHERHIGHER SURFACESURFACE AREAAREA ((11..55 –– 300000300000HIGHERHIGHER SURFACESURFACE AREAAREA ((11..55 –– 300000300000

cmcm22/g)/g) LEADSLEADS TOTO HIGHHIGH WATERWATER DEMANDDEMAND

&& AEA(AEA(..)) USEUSE HRWRAHRWRA FORFOR STRENGTHSTRENGTH &&

DURABILITYDURABILITY

�� CONSTRUCTIONCONSTRUCTION WORKERWORKER REQUIRESREQUIRES

TRAININGTRAINING

SF IN CONCRETESF IN CONCRETE

�� HARDENEND: HARDENEND:

�� IMPROVESIMPROVES DURABILITYDURABILITY && STRENGTHSTRENGTHDUEDUE TOTO INCREASEINCREASE ININ CC––SS––HH WITHWITHDUEDUE TOTO INCREASEINCREASE ININ CC––SS––HH WITHWITHLOWERLOWER CaO/SiOCaO/SiO22 RATIO,RATIO, (B)(B)REDUCTIONREDUCTION ININ pHpH VALUEVALUE && (C)(C)DILUTIONDILUTION EFFECTEFFECT ONON CC33AA

�� REDUCED PERMEABILITY REDUCED PERMEABILITY

SF ADDITION TO CEMENTSF ADDITION TO CEMENT

�� SFSF BLENEDBLENED CEMENTCEMENT NOTNOT COMMONYCOMMONY USEDUSED

�� MOSTLYMOSTLY ADDEDADDED TOTO CONCRETECONCRETE ASAS AACONSTITUENTCONSTITUENT MATERIAL,MATERIAL, ININ ADDITIONADDITION TOTOCEMENTCEMENT

�� RESULTSRESULTS ININ LARGERLARGER DOSEDOSE OFOF�� RESULTSRESULTS ININ LARGERLARGER DOSEDOSE OFOFSUPERPLASTICISERSUPERPLASTICISER ASAS WELLWELL ASAS THETHE AIRAIRENTRAININGENTRAINING AGENTAGENT TOTO CONCRETECONCRETE..

�� NEEDSNEEDS TOTO BEBE ADEQUATELYADEQUATELY JUSTIFIEDJUSTIFIED ONONCONSIDERATIONSCONSIDERATIONS OFOF COSTCOST VISVIS--AA--VISVISSTRENGTHSTRENGTH && DURABILITYDURABILITY

�� NORMALLYNORMALLY 33--1010%% SFSF ISIS ADDEDADDED TOTO HIGHHIGHPERFORMANCEPERFORMANCE CONCRETECONCRETE..

SF STANDARD SPECS

INDIAN STANDARD: IS 15388: 2003

EUROPEAN: EN 13263: 2005

AMERICAN STANDARD:

ASTM C1240

METAKAOLIN (MK)METAKAOLIN (MK)

METAKAOLIN (MK)

� HIGH REACTIVITY METAKAOLIN ORMETAKAOLIN (MK) IS AN ENGINEERED,HIGH STRENGTH, POZZOLANICMATERIALMATERIAL

� MANUFACTURED BY CALCINATION OFNATURALLY OCCURING KAOLIN CLAY

� IT IS AN AMORPHOUS ALUMINO-SILICATE (AL2O3.2SiO2)

KAOLIN DEPOSITS: INDIA

� TOTAL ESTIMATED: 2596 MILLION

TONNES

� DISTRIBUTED IN ALMOST EVERY

STATE IN REASONABLE QUANTITYSTATE IN REASONABLE QUANTITY

� MAJOR: KERALA (24%), RAJ (14%),

ORISSA (16%), KARNATAKA (10%)

COMMERCIAL MKCOMMERCIAL MK

�� AVAILABLE IN TWO FORMS:AVAILABLE IN TWO FORMS:

�� CLINKERCLINKER:: SIZESIZE 1919 –– 2525 mmmm ((..)) GOODGOODHANDLINGHANDLING ABILITYABILITY ANDAND RESISTANCERESISTANCE TOTODETERIORATIONDETERIORATION ((..)) CANCAN BEBE SHIPPEDSHIPPED ININBULKBULK && IDEALIDEAL FORFOR INTERGRINDINGINTERGRINDING WITHWITHBULKBULK && IDEALIDEAL FORFOR INTERGRINDINGINTERGRINDING WITHWITHPORTLANDPORTLAND CEMENTCEMENT CLINKERCLINKER FORFOR THETHEPRODUCTIONPRODUCTION OFOF BLENDEDBLENDED CEMENTCEMENT ((..))

�� POWDERPOWDER:: PRODUCEDPRODUCED BYBY FINEFINE GRINDINGGRINDINGCLINKERCLINKER ((99..55 -- 1818 mm22/g,/g, NITROGENNITROGENADSORPTION)ADSORPTION) && SOLDSOLD ININ PACKAGES,PACKAGES, BIGBIGSACKSSACKS OROR ININ BULKBULK..

MK FROM WASTE PAPER SLUDGEMK FROM WASTE PAPER SLUDGE

��HRMHRM PRODUCED,PRODUCED, CALCININGCALCINING WASTEWASTEPAPERPAPER SLUDGESLUDGE WHICHWHICH CONTAINSCONTAINSKAOLINKAOLIN ATAT 650650 –– 750750 00CC

��EFFECTIVEEFFECTIVE UTILISATIONUTILISATION OFOF WASTEWASTEPAPERPAPER SLUDGESLUDGE

POWDER MK

� OFF-WHITE COLOR

� SPECIFIC GRAVITY 2.5 - 2.6 & BULKDENSITY 0.3 – 0.4 t/m3

� SURFACE AREA RANGE: 9.5 - 18 m2/g(NITROGEN ADSORPTION) & AVERAGEPARTICLE SIZE: 1 – 9.5 micron

� ATTRACTIVE IN COLOR MATCHING ANDOTHER ARCHITECTURAL APPLICATIONS

STRENGTH & DURABILITY WITH MKSTRENGTH & DURABILITY WITH MK

�� ENHANCEMENT DUE TO:ENHANCEMENT DUE TO:

�� FILLERFILLER EFFECTEFFECT:: IMMEDIATEIMMEDIATE

�� ACCELERATIONACCELERATION OFOF CEMCEM HYDRATIONHYDRATION::FIRSTFIRST 2424 hh ((..)) TEMPTEMP INCREASEINCREASEFIRSTFIRST 2424 hh ((..)) TEMPTEMP INCREASEINCREASE

�� POZZOLANIC REACTION: 7 POZZOLANIC REACTION: 7 -- 14 DAYS 14 DAYS

�� 1010 --2525%% CEMENTCEMENT REPLACEMENTREPLACEMENT FORFORIMPROVEDIMPROVED STRENGTHSTRENGTH && DURABILITYDURABILITY

MK STANDARD SPECSMK STANDARD SPECS

�� INDIAN:INDIAN:

�� INDIAN STANDARD ON MK BEING INDIAN STANDARD ON MK BEING DRAFTEDDRAFTED

�� AMERICAN:AMERICAN:�� AMERICAN:AMERICAN:

�� ASTM C618: ASTM C618:

STANDARDSTANDARD SPECIFICATIONSPECIFICATION FORFOR COALCOALFLYFLY ASHASH ANDAND RAWRAW OROR CALCINEDCALCINEDNATURALNATURAL POZZOLANPOZZOLAN FORFOR USEUSE ININCONCRETECONCRETE

RICE HUSK ASH (RHA)RICE HUSK ASH (RHA)RICE HUSK ASH (RHA)RICE HUSK ASH (RHA)

RICE HUSK ASH (RHA)RICE HUSK ASH (RHA)

�� POZZOLANICPOZZOLANIC ADMIXTUREADMIXTURE OBTAINEDOBTAINED FROMFROMCOMBUSTIONCOMBUSTION OFOF RICERICE HUSKHUSK (RH)(RH) UNDERUNDERCONTROLEDCONTROLED TEMPERATURETEMPERATURE && RESIDENCERESIDENCETIMETIME && SUBSEQUENTSUBSEQUENT SIZESIZE REDUCTIONREDUCTION

�� LOWLOW UNBURNEDUNBURNED CC && SILICASILICA MOSTLYMOSTLYAMORPHOUSAMORPHOUS ((8787 –– 9494%%))

�� SPECIFICSPECIFIC GRAVITYGRAVITY:: 22..1515 –– 22..1616 && BULKBULKDENSITYDENSITY:: 00..44 –– 00..55 ((..)) SURFACESURFACE AREAAREA:: 2020 -- 4040mm22/g/g (BET),(BET), COMPARABLECOMPARABLE WITHWITH SFSF

SUSTAINABILITY OF RHA

� ABUNDANT AVAILABILITY OF RH IN RICEPRODUCING COUNTRIES

� HUGE SCOPE TO RECOVER HEAT VALUETO GENERATE POWER & TO USE RHAPRODUCED IN CEMENT & CONCRETEPRODUCED IN CEMENT & CONCRETE

� WORLD PADDY BY 2030: 847 – 915 MTPA

� ASIA BY 2030:� PADDY: AROUND 600 – 774 MTPA

� RH: AROUND 120 – 155 MTPA

� RHA: 24 – 31 MTPA

RHA FOR CEMENTRHA FOR CEMENT

��CEMENT REPLACEMENT UP TO 30%CEMENT REPLACEMENT UP TO 30%

��TO SATISFY ASTM C618, CLASS N:TO SATISFY ASTM C618, CLASS N:

��RETENTION 45 MICRON < 34%RETENTION 45 MICRON < 34%

��MOISTURE < 3%MOISTURE < 3%��MOISTURE < 3%MOISTURE < 3%

��LOI < 10%LOI < 10%

��STRENGTH ACTIVITY (CEMENT) > 75%STRENGTH ACTIVITY (CEMENT) > 75%

��SiO2 + Al2O3 + Fe2O3 > 70% SiO2 + Al2O3 + Fe2O3 > 70%

ADDING ADMIXTURES TO CONCRETE

� IS 456: 2000, CLAUSE 5.2.1 ON POZZOLANSMENTIONS:

� POZZOLANIC MATERIALS CONFORMING TORELEVANT INDIAN STANDARDS .. PERMISSION OFENGINEER-IN-CHARGE, PROVIDED UNIFORMENGINEER-IN-CHARGE, PROVIDED UNIFORMBLENDING WITH CEMENT IS ENSURED

� DRY BLENDING REQUIRES SPECIAL CARE DUEDIFFERENCE IN DENSITY AND PARTICLE SIZE

� WHEN INDIAN STANDARD NOT AVAILABLE, OTHERINTERNATIONAL STANDARDS WITH PERMISSION OFENGINEER-IN-CHARGE (. ) CONDUCT LAB TESTS

PERFORMANCE28 DAY COMPRESSIVE (MPA)

43 G

OPC

10% FA

3980

BLAINE

10% SF

19 m2/g

10% MK

14 m2/g

10%

RHA <

45

micron

36 35 40 40 41

COST COMPARISON

CEMENT MK RHA SFCEMENT MK RHA SF

1.0 1- 1.5 1 - 2 4.0

• Thanks!!