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NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
NEW BLENDED CEMENTS
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NEW BLENDED CEMENTS

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In India, majority of cement produced is of blended variety, with fly ash and blast furnace slag as the mineral admixtures used for blending. Blended cements production reduces clinker production …

In India, majority of cement produced is of blended variety, with fly ash and blast furnace slag as the mineral admixtures used for blending. Blended cements production reduces clinker production thereby leading to conservation of natural resources and energy and also substantial reduction in the CO2 generation, which is a green house gas. The production of blended cements also leads to utilization of two major industrial wastes, coming from thermal power stations and the integrated steel plants. The application of blended cement in concrete imparts better strength and durability properties to the structure. Keeping these aspects in mind, the presentation illustrates the characteristics of two varieties of blended cements, new to Indian cement industry, namely Portland Limestone Cement (PLC) and Portland High Volume fly Ash Cement (PHFC).

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  • 1. NEW BLENDED CEMENTS by Dr J D BAPAT www.drjdbapat.com INDIAN CEMENT REVIEW CONFERENCE 2014 on SUSTAINABILITY IN INDIAN CEMENT INDUSTRY 6 JUNE 2014, MUMBAI
  • 2. NEW BLENDED CEMENTS PRINCIPAL DEVELOPMENT GOALS  REDUCING CARBON (GHG) EMISSION THROUGH CLINKER SUBSTITUTION  REDUCING ENERGY CONSUMPTION  INCREASED PRODUCTION CAPACITY REDUCING SOLID WASTE  MAINTAINING QUALITY : STRENGTH & DURABILITY
  • 3. NEW BLENDED CEMENTS IS 456 – 2000 PROVISIONS ADMIXTURES PERMITTED BY INDIAN STANDARD CODE FOR PLAIN AND REINFORCED CONCRETE i.e. IS 456 – 2000  FLY ASH (15-35% )  BLAST FURNACE SLAG OR GGBS (25-70%)  SILICA FUME (3-10%)*  RICE HUSK ASH (25-30%)*  METAKAOLIN (10-25%)* * Recommended as per common practice
  • 4. NEW BLENDED CEMENTS  PORTLAND LIMESTONE CEMENT (PLC)  PORTLAND HIGH VOLUME FLY ASH CEMENT (PHFC)
  • 5. PORTLAND LIMESTONE CEMENT PLC
  • 6. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) INDIAN & INTERNATIONAL STANDARDS  INDIAN STANDARD IS 269 - 2013: PERMITS ADDITION OF LIMESTONE UPTO 5%, AS PERFORMANCE IMPROVER, IN OPC  EUROPEAN STANDARD EN 197-1 (2000):  5% LS ADDITION PERMITTED IN ALL 27 APPROVED TYPES, AS MINOR ADDITIONAL CONSTITUENT (MAC)  OUT OF THAT, 4 ARE PORTLAND LIMESTONE CEMENT, PERMITTING HIGHER ADDITIONS OF LS, IN ADDITION TO 5% MAC AS ABOVE  CEM II/A-L & CEM II/A-LL: 6 TO 20% & CEM II/B-L & CEM II/B-LL: 21-35%  US STANDARDS:  ASTM C150: 5% LS ADDITION PERMITTED IN TYPES I TO V  ASTM C595 & AASHTO M240: 5-15% LS ADDITION PERMITTED IN TYPE IL & IT CANADIAN STANDARD CSA A3001:  5% LS ADDITION PERMITTED IN PORTLAND CEMENT  6 - 15% LS ADDITION PERMITTED PORTLAND LIMESTONE CEMENT
  • 7. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) SIGNIFICANCE OF 15% LIMIT Matschei et al. 2007
  • 8. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) HOW LIMESTONE WORKS PARTICLE PACKING – IMPROVED PARTICLE SIZE DISTRIBUTION
  • 9. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) HOW LIMESTONE WORKS PROVIDES NUCLEATION SURFACES FOR PRECIPITATION OF HYDRATED CEMENT
  • 10. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) HOW LIMESTONE WORKS LS REACTS WITH ALUMINATES IN CEMENT TO FORM CARBOALUMINATES
  • 11. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) LIMESTONE REQUIREMENTS: EN STANDARDS  CALCIUM CARBONATE > 75%  TOTAL ORGANIC CARBON (TOC): MAX 0.5%  CLAY: MAX 1.2 g/100g
  • 12. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) PRODUCTION OF PLC  METERED PROPORTION OF CRUSHED, DRIED LS FED TO FINISH GRINDING MILL ALONG, WITH CLINKER & GYPSUM  LS IS MORE EASILY GROUND THAN CLINKER (HARDER) & GETS CONCENTRATED IN FINE PARTICLES  OVERALL FINENESS MUST BE HIGHER, FOR EQUIVALENT PERF (.) TO HAVE FINENESS OF THE CLINKER FRACTION TO BE SIMILAR TO OPC:  PRODUCTION RATE IS SLOWED  SOME ADDITIONAL GRINDING ENERGY REQUIRED BUT IS MORE THAN OFFSET BY LOWER CLINKER CONTENT & RELATED KILN FUEL SAVINGS  PARTICLE SIZE DISTRIBUTION IS ENHANCED  HYDRATION IS ENHANCED BY BOTH PHYSICAL AND CHEMICAL INTERACTION  SUSTAINABILITY BENEFITS SIGNIFICANT: REDUCED ASSOCIATED CARBON EMISSIONS & EMBODIED ENERGY (LESS CLINKER)
  • 13. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) PRODUCTION PLC INTER-GRINDING WITH CLINKER GRINDING ENERGY CONSUMPTION DECREASES WITH LS REPLACEMENT Opoczky, L., 1992
  • 14. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) FRESH CONCRETE WITH PLC  WATER DEMAND & WORKABILITY RELATED TO PARTICLE SIZE DISTRIBUTION OF LS IN RELATION TO CEMENT  GENERALLY INCREASED WATER IS NEEDED TO MAINTAIN CONSISTENCY OF CEMENT PASTES AS LS CONTENT INCREASES FINE LS PARTICLES ENHANCE OVERALL PARTICLE PACKING OF BINDER MATERIALS RESULTING IN LESS SPACE FOR WATER BETWEEN SOLID GRAINS DECREASING AVERAGE PARTICLE SIZE OF LS GIVES BETTER EARLY-AGE RHEOLOGICAL PROPERTIES
  • 15. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) FRESH CONCRETE WITH PLC REDUCED BLEEDING Specific Surface Area m2/kg Building Research Establishment , 1993
  • 16. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) FRESH CONCRETE WITH PLC HYDRATION  AS LIMESTONE ACTS AS NUCLEATION SITES FOR HYDRATION PRODUCTS ITS INCLUSION INCREASES RATE OF HYDRATION  LIMESTONE ADDITIONS GIVE EARLIER PEAK FOR HEAT OF HYDRATION
  • 17. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) MECHANICAL PROPERTIES: CONCRETE WITH PLC  LS UP TO 5% INCREASES EARLY-AGE STRENGTH DUE TO: IMPROVED PARTICLE PACKING , INCREASED RATE OF CEMENT HYDRATION & EARLY PRODUCTION OF CALCIUM CARBOALUMINATE (.) APPLIES TO BOTH INTER-GROUND & BLENDED PLC  HIGHER REPLACEMENTS: LOSS OF STRENGTH DUE TO DILUTION MUST BE COMPENSATED BY FINER GRINDING (.) VOGLIS ET AL (2005): SHOWED COMPARABLE STRENGTHS FOR PC & PLC WITH 15% LS, WHEN PLC WAS GROUND TO 511 m2/kg COMPARED WITH 303 m2/kg FOR PC  TSIVILIS ET AL (1999): APPROPRIATE CHOICE OF CLINKER QUALITY, LS QUALITY, % LS CONTENT & CEMENT FINENESS CAN LEAD TO PRODUCTION OF PLC WITH DESIRED PROPERTIES, AT LEAST FOR CEMENTS WITH UP TO 15% LS  TENSILE, FLEXURAL STRENGTH & MODULUS OF ELASTICITY: STANDARD EQUATIONS APPLICABLE (.) SHRINKAGE SAME BUT CREEP INCREASES
  • 18. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) DURABILITY OF CONCRETE WITH PLC CONCRETE PERMEABILITY Matthews, J.D. 1994.
  • 19. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) DURABILITY OF CONCRETE WITH PLC CHLORIDE DIFFUSION COEFFICIENT Dhir, R.K., et.al. 2007.
  • 20. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) DURABILITY OF CONCRETE WITH PLC CARBONATION Dhir, R.K., et.al. 2007
  • 21. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) DURABILITY OF CONCRETE WITH PLC CARBONATION  IN REFERENCE TO HYDRATED PLC, STRENGTH OF PLC AFTER ACCELERATED CARBONATION WAS 79% HIGHER AT 28 D, EVEN THOUGH ULTIMATE LS CONTENT IN CARBONATED PLC WAS OVER 40%  CALCIUM CARBONATES PRODUCED BY ACCELERATED CARBONATION GETS IMBEDDED IN C-S-H, FORMING INTERMINGLED MICROSTRUCTURE  HIGH CARBONATION REACTIVITY OF PLC ATTRIBUTED TO FINE PARTICLE SIZE & EXISTENCE OF LS POWDER NUCLEI FOR CALCIUM CARBONATE PRECIPITATION  USE OF PLC IN ACCELERATED CARBONATION OF CONCRETE PRODUCTS CAN SIGNIFICANTLY CONTRIBUTE TO A NET GAIN IN STRENGTH & CARBON EMISSION REDUCTION Ref: Shao Y., et. al. 2014
  • 22. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) DURABILITY OF CONCRETE WITH PLC SULPHATE RESISTANCE  STANDARDS DO NOT RECOMMEND USE OF PLC IN SULPHATE ENVIRONMENT  AT NORMAL TEMPERATURE, SULPHATE RESISTANCE OF PLC IS SUBSTANTIALLY IMPROVED WHEN 30-50% SLAG IS ADDED & LS REPLACEMENT OF 5-15% ARE ALLOWABLE  SIMILARLY AT 5 C ALSO, SULPHATE RESISTANCE IS SUBSTANTIALLY IMPROVED WITH THE ADDITION OF SLAG Ref: Ramezanianpour A. M., 2012
  • 23. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) DURABILITY OF CONCRETE WITH PLC OTHER DURABILITY PARAMETERS  SALT SCALING & FREEZE-THAW: LIMITED DATA AVAILABLE FOR AIR- ENTRAINED CONCRETE SHOW THAT FREEZE-THAW & SALT SCALING RESISTANCE OF PLC CONCRETE IS COMPARABLE TO THAT OF EQUIVALENT PC CONCRETE  ABRASION RESISTANCE: CONCRETES OF IDENTICAL 28-DAY STRENGTH HAVE SIMILAR ABRASION RESISTANCE, IRRESPECTIVE OF LS CONTENT OF CEMENT
  • 24. NEW BLENDED CEMENTS PORTLAND LIMESTONE CEMENT (PLC) SUMMARY  LS CEMENTS HAVE BEEN USED IN MANY COUNTRIES SINCE THE 1960’S & EU CEM II/A 6 TO 20% LIMESTONE CEMENTS ARE THE LARGEST SINGLE TYPE OF CEMENT CURRENTLY PRODUCED IN EUROPEAN COUNTRIES  LS FINENESS & PARTICLE SIZE DISTRIBUTION ARE KEY PARAMETRS ADVANTAGES:  PLC RESULTS IN REDUCED GHG EMISSIONS  WHEN PROPERLY OPTIMISED, PLC CONCRETE HAS FRESH PROPERTIES, BLEEDING & STRENGTH SIMILAR TO OPC CONCRETE REDUCED PERMEABILITY  SIMILAR CHLORIDE DURABILITY UP TO 15% REPLACEMENT  SIMILAR CARBONATION RATE UP TO 15% REPLACEMENT, AT LOW W/C RATIO  SUBSTANTIALLY IMPROVED SULPHATE RESISTANCE, WHEN PLC UP TO 15% LS, IS BLENDED WITH SLAG WITH 50% REPLACEMENT DISADVANTAGE:  PERFORMANCE IS AFFECTED BY (A) QUALITY OF LS, (B) WHETHER INTERGROUND OR BLENDED & (C) PARTICLE SIZE DISTRIBUTION
  • 25. PORTLAND HIGH VOLUME FLY ASH CEMENT PHFC
  • 26. NEW BLENDED CEMENTS PORTLAND HIGH VOLUME FLY ASH CEMENT (PHFC) PHFC REFERS TO BLENDED CEMENT PRODUCED IN CEMENT PLANT, WITH FA REPLACEMENT CEMENT >55% AT PRESENT HIGH VOLUMES OF FA (>55%) ARE ADDED AS REPLACEMENT OF CEMENT, AT RMC PLANTS, TO PRODUCE HIGH VOLUME FLY ASH CONCRETE (HVFAC) (.) IT NECESSITATES ADDITIONAL STORAGE SILOS & QUALITY CONTROL AT JOB SITE PHFC IS ONE OPTION, INCREASING AMOUNT OF FA THAT CAN REPLACE PORTLAND CEMENT (PC) FROM <20% IN CONVENTIONAL MIXES UP TO AS HIGH AS 55% PHFC CAN BE PRODUCED EITHER BY INTER-GRINDING FA WITH PC CLINKER & GYPSUM OR BY BLENDING DRY FA WITH PC (.) SOMETIMES DRY SUPER PLASTICISER IS ALSO INTERGROUND (.) PRODUCTION OF PHFC USING INTER-GRINDING METHOD APPEARS MOST COST-EFFECTIVE & PRACTICAL REQUIRED TO SATISFY MINIMUM STRENGTH AS PER ASTM C1157, OF 10 & 17 MPa AT 3 & 7 DAYS RESPECTIVELY
  • 27. NEW BLENDED CEMENTS PORTLAND HIGH VOLUME FLY ASH CEMENT (PHFC) WHY INTER-GRINDING EFFECT OF GRINDING ON FA PROPERTIES  SPECIFIC GRAVITY: INCREASES DUE TO CRUSHING OF PLEROSHERES AND CENOSHERES AND CONTUES FOR CERTAIN TIME PERIOD OF GRINDING  SPECIFIC SURFACE: INCREASES WITH GRINDING TIME, BUT AT THE EXPENSE OF GRINDING ENERGY  MORPHOLOGY: OPTIMUM GRINDING PERIOD DOES NOT AFFECT SPHERICAL SHAPE OF FA PARTICLES SIGNIFICANTLY  WATER REQUIREMENT OF MORTAR: DECREASES UP TO CERTAIN TIME PERIOD & LATER INCREASES (.) RELATED TO SPHERICAL SHAPE  POZZOLANIC ACTIVITY: INCREASES AT RAPID RATE UP TO CERTAIN TIME PERIOD, LATER RATE DECREASES  THESE ASPECTS SHOW PHFC SHOULD BE PREFERABLY PRODUCED BY INTER-GRINDING & GRINDING PERIOD SHOULD BE OPTIMISED.
  • 28. NEW BLENDED CEMENTS PORTLAND HIGH VOLUME FLY ASH CEMENT (PHFC) GRINDING SUPERPLASTICISER WITH CLINKER & GYPSUM WHEN NAPHTHALINE BASED SP WAS VARIED FROM 0-0.9% (MASS OF CLINKER+GYPSUM):  GRINDING TIME: SP ACTED AS GRINDING AID & GRINDING TIME REDUCED TO OBTAIN REQUIRED BLAINE FINENESS  WATER REQUIREMENT & COMPRESSIVE STRENGTH: SP ADDITION DURING GRINDING OR SEPARATELY AT THE MIXER PRODUCED SAME EFFECT  BLAINE: FIXED ON THE BASIS OF FA, BY CARRYING OUT TRIALS  BETTER TO ADD SP AT THE GRINDING STAGE  ADDITION OF SP ALSO ELIMINATES COMPATIBILITY ISSUES AT CONCRETING STAGE  PREDETERMINED QUANTITY OF SP MAY BE ADDED TO OBTAIN REQUIRED CONCRETE SLUMP
  • 29. NEW BLENDED CEMENTS PORTLAND HIGH VOLUME FLY ASH CEMENT (PHFC) CONCRETE WITH PHFC RESULTS OF LABORATORY TRIALS ON PHFC WITH 55% FA*  FRESH CONCRETE: CONCRETE WITH PHFC REQUIRED MORE SP & AEA, AS INTER-GRINDING INCREASED FINENESS  COMPRESSIVE STRENGTH: IRRESPECTIVE OF SOURCE & TYPE OF FA, CONCRETE WITH PHFC DEVELOPED BETTER STRENGTH COMPARED TO THAT PREPARED BY SEPARATE ADDITION OF CEMENT & UN-GROUND FA AT MIXER  CHLORIDE RESISTANCE: INTER-GRINDING IMPROVED CHLORIDE RESISTANCE OF CONCRETE *Ref: Electric Power Research Institute (EPRI), USA, 2001
  • 30. NEW BLENDED CEMENTS PORTLAND HIGH VOLUME FLY ASH CEMENT (PHFC) SUMMARY PHFC IS FACTORY MADE WITH FA REPLACING CEMENT AT 55% ADDING SP TO CLINKER AT FINISH GRINDING STAGE HELP REDUCE GRINDING ENERGY & ALSO SOLVES COMPATIBILITY ISSUES AT CONCRETING STAGE INTER-GRINDING FA WITH GROUND CEMENT FOR FIXED TIME PERIOD IMPARTS BETTER CONCRETE PROPERTIES PHFC HAS VERY GOOD RESISTANCE TOWARDS CHLORIDE PENETRATION
  • 31. NEW BLENDED CEMENTS  NO CEMENT OR ADMIXTURE CAN OFFSET LOW QUALITY CONCRETE  DURABLE CONCRETE DEPENDS ON:  APPROPRIATE MIXTURE PROPORTIONS  LOWER w/c RATIO  PROPER PLACEMENT  CURING  MAINTENANCE  WHEN GOOD PRACTICES ARE FOLLOWED, CONCRETE WILL ATTAIN ITS EXPECTED SERVICE LIFE
  • 32. JOIN MY NETWORK YOU ARE WELCOME TO JOIN ME  FACEBOOK: Jayant D Bapat  TWITTER: @cemcretecon & @drjdbapat  LINKEDIN: Dr J. D. Bapat (email: jdbapat@yahoo.co.in)  EMAIL_1: consult@drjdbapat.com  EMAIL_2: consult.bapat@yahoo.com  URL: http://www.drjdbapat.com
  • 33. NEW BLENDED CEMENTS Thanks!!!

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