2. QUALITYAS A CONCEPT
• QUALITY AND ITS SPECIFICATION (STANDARD) ARE USUALLY LINKED TO
1/ PURPOSE FOR WHICH IT IS USED. UNIQUENESS AND ITS NOBILITY (RARITY)
2/ COST -- WHAT QUALITY AT WHAT COST ?
3/ WHAT ADDITIONAL FEATURES FOR THE GIVEN COST
4/ EASE OR CONSTRAINTS OF APPLICATION
5/ LUXURY AND CUSTOMER EGO SATISFACTION
FOR CEMENT IT MEANS THE FOLLOWING :
1/ GENERAL OR SPECIAL CONSTRUCTIONS OR APPLICATION REQUIREMENTS
2/ GRADE AND APPLICATION LINKED COSTS
3/ WHAT FAVOURABLE OR ADVERSE FEATURES DOES THE CEMENT HAVE WHICH MAKES
ONE DECIDE ONE FROM THE OTHER CEMENT
4/ SPECIAL DEMANDS ON ITS PREPARATION AND APPLICATION
5/ LUXURY CEMENT AND APPLICATION OF PIGMENTS FOR COLOUR AESTHETICS APART FROM
MAIN PURPOSE
3. COMMONCONSTRUCTIONCEMENTS
• TYPES OF CEMENTS
• GRADES AS PER RATE OF STRENGTH
DEVELOPMENT
• FORMULATION OF STANDARDS AND
INDIAN STANDARD SPECIFICATIONS
4. TYPES OF CEMENTS
• TYPES OF CEMENTS ARE WIDELY DIFFERENT AND DEPEND
ON THE HUMAN NEEDS TO FULFILL CERTAIN
REQUIREMENTS
• A DENTAL CEMENT BESIDES FILLING TOOTH CAVITY
MUST BE NON TOXIC , SALIVA AND MICROBE RESISTANT
STRONG AND NEARLY HAVE TOOTH COLOUR ETC
• BONE CEMENT BESIDES ABOVE REQUIREMENTS MUST
BE LOAD BEARING AND PROVIDE SOME FLEXIBLE BOND
5. OTHER TYPES OF CEMENTS
• COMMON HYDRAULIC CEMENTS
FOR CONSTRUCTION
• OIL WELL CEMENTS
• REFRACTORY CEMENTS
• WHITE CEMENT
• MASONRY CEMENTS
• EXPANSIVE CEMENTS AND SHRINKAGE
• COMPENSATED CEMENTS
• OTHERS SUCH AS SOREL , FERROCEMENT ETC
6. CEMENTSOFBUILDINGINDUSTRY
OPCANDTHEIRDERIVATIVES
• ORDINARY PORTLAND CEMENT IS GENERATED
BY CEMENT INDUSTRY FROM OPC CLINKER AND
GYPSUM
• WITH OPC CLINKER AS THE BASIC MATERIAL
MANY CEMENTS WITH MODIFIED PROPERTIES
ARE PRODUCED FOR DIFFERENT PURPOSES
• MANY VALUE ADDED AND ECOFRIENDLY
CEMENTS ARE MADE USING INDUSTRIAL WASTES SUCH
AS FLY-ASH, SLAG ETC
• EVEN MANY TOXIC WASTES ARE ACCOMODATED
7. OPCAND THEIRDERIVATIVES
• OPC WITH DIFFERENT GRADES OF STRENGTH
33, 43 AND 53 GRADES
RAPID HARDENING CEMENT (RHC)
LOW HEAT CEMENT (LHC)
SULPHATE RESISTING CEMENT (SRC)
RAILWAY SLEEPER CLASS CEMENT
OIL WELL CEMENT
• PORTLAND POZZOLANA CEMENT (PPC) WITH FLY-ASH OR BURNT
CLAY AS ADDITION. IT IS PRESCRIBED WITH A
LIMIT OF 33 GRADE
• PORTLAND SLAG CEMENT (PSC) USING GRANULATED BLAST FURNACE
SLAG OF STEEL INDUSTRY AS MAJOR
ADDITION IN OPC. STRENGHTH SAME AS 33 G
• MASONRY CEMENT, RARELY MADE AND USED
8. GRADESOF THE COMMONCEMENTS
• OPC IS GENERALLY AVAILABLE IN 3 GRADES AS
MENTIONED
• IN PPC THE REPLACEMENT OF CEMENT CLINKER IS TO
EXTENT OF 15 TO 35 % BY FLY-ASH USUALLY
• SIMILARLY, GRANULATED SLAG REPLACES EVEN UPTO
55 % IN PSC IN NORMAL CONSTRUCTION
• SINCE POZZOLAN AND SLAG GAIN STRENTH MUCH
SLOWER THAN HIGH GRADE OPC CLINKER, PPC AND
PSC ARE CLASSIFIED EQUIVALENT TO 33 G AND ARE
EXPECTED TO REACH ONLY 33 MPa IN 28 DAYS. OF COURSE THEY REACH
MUCH HIGHER STRENGTH IN REALITY
• RHC AND SLEEPER CLASS AND SOME OIL WELL CEMENT S OF
OPC ORIGIN REACH HIGHER THAN 53 G STRENGTH AND HAVE
GRADES AS PER CUSTOMER REQUIREMENTS.
9. PRINCIPLE OF GRADING OPC
• CEMENT CLINKER IS MADE FROM LIMESTONE, CLAY OR SAND, IRON AND ALUMINA
BEARING MATERIALS. WHEN BURNT AT +1400 * C , CALCIUM SILICATES C3S AND C2S
ARE FORMED ALONG WITH ALUMINATES AND FERRO ALUMINATES (C3A AND C4AF).
FIRST TWO DETERMINE
RATE OF STRENGTH DEVELOPMENT WHILE THE OTHER TWO SETTING
CHARACTERISTICS. IN CLINKER BURNING F AND A ACT AS FLUXES FOR REDUCING
TEMPERATURE OF BURNING
• ORIGINAL INTENTION OF BIS IS TO PRODUCE CEMENT CLINKERS WITH DIFFERENT
MINERAL CONTENTS FOR ACHIEVING DIFFERENT STRENGTHS
• FOR THIS CLINKERS WITH DIFFERENT LEVELS OF TRI CALCIUM SILICATE AND
DICALCIUM SILICATE AND ALSO ALUMINATES ARE PRODUCED
• SINCE C3S AND C3A GIVE VERY HIGH HEAT OF HYDRATION, THE HEAT
EVOLUTION DURING HARDENING IS ACHIEVED BY CONTROLLING THEIR
LEVEL IN CLINKER
• C3S IS USUALLY BETWEEN 25 TO 50 % m/m AND C3A LESS THAN 10% IN
CLINKER
10. CLASSIFICATIONOF CEMENTTYPES
• GENERAL PURPOSE CONSTRUCTION 33 43 GRADE
AND ORDINARY CONCRETE BLENDED CEMENTS
• HIGH EARLY STRENGTH 53 G , HAC*(REFRY)
RAPID REPAIR WORK (TUNNELS, BRIDGE) JET CEMENT
• LOW HEAT EVOLUTION LHC, PPC, PSC
• DELAYED SETTING AT HIGH TEMP OIL WELL CEM
RAPID STRENGTH LATER
• SULPHATE RESISTANCE SRC ( T-V) , PSC
• SULFATE + CHLORIDE RESISTANCE PSC
• PLASTERING , MASONRY WORK BLENDED, MASONRY
• DECORATIVE , KUXURY WHITE CEMENT
11. NORMSFORORDINARYPORTLANDCEMENTS
ASTM IS EQVT C3S % C2S % C3A % C4AF %
TYPE I 33 - 43 G 30—60 10 - 45 0—15 0—15
TYPE II MAX. 58 * MAX 8
TYPE III + 53 G MIN 45 MAX 15
E.S/ RH
TYPE IV LHC MAX 35 MIN 45 MAX 7
TYPE V SRC MAX 5 MAX 25++
•( C3S + C3A) = 58 + TYPICAL OF IR SLEEPER CLASS
++ ( 2C3A + C4AF) = 25
--------------------------------------------------------------------------------------------------
OIL WELL CEMENT -TYPE G SIMILAR TO HIGH STR. SRC
WHITE CEMENT (OPC) LIKE RHC BUT VERY LOW FE OX ( SAY < 1)
12. INDIANSTANDARDSPECIFICATIONS
• BY STATUTORY LAW, BUREAU OF INDIAN STANDARDS (BIS)
HAS BEEN VESTED WITH POWERS FOR LICENSING AND CERTIFICATION OF
CEMENT S.
• THE CEMENT PLANTS PAY MARKING FEES OR LECENSING FEES
FOR PRODUCTION AND MARKETING USING THE APPROPRIATE
PRODUCT SPECIFICATION MARKING OR SALE DOCUMENT FOR
BULK CEMENTS
• TYPICALLY FOR CONSTRUCTION PURPOSES SEVERAL GRADES
AND TYPES OF CEMENTS ARE AVAILABLE AND MARKED
ACCORDINGLY.
• FOR EXAMPLE UNDER ORDINARY PORTLAND CEMENTS WE HAVE
33 , 43 AND 53 GRADES, DEPENDING ON STRENGTH ACHIEVED
BY CEMENT MORTAR CUBES TESTED UNDER STANDARD
CONDITIONS
13. FORMULATION&CONTENTSOFSTANDARDS
• EMINENT MEMBERS OF MANUFACTURERS, CONSTRUCTION INDUSTRY ,
BUILDING MATERIAL RESEARCH BODIES JOINTLY
EVOLVE , AFTER CONSULTATION OF MANY AVAILABLE INTERNATIONAL
STANDARDS THE MOST APPROPRIATE STANDARD FOR EACH PRODUCT.
• THE STANDARD GOES THROUGH AN ELABORATE PROCESS OF
APPROVAL BY THE SET COMMITTEE AND ADOPTED LATER
ADOPTED AND ISSUED AS STANDARD BY BIS
• FROM THEN ON IT IS MANDATORY FOR CEMENT PLANTS TO CONFORM TO
SUCH STANDARD AND ADOPT APPROPRIATE PRODUCTION AND TEST
METHODS FOR CONFORMANCE.
• THERE ARE TWO ASPECTS TO THE CONFORMANCE OF PRODUCT.
1/ PRODUCT SPECIFICATION 2/ TEST METHODS STANDARD
FOR A SET OF PARAMETERS
14. REALITYINMANUFACTURE
• I S IT NOT TOO MUCH OF A LUXURY TO HAVE DIFFERENT CLINKERS ?
EVERY MINERAL RESOURCE IS PRECIOUS FOR THE COUNTRY, NON-
RENEWABLE – COST PROHIBITIVE MARKET CAN NOT BEAR
• WHAT ABOUT SEPARATE PROCESSING , STORAGE, MATERIAL HAND
LING , GRINDING, PACKING UNITS WHICH IS CAPITAL EXPENSIVE
• IN MANY CASES NATURE HAS NOT BLESSED EVERY PLANT WITH THE
BEST MATERIALS AND IT IS VERY DIFFICULT EVEN TO MAKE ONE GOOD
OPC CLINKER CONSISTENLY
• GENERALLY A MEDIUM GRADE OPC CLINKER IS GROUND TO DIFFE
RENT FINENESS TO ACHIEVE THE STRENGTH LEVELS
WHEN PRICE IS ATTRACTIVE AND CUSTOMER HAS OWN SPEC (IND.RY)
SPL CLINKERS ARE PRODUCED AND GROUND AND PACKED
15. FURTHERDIFFERENCESINPROPERTIES
• IN CLINKER 95 % MASS IS CONTRIBUTED BY THE ABOVE 4 MINERALS
APART FROM STRENGTH & SET , ANOTHER PROPERTY OF NOTICE
IS HEAT OF HYDRATION
• HEAT OF HYDRATION HAS TWO PARTS : QUANTITY OF HEAT SAY
PER KG AND RATE OF HEAT EVOLUTION
INDIVIDUALLY HOW THEY REACT WITH WATER :
• C3A HAS HIGHEST HEAT AND FASTEST TO REACT WITH H20
207 CAL/G 100 % IN 3D AT 30 deg C
• C3S IS NEXT WITH 120 CAL/G NEARLY 90 % IN 28 D
• C4AF COMES THIRD WITH 100 CAL/G ABOUT 80 % IN 28 D
• B-C2S SLOW 62 CAL/G ONLY ABOUT 50 % IN 28 D
• CaO HAS V.HIGH HEAT 279 CAL/G MgO 203 CAL/G
QUNTITIES IN CEMENT ARE SMALL
REACTIONS IN CEMENT MATRIX WITH GYPSUM IS SLIGHTLY DIFFT
• WHY ARE THESE RATES DIFFERENT ? WHAT ARE PARAMETERS ON
WHICH THEY DEPEND ? WHAT HAPPENS IN COLD /HOT WEATHER ?
17. MARKINGANDSTANDARDS
• LIKE NUMEROUS INDUSTRIAL PRODUCTS, CEMENT IS COVERED
UNDER VARIOUS STANDARDS AND CERTIFIED MANDATORILY
BY BUREAU OF INDIAN STANDARDS.
• BIS PERIODICALLY INSPECTS THE PRODUCTS AND CERTIFIES
PRODUCT FOR CONFORMANCE TO SPECIFIED STANDARDS
• TYPICALLY STANDARDS SPECIFY BOTH PERFORMANCE AND
PRESCRIPTIVE (GENERALLY CHEMICAL) REQUIREMENTS
TO ENSURE ITS FITNESS FOR USE IN THE AREA OF APPLICATION
• AFTER NECESSARY LICENSING BY BIS, THE CEMENT PLANTS
DO THE NECESSARY MARKING ON BAGS INDICATING THE
RELEVANT STANDARD AND PERIOD OF MANUFACTURE (WEEK)
• WHILE CEMENTS, SLAGS LARGELY CONFORM TO STANDARDS,
MANDATORY STIPULATIONS DO NOT BIND FLY-ASH SUPPLIERS
SUCH AS THERMAL POWER PLANTS, LARGELY UNDER GOVT.
• TAKE IT OR LEAVE IT ATTITUDE MAKES PPC MORE UNPREDICTABLE IN
PERFORMANCE AND HENCE MARKETING
FOR CONCRETE PRODUCT MANUFACTURERS
18. TYPICALISSTANDARDSOFCOMMONCEMENTS
• IS 269: 1989 - 33 GRADE OPC
• IS 8112: 1989 - 43 GRADE OPC
• IS 12269 : 1987 - 53 GRADE OPC
• IS 1489 : 1997 - PORTLAND POZZOLANA CEMEN T
PPC (Pt 1 FLY ASH BASED)
• IS 455 :1989 - PORTLAND SLAG CEMENT
• IS 12600:1989 - LOW HEAT CEMENT LHC
• IS:12330 -1988 - SULPHATE RESISTING CEMENT, SRC
• IS:8041-1989 - RAPID HARDENING CEMENT, RHC
• IS:8012 -1989 - WHITE CEMENT
• IS:3466-1988 - MASONRY CEMENTS
• IS: 3812 -1981 . FLY-ASH
• IS: 12089- 1987 - GRANULATED BF SLAG
• NOTE: THESE STANDARDS CONTAIN ONLY SPECIFICATIONS OF VARIOUS
PARAMETERS
19. SOMECOMMONASPECTSOFBLENDEDCEMENTS
• SINCE THERE ARE PERMITTED MINOR ADDITIONS IN CEMENT, OPC IN REAL
SENSE IS NO MORE IN THE MARKET . UNLESS THE
INGREDIENTS ARE WELL KNOWN , ANALYSIS AND PREDICTION OF
BEHAVIOUR IS COMPLEX.
• ALL PERFORMANCE INDICES SUCH AS SETTING TIME, STRENGTH
DEVELOPMENT, VOLUME STABILITY, DURABILITY, HEAT OUT PUT,
ENVIRONMENT FRIENDLINESS , EVEN AESTHETICS CAN GET ALTERED.
• BLENDED CEMENTS OCCUR IN VERIETY OF FORMS SUCH AS
POZZOLANA CEMENTS, SLAG CEMENTS, MASONRY CEMENTS,OR EVEN
MULTICOMPONENT CEMENTS CONTAINING GBFS, FLY-ASH, BURNT CLAY,
LIMESTONE, LIME, ETC
• HENCE DIFFERENT CEMENTS ARE CHOSEN FOR DIFFERENT
PERFORMANCE REQUIREMENTS. LOW HEAT, MARINE ENVIRONS,
DURABILITY, RAPID AND HIGH STRENGTH ( RAILWAY)
20. SLAGCEMENTS
• SLAGS ARE BY-PRODUCTS OF STEEL INDUSTRY . WHEN IRON ORE
IS BURNT WITH COKE TO MAKE STEEL IN BLAST FURNACE,
UNWANTED IMPURITY MATERIALS COME FLOATING AS SLAG AND IS TAPPED OFF. IT IS
SUDDENLY QUENCHED IN A BLAST OF WATER AND AIR . WE THEN GET WET GRANULAR
MATERIAL CALLED GRANULATED BLAST FURNACE SLAG OR GBFS.
• THE DRY GBFS IS VERY FINELY GROUND TO MAKE MORE REACTIVE. LIKE CEMENT THIS
CAN DIRECT LY REACT WITH WATER TO FORM A BINDER WHEN FURTHER ACTIVATED
WITH
LIME OR GYPSUM OR CEMENT
• THUS A BLEND OF CEMENT AND SLAG USUALLY BEYOND 40%
REPLACEMEN OF CEMENT FORMS A SLAG CEMENT.
• JUST AS FLY-ASH, SLAG CEMENT IS HIGHLY ECO-FRIENDLY, REDUCES CO2 EMISSION
PER TONNE OF CEMENT, IMPROVES VIABILITY OF BOTH STEEL AND CEMENT INDUSTRY
ANDGIVES
A VERY VALUABLE PRODUCT TO THE CEMENT INDUSTRY
• FURTHER IT HAS VERY SPECIAL PROPERTIES UNAVAILABLE WITH
OTHER CEMENTS
• ONE HAS TO BE VERY CAREFUL IN SELECTION OF SLAG AND ITS
SOURCE. CHEM COMPSN AND GLASS CONTENT ARE VITAL FOR
PERFORMANCE OF SLAG
21. IS 3812: 2003 (Pt 1) SPECIFICATIONS
CHEMICAL REQUIREMENTS PHYSICAL REQUIREMENTS
SPFA CPFA
1/ S + A + F ..(min) 70 50 BLAINE (min) 320 M2/Kg
2/ S (min mass %) 35 25 RESIDUE (wet sieve 34 (optnl)
45 mic max mass %)
3/ MgO (max %) 5 5 LIME REACTIVITY 4.5
(C.St min N/ mm2)
4/ TOTAL SO3 (mass %) 3.0 3.0
maximum COMPRESSIVE STR not < 80%
( 28 d min N/mm2 of plain cement
5/ AVAILABLE ALKALIS 1.5 1.5 20 % cem replmt) mortar
(as Na2O max mass % )
6/ TOTAL Cl- (max m %) 0.05 0.05 SOUNDNESS (max %) 0.8
(auto clave expansion)
7/ LOSS ON IGNTN 5.0 5.0
NOTE: optional chemical tests are not given here . Most of the tests are as per IS 1727 and
IS :4032
22. IMPORTANTASPECTSOF IS:3812—2003(Pt 1)
PULVERISEDFUELASH-SPECIFICATION
• TAKING VARIOUS CLAUSES TOGETHER PFA REFERS TO ESSENTIALLY THE FLY-ASH
COLLECTED BY CYCLONES OR ESP, PREFERABLY LATER CHAMBERS OR PROCESSED
OR BENEFICIATED ASHES FROM THESE SOUCES
• FOR INTENDED USE AS A POZZOLANA ( CEMENT REPLACEMENT), BOTH CHEMICAL
AND PHYSICAL REQUIREMENTS ARE TO BE MET AS PER THIS STANDARD
• THIS APPLIES TO PPC PREPARED BY INTERGRINDING WITH CLINKER AND GYPSUM,
BLENDED WITH OPC AND SUPPLIED OR USED IN CONCRETE DIRECTLY AS IN THE
CASE OF RMCs OR LIME-MORTAR PRODUCTION
• FOR INTERGRINDING PURPOSES IT IS PERMITTED TO USE FLY-ASH OF MIN 250 M2/Kg
BLAINE FINENESS, THIS FLY-ASH SHALL MEET ALL THE REQUIRMENTS OF THIS
STANDARD AT 320M2/Kg OR LOWER FINENESS OF PPC MADE PROVIDED AT THIS
LEVEL OF FINESS IT PASSES ALL TESTS OF THIS STANDARD. THIS MEANS THAT WHEN
PPC FINENESS IS LOWER THAN 320 M2/Kg , THE FLY-ASH MUST MEET ALL SPECS
(EXCEPT FINENESS) AT THIS LEVEL. HENCE FLY-ASH HAS TO BE GROUND TO THIS
PLANT CHOSEN FINENESS ( <320 M2/Kg) AND ESTABLISH THAT IT IS A GOOD POZZOLAN.
23. IS 1489:1991 PPCSPECIFICATIONS
• THE LATEST VERSION OF THE STANDARD IS REAFFIRMED IN 2005 AND HAS
TWO PARTS
• Pt – 1 DEALS WITH PPC MADE FROM FLY-ASH
• Pt - 2 DEALS WITH BURNT CLAY POZZOLAN CEMENT OR A BLEND OF BOTH
• BOTH PARTS REQUIRE ONLY CEMENT CLINKER/ CEMENT CONFORMING TO
SPECIFICATION FOR 33 G CEMENT. , I.e IS 269 ; 1989
• BURNT CLAY IS COVERED UNDER IS 1344:1981 . THIS STANDARD IS SIMILAR
TO IS 3812 IN MOST ASPECTS AND TEST METHODS. LIME REACTIVITY AS
PER IS 1727 HAS TO BE MINIMUM 4 N/mm2
BURNT CLAY AS A POZZOLANA IS TO HAVE A MINIMUM FINENESS OF 300
M2/KG ( MIN FINENESS OF GROUND CEMENT ) FOR TEST OR ITS NATURAL
FINENESS IF THE FINENESS IS HIGHER THAN 300 M2/Kg
THIS IMPLIES THAT THE BURNT CLAY HAS TO BE GROUND ( IF COARSE )
TO A MINIMUM OF 300 M2/Kg OR TO THE FINENESS OF PPC MADE , PPC
BEING USUALLY HIGHER THAN 300 M2/Kg.
• IS 1489 PART II HAS THE SAME LEVEL OF LIMITS FOR LOI, IR, MgO AND SO3
24. FURTHERSPECSIN IS 1489:1991 (Pt-1)
CHEMICAL REQUIREMENT PHYSICAL REQUIREMENT
1/ LOSS ON IGNTN (mass % max ) 5.0 SETTING TIME (initial min) 30 (Min)
2/ MAGNESIA (mass % max ) 6.0 (Final min) 600 (Max)
3/ SO3 (mass % max ) 3.0 COMPRESSIVE STRENGTH (N/ mm2)
4/ INSOL. RESIDUE (mass % max) SEE 3 days 16
BELOW
x + ( 4.0 ( 100 - x) /100) 7 days 22
28 days 33
FINENESS ( air permeability) M2/Kg
Minimum 300
PLEASE NOTE :
DRYING SHRINKAGE L % 0.15 (max)
ALL CHEMICAL TESTS AS PER IS 4032: 1985
ALL PHYSICAL TESTS AS PER IS 4031: 1988
25. ADVANTAGESOF PPC
• LOW HEAT OF HYDRATION - MOST APPROPRIATE FOR MASS CONSTRUCTION
WHERE EXCESS HEAT WILL DAMAGE THE STRUCTURE
• IDEAL FOR PLASTERING AND FINISHING – GOOD WORKABILITY OF MORTAR
LOW HEAT AND HENCE LESS PROBLEM OF THERMAL STRESS CRACKS
HIGH STRENGTH IS NOT REQUIRED. LOW IMPERMEABLE MORTAR OR CONCRETE
CAN REDUCE COST OF WATER PROOFING
• WITH ADEQUATE LEVEL OF OPC REPLACEMENT IN CONCRETE THE DURABILITY
OF STRUCTURE IS INCREASED. IT IS ESSENTIALLY DUE TO THE OVERALL
REDUCTION OF FREE LIME AND EXCESS CONVERTIBLE/ LEACHABLE ALKALI.
PORE STRUCTURE IS VERY FAOURABLY MODIFIED THAT IT STRONGLY
INHIBITS THE INGRESS OF Cl-, SO4 -- IONS AND ATTACK OF CO2 BY DIFFUSION.
• THE LEVEL OF ALKALINITY FOR CORROSION INHIBITION IS STILL MAINTAINED.
THE REINFORCEMENT IS WELL PROTECTED. DAMAGE IS MORE DUE TO THE
AGGRESSIVE ION ENTRY AND THIS IS TAKEN CARE OF AS STATED ABOVE
• IT IS COST EFFECTIVE AND ECO-FRIENDLY. USE OF THERMAL POWER PLANT
WASTE WHEN PFA IS USED. LESS GREEN HOUSE GAS EMISSION PER Kg OF
CEMENT PRODUCED. IT IS A VALUE ADDED CEMENT . IMPORTANT CEMENT
FOR SUSTAINABLE DEVELOPMENT SINCE USES LESS ENERGY AND LESS NON-
RENEWABLE RESOURCES PER UNIT MASS PRODUCED AND USED
26. THE FLIPSIDETO PPC
• ONE OF MOST COMMON PERCEPTION OF PPC AND BAD PROPAGANDA IS
SLOW SETTING AND STRENGTH DEVELOPMENT
• THE BEHAVIOUR OF PPC IS NOT SIMILAR OR EQUIVALENT TO THAT
OF OPC
• THE QUALITY OF FLY-ASH IS NOT WELL CONTROLLED AND HENCE THE
PPC PRODUCED IS HIGHLY VARIABLE IN QUALITY
• POWER PLANTS DO NOT PAY MUCH ATTENTION TO THE FLY-ASH AND
HENCE THE LARGE CARBON CONTENT (LOI) PRODUCES BLACK SLIMY
FLOATING MASS IN CEMENT MORTAR OR CONCRETE AND IS NOT
ACCEPTABLE
• FLY-ASH IS USED MORE AS AN ADULTERANT THAN AS A POZZOLAN
AND PERFORMANCE ENHANCER
• SOME MAIN USERS LIKE CPWD AVOID THE USE OF PPC IN THEIR TENDERS
FOR USE IN PRESTRESSED AND RE-INFORCED CONCRETE CONSTRUCTIONS
• DARK COLOUR OPC IS SUPERIOR !
27. PROMOTIONOF PPC
• LET US EXAMINE SOME OF MAIN ASPECTS OF THE MARKETING PEOPLE’S
TASK
1/ UNDERSTANDING THE NATURE OF USE AND HENCE THE CUSTOMER’S
REQUIRMENT
2/ PRODUCT QUALITY AND HOW AND WHERE QUALITY COMPLAINTS
ARISE
3/ SELLING YOUR PRODUCT AND THE TECHNICAL SERVICES YOU
CAN PROVIDE BEFORE AND AFTER SALES
4/ HOW YOU PROMOTE QUALITY FIRST AND THEN COST LATER
5/ MARKETING STRATEGIES AND MORE DON’Ts THAN DOs
28. TIPSTO SUCCESSFULUSE OF PPC
• UNDERSTAND HOW FLY-ASH OR EVEN SLAG MODIFIES THE PROPERTIES OF OPC
• PORTD CEM REACTS FASTEST. FLY-ASH REACTS SLOWLY. ALLOW GOOD TIME
FOR CURING. IN HOT WEATHER LARGE EXPOSED SURFACES AND DEEP SECTIONS
ARE SUSCEPTIBLE FOR PLASTIC SHRINKAGE CRACKING. COMMENCE EARLY
CURING
• PORTLAND CEMENT IS BEST ACTIVATOR FOR FLY-ASH POZZOLAN. USE OF FINE
FLY-ASH HELPS EVEN FOR EARLY STRENGTH
• HIGH W/B RATIO IS FACTOR RUINING CONCRETE. CEMENT REQUIRES < 18 % WATER
FOR COMPLETE CONVERSION. EXTRA WATER IS ONLY FOR WORKABILITY. EXCESS
WATER ALLOWS PORES TO FORM AND ALSO ENTRY OF CORROSIVE IONS. THIS
WEAKENS CONCRETE. WORK WITH LEAST AMOUNT OF WATER FOR PPC /PSC.
• HRWRA ARE RECOMMENDED TO GET EARLY AND LONG TERM STRENGTH AND
DURABLE CONCRETE
• WATER REDUCING ADMIXTURES WITH PFA INCREASE COHESIVENESS OF CONCRETE
AND REDUCE BLEEDING
• TO FURTHER REDUCE BLEEDING USE FINE FLY-ASH. INCREASE THE FINES IN SAND
AND WATCH THE FINENESS MODULUS OF SAND AND SHAPE INDEX OF COARSE
AGGREGATE
29. FURTHERTIPSIN USE OF PPC
• REALISE THAT PPC MORTAR/ CONCRETE IS VERY VULNERABLE IN EARLY
PERIODS. PROTECT AND START CURING IMMEDIATELY AFTER SET. DO NOT
ALLOW TO DRY.
• W/(C+ P) AFFECTS THE EARLY STRENGTH MORE SHARPLY THAN LATER
STRENGTH. WORK WITH LOWEST W/B RATIO PRACTCABLE FOR BEST
STRENGTH ACHIEVABLE
• DURABILITY ESSENTIALLY DEPENDS ON THE PORE STRUCTURE AND PORE
VOLUME OF CONCRETE . SUCCESS DEPENDS ON PORE REFINEMENT BY
POZZOLAN. MARKET THE BEST PPC WITH GOOD UNDERSTANDING OF THE
REQUIREMENTS FOR MORTAR AND CONCRETE. MAKE PROFESSIONAL PPC
AND NOT JUST ANY PPC. UNDERSTAND THE BEST CEMENT REPLACEMENT
LEVELS FOR YOUR CEMENT. IF NEED BE GRIND CEMENT AND FLY-ASH
SEPARATELY AND BLEND TO GET THE BEST PASTE VOLUME AND CHARACTER
IN CONCRETE. DESIGN PPC FOR CONCRETE
• EARLY STRENGTH (SAY UP TO 3 DAYS) OF PPC DEPENDS ON THE FINENESS
AND QUALITY OF CEMENT USED. ITS C3A LEVEL, GYPSUM/ANHYDRIDE
TO SOME EXTENT CONTROLS WORKABILITY AND BLEEDING. PAY ATTENTION
WHEN IT IS NECESSARY.
