4. 3)3) Argillaceous Rocks (CaCOArgillaceous Rocks (CaCO33 << 40%)40%)
ClaysClays
ShalesShales
SlatesSlates
Portland cement is made by mixingPortland cement is made by mixing
substances containing CaCOsubstances containing CaCO33 withwith
substances containing SiOsubstances containing SiO22, Al, Al22OO33, Fe, Fe22OO33
and heating them to a clinker which isand heating them to a clinker which is
subsequently ground to powder andsubsequently ground to powder and
mixed with 2-6 % gypsum.mixed with 2-6 % gypsum.
6. PRODUCTION STEPSPRODUCTION STEPS
1)1) Raw materials are crushed, screemed &Raw materials are crushed, screemed &
stockpiled.stockpiled.
2)2) Raw materials are mixed with definiteRaw materials are mixed with definite
proportions to obtain “raw mix”. They areproportions to obtain “raw mix”. They are
mixed either dry (dry mixing) or by water (wetmixed either dry (dry mixing) or by water (wet
mixing).mixing).
3)3) Prepared raw mix is fed into the rotary kiln.Prepared raw mix is fed into the rotary kiln.
4)4) As the materials pass through the kiln theirAs the materials pass through the kiln their
temperature is rised upto 1300-1600temperature is rised upto 1300-1600 °°C. TheC. The
process of heating is named as “burning”. Theprocess of heating is named as “burning”. The
output is known as “clinker” which is 0.15-5 cmoutput is known as “clinker” which is 0.15-5 cm
in diameter.in diameter.
7. 5)5) Clinker is cooled & stored.Clinker is cooled & stored.
6)6) Clinker is ground with gypsum (3-6%) toClinker is ground with gypsum (3-6%) to
adjust setting time.adjust setting time.
7)7) Packing & marketting.Packing & marketting.
8.
9.
10.
11. REACTIONS IN THE KILNREACTIONS IN THE KILN
~~100100°°CC→ free water evaporates.→ free water evaporates.
~~150-350C150-350C°→°→ loosely bound water is lost fromloosely bound water is lost from
clay.clay.
~~350-650350-650°°CC→→decomposition of clay→SiOdecomposition of clay→SiO22&Al&Al22OO33
~~600600°°CC→→decomposition of MgCOdecomposition of MgCO33→→MgO&COMgO&CO22
(evaporates)(evaporates)
~~900900°°CC→→decomposition of CaCOdecomposition of CaCO33→→CaO&COCaO&CO22
(evaporates)(evaporates)
12. ~~1250-12801250-1280°°CC→→liquid formation & start ofliquid formation & start of
compound formation.compound formation.
~~12801280°°CC→→clinkering begins.clinkering begins.
~~1400-15001400-1500°°CC→→clinkeringclinkering
~~100100°°CC→→clinker leaves the kiln & falls into aclinker leaves the kiln & falls into a
cooler.cooler.
Sometimes the burning process of raw materialsSometimes the burning process of raw materials
is performed in two stages: preheating uptois performed in two stages: preheating upto
900900°°C & rotary kilnC & rotary kiln
13. CHEMICAL COMPOSITIONCHEMICAL COMPOSITION
OF P.C.OF P.C.
Portland cement is composed of fourPortland cement is composed of four
major oxides (CaO, SiOmajor oxides (CaO, SiO22, Al, Al22OO33, Fe, Fe22OO33
≥90%) & some minor oxides. Minor refers≥90%) & some minor oxides. Minor refers
to the quantity not importance.to the quantity not importance.
14. Oxide Common Name Abbreviation Approx. Amount (%)
CaO Lime C 60-67
SiO2 Silica S 17-25
Al2O3 Alumina A 3-8
Fe2O3 Iron-oxide F 0.5-6
MgO Magnesia M 0.1-4
Na2O Soda N
0.2-1.3
K2O Potassa K
SO3 Sulfuric Anhydride ŚŚ 1-3
CaOCaO→limestone→limestone
SiOSiO22-Al-Al22OO33→Clay→Clay
FeFe22OO33→Impurity in Clays→Impurity in Clays
SOSO33→from gypsum→not from the clinker→from gypsum→not from the clinker
S
15. The amount of oxides in a P.C. Depend on theThe amount of oxides in a P.C. Depend on the
proportioning of the raw materials and how well theproportioning of the raw materials and how well the
burning is done in the kiln. The chemical composition isburning is done in the kiln. The chemical composition is
found by chemical analysis.found by chemical analysis.
A typical analysis of O.P.C.A typical analysis of O.P.C.
Insoluble residue=0.2Insoluble residue=0.2
Loss on ignition=1.4Loss on ignition=1.4
C 63.6
S 20.7
A 6
F 2.4
ŚŚ 2.1
M 2.6
N 0.1
K 0.9
Free C 1.4
Total 99.8
16. CaO (C), SiOCaO (C), SiO22 (S), Al(S), Al22OO33 (A) & Fe(A) & Fe22OO33 are theare the
major oxides that interact in the kiln & form themajor oxides that interact in the kiln & form the
major compounds.major compounds.
The proportions of these oxides determine theThe proportions of these oxides determine the
proportions of the compounds which affect theproportions of the compounds which affect the
performance of the cement.performance of the cement.
SOSO33→comes largely from gypsum→comes largely from gypsum
P.C. alone sets quickly so some gypsum isP.C. alone sets quickly so some gypsum is
ground with clinker to retard the setting time.ground with clinker to retard the setting time.
17. If too much gypsum is included it leads toIf too much gypsum is included it leads to
distruptive expansions of the hardeneddistruptive expansions of the hardened
paste or concrete.paste or concrete.
ASTM C 150ASTM C 150 → SO→ SO33 ≤ 3% in O.P.C.≤ 3% in O.P.C.
MgO+HMgO+H2O→MHO→MH
C+H→CH volume expansion & causeC+H→CH volume expansion & cause
cracking.cracking.
ASTM C 150 → MASTM C 150 → M<<6%6%
free Cfree C << 3%3%
18. Alkalies (NaAlkalies (Na22O & KO & K22O) may cause someO) may cause some
dificulties if the cement is used with certaindificulties if the cement is used with certain
types of reactive aggregates in makingtypes of reactive aggregates in making
concrete. The alkalies in the form ofconcrete. The alkalies in the form of
alkaline hydroxides can react with thealkaline hydroxides can react with the
reactive silica of the aggregate & resultingreactive silica of the aggregate & resulting
in volume expansion after hardening. Thisin volume expansion after hardening. This
process may take years.process may take years.
NaNa22O & KO & K22O ≤ 0.6%O ≤ 0.6%
19. Insoluble Residue:Insoluble Residue: is that fraction of cementis that fraction of cement
which is insoluble in HCl. It comes mainly fromwhich is insoluble in HCl. It comes mainly from
the silica which has not reacted to formthe silica which has not reacted to form
compounds during the burning process in thecompounds during the burning process in the
kiln. All compounds of P.C. is soluble in HClkiln. All compounds of P.C. is soluble in HCl
except the silica.except the silica.
The amount of I.R., determined by chemicalThe amount of I.R., determined by chemical
analysis, serves to indicate the completeness ofanalysis, serves to indicate the completeness of
the reactions in the kiln.the reactions in the kiln.
ASTM C 150ASTM C 150 → I.R. ≤ 0.75%→ I.R. ≤ 0.75%
20. Loss on Ignition (L.O.I.):Loss on Ignition (L.O.I.): is the loss inis the loss in
weight of cement after being heated toweight of cement after being heated to
10001000°°C. It indicates the prehydration orC. It indicates the prehydration or
carbonation due to prolonged or impropercarbonation due to prolonged or improper
storage of cement & clinker.storage of cement & clinker.
If cement is exposed to air, water & COIf cement is exposed to air, water & CO22
are absorbed & by heating the cementare absorbed & by heating the cement
upto 1000upto 1000°°C loose these two substances.C loose these two substances.
ASTM C 150ASTM C 150 → L.O.I. ≤ 3% for O.P.C.→ L.O.I. ≤ 3% for O.P.C.
21. COMPOUNDCOMPOUND
COMPOSITION OF P.C.COMPOSITION OF P.C.
(OR CLINKER)(OR CLINKER)
Oxides interact with eachother in the kilnOxides interact with eachother in the kiln
to form more complex productsto form more complex products
(compounds). Basically, the major(compounds). Basically, the major
compounds of P.C. can be listed as:compounds of P.C. can be listed as:
Name Chemical Formula Abbreviations
Tri Calcium Silicate 3CaO.SiO2 C3S
Di Calcium Silicate 2CaO.SiO2 C2S
Tri Calcium Aluminate 3CaO.Al2O3 C3A
Tetra Calcium Alumino
Ferrite
4CaO.Al2O3.Fe2O3 C4AF
22. The degree to which the potentialThe degree to which the potential
reactions can proceed to “equilibrium”reactions can proceed to “equilibrium”
depends on:depends on:
1)1) Fineness of raw materials & theirFineness of raw materials & their
intermixing.intermixing.
2)2) The temperature & time that mix is heldThe temperature & time that mix is held
in the critical zone of the kiln.in the critical zone of the kiln.
3)3) The grade of cooling of clinker may alsoThe grade of cooling of clinker may also
be effective on the internal structure ofbe effective on the internal structure of
major compounds.major compounds.
23. There are also some minor compoundsThere are also some minor compounds
which constitute few %, so they arewhich constitute few %, so they are
usually negligible. Moreover, portlandusually negligible. Moreover, portland
cement compounds are rarely pure.cement compounds are rarely pure.
For example in CFor example in C33S, MgO & AlS, MgO & Al22OO33 replacesreplaces
CaO randomly.CaO randomly.
CC33SS→ALITE & C→ALITE & C22S→BELITES→BELITE
Ferrite Phase:Ferrite Phase: CC44AF is not a trueAF is not a true
compound. The ferrite phase ranges fromcompound. The ferrite phase ranges from
CC22AF to CAF to C66AF. *CAF. *C44AF represents anAF represents an
average.average.
24. Methods of DeterminingMethods of Determining
Compound CompositionCompound Composition
Each grain of cement consists of an intimateEach grain of cement consists of an intimate
mixture of these compounds.mixture of these compounds.
They can be determined by:They can be determined by:
1)1) MicroscopyMicroscopy
2)2) X-Ray DiffractionX-Ray Diffraction
But due to the variabilities involved theBut due to the variabilities involved the
compound composition is usually calculatedcompound composition is usually calculated
using the oxide proportions.using the oxide proportions.
3)3) Calculations (Bouge’s Equations)Calculations (Bouge’s Equations)
25. AssumptionsAssumptions
1)1) The chemical reactions in the kilnThe chemical reactions in the kiln
proceeded to equilibrium.proceeded to equilibrium.
2)2) Compounds are in pure form such asCompounds are in pure form such as
CC33S & CS & C22SS
3)3) Presence of minor compounds arePresence of minor compounds are
ignored.ignored.
4)4) Ferrite phase can be calculated as CFerrite phase can be calculated as C44AFAF
5)5) All oxides in the kiln have taken part inAll oxides in the kiln have taken part in
forming the compounds.forming the compounds.
27. Ex:Ex:Given the following oxide composition ofGiven the following oxide composition of
a portland cement clinker.a portland cement clinker.
CaO=64.9% SiOCaO=64.9% SiO22=22.2%=22.2%
AlAl22OO33=5.8% Fe=5.8% Fe22OO33=3.1% MgO=4%=3.1% MgO=4%
Using Bogue’s eqn’s calculate theUsing Bogue’s eqn’s calculate the
compound composition of the P.C.compound composition of the P.C.
clinker?clinker?
CC33S=4.071*64.9-7.6*22.2-6.718*5.8-S=4.071*64.9-7.6*22.2-6.718*5.8-
1.43*3.1=52.1%1.43*3.1=52.1%
CC22S=2.876*22.2-0.7544*52.1=24.5%S=2.876*22.2-0.7544*52.1=24.5%
28. CC44AF=3.043*3.1=9.4%AF=3.043*3.1=9.4%
To see the effect of change in oxide compositionTo see the effect of change in oxide composition
on the change in compound composition,on the change in compound composition,
assume that CaO is 63.9% & SiOassume that CaO is 63.9% & SiO22 is 23.2% andis 23.2% and
others are the same.others are the same.
CC33S=40.4% , CS=40.4% , C22S=36.2% , CS=36.2% , C33A=10% , CA=10% , C44AF=9.4%AF=9.4%
CC33S changed from 52.1%S changed from 52.1%→40.4%→40.4%
CC22S changed from 24.5%→36.2%S changed from 24.5%→36.2%
1% change in CaO & SiO1% change in CaO & SiO22 resulted in more thanresulted in more than
10% change in C10% change in C33S & CS & C22S content.S content.
29. Influence of CompoundInfluence of Compound
Composition onComposition on
Characteristics of P.C.Characteristics of P.C.
P.C.+waterP.C.+water→the compounds in the cement→the compounds in the cement
undergo chemical reactions with the waterundergo chemical reactions with the water
independently, and different products result fromindependently, and different products result from
these reactions.these reactions.
C3S C2S C3A C4AF
Rate of Reaction Moderate Slow Fast Moderate
Heat Liberation High Low Very High Moderate
Early Cementitious Value Good Poor Good Poor
Ultimate Cementitious Value Good Good Poor Poor
30. ASTM Type & Name
of P.C.
Average Compound
Composition
C3S C2S C3A C4AF
Type I - O.P.C. 49 25 12 8 General Purpose
Type II - Modified 46 29 6 12
For Moderate Heat of
Hydration
Type III - High Early
Strength 56 15 12 8
C3S&C3A increased, C2S
decreased
Type IV - Low Heat
P.C. 30 46 5 13 C2S increased
Type V - Sulfate
Resistant P.C. 43 36 4 12
Limit on C3A≤5%,
2C3A+C4AF≤25%
31. Hydration of P.C.Hydration of P.C.
Hydration:Hydration: Chemical reactions with water.Chemical reactions with water.
As water comes into contact with cementAs water comes into contact with cement
particles, hydration reactions immediatelyparticles, hydration reactions immediately
starts at the surface of the particles.starts at the surface of the particles.
Although simple hydrates such as C-H areAlthough simple hydrates such as C-H are
formed, process of hydration is a complexformed, process of hydration is a complex
one and results in reorganization of theone and results in reorganization of the
constituents of original compounds to formconstituents of original compounds to form
new hydrated compounds.new hydrated compounds.
32.
33. At any stage of hydration the hardenedAt any stage of hydration the hardened
cement paste (hcp) consists of:cement paste (hcp) consists of:
Hydrates of various compounds referred toHydrates of various compounds referred to
collectively as GEL.collectively as GEL.
Crystals of calcium hydroxide (CH).Crystals of calcium hydroxide (CH).
Some minor compound hydrates.Some minor compound hydrates.
Unhydrated cementUnhydrated cement
The residual of water filled spaces – pores.The residual of water filled spaces – pores.
34. As the hydration proceeds the deposits ofAs the hydration proceeds the deposits of
hydrated products on the original cementhydrated products on the original cement
grains makes the diffusion of water tograins makes the diffusion of water to
unhydrated nucleus more & more difficult.unhydrated nucleus more & more difficult.
Thus, the rate of hydration decreases withThus, the rate of hydration decreases with
time & as a result hydration may taketime & as a result hydration may take
several years.several years.
Major compounds start to produce:Major compounds start to produce:
Calcium-silicate-hydrate gelsCalcium-silicate-hydrate gels
Calcium hydroxide cementCalcium hydroxide cement
Calcium-alumino-sulfohydrates gelCalcium-alumino-sulfohydrates gel
35. At the beginning of mixing, the paste has aAt the beginning of mixing, the paste has a
structure which consists of cement particlesstructure which consists of cement particles
with water-filled space between them. Aswith water-filled space between them. As
hydration proceeds, the gels are formed &hydration proceeds, the gels are formed &
they occupy some of this space.they occupy some of this space.
1cc of cement1cc of cement → 2.1cc of gel→ 2.1cc of gel
Gel Pores:Gel Pores: 28% of the total gel volume have28% of the total gel volume have
diameter of 0.015-0.020diameter of 0.015-0.020 μμm. (very small-m. (very small-
loss or gain of water is difficult)loss or gain of water is difficult)
36. Capillary PoresCapillary Pores: 12.5: 12.5 μμm diameter, with varyingm diameter, with varying
sizes, shapes & randomly distributed in the paste.sizes, shapes & randomly distributed in the paste.
Volume of capillary pores decreases as hydrationVolume of capillary pores decreases as hydration
takes place. Water in capillary pores is mobile,takes place. Water in capillary pores is mobile,
can not be lost by evaporation or water can getcan not be lost by evaporation or water can get
into the pores. They are mainly responsible forinto the pores. They are mainly responsible for
permeability.permeability.
- w/c ratio- w/c ratio
capillary porositycapillary porosity
- degree of hydration- degree of hydration
37. CC22S & CS & C33S:S: 70-80% of cement is composed of70-80% of cement is composed of
these two compounds & most of the strengththese two compounds & most of the strength
giving properties of cement is controlled by thesegiving properties of cement is controlled by these
compounds.compounds.
Upon hydration both calcium-silicates result in theUpon hydration both calcium-silicates result in the
same products.same products.
2C2C33S+6HS+6H → C→ C33SS22HH33 + 3CH+ 3CH
2C2C22S+4H → CS+4H → C33SS22HH33 + CH+ CH
Calcium-Silicate-Hydrate (C-S-H gel) is similar toCalcium-Silicate-Hydrate (C-S-H gel) is similar to
a mineral called “TOBERMORITE”. As a result ita mineral called “TOBERMORITE”. As a result it
is named as “TOBERMORITE GEL”is named as “TOBERMORITE GEL”
38. Upon hydration CUpon hydration C33S & CS & C22S, CH also formsS, CH also forms
which becomes an integral part ofwhich becomes an integral part of
hydration products. CH does not contributehydration products. CH does not contribute
very much to the strength of portlandvery much to the strength of portland
cement.cement.
CC33S having a faster rate of reactionS having a faster rate of reaction
accompanied by greater heat generationaccompanied by greater heat generation
developes early strength of the paste. Ondevelopes early strength of the paste. On
the other hand, Cthe other hand, C22S hydrates & hardensS hydrates & hardens
slowly so results in less heat generation &slowly so results in less heat generation &
developes most of the ultimate strength.developes most of the ultimate strength.
39. Higher CHigher C33SS→higher early strength-higher→higher early strength-higher
heat generation (roads, cold environments)heat generation (roads, cold environments)
Higher CHigher C22S→lower early strength-lowerS→lower early strength-lower
heat generation (dams)heat generation (dams)
CC33AA: is characteristically fast reacting with: is characteristically fast reacting with
water & may lead to a rapid stiffening of thewater & may lead to a rapid stiffening of the
paste with a large amount of the heatpaste with a large amount of the heat
generation (Flash-Set)-(Quick-Set). In ordergeneration (Flash-Set)-(Quick-Set). In order
to prevent this rapid reaction gypsum isto prevent this rapid reaction gypsum is
added to the clinker. Gypsum, Cadded to the clinker. Gypsum, C33A&waterA&water
react to form relatively insoluble Calcium-react to form relatively insoluble Calcium-
Sulfo-Aluminates.Sulfo-Aluminates.
40. CC33A+CA+CŚŚHH22+10H+10H→C→C44AAŚŚHH1212 (calcium- alumino-(calcium- alumino-
monosulfohydrate)monosulfohydrate)
CC33A+3CA+3CŚŚHH22+26H+26H→C→C66AAŚŚ33HH3232 (calcium-alumino-(calcium-alumino-
trisulfohydrate “ettringite”)trisulfohydrate “ettringite”)
When there is enough gypsum “ettringite” formsWhen there is enough gypsum “ettringite” forms
with great expansionwith great expansion
If there is no gypsumIf there is no gypsum→flash-set→flash-set
more gypsum→ettringitemore gypsum→ettringite
formation increasesformation increases
which will cause crackingwhich will cause cracking
41. Also Calcium-Sulfo Aluminates are prone (lessAlso Calcium-Sulfo Aluminates are prone (less
resistant) to sulfate attack & does not contributeresistant) to sulfate attack & does not contribute
much for strength. The cement to be used inmuch for strength. The cement to be used in
making concretes that are going to be exposedmaking concretes that are going to be exposed
to soils or waters that contain sulfates shouldto soils or waters that contain sulfates should
not contain more than 5% Cnot contain more than 5% C33A.A.
CC44AFAF: The hydration of ferrite phase is not well: The hydration of ferrite phase is not well
understand. Ferrite phase has lesser role inunderstand. Ferrite phase has lesser role in
development of strength. The hydration productsdevelopment of strength. The hydration products
are similar to Care similar to C33A. Alumina & iron oxide occurA. Alumina & iron oxide occur
interchangebly in the hydration products.interchangebly in the hydration products.
CC44AAŚŚHH1212 or Cor C44FFŚŚHH1212
CC66AAŚŚ33HH3232 or Cor C66FFŚŚ33HH3232
42. HEAT OF HYDRATIONHEAT OF HYDRATION
Hydration process of cement is accompanied byHydration process of cement is accompanied by
heat generation (exothermic).heat generation (exothermic).
As concrete is a fair insulator, the generatedAs concrete is a fair insulator, the generated
heat in mass concrete may result in expansion &heat in mass concrete may result in expansion &
cracking. This could be overcome by usingcracking. This could be overcome by using
suitable cement type.suitable cement type.
It could also be advantages for cold wheatherIt could also be advantages for cold wheather
concreting.concreting.
The heat of hydration of OPC is on the order ofThe heat of hydration of OPC is on the order of
85-100 cal/gr.85-100 cal/gr.
About 50% of this heat is liberatedwithin 1-3About 50% of this heat is liberatedwithin 1-3
days & 75% within 7 days.days & 75% within 7 days.
By limiting CBy limiting C33S&CS&C33A content heat of hydrationA content heat of hydration
can be reduced.can be reduced.
43.
44. Heat of Hydration of PureHeat of Hydration of Pure
CompoundsCompounds
Heat of
Hydration
(cal/gr)
C3S 120
C2S 62
C3A 207
C4AF 100
The amount of heatThe amount of heat
liberated is affected by theliberated is affected by the
fractions of thefractions of the
compounds of thecompounds of the
cement.cement.
Heat ofHeat of
Hydration(cal/gr)=120*(%Hydration(cal/gr)=120*(%
CC33S)+62*(%CS)+62*(%C22S)S)
+207*(%C+207*(%C33A)+100*(CA)+100*(C44AF)AF)
45.
46. FINENESS OF CEMENTFINENESS OF CEMENT
As hydration takes place at the surface ofAs hydration takes place at the surface of
the cement particles, it is the surface area ofthe cement particles, it is the surface area of
cement particles which provide the materialcement particles which provide the material
available for hydration. The rate of hydrationavailable for hydration. The rate of hydration
is controlled by fineness of cement. For ais controlled by fineness of cement. For a
rapid rate of hydration a higher fineness israpid rate of hydration a higher fineness is
necessary.necessary.
47. However,However,
Higher fineness requires higher grindingHigher fineness requires higher grinding
(cost )(cost )
Finer cements deteriorate faster uponFiner cements deteriorate faster upon
exposure to atmosphere.exposure to atmosphere.
Finer cements are very sensitive to alkali-Finer cements are very sensitive to alkali-
aggregate reaction.aggregate reaction.
Finer cements require more gypsum forFiner cements require more gypsum for
proper hydration.proper hydration.
Finer cements require more water.Finer cements require more water.
48. Fineness of cement is determined by airFineness of cement is determined by air
permeability methods. For example, in thepermeability methods. For example, in the
Blaine air permeability method a knownBlaine air permeability method a known
volume of air is passed through cement.volume of air is passed through cement.
The time is recorded and the specificThe time is recorded and the specific
surface is calculated by a formula.surface is calculated by a formula.
Fineness is expressed in terms of specificFineness is expressed in terms of specific
surface of the cement (cmsurface of the cement (cm22
/gr). For OPC/gr). For OPC
specific surface is 2600-3000 cmspecific surface is 2600-3000 cm22
/gr./gr.
50. SETTINGSETTING
Setting refers to a change from liquid state toSetting refers to a change from liquid state to
solid state. Although, during setting cementsolid state. Although, during setting cement
paste acquires some strength, setting is differentpaste acquires some strength, setting is different
from hardening.from hardening.
The water content has a marked effect on theThe water content has a marked effect on the
time of setting. In acceptance tests for cement,time of setting. In acceptance tests for cement,
the water content is regulated by bringing thethe water content is regulated by bringing the
paste to a standard condition of wetness. This ispaste to a standard condition of wetness. This is
called “normal consistency”.called “normal consistency”.
51. Normal consistency of O.P.C. Ranges from 20-Normal consistency of O.P.C. Ranges from 20-
30% by weight of cement.30% by weight of cement.
Vicat apparatus is used to determine normalVicat apparatus is used to determine normal
consistency. Normal consistency is that conditionconsistency. Normal consistency is that condition
for which the penetration of a standard weighedfor which the penetration of a standard weighed
plunger into the paste is 10mm in 30sec. By trialplunger into the paste is 10mm in 30sec. By trial
& error determine the w/c ratio.& error determine the w/c ratio.
In practice, the terms initial set&final set are usedIn practice, the terms initial set&final set are used
to describe arbitrary chosen time of setting. Initialto describe arbitrary chosen time of setting. Initial
set indicates the beginning of a noticeableset indicates the beginning of a noticeable
stiffening & final set may be regarded as the startstiffening & final set may be regarded as the start
of hardening (or complete loss of plasticity).of hardening (or complete loss of plasticity).
53. Setting can be obtained by using the vicatSetting can be obtained by using the vicat
apparatus.apparatus.
Initial setting timeInitial setting time>>45min45min
ASTM C150ASTM C150
Final setting timeFinal setting time<<375min375min
InitialInitial >> 1hr (60min)1hr (60min)
TS 19TS 19
FinalFinal << 8hr (480min)8hr (480min)
54. Factors Affecting Setting TimeFactors Affecting Setting Time
Temperature & HumidityTemperature & Humidity
Amount of WaterAmount of Water
Chemical Composition of CementChemical Composition of Cement
Fineness of Cement (finer cement, fasterFineness of Cement (finer cement, faster
setting)setting)
Flash-setFlash-set
Abnormal SettingsAbnormal Settings
False-setFalse-set
55. Flash-SetFlash-Set: is the immediate stiffening of cement: is the immediate stiffening of cement
paste in a few minutes after mixing with water. Itpaste in a few minutes after mixing with water. It
is accompanied by large amount of heatis accompanied by large amount of heat
generation upon reaction of C3A with water.generation upon reaction of C3A with water.
Gypsum is placed in cement to prevent flash-Gypsum is placed in cement to prevent flash-
set. The rigidity can not be overcome & plasticityset. The rigidity can not be overcome & plasticity
may not be regained without addition of water.may not be regained without addition of water.
Amount of gypsum must be such that it will beAmount of gypsum must be such that it will be
used upto almost hardening. Because expansionused upto almost hardening. Because expansion
caused by ettringite can be distributed to thecaused by ettringite can be distributed to the
paste before hardening. More gypsum will causepaste before hardening. More gypsum will cause
undesirable expansion after hardening.undesirable expansion after hardening.
56. False-SetFalse-Set: is a rapid development of rigidity of cement: is a rapid development of rigidity of cement
pastepaste without generation of much heat.without generation of much heat. ThisThis
rigidity can be overcome & plasticity can berigidity can be overcome & plasticity can be
regained by further mixing without addition ofregained by further mixing without addition of
water. In this way cement paste restores itswater. In this way cement paste restores its
plasticity & sets in a normal manner without anyplasticity & sets in a normal manner without any
loss of strength.loss of strength.
Probable Causes of False-Set:Probable Causes of False-Set:
1)1) When gypsum is ground by too hot of a clinker,When gypsum is ground by too hot of a clinker,
gypsum may be dehydrated into hemihydrategypsum may be dehydrated into hemihydrate
(CaSO(CaSO44.1/2H.1/2H22O) or anhydrate (CaSOO) or anhydrate (CaSO44). These). These
materials when react with water gypsum ismaterials when react with water gypsum is
formed, which results in stiffening of the paste.formed, which results in stiffening of the paste.
57. 2)2) Alkali oxides in cement may carbonateAlkali oxides in cement may carbonate
during storage. Upon mixing such aduring storage. Upon mixing such a
cement with water, these alkali carbonatescement with water, these alkali carbonates
will react with Ca(OHwill react with Ca(OH22) (CH-Calcium) (CH-Calcium
Hydroxide) liberated by hydrolysis of CHydroxide) liberated by hydrolysis of C33SS
resulting in CaCOresulting in CaCO33. CaCO. CaCO33 precipates inprecipates in
the mix & results in false-set.the mix & results in false-set.
58. SOUNDNESS OF CEMENTSOUNDNESS OF CEMENT
Soundness is defined as the volume stability of cementSoundness is defined as the volume stability of cement
paste.paste.
The cement paste should not undergo large changes inThe cement paste should not undergo large changes in
volume after it has set. Free CaO&MgO may result involume after it has set. Free CaO&MgO may result in
unsound cement. Upon hydration C&M will form CH&MHunsound cement. Upon hydration C&M will form CH&MH
with volume increase thus cracking.with volume increase thus cracking.
Since unsoundness is not apparent until several monthsSince unsoundness is not apparent until several months
or years, it is necessary to provide an acceleratedor years, it is necessary to provide an accelerated
method for its determination.method for its determination.
1)1) Lechatelier Method: Only free CaO can be determined.Lechatelier Method: Only free CaO can be determined.
2)2) Autoclave Method: Both free CaO&MgO can beAutoclave Method: Both free CaO&MgO can be
determined.determined.
59. STRENGTH OF CEMENTSTRENGTH OF CEMENT
Strength tests are not carried out on neatStrength tests are not carried out on neat
cement pastes, because it is very difficultcement pastes, because it is very difficult
to form these pastes due to cohesiveto form these pastes due to cohesive
property of cement.property of cement.
Strength tests are carried out on cementStrength tests are carried out on cement
mortar prepared by standard gradation (1mortar prepared by standard gradation (1
part cement+3 parts sand+1/2 part water)part cement+3 parts sand+1/2 part water)
60. 1)1) Direct Tension (Tensile Strength):Direct Tension (Tensile Strength):
σσtt=P/1in=P/1in22
Difficult test procedureDifficult test procedure
PP
1”
1”
61.
62. 2)2) Flexural Strength (tensile strength in bending):Flexural Strength (tensile strength in bending):
σσf=(M*C)/If=(M*C)/I
M:maximum momentM:maximum moment
I:moment of inertiaI:moment of inertia
C:distance to bottom fiber from C.G.C:distance to bottom fiber from C.G.
P
L
4cm
4cm
C
63.
64. 3)3) Compression Test:Compression Test:
i) Cubic Sample ii)Flexural Sample after iti) Cubic Sample ii)Flexural Sample after it
is brokenis broken
P
P
σc=P/A
4cm
4cm
4cm
σc=P/A
A=4x4
65.
66. TYPES OF PORTLANDTYPES OF PORTLAND
CEMENTCEMENT
Cements of different chemical compositionCements of different chemical composition
& physical characteristics may exhibit& physical characteristics may exhibit
different properties when hydrated. Itdifferent properties when hydrated. It
should thus be possible to select mixturesshould thus be possible to select mixtures
of raw materials for the production ofof raw materials for the production of
cements with various properties.cements with various properties.
In fact several cement types are availableIn fact several cement types are available
and most of them have been developed toand most of them have been developed to
ensure durability and strength propertiesensure durability and strength properties
to concrete.to concrete.
67. It should also be mentioned that obtaining someIt should also be mentioned that obtaining some
special properties of cement may lead tospecial properties of cement may lead to
undesirable properties in another respect. Forundesirable properties in another respect. For
this reason a balance of requirements may bethis reason a balance of requirements may be
necessary and economic aspects should benecessary and economic aspects should be
considered.considered.
1)1) Standard TypesStandard Types: these cements comply with: these cements comply with
the definition of P.C., and are produced bythe definition of P.C., and are produced by
adjusting the proportions of four majoradjusting the proportions of four major
compounds.compounds.
2)2) Special TypesSpecial Types: these do not necessarily couply: these do not necessarily couply
with the definiton of P.C. & are produced bywith the definiton of P.C. & are produced by
using additional raw materials.using additional raw materials.
68. Standard Cements (ASTM)Standard Cements (ASTM)
Type IType I: Ordinary Portland Cement: Ordinary Portland Cement
Suitable to be used in general concreteSuitable to be used in general concrete
construction when special properties are notconstruction when special properties are not
required.required.
Type IIType II: Modified Portland Cement: Modified Portland Cement
Suitable to be used in general concreteSuitable to be used in general concrete
construction. Main difference between Type I&IIconstruction. Main difference between Type I&II
is the moderate sulfate resistance of Type IIis the moderate sulfate resistance of Type II
cement due to relatively low C3A content (≤%8).cement due to relatively low C3A content (≤%8).
Since CSince C33A is limited rate of reactions is slowerA is limited rate of reactions is slower
and as a result heat of hydration at early ages isand as a result heat of hydration at early ages is
less. *It is suitable to be used in small scaleless. *It is suitable to be used in small scale
mass concrete like retaining walls.mass concrete like retaining walls.
69. Type IIIType III: High Early Strength P.C.: High Early Strength P.C.
Strength development is rapid.Strength development is rapid.
3 days f’3 days f’cc=7 days f’=7 days f’cc of Type Iof Type I
It is useful for repair works, cold weather & forIt is useful for repair works, cold weather & for
early demolding.early demolding.
Its early strength is due to higher CIts early strength is due to higher C33S & CS & C33AA
content.content.
Type IVType IV: Low Heat P.C.: Low Heat P.C.
Generates less heat during hydration & thereforeGenerates less heat during hydration & therefore
gain of strengthis slower.gain of strengthis slower.
In standards a maximum value of CIn standards a maximum value of C33S&CS&C33A& aA& a
minimum value for Cminimum value for C22S are placed.S are placed.
It is used in mass-concrete and hot-weatherIt is used in mass-concrete and hot-weather
concreting.concreting.
70. Type V:Type V: Sulfate Resistant P.C.Sulfate Resistant P.C.
Used in construction where concrete will beUsed in construction where concrete will be
subjected to external sulfate attack – chemicalsubjected to external sulfate attack – chemical
plants, marine & harbor structures.plants, marine & harbor structures.
i)i) During hydration CDuring hydration C33A reacts with gypsum &A reacts with gypsum &
water to form ettringite. In hardened cementwater to form ettringite. In hardened cement
paste calcium-alumino-hydrate can react withpaste calcium-alumino-hydrate can react with
calcium&alumino sulfates, from externalcalcium&alumino sulfates, from external
sources, to form ettringite which causessources, to form ettringite which causes
expansion & cracking.expansion & cracking.
ii)ii) C-H and sulfates can react & form gypsumC-H and sulfates can react & form gypsum
which again causes expansion & cracking.which again causes expansion & cracking.
* In Type V C* In Type V C33A is limited to 5%.A is limited to 5%.
71. Type IA, IIA, IIIAType IA, IIA, IIIA: Air Entrained Portland: Air Entrained Portland
CementCement
Only difference is adding an air-entrainingOnly difference is adding an air-entraining
agent to the cement during manufacturingagent to the cement during manufacturing
to increase freeze-thaw resistance byto increase freeze-thaw resistance by
providing small sized air bubbles inproviding small sized air bubbles in
concrete.concrete.
72. SPECIAL CEMENTSSPECIAL CEMENTS
Portland Pozzolan Cement (P.P.C.)Portland Pozzolan Cement (P.P.C.)
By grinding & blending P.C.By grinding & blending P.C.
Clinker+Pozzolan+GypsumClinker+Pozzolan+Gypsum
P.P.C. Produces less heat of hydration &P.P.C. Produces less heat of hydration &
offers higher sulfate resistance so it canoffers higher sulfate resistance so it can
be used in marine structures & massbe used in marine structures & mass
concrete.concrete.
However, most pozzolans do notHowever, most pozzolans do not
contribute to strength at early ages.contribute to strength at early ages.
The early strength of PPC is less.The early strength of PPC is less.
73. Portland Blast Furnace Slag Cement (P.B.F.S.C.)Portland Blast Furnace Slag Cement (P.B.F.S.C.)
By intergrinding B.F.S.+P.C. Clinker+GypsumBy intergrinding B.F.S.+P.C. Clinker+Gypsum
This cement is less reactive (rate of gain of strengthThis cement is less reactive (rate of gain of strength
& early strength is less but ultimate strength is& early strength is less but ultimate strength is
same)same)
High sulfate resistanceHigh sulfate resistance
Suitable to use in mass concrete constructionSuitable to use in mass concrete construction
Unsuitable for cold weather concretingUnsuitable for cold weather concreting
Both P.P.C.&P.B.F.S.C. Are called blendedBoth P.P.C.&P.B.F.S.C. Are called blended
cements. Their heat of hydration & strengthcements. Their heat of hydration & strength
development are low in early days. Because upondevelopment are low in early days. Because upon
adding water Cadding water C33S compounds start to produce C-S-S compounds start to produce C-S-
Hgels & CH. The Ch & the pozzolanic material reactHgels & CH. The Ch & the pozzolanic material react
together to produce new C-S-H gels. That’s why thetogether to produce new C-S-H gels. That’s why the
early strength is low but the ultimate strength is theearly strength is low but the ultimate strength is the
same when compared to O.P.C.same when compared to O.P.C.
74. White Portland CementWhite Portland Cement
W.P.C. İs made from materials containingW.P.C. İs made from materials containing
a little iron oxide & manganese oxide.a little iron oxide & manganese oxide.
FeFe22OO33 + MnO ≤ 0.8%+ MnO ≤ 0.8%
To avoid contamination by coal ash, oil isTo avoid contamination by coal ash, oil is
used as fuel.used as fuel.
To avoid contamination by iron duringTo avoid contamination by iron during
grinding, instead of steel balls nickel-grinding, instead of steel balls nickel-
molybdenum alloys are used.molybdenum alloys are used.
75. High Alumina CementHigh Alumina Cement
The raw materials for H.A.C. İs limestoneThe raw materials for H.A.C. İs limestone
and Bauxite (Aland Bauxite (Al22OO33 & Fe& Fe22OO33))
These raw materials are interground &These raw materials are interground &
introduced in the kiln clinkered at 1600introduced in the kiln clinkered at 1600°°C.C.
Then the obtained material is ground to aThen the obtained material is ground to a
fineness of 2500-3000 cm2/gr.fineness of 2500-3000 cm2/gr.
The oxide composition is quite differentThe oxide composition is quite different
AlAl22OO33 → 40-45%→ 40-45%
CaO → 35-42%CaO → 35-42%
FeFe22OO33 → 5-15%→ 5-15%
SiOSiO22 → 4-10%→ 4-10%
76. Major compounds are CA & C2SMajor compounds are CA & C2S
It is basically different from O.P.C. & theIt is basically different from O.P.C. & the
concrete made from this cement has veryconcrete made from this cement has very
different properties.different properties.
It has high sulfate resistance.It has high sulfate resistance.
Very high early strength (emergency repairs)Very high early strength (emergency repairs)
About 80% of ultimate strength is obtained withinAbout 80% of ultimate strength is obtained within
24 hours. But the strength is adversely affected24 hours. But the strength is adversely affected
by temperature. The setting time is not as rapidby temperature. The setting time is not as rapid
as gain of strength.as gain of strength.
Initial setting time is 4 hrs & final setting time is 5Initial setting time is 4 hrs & final setting time is 5
hrs.hrs.
77. STANDARD TURKISH CEMENTSSTANDARD TURKISH CEMENTS
(TS 19) – Cancelled(TS 19) – Cancelled
TS 19 groups them into 3TS 19 groups them into 3
P.Ç. 32.5P.Ç. 32.5 → min. Compressive strength is 32.5 MPa in→ min. Compressive strength is 32.5 MPa in
28 days.28 days.
P.Ç. 42.5P.Ç. 42.5
P.Ç. 52.5P.Ç. 52.5
Special Cements are:Special Cements are:
TS 20 –Blast Furnace Slag CementTS 20 –Blast Furnace Slag Cement
CÇ 32.5 – Cüruflu ÇimentoCÇ 32.5 – Cüruflu Çimento
CÇ 42.5CÇ 42.5
TS 21 – White Portland Cement BPÇ 32.5-42.5TS 21 – White Portland Cement BPÇ 32.5-42.5
TS22 – Masonry Cement, HÇ 16 (Harç Çimentosu)TS22 – Masonry Cement, HÇ 16 (Harç Çimentosu)
TS 26 – Trass Cement, TÇ 32.5 (Traslı Çimento)TS 26 – Trass Cement, TÇ 32.5 (Traslı Çimento)
TS 640 – Fly Ash Cement, UKÇ 32.5 (Uçucu KüllüTS 640 – Fly Ash Cement, UKÇ 32.5 (Uçucu Küllü
Çimento)Çimento)
78. TS EN 197-TS EN 197-
11
NEWNEW
CEM cementsCEM cements
CEM I – Portland Cement
CEM II – Portland Composite
Cement
CEM III – Portland Blast Furnace
Slag Cement
CEM IV – Pozzolanic Cement
CEM V – Composite Cement
27 different cements
79. TS EN 197-1TS EN 197-1
CEM cements :CEM cements :
– Binding property is mainly due to hydration ofBinding property is mainly due to hydration of
calcium-silicatescalcium-silicates
– Reactive C + Reactive S > 50%Reactive C + Reactive S > 50%
Clinker, major and minor mineral admixturesClinker, major and minor mineral admixtures
– Clinker + Major + Minor = 100% (mass) + GypsumClinker + Major + Minor = 100% (mass) + Gypsum
– Major > 5% by massMajor > 5% by mass
– MinorMinor ≤≤ 5% by mass5% by mass
80. TS EN 197-1TS EN 197-1
Mineral AdmixturesMineral Admixtures
K : ClinkerK : Clinker
D : Silica FumeD : Silica Fume
P : Natural PozzolanP : Natural Pozzolan
Q : Calcined Natural PozzolanQ : Calcined Natural Pozzolan
T : Calcined ShaleT : Calcined Shale
W : Class – C Fly AshW : Class – C Fly Ash
V : Class – F Fly AshV : Class – F Fly Ash
L : Limestone (Organic compound < 0.5%)L : Limestone (Organic compound < 0.5%)
LL : Limestone (Organic compound < 0.2%)LL : Limestone (Organic compound < 0.2%)
S : Granulated Blast Furnace SlagS : Granulated Blast Furnace Slag
81. TS EN 197-1TS EN 197-1
CompositionComposition
A : Lowest amount of mineral admixtureA : Lowest amount of mineral admixture
B : Mineral admixture amount is > AB : Mineral admixture amount is > A
C : Mineral admixture amount is > BC : Mineral admixture amount is > B
82. TS EN 197-1TS EN 197-1
CompositionComposition
CEM I :CEM I : Portland CementPortland Cement
95-100%95-100% KK + 0-5%+ 0-5% MinorMinor
83. TS EN 197-1TS EN 197-1
CompositionComposition
CEM II :CEM II : Portland Composite CementPortland Composite Cement
CEM II/A-S :CEM II/A-S : Portland Slag CementPortland Slag Cement
80-94%80-94% KK + 6-20%+ 6-20% SS + 0-5%+ 0-5% MinorMinor
CEM II/B-S :CEM II/B-S : Portland Slag CementPortland Slag Cement
65-79%65-79% KK + 21-35%+ 21-35% SS + 0-5%+ 0-5% MinorMinor
CEM II/B-P :CEM II/B-P : Portland Pozzolanic CementPortland Pozzolanic Cement
65-79%65-79% KK + 21-35%+ 21-35% PP + 0-5%+ 0-5% MinorMinor
CEM II/A-V :CEM II/A-V : Portland Fly Ash CementPortland Fly Ash Cement
80-94%80-94% KK + 6-20%+ 6-20% VV + 0-5%+ 0-5% MinorMinor
84. TS EN 197-1TS EN 197-1
CompositionComposition
CEM III :CEM III : Portland Blast Furnace Slag Cement
CEM III/A :CEM III/A : Portland Blast Furnace SlagPortland Blast Furnace Slag
CementCement
35-64%35-64% KK + 36-65%+ 36-65% SS + 0-5%+ 0-5% MinorMinor
CEM III/B :CEM III/B : Portland Blast Furnace SlagPortland Blast Furnace Slag
CementCement
20-34%20-34% KK + 66-80%+ 66-80% SS + 0-5%+ 0-5% MinorMinor
CEM III/C :CEM III/C : Portland Blast Furnace SlagPortland Blast Furnace Slag
CementCement
85. TS EN 197-1TS EN 197-1
CompositionComposition
CEM IV :CEM IV : Pozzolanic Cement
CEM IV/A :CEM IV/A : Pozzolanic CementPozzolanic Cement
65-89%65-89% KK + 11-35%+ 11-35% (D,P,Q,V,W)(D,P,Q,V,W) + 0-5%+ 0-5% MinorMinor
CEM IV/B :CEM IV/B : Pozzolanic CementPozzolanic Cement
45-64%45-64% KK + 36-55%+ 36-55% (D,P,Q,V,W)(D,P,Q,V,W) + 0-5%+ 0-5% MinorMinor
86. TS EN 197-1TS EN 197-1
CompositionComposition
CEM V :CEM V : CompositeComposite Cement
CEM V/A :CEM V/A : Composite CementComposite Cement
40-64%40-64% KK + 18-30%+ 18-30% SS + 18-30%+ 18-30% (P,Q,V)(P,Q,V) + 0-5%+ 0-5%
MinorMinor
CEM V/B :CEM V/B : Composite CementComposite Cement
20-38%20-38% KK + 31-50%+ 31-50% SS + 31-50%+ 31-50% (P,Q,V)(P,Q,V) + 0-5%+ 0-5%
MinorMinor
