TYPES OF PORTLAND CEMENT
EMIL HAJILI
OUTLINEO Introduction
O Standard Types
O Special Types
INTRODUCTIONCements of different chemical composition & physical characteristics may exhibit different properties when hydrated. It should thus be possible to select mixtures of raw materials for the production of cements with various properties.
INTRODUCTIONIt should also be mentioned that obtaining some special properties of cement may lead to undesirable properties in another respect. For this reason a balance of requirements may be necessary and economic aspects should be considered. There are two main types of cement: Standard Types Special Types
STANDARD TYPESStandard type cements comply with the definition of P.C., and they are produced by adjusting the proportions of four major compounds, which are C3S, C2S, C3A and C4AF.There are 5 standard type cements.o Type Io Type IIo Type IIIo Type IVo Type V
TYPE IO It is ordinary Portland Cement and used for
general construction work when the special properties of the other types are not required.
O It is normally used for reinforced concrete buildings, bridges, pavements and sidewalks when the soil conditions are normal, for concrete masonry units, and for all uses where the concrete is not subjected to special sulfate hazard, heat of hydration is not objectionable, where freezing-thawing is not expected.
TYPE IIIt is modified Portland Cement.O It has better resistance to the action of
sulfates than ordinary Portland cement (Type I) and used where sulfate concentrations in groundwater are higher than normal but not very severe.
O Generates heat at a slower rate than OPC and is used in certain concrete mass work like retaining walls.
O Reduced temperature rise is beneficial for hot weather concrete, too.
TYPE IIIIt is high early strength cement. O Used where high early strengths are required
at early periods, usually a week or less. O It is particularly useful where it is required to
remove forms as soon as possible or when the structure must be brought into service quickly.
O High-early strength makes it possible to reduce the period of protection for concrete during cold weather.
TYPE IVIt is low heat Portland Cement.O It is used where the amount and rate
of heat generation must be minimized.
O Strength is also developed at a slower rate. It is intended for use in massive concrete structures such as dams.
Type VIt is sulfate resistant Portland Cement.O It is used in structures subject to
sulfate attack, chemical plants, etc. O It is also resistant to the action of
sea water.
AIR ENTRAINED PORTLAND CEMENT
There are three types air entrained Portland cement.O Air Entrained Type IO Air Entrained Type IIO Air Entrained Type IIIOnly difference is adding an air-entraining agent to the cement during manufacturing to increase freeze-thaw resistance by providing small sized air bubbles in concrete.
STANDARD TYPES
Classification CharacteristicsType I General purpose Fairly high C3S content for
good early strength development
Type II Moderate sulfate resistance Low C3A content (<8%)Type III High early strength Ground more finely, may
have slightly more C3SType IV Low heat of hydration Low content of C3S
(<50%) and C3AType V High sulfate resistance Very low C3A content
(<5%)
SPECIAL TYPESSpecial cements are cements that serve some specific function such as altering the setting or hardening behavior of a concrete, producing different colors for architectural effects, imparting superior workability, imparting water retention and plasticity to mortars, resisting the penetration of water in walls or containment vessels or simply reducing the cost of the cementing agent.
PORTLAND POZZOLAN CEMENT
Portland pozzolan (the name came from Volcanic dust found at Pozzuoli, Italy ) cement is also an environment friendly product of cement which uses hazardous substituents (artificial pozzolan) like Fly ash, slag (blast-furnace) and silica fume. Volcanic ash (natural pozzolan) is also substituent of pozzolan cement.
O All pozzolans contain silica and siliceous or aluminous minerals. O Portland Pozzolan Cement produces less heat of hydration and
offers greater resistance to the sulfate attack than OPC .O Most pozzolans do not contribute to the strength at early ages,
so strength gain of these cements is slow. O Therefore they require larger curing period, but the ultimate
strength is the same as OPC.
PORTLAND POZZOLAN CEMENT
Chemical PropertiesLOI % MgO % SO3 % Pozzolan substance
%5.0 6.0 3.0 15-35
Physical PropertiesFinenes
s (m2/kg)
Setting time (min)
Compressive Strength (MPa)
Soundness
Initial Final 3 day 7 day 28 day
LeChtelier
In (mm)225 30 600 16 22 33 10
PORTLAND BLAST-FURNACE SLAG CEMENT
Granulated blast-furnace slag is a waste product of the manufacture of iron. The amount of iron and slag being obtained is in the same order. This cement is less reactive than OPC and gains strength at a slower rate during first 28 days, so adequate curing is essential. O suitable for mass concrete O unsuitable for cold weather O has high sulfate resistance (suitable for use in
sea-water construction).
PORTLAND BLAST-FURNACE SLAG CEMENTBoth P.P.C.&P.B.F.S.C. are called blended cements. Their heat of hydration & strength development are low in early days. Because upon adding water C3S compounds start to produce C-S-H gels & CH. The CH & the pozzolanic material react together to produce new C-S-H gels. That’s why the early strength is low but the ultimate strength is the same when compared to O.P.C.
PORTLAND BLAST-FURNACE SLAG CEMENT
Chemical PropertiesLOI % MgO % SO3 % IR % Cl % Slag %5.0 6.0 3.0 3.0 0.1 25-70
Physical PropertiesFinenes
s (m2/kg)
Setting time (min)
Compressive Strength (MPa)
Soundness
Initial Final 3 day 7 day 28 day
LeChtelier
In (mm)225 30 600 16 22 33 10
HIGH ALUMINA CEMENT
The raw materials for H.A.C. are limestone and bauxite (Al2O3 & Fe2O3) which are interground & introduced in the kiln clinkered at 1600°C. The solidified material is fragmented and ground to a fineness of 2500-3000 cm2/gr. Its color is dark grey. O Major compounds are C3A & C2SO With special aggregates such as firebrick, it can be used to make
refractory concrete that can stand high furnace temperature (T> 1300oC).
O It has high sulfate resistance.O Very high early strength (emergency repairs)O About 80% of ultimate strength is obtained within 24 hours. But
the strength is adversely affected by temperature. The setting time is not as rapid as gain of strength.
O Initial setting time is 4 hrs & final setting time is 5 hrs.
WHITE PORTLAND CEMENT
It is made from raw materials containing very little iron oxide and manganese oxide (Fe2O3 + MnO ≤ 0.8%).O To avoid contamination, oil is used as fuel in the kiln
instead of coal ash and nickel-molybdenum alloys are used in grinding process instead of steel balls.
O The cost of grinding is higher and this completed with the more expensive raw materials makes White Cement rather expensive (about 2 times).
O Specific gravity and strength of White Portland Cement are less than those of OPC.
O WPC is used for architectural purposes. It is not liable to cause staining, since it has a low content of soluble alkalies.
MASONRY CEMENTMasonry Cement is a special type of Cement which is exclusively used for Plastering and brick work. It is very smooth and gives super surface finish. Masonry Cement is produced by intimately grinding Portland cement clinker with pozzolonic materials or inert materials and gypsum.O It has low compressive strength that is why it
can’t be used for structural concrete, flooring and foundation work.
O It contains air-entering agents which improve air retentivity, Plasticity, and workability of motors.
NOMENCLATURE FOR CEMENT
Cement is described in terms of cement type, strength class and rate of early strength development.
NOMENCLATURE FOR CEMENT
For example;CEM II/A-S42.5N O CEM II: Type of cement O A: Proportion of cement clinker O S: Sub-type indicates the second main
constituentO 42.5: Standard strength at 28 daysO N: Sub-class indicates the rate of early
strength development (R: rapid, N: normal, L: low)
Type of CementO CEM I – Portland CementO CEM II – Portland Composite CementO CEM III – Portland Blast Furnace Slag
CementO CEM IV – Pozzolanic CementO CEM V – Composite Cement
Proportion of Cement Clinker
O A: high amount of clinker
O B: medium amount of clinker
O C: low amount of clinker
The Second Main Constituent
O K : ClinkerO D : Silica FumeO P : Natural PozzolanO Q : Calcined Natural PozzolanO T : Calcined ShaleO W : Class – C Fly AshO V : Class – F Fly AshO L : Limestone (Organic compound < 0.5%)O LL : Limestone (Organic compound < 0.2%)O S : Granulated Blast Furnace Slag
Standard Strength at 28 days
O 32.5 – 32.5 MPa at 28 day
O 42.5 – 42.5 MPa at 28 day
O 52.5 – 52.5 MPa at 28 day
Rate of Early Strength Development
O R: rapid early strength development
O N: normal early strength development
O L: low early strength development
Clin
ker
Additive name
Addi
tive
amou
nt
CEM I Portland cement CEM I 95-100 ─ ─ 0-5CEM II/A-S 80-94 6-20 0-5CEM II/B-S 65-79 21-35 0-5
Portland-silica fume cement CEM II/A-D 90-94 Silica fume 6-10 0-5CEM II/A-P 80-94 6-20 0-5CEM II/B-P 65-79 21-35 0-5CEM II/A-Q 80-94 6-20 0-5CEM II/B-Q 65-79 21-35 0-5CEM II/A-V 80-94 6-20 0-5CEM II/B-V 65-79 21-35 0-5CEM II/A-W 80-94 6-20 0-5CEM II/B-W 65-79 21-35 0-5CEM II/A-T 80-94 6-20 0-5CEM II/B-T 65-79 21-35 0-5CEM II/A-L 80-94 6-20 0-5CEM II/B-L 65-79 21-35 0-5
CEM II/A-LL 80-94 6-20 0-5CEM II/B-LL 65-79 21-35 0-5CEM II/A-M 80-94 6-20 0-5CEM II/B-M 65-79 21-35 0-5CEM III/A 36-64 36-65 0-5CEM III/B 20-34 66-80 0-5CEM III/C 5-19 81-95 0-5CEM IV/A 65-89 11-35 0-5CEM IV/B 45-64 36-55 0-5CEM V/A 40-64 18-30 0-5CEM V/B 20-38 31-50 0-5
Type Name
Sym
bol
Blastfurnace slag
Mixture of Silica, Pozzolan and Fly ash
Mixture of all materials
Mixture of Pozzolan and Fly ash siliceous
Min
or co
nstit
uent
Natural pozzolana
Natural calcined
Fly ash siliceous
Fly ash calcareous
Burnt shale
Limestone
Blastfurnace cementCEM III
CEM V
CEM IV
Composite cement
Pozzolanic cement
Main constituent
Portland-slag cement
Portland-pozzolana cement
Portland-fly ash cement
Portland-burnt shale cement
Portland-limestone cement
Portland-composite cement
CEM II
Blastfurnace slag
REFERENCE1. Ciment-Catala, “Cement
Classification”. www.ciment-catala.org. Iyun 2000.
2. Hewlett, P. C. (1998). Lea`s Chemistry of Cement and Concrete. Dundee: Butterworth-Heinemann.
3. N.Winter. (2005). Retrieved from http://www.understanding-cement.com/.
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