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/.