GROUP 5LOW HEAT PORTLAND

CEMENT (TYPE IV)

Team members :

INTRODUCTION

LOW HEAT PORTLAND CEMENT (TYPE IV)

Type IV is a low heat of hydration cement for use where the rate and amount of heat generated must be minimized.

It develops strength at a slower rate than Type I cement (Original Portland Cement).

Classification : Low Heat of hydration (slow reacting)

•

A limitation on this type is that the maximum percentage of (C3A) is seven, and the maximum percentage of (C3S) is thirty-five.

Typical Compound Composition :

28% (C3S), 49% (C2S), 4% (C3A), 12% (C4AF), 1.8% MgO, 1.9% (SO3), 0.9% Ignition loss, and 0.8% free CaO.

•The percentages of (C2S) and (C4AF) are relatively high and (C3S) and (C3A) are relatively low .

Characteristics Low content of C3S (<50%) and C3A (max % is 7)

Parameter CCL typical AS3792 Limits

Test Method

Si02AI2O3Fe2O3CaOMgOSO3LOI

ChorideNa2O

Equivalent

29.2%11.1%1.2%

50.4%4.6%2.2%0.7%

0.01%0.4%

3.5%

XRFXRFXRFXRFXRFXRF

AS2350.2ASTM C114ASTMC114

Chemical Properties

Benefits of Low Heat Cement :

1) Assists in minimising the potential for thermal cracking in thick concrete sections

2) Significantly improved later-age concrete strengths

3) Improved durability performance

4) Increased workability and pumpability with large pours

Constructing dams

Product applications

1.

- Low Heat Cement is ideal for mass concrete applications, including :

Bakun Dam at Sarawak

- Low Heat Cement can also be used in soil stabilisation , underground mining and marine concrete applications where engineering properties such as

workability and durability are required.

Large footings, large raft slabs, wind turbine plinths2.

Large footings

wind turbine plinths

Large raft slabs

Very high strength concrete3.

Was used in the u-beams of the North Boulevard Bridge

KLCC Flowable concrete was used in the curved and straight girders

Extra thick (1.5m) walls required for the hospital’s radiation unit

Low Heat Cement Properties

- The following table details the relevant specified requirements of AS 3972 and the typical values achieved by Low Heat Cement

Compatibilities- Low Heat Cement is compatible with :

Admixtures that comply with AS 1478 – Chemical Admixtures for Concrete.1.

Fly ashes complying with AS 3582.1 – Supplementary Cementitious Materials for Use with Portland cement: Fly ash.

Ground granulated blast furnace slags complying with AS3582.2 - Supplementary cementitious materials for use with Portland cement: Slag - ground granulated Ironblast-furnace.

Amorphous Silica complying with AS3582.3 -Supplementary cementitious materials for use with Portland cement : Amorphous silica.

Other cements complying with AS3972 - Portland and blended cements.

2.

3.

4.

5.

Concrete Properties- Strength development in Portland cement concrete is affected by a number of factors such as

the physical and chemical properties of the cement, water cement ratio, admixtures, curing and environmental conditions.

- The following graph depicts indicative compressive strength development for Low Heat Cement.

Effect of Excess Water Addition on Concrete Compressive Strength

Is generally not stocked by manufacturers but some might

consider a large special order.

Has not been made for many years and rarely used today,

because similar properties can be obtained by using a blended cement.

LOW HEAT PORTLAND CEMENT

(TYPE IV)

ConclusionContent:C3A & C3S is lowerC2S is higher

Characteristic :-Slow rate of reaction-Produce low heat for hydration-Low early strength-Higher ultimate strength

-Less cracking-Min specific surface by ISI : 3200cm²/g

Strength start after 7 days & gradually continue up to 1 year

Use :-Mass concrete-Marine (Better sulphate resisteance, <C3A )

Not suitable :-Cold weather-Post-tensioning job

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