ASTM Types of Cement

 

There are following types of cement.

1. Type I Normal cement
   
2. Type IA Normal + air entrained agents
   
3. Type II Moderate sulphate resistant cement
   
4. Type IIA Moderate sulphate resistant cement + air entrained agents
   
5. Type III High early strength cement
   
6. Type IIIA High early strength cement + air entrained agents
   
7. Type IV Low heat cement
   
8. Type V High sulphate resistant cement
   
   

   Type I  Normal Cement.

   Characteristics

9. Used for general purpose
   
10. Available widely
    
11. Used where concrete is not subjected to specific exposures such as sulphate attacks from soil or water or to an objectionable temperature rise due to heat of hydration
    
12. Suitable for all uses e.g pavement, sidewalk, R.C buildings, bridges, water tanks, culverts, sewers etc.
    This type of cement reaches its design strength in 28 days.

Contents

1. MgO is less than 0.6 %
   
2. Insolouble residue is less than 0.75 %
   
3. Loss on ignition is less than 3%
   
4. Insolouble residue
   
5. It is determined by treatment with HCl. It is due to impurities in Gypsum. 

Loss on ignition:

• 200°C temperature is maintained for 1 hour for 10 grams of material.

Air entrained agents:

Smaller quantities of air entraining materials are interground with clinker at the time of manufacture to produce minte, well distributed and completely separated air bubbles. These are in millions per cubic feet. Used against freezing and thawing.

Type II (Moderate Sulphate Resistance Cement)

This type of cement is used where precaution against moderate sulphate attack is important. Like where concrete will come in  contact with ground or buried in ground. e.g in drainage structures, large piers, retaining walls etc
Type II generates less heat than type I and reaches its desired strength in 45 days

Type IIA

It is same as Type II but just having air entraining agents.

Type III (High early strength cement/Rapid hardening cement)

1. High C3S content upto 70%
   
2. Also it has high fineness and have minimum surface area of 325 m2/kg
   
3. It is used where formwork is to be removed quickly or sufficient strength for further construction is required. It has high heat of hydration and achieves its design strength in 7 days or less. Due to high heat generation, it should not be used in mass concreting or large structural section. Though in cold climate it may serve well.
   

Type IIIA

It is the same as Type III plus air entrained agents

Type IV (Low heat cement)

this type of cement is used in mass concreting because it generates less heat, though sets slowly but becomes much stronger after curing. Its design strength is 90 days.

Type V (High sulphate resisting cement)

When concrete is exposed to highly alkaline soil or water having high sulphate content then this type is used.
This cement has a low C3A content so as to avoid sulphate attack from outside the concrete. Otherwise the formation of calcium sulphoaluminate and gypsum would cause disruption of conrete due to an increase in volume of resultant compounds.