The ingredients of concrete:cement

The properties of the concrete are depend on the quantities and the qualities of its components. Cement acts as the most active component in concrete manufacturing and it has the largest unit cost. Thus, select the type of cement that use for concrete manufacturing is most important to obtain the balance on the qualities of the concrete made and the economically of costs.

Portland cement is the most common type of cement that generally used in construction. The types of Portland cement represent its durability, strength and hardness. It indicates its ability to withstand the load, the flexibility to the temperature and moisture changes and its performance of durability.

Normally, Portland cement is classified into types I, II, III and IV. 

Type I Portland cement which called ordinary Portland cement (OPC) is the general type of cement used. It normally used for making precast and precast-prestressed concrete that is not in contact with the soils or ground water. The manufactures of OPC are decreasing all around the world nowadays since that is contention about the environmental pollution, economic and the lower energy consumption.

Type II is moderate sulfate resistant cement. This type of cement is normally used for the construction of buildings at the place which is exposed to the sulfate attack. Sulfate in solution can permeate into hardened concrete and attack the calcium hydroxide inside and even hydrated silicates. Uses of Type II cement:

- concrete use in marine condition

- concrete use in foundation of building, normally soil infested with sulfate

- concrete use in sewage disposal system

Type III is High early strength cement. This cement is similar to Type I and II cement, but ground finer. This cement have typically high C3S or C3A content which gives it have the compressive strength in shorter time when compare to Type I and II at the same time. The development of Type III is used in emergency work or repair.

Type IV is low heat cement. It is known with its ability to produce large quantities of heat during hydration. The low-heat evolution is achieved by reducing the contents of C3S and C3A which can eliminate the maximum heat of hydration. It has other properties that same with OPC which is setting time and soundness.

Type of cement	Uses
I	General purpose cement
II	For moderate sulfate resistance
III	Has early early strength gain
IV	Use in dams or large projects where the heat hydration is minimize