Types of Cement in Nepal

In Nepal, there are various kind of cements available. Each of the cements has it’s own properties, advantages and uses. Indian Standard IS code is also in use in Nepal and cement manufacturers in Nepal also follow the same standard. There are different standards for different Kinds of Cement of different price ranges.

After Nepal had 7.8 Richter Earthquake in 2072 B.S, construction industry scaled to a higher quantity and at the same time, cement manufacturers were given license for manufacturing cement in Nepal.

All the types of cement available in Nepal are explained below.

Various Cement Types with Explanations

Ordinary Portland Cement

Ordinary Portland Cement is the most widely used cement. It is also called OPC cement. The relevant standard to OPC cement is IS 269-1976. Recently, reports have been released that Nepal has exported cement of around 4000 Million NPR and the majority of the cement manufactured is OPC cement.

The ordinary Portland cement is made by crushing the clinker and mixing it with 2 to 3 percent of gypsum. The chemical composition of OPC cement is Tricalcium silicates (25 to 50%), DiCalcium Silicate (20 to 45%), Tricalcium Aluminate (5 to 12%), TetraCalcium Aluminoferrite ( 6 to 12% ), and Gypsum. It also has magnesium oxide and it’s quantity should not exceed more than 5% according to the Indian Standard.

OPC cement is available in three grades, namely 33 grade, 43grade and 53 grade. Hongshi Cement is an example of OPC cement in Nepal.

Portland Pozzolona Cement

Portland Pozzolona cement is manufactured by mixing cement clinker with gypsum and pozzolanic material. The pozzolanic material is reactive silica and alumina material. These pozzolanic material reacts with Lime when water is added to produce cementious material. The quantity of pozzolanic material may range from 15 percent to 35 percent.

In Nepal, PPC cement is only available in 33 grade.

PPC cement is popular because PPC cement is considered more durable, workable, has more finishing quality and fineness than OPC cement. The main difference between PPC cement and OPC cement lies in their setting time.

Rapid Hardening Cement

The Rapid Hardening Cement is different from OPC cement. The composition of Rapid Hardening cement is

• 60% Tricalcium Silicate (C3S)
• 15% Dicalcium Silicate (C2S)
• 10% Tricalcium Aluminate (C3A) and
• 8% TetraCalcium Aluminoferrite  of the total weight of cement.

It sets quickly than OPC cement. It is because it has higher percent of Tricalcium Silicate as compared to OPC cement.

For a same water cement ratio, Rapid hardening cement will gain same strength in 3 days as does OPC cement in 7 days.

Quick Setting Cement

Quick Setting Cement is used in places where concreting is required to be done.  Aluminium Sulphate is added in the ratio of 1% to 3% against 100% of clinker to form Quick Setting Cement.

The initial setting time of the quick setting cement is 5 minutes and final setting time is 30 minutes. Quick setting cement can’t be used in above the ground construction works because it has high heat of hydration and therefore cracks will easily appear.

Low Heat Cement

Low heat cement has higher proportion of Dicalcium silicates and lower percentage (6%) of tricalcium silicates. The cement is less reactive and takes longer time to achieve initial and final setting time.

Because of low setting time, this cement is used for construction of gravity dams.

Sulfates Resisting Cement

Sulfate Resisting Cement is used in construction work in soils where sulphate content is very high. The cement has reduced content of Tricalcium Aluminate which is responsible for reacting with sulphate. The sulphate content of the cement is also made low.

This category of cement is extensively used in siphon, culverts, canals, retaining walls and in similar structures.

Blast Furnace Slag Cement

Blast Furnace Slag cement is produced by mixing the byproduct slag obtained from iron refinery industry with the cement clinker and grinding them finely to produce cement.

The percentage of slag differs for different construction purposes. For example, slag percentage up to 40% is used for general construction whereas slag percentage for marine structures, structures prone to chloride and sulphide attack is 80%.

The initial setting time of this cement is higher but the final strength is similar to OPC cement.

High Alumina Cement

High Alumina Cement is a kind of rapid hardening cement. It’s initial setting time is 3.5 hours and final setting time is 5 hours.

This cement is used in places where concrete will be exposed to frost, high temperature or severe weather. This cement is more workable than OPC cement.

White Cement

White Cement has similar composition to OPC cement except that the raw materials having content of iron oxide is not used at all. This is costlier than OPC cement and they are used for architectural purposes like curtain wall, ornamental concrete products, landscaping structures in gardens.

Colored Cement

Colored pigments are mixed with normal Cement to formed colored cement. This cement is used for decorative purpose and is a bit expensive than OPC cement.

Air Entraining Cement

Air Entraining Cement is used to manufacture frost resistant cement. They are manufactured by mixing air entraining agents like sodium sulphates, glues and various resins.

This cement is also more workable than ordinary OPC cement.

Expansive Cement

Expansive cement is used for grouting purpose or in prestressed structural members. It is made by mixing and grinding sulphoaluminate clinker with limestone and clay mixed clinker. Sulphoaluminate compound gives expansive properties to cement.

Hydrophophic Cement

Hydrophobic cement is obtained by mixing the normal OPC cement clinker with hydrophobic chemical such as oleic acid. Hydrophobic chemical is mixed in order to prolong the life of cement in case of long term storage.