HYDROPHOBIC CEMENT - MANUFACTURE, PROPERTIES AND USES

Hydrophobic Cement

Hydrophobic cement contains admixtures which decreases the wetting ability of cement grains.The usual hydrophobic admixtures are acidol,naphthensoap,oxidized petrolatum etc.Hydrophobic cement is obtained by grinding Ordinary Portland Cement clinkers with water repellent film-forming substance such as stearic acid and oleic acid in order to reduce the rate of deterioration when the cement stored under unfavourable conditions.It is also known as Hydrophobic Cement.

Manufacture of Hydrophobic Cement

Hydrophobic cement is manufactured from ordinary portland cement clinkers.After grinding cement into fine particles these fine particles are sprayed in one direction and water repellent film forming substance such as stearic acid or oleic acid is sprayed from opposite direction.Using this method each particle of cement gets uniformly coated with repellent film forming substance.This layer protects cement from the bad effect of moisture during storage and transportation.

Properties of Hydrophobic Cement

PROPERTIES	VALUE
Fineness	350m2/kg
SOUNDNESS
Lechatelier (mm)	10mm
Autoclave	0.8%
SETTING TIME
Initial Setting	30min
Final Setting	600min
COMPRESSIVE STRENGTH
3 Days	16 MPa
7 Days	22 MPa
28 Days	30 MPa
Water Absorption	0.3-1  %

Uses of Hydrophobic Cement

• Used in water treatment plant.
• Used in dams and retaining walls.
• Used in hydro technical construction.
• Used in marine structures. 
• Used in mass concrete work.
• Used in longer storage periods and extremely wet climatic condition.

Advantages of Hydrophobic Cement

• Its strength is same as that of ordinary cement after 28 days.
• It sets and hardens fast,normally three minutes after being mixed with water.
• It is used in the construction of water structures such as dams,spillway etc.
• It is used in cold climatic conditions.

Disadvantages of Hydrophobic Cement

• It can not be used when temperature is below 40℉.
• It does not work on frozen surfaces.
• It required skilled labour.
• It is very costly.