Portland Pozzolana Cement (PPC)
The Portland Pozzolana Cement is a kind of Blended Cement which is produced by either intergrinding of OPC clinker along with gypsum and pozzolanic materials in certain proportions or grinding the OPC clinker, gypsum and Pozzolanic materials separately and thoroughly blending them in certain proportions.
Pozzolana is a natural or artificial material containing silica in a reactive form. It may be further discussed as siliceous or siliceous and aluminous material which in itself possesses little, or no cementitious properties but will in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperature to form compounds possessing cementitious properties. It is essential that pozzolana be in a finely divided state as it is only then that silica can combine with calcium hydroxide (liberated by the hydrating Portland Cement) in the presence of water to form stable calcium silicates which have cementitious properties. The pozzolanic materials commonly used are:
OPC is environment friendly as well as economical
Ordinary Portland Cement (OPC-53, OPC-43, OPC-33)
The 43 grade OPC is the most popular general-purpose cement in the country today. The production of 43 grade OPC is nearly 50% of the total production of cement in the country.
The 43 grade OPC can be used for following applications:
General Civil Engineering construction work
RCC works(preferably where grade of concrete is up to M-30)
Pre-cast items such as blocks, tiles, pipes etc
Asbestos products such as sheets and pipes
Non-structural works such as plastering, flooring etc.
The compressive strength of cement when tested as per IS code shall be minimum 43 MPa. The physical and chemical properties of this cement are given in the table:
Physical Characteristics of 43 Grade OPC (BIS Requirement)
Is Code Finene SS (sq.m/k g Min) Soundness by Setting Time Compressive Strength
Lechatlier (mm)max Auto clave Max (%) Initial (mts) min Final (mts) Max 1 day Min Mpa 3 day Min Mpa 7 day Min Mpa 28 day Min Mpa
(IS 8112- 1989) 225 10 0.8 30 600 Not specified 23 33 43
Chemical Characteristics of 43 Grade OPC (BIS Requirement)
Is Code Lime Saturation Factor Alumina Ration Min Insoluble MgO (%) Sulphuric Anhydride Loss ignition (%) Max
(IS 8112 - 1989) 0.66 Min 1.02 Max 0.66 3 6 2.5% Max when C3A is 5 or less. 3% Max when C3A is greater than 5 5