Heidelberg Cement India Limited Imlai Daimond -1 Damoh, Madhya Pradesh

PSC or Portland Slag cement is manufactured by either grinding the Portland clinker with gypsum and granulated slag or blending the ground granulated blast furnace slag (GGBS) with Ordinary Portland cement by means of mechanical blenders. Normal composition of portland cement is 30 % clinker, 5 % gypsum and 70 % blast furnace granulated slag. The quality of slag used in cement manufacturing is governed by IS 12089:1987. PSC has been voted as the most suitable cement for mass construction because of its low heat of hydration. Slow hydration of PSC liberates the C-S-H gel over a longer time period thus reducing the pores porosity of concrete. The dense concrete is more suitable for structures in the coastal regions as the flow of water inside the concrete is restricted resulting in the increase durability of the structure. PSC (in required proportion) offers an improved resistance to sulphate attack from the sea water because of low water permeability, depleted quantum of Ca(OH)2 and C3A content.

PPC or Portland Pozzolana Cement is a kind of Blended Cement which is produced by grinding the Portland clinker with gypsum and pozzolanic materials in measured proportions or by blending Ordinary Portland Cement (OPC), with Pozzolanic materials in certain proportions. Pozzolana is any natural or artificial material containing silica in a reactive form. The pozzolana is in a finely divided state to allowsilica to combine with calcium hydroxide (liberated by the hydrating Portland cement) in the presence of water forming stable Calcium Silicates Hydrate that have the cementitious properties. The pozzolanic materials commonly used are Calcined clay, Fly ash, Silica fumes.

Pozzolana is any natural or artificial material containing silica in a reactive form. The pozzolana is in a finely divided state to allowsilica to combine with calcium hydroxide (liberated by the hydrating Portland cement) in the presence of water forming stable Calcium Silicates Hydrate that have the cementitious properties. The pozzolanic materials commonly used are Calcined clay, Fly ash, Silica fumes.

PSC or Portland Slag cement is manufactured by either grinding the Portland clinker with gypsum and granulated slag or blending the ground granulated blast furnace slag (GGBS) with Ordinary Portland cement by means of mechanical blenders. Normal composition of portland cement is 30 % clinker, 5 % gypsum and 70 % blast furnace granulated slag. The quality of slag used in cement manufacturing is governed by IS 12089:1987.

The Indian standards for Portland Pozzolana Cement have been issued in two parts based on the type of pozzolanic materials to be used in manufacturing of Portland Pozzolana Cement as given below: IS 1489 (Part 1) 1991, Portland Pozzolana Cement – specification (fly ash based),IS 1489 (Part 2) 1991, Portland Pozzolana Cement – specification (Calcined clay based) the quality of flyash or calcined clay to be used in manufacturing of PPC is also specified by BIS in the following standards:IS 3812 1981 – specification for flyash as pozzolana and admixture IS 1344 1981 – specification for calcined clay pozzolana.