What is Portland Slag Cement?

Portland Slag Cement (PSC) is manufactured by either inter-grinding in the Portland cement clinker, Gypsum & Granulated Slag or mixing the Ground Granulated Blast Furnace Slag (GGBS) with Ordinary Portland Cement by means of mechanical blenders.  It is created with a blend of 45- 50% slag, 45% – 50% clinker, and 3-5% gypsum. Portland slag cement is the most suitable cement for concrete paths, mass concrete uses, structures and bases, pre-cast concrete, concrete open to sea water and oceanic use.

All compositions produce high ultimate strength, but as slag content is increased, initial strength is reduced, while sulfate resistance upsurges and heat evolution moderates.  The hydration of slag is initiated when lime liberated in the hydration of Portland cement provides the correct alkalinity; later hydration does not depend on lime.

Physical requirements:

• The specific surface (fineness) of slag cement shall not be less than 225 m2/kg
• Portland slag cement shall not have an expansion of more than 10 mm and 0.8 percent respectively.
• Initial setting time shall not be less than 30 minutes and final setting time shall not be less than 600 minutes.
• Compressive strength should not be less than 16 Mpa after 3 days, 22 Mpa after 7 days, 33 Mpa after 28 days.  

Advantages of PSC cement:

•         High compressive strength
•         High resistance to chloride and sulphate
•        Good workability
•         Good resistance against alkali-silica reaction
•         Low risk of cracking
•     Superior Finish

Applications:

•          Marine and offshore structures
•         Sewage disposal treatment works
•         Water treatment plants
•         Pre cast concrete products
•          Concrete roads and flyovers
•          Bridges and dams
•         Foundation constructions