What is Portland Slag Cement?
Portland Slag Cement, commonly identified as PSC, is blended cement that is used
in various infrastructure projects. Slag is a non-metallic substance comprising
around 90% glass with silicates and lime alumino-silicates. PSC has 25 to 70%
granulated slag, 3% gypsum, and the remaining portion is clinker. The high flexural
strength of PSC makes it favourable for infrastructure projects. High strength, low
risk of cracking, improved functionalities and superior finish are the advantages of
PSC.
Using slag cement to replace a portion of portland cement in a concrete mixture is
an effective method to make concrete more consistent. Improvements in PSC
include higher workability, lower permeability, improved resistance to aggressive
chemicals, higher finishability, consistent plastic and hardened properties, flexural
strengths, and highest compressive strength.
Slag cement is a hydraulic cement formed when granulated blast furnace slag
(GGBFS) is developed to suitable fineness and is used to replace a part of portland
cement. It is a byproduct in the manufacture of pig iron. It is a mixture of lime, silica
and alumina, the same oxides that form Portland cement. Cement-like properties are
developed when ground granulated slag reacts with water.
Molten slag diverted from the iron blast furnace is rapidly cooled, which produces
glassy granules that give the required reactive cement characteristics when beaten
to cement fineness. The slag becomes usage-ready once it cools down.
Benefits of PSC
- Higher flexural strength to concrete, which increases its structural stiffness
and reduces load deflections
- Higher compressive strength in concrete, compared to OPC
- Improved workability
- Environment friendliness due to reduced GHG emissions
- High compressive strength
- Strong resistance to chloride and sulphate attacks
- Low risk of cracking
- Better compatibility with all types of admixtures
- Superior finish
- Brings down ingression of harmful substances such as chlorides and
sulphates due to low permeability
- Improved resistance against alkali-silica reaction
- Reduced shrinkage cracks
PSC consumption across the world:
Portland Slag Cement is used widely for infrastructure projects. PSC is primarily
used around the world for the following purposes:
- Residential, commercial and industrial projects
- Dams and other mass concrete works
- Water-retaining structures and marine construction
- Concrete roads and flyovers
- Precast concrete products
- PSC provides improved resistance to sulfate and chloride and has corrosion
resistance properties, due to which it is widely used in coastal regions,
sewage disposal, and water treatment plants.
Countries that widely use PSC Cement:
- Japan
- United States
- India
Why is PSC preferred in other countries over OPC PPC?
Portland Slag Cement’s chemical composition makes it advantageous over ordinary
cement. It is eco-friendly, and has ultimate compressive strength and offers excellent
resistance to sulphate and chloride attacks. These specifications lower the risks of
cracking and improves workability. It boasts a superior finish and minimised
shrinkage cracks. PSC cement can be used for all types of residential and
commercial projects.
It also complements work on dams and other water retaining structures due to its
high resistance alkali-silica reactions and fewer shrinkage cracks.Due to this, it is
mostly used for marine constructions.
Prominent structures built using PSC:
- One Manhattan Square - New York, United States
- NVIDIA Building - California, United States
- National Veterans Memorial and Museum - Ohio, United States
- One World Trade Center - New York, United States