10 Aug 2025

Introduction

Choosing the right cement is one of the most important decisions in any construction project. Whether you are building a home, a commercial structure, or a large infrastructure project, understanding the difference between Ordinary Portland Cement(OPC) and Pozzolana Portland Cement(PPC ) ensures better performance, durability, and cost-efficiency.

This guide will help you clearly understand the key differences, technical properties, advantages, and best uses of OPC and PPC, simple enough for homeowners and detailed enough for engineers and contractors.

What Is OPC Cement?

Ordinary Portland Cement (OPC) is the most used cement in Nepal and worldwide. It is manufactured by grinding clinker with 3–5% gypsum. OPC is known for

  •  High early strength
  •  Fast setting time
  •  Superior performance in structural applications

Sarbottam Cement produces two types of OPC:

   ✔ OPC 43 Grade: Best for general construction, plastering, non-structural work.

   ✔ OPC 53 Grade: Most commonly used for high-load structural work.

(Both meeting NS 49 standards)

What Is PPC Cement?

Pozzolana Portland Cement (PPC) is made by blending clinker, high-reactivity fly ash, and gypsum. The addition of fly ash provides:

  •  Long-term strength
  •  Lower heat of hydration
  •  High resistance to chemical attacks
  •  Better workability
  •  Eco Friendly

Sarbottam PPC meets NS 385 standards and is ideal for Nepal’s diverse climate and soil conditions.

Explore more: Check the quality of cement before use

Key Difference Between OPC and PPC Cement

1. What They Are Made Of

  •  OPC is made from clinker and a small amount of gypsum only.
  •  PPC is made from clinker, gypsum, and fly ash, which is a fine powder from coal plants.

2. How Fast They Become Strong

  •  OPC becomes strong very quickly after construction starts.
  •  PPC takes more time to gain strength in the beginning.

3. Strength Over Time

  •  OPC gives good strength and remains stable over time.
  •  PPC becomes even stronger as time passes, which helps buildings last longer.

4. Setting Time (Hardening Speed)

  •  OPC sets faster, so work needs to be done quickly.
  •  PPC sets slowly, giving more time to work and finish properly.

5. Heat Produced During Construction

  •  OPC produces more heat while hardening, which can cause cracks in large concrete work.
  •  PPC produces less heat, reducing the chance of cracks.

6. Resistance to Water and Chemicals

  •  OPC is less resistant to sulphates and chemicals found in soil and water.
  •  PPC is more resistant, making it safer for long-term use.

7. Ease of Working (Workability)

  •  OPC is normal to work with.
  •  PPC is easier to work with and gives a smoother finish.

8. Life of the Structure

  •  OPC provides a long-lasting structure.
  •  PPC provides an even longer service life due to better durability.

9. Cost

  •  OPC is slightly more expensive because it gives fast strength.
  •  PPC is more economical and saves cost in the long run.

Which Cement Should You Choose?

Choose OPC if you need:

  • Rapid strength gain
  • High structural performance
  • Use in RCC, beams, slabs, columns
  • Construction in cold areas where fast setting is preferred

Choose PPC if you need:

  • Higher long-term durability
  • Better resistance to chemicals
  • Economical and eco-friendly option
  • Plastering, masonry, residential buildings
  • Mass concreting (dams, reservoirs, bridges)

Conclusion

OPC is best for projects needing high early strength, while PPC is ideal for long-term durability and cost efficiency. Understanding these differences helps you choose the right cement for a stronger, longer-lasting structure.