Construction materials have come a long way in the history of civilization. From the wood and rock structures millennia ago, humans have reached above clouds to boast about their potential and capabilities. Skyscrapers have become common manmade structures. It is possible due to the immense effort of engineers and scientists who have come up with extra strong building materials. Much of it is likely due to the production of concrete. Strong concrete foundations work as the primary requirement of gigantic structures. One of the main ingredients of concrete is cement.

Ordinary Portland Cement or OPC is the most commonly popularly used cement all over the globe. Still, another option, Portland Pozzolana Cement or PPC, has also risen to prominence in recent years due to its several benefits. In most cases, both types of cement can be used interchangeably. However, there are some fundamental differences between OPC and PPC.

Key Differences Between OPC and PPC

As the name suggests, OPC is the most ordinary or standard type of cement available in the market. It is the essential component used for concrete, mortars, stucco, and other common construction materials that require cement mixtures. It is a type of hydraulic cement that starts hardening as soon as it comes into contact with water and becomes water-resistant once it cures. The making process of cement involves numerous sophisticated methods and requires extensive care while following each step to produce good quality cement. Generally, Portland cement clinkers are pulverized, consisting of hydraulic calcium silicates, making a fine powder. The clinker mixture is produced by heating raw materials like limestone. Some other materials are sources of aluminosilicate, shale, sand, iron ore, etc. Temperatures can reach 1450 degrees Celsius in the grinding process.

Ordinary Portland Cement is the most prevalent because of its readily available raw materials and comparatively easy manufacturing process. The popularity of OPC is very high globally as it can be produced at cheap rates while maintaining appropriate strength and quality.

On the other hand, PPC refers to Portland Pozzolana Cement. It is produced by adding pozzolans to the mixture. Adding pozzolanic materials can increase the strength and durability of cement and, at the same time, reduce the costs of production. The term pozzolana originally refers to volcanic ash. Adding pozzolanic materials into a hydraulic cement like OPC or other materials leads to a pozzolanic reaction. It helps to create higher quality cement that excels in durability and strength compared to cement that does not contain pozzolanic materials. However, pozzolanic materials do not contain any cementitious properties, but adding them into a cement mixture will result in the above results. Around 15% – 30% of pozzolana materials are mixed to produce PPC. Volcanic ash was first used as pozzolanic materials, but later, natural and artificial siliceous or aluminous materials like clay, slag, silica fume, fly ash, and shales were also used. Coal-based power generation plants create some of these materials as waste. But these waste materials can significantly improve the quality of cement.

Source: Civil Lead

Here is a chart containing helpful information on the primary differences between OPC and PPC.

Description

OPC

PPC

Definition

OPC stands for Ordinary Portland Cement

PPC stands for Portland Pozzolana Cement

Raw Materials

OPC is manufactured from a mixture of limestone, raw argillaceous, calcareous materials, and gypsum

PPC cement is manufactured by mixing around 15% – 30% of pozzolanic materials with OPC cement clinkers

Composition

OPC mainly consists of a large amount of Limestone powder

PPC mainly consists of pozzolanic materials like volcanic ash, fly ash, slag, etc.

Durability

The durability of concrete made with OPC cement is less compared to PPC

The durability of concrete made with PPC cement is more than OPC cement

Initial Strength

The initial strength of OPC is higher when compared with PPC, which makes it a practical choice for fast faced construction work

The initial strength is less with PPC cement, but in the long run, the power of PPC is comparatively higher than OPC cement.

Grades

Three different grades of OPC are available: OPC33, OPC43, and OPC53. These grades signify different categories of strength

There are no grades in PPC cement. The strength of PPC matches with the OPC33 grades. PPC cement is differentiated based on the type of pozzolanic materials like fly ash, volcanic ash, etc.

Environmental Impact

OPC cement production can have a harmful effect on the environment. OPC cement production requires extracting natural elements, which can create depletion of natural resources from Earth.

PPC cement production is an eco-friendly operation. It has fewer carbon footprints when compared with OPC cement. Furthermore, PPC cement utilizes various waste materials, which increases its efficiency.

Heat of Hydration

OPC cement generates more heat after mixing with the water, which makes OPC not suitable for mass casting or mass concreting works

PPC cement has a slow heat hydration rate. So, PPC cement is more suitable for mass concreting works.

Cost

OPC cement costs more than PPC cement

The cost of PPC cement is less due to the incorporation of various waste materials. Hence, opting for PPC cement is an economically better decision

Permeability and Fineness

Lower fineness results in higher permeability. OPC cement has a fineness of 225m^2/kg

PPC has a fineness of 300m^2/kg. Hence. PPC cement has a lower permeability with higher durability.

Workability of Concrete

Good workable concrete can be made using OPC cement. However, the workability is less compared with PPC cement

Concrete made using PPC cement has more workability than concrete made using OPC cement

Volume of Mortar

The volume of mortar achieved is less when compared with PPC cement as OPC cement is less fine

The volume of mortar achieved using PPC is higher than OPC

Curing Period

The minimum curing period should not be less than seven days when exposed to hot weather conditions, and the curing period should be at least ten days. The standard curing period is 28 days

The minimum curing period of PPC cement should not be less than ten days in hot climatic conditions and should be at least 14 days. The standard curing period is 28 days

Resistance to Chemical Attacks

The resistance capabilities of OPC cement to chlorides and sulfates are less than PPC cement

PPC cement has good resistance against chemical attacks of chlorides and sulfates

Setting Time

The initial setting time of OPC is 30 minutes. The final setting time of OPC is 600 minutes

The initial setting time of PPC cement is 30 minutes. The final setting time of PPC is 600 minutes

Suitability

OPC cement is the most common type of cement for general use worldwide. OPC is less suitable in aggressive weather conditions than PPC cement

PPC is highly suitable for aggressive conditions as it is more resistant to chemical attacks. PPC cement can be used to construct dams, reservoirs, etc.

Shrinkage/Cracks

OPC cement will be prone to more shrinkage or cracks due to the high heat of hydration

PPC cement will face less shrinkage or cracks in its lifetime

Construction Speed

Faster construction speed is possible with OPC cement as it gains strength earlier than PPC cement

PPC cement takes more time to gain strength. Hence, the construction pace will be lower

Usage

OPC cement has different grades depending on its strength. For instance, OPC53 grade cannot be recommended for plastering work as it is known to develop shrinkage cracks due to high strength. OPC cement can be used for structural members like slab, column, and beam. The ideal application sector includes commercial and industrial complexes, high-rise buildings, roads, bridges, flyovers, heavy defense structures, etc.

PPC cement can be used in all types of construction works like RCC work in residential, commercial, or industrial buildings, marine works, and mass concrete works like dams, foundation roads, runways, bridges, and flyovers. PPC cement is also helpful for plastering, masonry, tiling, and waterproofing.

Which Cement is Best, OPC or PPC?

The question will arise automatically in your mind about which cement is between OPC and PPC. As a matter of fact, there is no direct answer to this question. Both types of cement have their pros and cons. The significant differences between the two types have already been discussed. However, using different kinds of cement for specific purposes is a reasonable construction practice. It can ensure you are getting the best result out of your project. Many people prefer PPC cement over OPC due to its low cost and environmentally friendly aspects. PPC cement is also an integral part of building homes sustainably. Discuss with your contractor to determine which is best for your home. If you have a different project in mind, discuss it also.

Summary

Both OPC and PPC cement is used in Bangladesh for standard construction practices. These two types of cement have their pros and cons. However, PPC cement is used as a substitute for OPC nowadays.

Environmental aspects are coming to the forefront, and people are opting for substitutes that can reduce their impact on the environment. Furthermore, people prefer developers who use environmentally friendly products. As a result, the popularity of PPC cement is increasing. Its lower cost and greener properties encourage more people to use it instead of OPC cement.

Frequently Asked Questions (FAQs)

Q. Which cement is better, OPC or PPC?

Ans: It depends on the construction work you plan to do. Generally, both cement types can be used interchangeably.

Q. What is the main difference between OPC and PPC cement?

Ans: The main difference is the addition of pozzolanic materials like volcanic ash, fly ash, slag, etc., in PPC cement. The addition of such materials changes the cementitious properties significantly.

Q. Is PPC cement more expensive than OPC cement?

Ans: No. PPC cement is cheaper than OPC cement.

Q. Is PPC cement suitable for slab?

Ans: PPC cement and OPC cement are suitable for constructing concrete slabs.

Q. Can I purchase PPC cement in Bangladesh?

Ans: Yes. Many renowned manufacturers produce PPC cement in Bangladesh.

 

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