Difference Between OPC and PPC Cement
The long-form of OPC is Ordinary Portland Cement and the long-form of PPC is Portland Pozzolana Cement.
Generally, the ISI mark on the ordinary Portland cement bag is black in colour whereas the ISI mark on the Portland pozzolana cement bag is red in colour. The difference between OPC and PPC cement are as follows:
The raw material used to manufacture OPC are calcareous materials containing limestone that is 62 to 70%, argillaceous materials containing silica 17 to 25% Alumina 3 to 8% and oxide of iron 0.5 to 6% gypsum, magnesia, sulphur trioxide, potash and soda 0.5 to 1.3%.
All these materials are mixed in a fixed proportion and heated in kilns to form clinkers which are then grinded to the required fineness to obtain ordinary Portland cement.
Whereas the raw materials used to manufacture PPC are OPC cement clinkers 75 to 76 % and gypsum 3 to 5% and pozzolanic material 10 to 25% which can be fly ash, rice husk Ash, volcanic tuff, Pumicites, clay and shale all these materials are mixed and grinded to obtain the Portland pozzolana cement.
As per the classification of the Bureau of Indian, Standard OPC is available in 33, 43 and 53 Grades.
Whereas as per the Bureau of Indian, Standard PPC is available in 1 grade and its strength match to strength of 33 grade OPC after curing.
- In 3 days OPC achieve a compressive strength of 35 N/mm2
- In 7 days OPC gained a compressive strength of 43.5 N/mm2
- In 28 OPC gained a compressive strength of 55 N/mm2
- In 3 days PPC achieved a compressive strength of 29 N/mm2
- In 7 days PPC achieved a compressive strength of 39 N/mm2
- In 28 days PPC achieved a compressive strength of 56.5 N/mm2
The initial strength of ordinary Portland cement is higher than Portland pozzolana cement whereas the long-term strength of Portland pozzolana cement is higher than that of ordinary Portland cement so it’s pretty clear now if you need high strength at the initial stage then go for OPC.
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Workability means how easily it can flow on the surface. the concrete made using OPC cement has lower workability.
Whereas the concrete made using PPC cement has higher workability.
Heat of hydration
The heat of hydration is the heat generated when water and cement react. In the case of OPC, the hydration process takes less time for completion and it produces more heat than PPC.
If cement produces more heat in less time then it cannot be used for mass concreting as it may generate cracks in the structure
Whereas in the case of PPC, the hydration process takes a long time and produces less heat during the hydration process. Hence it is ideal for mass concreting.
The initial setting time of OPC and PPC is the same and is 30 minutes whereas the final setting time of OPC is 280 minutes which is 4.67 hours. Its setting time is less than PPC so it is recommended in the project where props are to be removed early.
On the other hand, the final setting time of PPC is 600 minutes which is 10 hours. PPC cement prolongs the setting time of concrete and hence it helps in better finishing of concrete.
Also, Read - 14 Types of Cement and Their Uses.
IS code used for OPC 33 Grade Cement is IS: 269, for 43 Grade Cement IS: 8112 is used and for 53 Grade Cement IS: 12269 is used.
Whereas the IS code used for PPC is 1489 (part 1 & 2) 1991.
The fineness of OPC is at least 225 square metres per kg which are lower than PPC hence it is easy to handle.
Whereas the finance of PPC is at least 300 square meters per kg which are higher than OPC hence it isn’t easy to handle but it is not a major thing.
Permeability is the quality of any substance to measure how much liquid or water can pass through them due to the absence of pozzolanic material ordinary Portland cement is highly permeable to the water.
On the other hand, pozzolana cement is less permeable and it is suitable for a structure Such as bridge piers or a Foundation, where a waterproof structure is recommended.
Resistance to attack against chemicals
In the case of OPC resistance to attack against sulphate, alkalies, Chloride and chemicals is slower as compared to PPC.
Whereas PPC has more resistance towards the attack of sulphate alkyl Chloride and Chemicals as compared to OPC.
The durability of concrete made using OPC cement is less than that of concrete made using PPC cement.
Whereas the durability of concrete made using PPC is higher than OPC which means the structure made up of PPC will last longer.
OPC requires a minimum curing period of 7 days. When OPC is exposed to hot and dry weather conditions the minimum curing period required shall not be less than 10 days.
Whereas PPC required a minimum curing period of 10 days. whereas when PPC is exposed to hot and dry weather conditions the minimum curing period required shall not be less than 14 days.
Here you can see the curing period of OPC is less than PPC hence the curing cost reduces and that’s why OPC is recommended curing cost is prohibited.
During the manufacturing process of OPC large amount of CO2 emits.
Whereas PPC contains 10 to 25% pozzolanic material hence it emits less CO2 during the manufacturing process here PPC is called environment-friendly as it utilizes by-products of the thermal station which reduces the environmental problem.
Also, Read - Soundness Test of Cement By Le-chatelier Apparatus.
The cost of OPC is around 300 rupees per bag which is slightly more expensive than PPC.
Whereas in the case of PPC, the expensive clinker is replaced by pozzolanic Material such as fly ash hence the price of PPC is slightly less than that of OPC.
Generally, there is a price difference of approximately 5 rupees. but this slightly lesser price creates a considerable difference in the overall cost of building and impact on the environment.
OPC is the most commonly used cement in construction. A higher grade like grade 53 is not recommended to be used for plastering as it is known to develop shrinkage cracks due to its high strength.
OPC is also not used in masonry as mortar strength in the initial period is not that critical.
OPC can be used for structural members like slab, column and beam. Ideal application for ordinary Portland cement is commercial and industrial complexes, High-rise Building, Road, Bridges, Flyover, Heavy defence structure etc.
PPC can be used in all types of construction works like RCC work in Residential Commercial and Industrial Building, Marine work Mass concrete work like Dam, Huge Foundations Roads, Runway, Bridges and Flyover etc.
Especially PPC is used in Plastering, Masonry, Tiling and Waterproofing work as strength is not the major standard in this work.
Both OPC and PPC are commonly used Cement in construction and both have their pros and cons. Nowadays PPC is used as a substitute for ordinary Portland cement.
Since PPC contains pozzolanic material it helps to enhance the strength of concrete and also complete the green building criteria as a result nowadays most OPC manufacturers are shifting to PPC.
I hope now you understood the difference between these two types of cement and can make the correct choice between OPC and PPC after reading this article.
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