OPC vs PPC | Difference between OPC and PPC Cement
In this article, we will see the differences between OPC and PPC.
So, Let’s start,
The long form of OPC is ordinary Portland cement and the long form of PPC is Portland pozzolana cement.
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.
1). Manufacturing process
The raw materials used to manufacture OPC are calcareous materials containing limestone which is 60 to 70%.
Argillaceous materials containing silica 17 to 25%,
Alumina 3 to 8% and oxides of iron 0.5 to 6%.
Gypsum, magnesia, sulphur trioxide, potash or soda point 0.5 to 1.3%.
All these materials are mixed in a fixed proportion and heated in kilns to form clinkers which are then grinding to the required fineness to obtain ordinary Portland cement.
The raw materials used to manufacture PPC are OPC cement clinker 75 to 77%.
Gypsum 3 to 5% and pozzolanic materials 10 to 25% which can be fly ash, rice husk Ash, volcanic tuffs, clay and shale. All these materials are mixed and grinder to obtain the Portland pozzolana cement.
As per the classification of the Bureau of Indian Standards, OPC is available in 33 grade 43 grade and 53 Grade.
As per the Bureau of Indian Standards, PPC is available in 1 grade and its strength matches the strength of 33-grade OPC after curing.
3). IS Codes
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.
The IS code used for PPC is IS 1489 parts 1 and 2 1991.
In 3 days OPC achieves a compressive strength of 35N/mm2.
In 7 days OPC achieves a compressive strength of 43.5N/mm2.
In 28 days OPC achieves a compressive strength of 55N/mm2.
In 3 days PPC achieves a compressive strength of 29N/mm2.
In 7 days PPC achieves a compressive strength of 39N/mm2.
In 28 days PPC achieves a compressive strength of 56.5N/mm2.
The initial strength of ordinary Portland cement is higher than Portland pozzolana cement.
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.
The durability of concrete made using OPC cement is less than that of concrete made using PPC cement.
The durability of concrete made using PPC is higher than OPC which means the structure made up of PPC will last longer.
Workability means how easily it can flow on the surface.
Concrete made using OPC cement has lower workability.
Concrete made using PPC cement has a higher workability.
Permeability is the quality of any substance to measure how much liquid or water can pass through them.
Due to the absence of pozzolanic materials ordinary Portland cement is highly permeable to water.
on the other hand
Portland pozzolana cement is less permeable hence it is suitable for a structure such as Bridge Pier
or a Foundation where the waterproof structure is recommended.
8). Heat of Hydration
The heat of hydration is the heat generated when water and cement react.
In the case of OPC, Hydration Process takes less time to complete and it produces more heat than PPC. Please note if cement produces more heat in less time then it cannot be used for mass concreting. As it may generate cracks in structures.
In the case of PPC, the Hydration process takes a long time and produces less heat the hydration process, Hence it is ideal for mass concreting.
9). Setting Time
The initial setting time of your OPC and PPC is the same and it is 30 minutes and the final setting time of your OPC is 280 minutes which is 11.67 days its setting time is less and PPC. So it is recommended in projects where props are to be removed early.
on the other hand
The final setting time of PPC is 600 minutes which is 25 days PPC cement prolongs the setting time of concrete Hence, it helps in better finishing of concrete.
The fineness of OPC is at least 225m2/kg which is lower than PPC hence it is easy to handle.
The fineness of PPC is at least 300m2/kg which is higher than PPC hence it is difficult to handle but it is not a major thing.
11). Resistance To Attack Against Chemicals
In the case of OPC, Resistance to attack against sulphates, alkalis, chlorides and chemical is lower as compared to PPC.
PPC has more resistance towards the attack of sulphates, alkalis, chloride and Chemicals as compared to OPC.
12). Curing Time
OPC required 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
PPC required a minimum curing period of 10 days.
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 when the curing is cost prohibitive.
13). Environmental Impact
During the manufacturing process of OPC, a large amount of CO2 emits.
PPC contains 10 to 25% pozzoloanic materials. Hence, It emits less CO2 manufacturing process. Here PPC is called environment friendly as it utilizes by-products of the thermal station which reduces environmental problems.
The cost of your OPC is around 380/-bag which is slightly more expensive than PPC.
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 OPC. Generally, there is a price difference of Rs.5 to 10/- 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 slabs, columns and beams. Ideal applications for ordinary Portland cement are commercial and industrial complexes, high-rise buildings, roads, bridges, flyovers, heavy different structures etc.
on the other hand
PPC can be used in all types of construction works like RCC work in residential, commercial and industrial buildings, Marine works, and mass concrete work, like Dams, huge foundations, roads Runway, bridges & flyovers etc.
Specially PPC is used in plastering, masonry, tiling and waterproofing works. In these works, strength is not the major criterion.
Both OPC and PPC have 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 materials, it helps to enhance the strength of concrete and also fulfils the green building criteria.
As a result of this, Nowadays, Most OPC manufacturers are shifting to PPC.
I hope this article will definitely help you to choose to make the correct choice between OPC and PPC.
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