Pros & Cons of Ordinary Portland Cement (OPC) Over Portland Pozzolana Cement (PPC)
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There are many types of cement in the market to suit every need. Both Ordinary Portland Cement (OPC) and Portland Pozzolana Cement (PPC) are used in constructions. However, some pros and cons of OPC over PPC are listed below.
Pros of OPC over PPC:
01. Initial setting time of OPC is faster than PPC so it is recommended in projects where props are to be removed early.
02. It is easy to handle as compared to PPC.
03. Its initial strength higher than PPC.
04. Curing period of OPC is less than PPC and curing cost reduces. Hence recommended where curing cost prohibitive.
Cons of OPC over PPC:
01. It cannot be used for mass concreting as it has high heat of hydration as compared to PPC.
02. Higher grade like 53 is not recommended to be used for plastering as it is known to develop shrinkage cracks due to its high strength.
03. Very few manufacturers are known to produce 33 grade of cement.
04. The durability of concrete made using OPC is less than that of the concrete made using PPC.
05. Its resistance to aggressive chemicals is lower than PPC.
06. In manufacturing of OPC, it emits CO2 which is harmful to the environment.
07. It produces comparatively less cohesive concrete than PPC, hence concrete pumping becomes a little difficult.
08. OPC has lower fineness, hence has higher permeability and as a result it has lower durability.
09. The concrete made using OPC cement has lower workability as compared to the concrete made using PPC. Hence, admixtures are added to make concrete workable which affects the overall cost of construction.
10. OPC is costlier than PPC.
In manufacturing of cement, more amount of limestone is used and in few decades there will be a great shortage of limestone. PPC is made by using a fly ash and it is a waste by-product from coal fired thermal power stations and solves the huge disposal problem and also utilizes the waste product. Hence limestone can be saved by partially replacing OPC with fly ash in PPC. Therefore it is recommended to use Portland Pozzolana Cement (PPC) rather than Ordinary Portland Cement (OPC).