PPC or OPC And Their Difference

subhajit basak 21:12 Construction Materials,

PPC or OPC

OPC = Ordinary Portland Cement PPC : Pozzolonic Portland cement (FYI : PPC is environment friendly as it consists y ash in some specic percentages by parts, which is a waste product of burnt coal, usually collected from thermal power plants) OPC (m53) attains strength in a shorter time, while PPC (m43) takes longer. OPC therefore dries more quickly, but produces more heat during chemical reaction during which it gains strength, as compared to PPC Faster is the drying process, more is the risk of cracking of cement, and therefore it need more care and more amount of water for curing in a lesser time. PPC on the other hand can attain strength equal to OPC, but takes a longer time. For a building slab, PPC is more widely used since it requires less care. The strength depends on design mix (the water cement and aggregate ratio) more than type of cement. so essentially, If you need construction to take place faster and have means for good curing, you may use OPC. But if you need better quality and strength in less eort, use PPC. It still depends on the structure’s design requirements and a structural designer’s advice is to be followed.

PPC is economically better than OPC. Strengthwise , PPC is always grade 33 ( although this is never mentioned on the bag ) whereas OPC is availabie in grades 43 & 53. The setting process of PPC is slower than OPC and hence the striking o period for the form work gets extended by about 50%. PPC has a relatively low heat emission process as compared to OPC and hence the ner shrinkage cracks which are normally seen on fresh RCC slab cast with higher grade cement are not seen with PPC. In case , a nominal mix is used for the concrete ( say 1:1.5: 3 ), which assumes grade 33 cement is used , PPC matches the strength requirements. If design mix is opted , the laboratory does consider the exact strength available from the specic brand/ grade of cement being deployed . Thus use of OPC or PPC cement shall be properly weighed in the design mix.

Difference Between OPC and PPC

In the following table the main differences between OPC and PPC cement are given:

	Sources	Shallow Foundation	Deep Foundation
1	Definition/ Components	A mixture of limestone and other raw materials like argillaceous, calcareous, gypsum is prepared and then grinded to prepare OPC.	PPC is prepared by adding Pozzolanic materials to OPC. So, the main components are OPC clinker, gypsum and pozzolanic materials (15~35%) which includes calcined clay, volcanic ash, fly ash or silica fumes.
2	Strength	Initial strength is higher than PPC.	PPC has higher strength than OPC over a longer period of time.
3	Heat of hydration	Generates more heat than PPC in hydration reaction which makes it less suitable for mass casting.	It has a slow hydration process and thus generates less heat than OPC.
4	Durability	Less durable in aggressive weather.	More durable in aggressive weather.
5	Cost	Costlier than PPC.	Cheaper than OPC.
6	Environmental Impact	Emits CO2 during the manufacturing process.	It constitutes industrial and natural waste which makes it eco-friendly.
7	Application/ uses	It is suitable where fast construction is required but not suitable for mass concreting due to heat issue as mentioned above.	It is suitable for all types of construction work. For example RCC casting of buildings, mass concreting for bridges and even plastering and other non-structural works.
8	Setting Time	Lower than PPC. Its initial setting time is 30 minutes and final setting time is 280 minutes. Its faster setting time helps faster construction.	Setting time of PPC us higher than OPC. Its initial setting time is 30 minutes and final setting time is 600 minutes. Its slower setting time helps to get better finishing.
9	Fineness	OPC has finiteness of 225 sq.m/kg. It has lower fineness than PPC. So, it has higher permeability resulting lower durability.	OPC has finiteness of 300 sq.m/kg. It has higher fineness than OPC. So, it has lower permeability resulting in higher durability.
10	Grades available	33 Grade, 43 Grade, and 53 Grade OPC cement are available.	No specified grade of PPC cement is available.
11	Workability	Lower than PPC.	Higher than OPC.
12	Resistance against chemical attack	It has lower resistance against alkalis, sulphates, chlorides etc.	It has higher resistance against alkalis, sulphates, chlorides etc.