In a previous discussion, we explored various types of cement, laying the groundwork for a more comprehensive understanding. If you haven’t had a chance to explore that, feel free to take a look.
1. Composition and Grades of OPC: Ordinary Portland Cement, or OPC, is a blend of limestone, raw argillaceous, calcareous materials, and gypsum. It comes in three different grades: OPC33, OPC43, and OPC53.
2. Eco-Friendliness and Heat Generation: OPC is considered eco-friendly as most of its components are naturally available. However, it tends to generate more heat upon mixing with water, making it less suitable for mass casting.
3. Cost and Workability: OPC comes at a higher cost compared to PPC. While it can yield good workable concrete, its workability is somewhat lower than that of PPC.
4. Fineness and Permeability: The fineness of OPC, measured at 225m2/kg, is inversely related to permeability—lower fineness corresponds to higher permeability. This results in achieving a lower volume of mortar compared to PPC.
5. Setting Times and Resistance: According to IS456:2000, OPC has an initial setting time of 30 minutes and a final setting time of 600 minutes. Its resistance to chlorides and sulfates is relatively lower.
1. Composition and Strength: PPC, standing for Pozzolana Portland Cement, is a blend of 30% pozzolana and Ordinary Portland cement clinkers. The pozzolana material is a siliceous substance formed from volcanic eruptions, containing around 80% clay.
2. Eco-Friendliness and Heat Generation: PPC boasts enhanced eco-friendliness with lower carbon footprints, making it a more environmentally friendly option. Its slower hydration process results in lower heat generation.
3. Cost and Fineness: PPC is economically advantageous, being less costly than OPC. It exhibits a higher fineness of 300m2/kg, leading to lower permeability and increased durability.
4. Workability and Mortar Volume: Concrete made with PPC demonstrates superior workability compared to OPC. Additionally, due to its lower density, PPC achieves a higher volume of mortar.
5. Setting Times and Resistance: As per IS456:2000, PPC shares the same initial and final setting times as OPC—30 minutes and 600 minutes, respectively. However, PPC exhibits higher resistance to chlorides and sulfates.
In summary, while OPC offers initial strength and workable concrete, PPC shines in terms of durability, eco-friendliness, and cost-effectiveness. The choice between the two depends on the specific requirements of the construction project, taking into account factors such as heat generation, setting times, and resistance to environmental elements.