Step 1: Understanding the Question:
The question asks for the typical weight percentage of Lime (Calcium Oxide, CaO) in the chemical composition of Ordinary Portland Cement (OPC).
Step 2: Detailed Explanation:
Cement Chemistry: Portland cement is manufactured by burning a mixture of calcareous (lime-rich) and argillaceous (clay-rich) materials.
Major Oxides in OPC:
- Lime (CaO): $60% - 67%$
- Silica ($SiO_2$): $17% - 25%$
- Alumina ($Al_2O_3$): $3% - 8%$
- Iron oxide ($Fe_2O_3$): $0.5% - 6%$
Significance of CaO: Lime is the most abundant ingredient. It is responsible for forming the strength-giving silicates ($C_3S$ and $C_2S$). If lime is in excess, the cement becomes unsound (unstable). If it is deficient, the strength is reduced and the cement sets too quickly.
Review of Options:
- Option (D) 60-65%: This matches the standard industrial specification for Portland cement.
- Option (B) 70-75%: This is too high and would lead to an unsound, cracking product.
- Options (A) and (C): These values are too low for standard Portland cement.
Step 3: Final Answer:
Portland cement typically contains $60% - 65%$ Calcium Oxide (CaO). Thus, option (D) is the correct answer.