Question

The major components of cement are:

• A. \( \text{SiO}_2, \text{Al}_2\text{O}_3 \)
• B. \( \text{SiO}_2, \text{Fe}_2\text{O}_3 \)
• C. \( \text{Al}_2\text{O}_3, \text{Fe}_2\text{O}_3 \)
• D. \( \text{SiO}_2, \text{CaO} \)

Hint:

Ordinary Portland Cement typically has the highest proportions of \(\text{CaO}\) and \(\text{SiO}_2\). - Lesser components include \(\text{Al}_2\text{O}_3\) and \(\text{Fe}_2\text{O}_3\).

Answer 1

The Correct Option is D

Step 1: Composition of Ordinary Portland Cement \begin{itemize} \item The primary components of Ordinary Portland Cement (OPC) are: \[ \text{CaO} \approx 60\%, \quad \text{SiO}_2 \approx 20\%, \quad \text{Al}_2\text{O}_3 \approx 6\%, \quad \text{Fe}_2\text{O}_3 \approx 3\%. \] \end{itemize} Step 2: Determining the Major Components \begin{itemize} \item Among these, \(\text{CaO}\) (lime) and \(\text{SiO}_2\) (silica) are the most abundant. \item Hence, from the given options, the pair of major components is \(\text{SiO}_2\) and \(\text{CaO}\). \end{itemize} Hence, the correct answer is \(\text{SiO}_2, \text{CaO}\).