MCQ
Percentage of $\ce{CaO}$ present in Portland cement is :
- ✓$50-60\%$
- B$70-80\%$
- C$90\%$
- D$40\%$
✓
Answer
Correct option: A.
$50-60\%$
The average composition of Portland cement is $\mathrm{Cao}, 50 \%-60 \%, \mathrm{SiO}_2, 20-25 \% ; \mathrm{Al}_2 \mathrm{O}_3, 5-10 \% ; \mathrm{MgO}, 2-3 \% ; \mathrm{Fe}_2 \mathrm{O}_3, 1-$ $2 \%$ and $\mathrm{SO}_3, 1-2 \%$.
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