Question

Consider the following statements:
High early strength of cement is obtained as a result of
A. Fine grinding
B. Decreasing the lime content
C. Burning at higher temperatures
D. Increasing the quantity of gypsum
Which of these statements are correct?

• A. Only A and B
• B. Only A and C
• C. Only B, C and D
• D. Only A, C and D

Answer 1

The correct option is B Only A and C

• For high early strength of cement it should be grounded more finely.
• Lime content should be less. An increase in lime content beyond a certain limit, makes it difficult to combine completely with other compounds.
• Consequently free lime will result in an unsound cement.
• Clinker is obtained as a result of incipient fusion and sintering at a temperature of about 1400${}^o$C to 1500${}^o$C. Because ferric oxide has a lower melting point than the other oxides, it acts as a flux.
• Increasing the quantity of gypsum causes increased setting time.