11) The strength of white cement is ................. that of ordinary cement.

• (a) equal to
• (b) less than
• (c) greater than

12) The percentage of the slag component of Portlandslag cement varies from

• (a) 10 to 40%
• (b) 40 to 70%
• (c) 70 to 80%
• (d) 80 to 90%

13) The rapid hardening Portland cement has a

• (a) lower heat of hydration
• (b) higher heat of hydration
• (c) lower shrinkage coefficient
• (d) higher shrinkage coefficient

14) The initial setting of cement is caused due to

• (a) di-calcium silicate
• (b) tri-calcium silicate
• (c) tri-calcium aluminate
• (d) tri-calcium alumino ferrite

15) The rapid hardening Portland cement is obtained by

• (a) grinding the clinker to a high degree of fineness
• (b) adding calcium sulphate to the mixture
• (c) adding gypsum after grinding
• (d) burning the mixture at a lower temperature