Which of the following pairs gives a correct combination of the useful and harmful constituents respectively of a good brick earth ?
(A) lime stone and alumina
(B) silica and alkalies
(C) alumina and iron
(D) alkalies and magnesium
According to IS specifications, the compressive strength of ordinary portland cement after three days should not be less than________________?
(A) 7 MPa
(B) 11.5 MPa
(C) 16 MPa
(D) 21 MPa
Early attainment of strength in rapid hardening cement is mainly due to_______________?
(A) gypsum
(B) finer grinding
(C) tricalcium silicate
(D) tricalcium aluminate
For testing compressive strength of cement, the size of cube used is_______________?
(A) 50 mm
(B) 70.6 mm
(C) 100 mm
(D) 150 mm
The main constituent of cement which is responsible for initial setting of cement is_________________?
(A) dicalcium silicate
(B) tricalcium silicate
(C) tricalcium aluminate
(D) all of the above
The main constituent which imparts hydraulicity to hydraulic lime is______________?
(A) calcium oxide
(B) silica
(C) clay
(D) water
Assertion A : Pure lime takes a long time to develop adequate strength. Reason R : Pure lime has slow hardening characteristics. Select your answer according to the coding system given below ?
(A) Both A and R are true and R is correct explanation of A
(B) Both A and R are true and R is not a correct explanation of A
(C) A is true but R is false
(D) A is false but R is true
Study the following statements. (1) Hydraulic lime is suitable for white washing, (2) Fat lime is suitable for whitewashing, (3) Hydraulic lime is suitable for making mortar, (4) Fat lime is suitable for making mortar. The correct answer is______________?
(A) (1) and (4)
(B) (2) and (3)
(C) (1) and (2)
(D) (3) and (4)
As per IS specifications, the maximum final setting time for ordinary Portland cement should be_______________?
(A) 30 minutes
(B) 1 hour
(C) 6 hours
(D) 10 hours
The constituent of cement which is responsible for all the undesirable properties of cement is____________?
(A) dicalcium silicate
(B) tricalcium silicate
(C) tricalcium aluminate
(D) tetra calcium alumino ferrite