QHR f
2w
- For a give environment, the most significant factor that influences the total shrinkage of
concrete is
(a) cement content of mix
(b) total amount of water added at the time of mixing
(c) size of the member concreted
(d) maximum size of the coarse aggregate used - Consider the following statements:
The effect of air enterainment in concrete is to- increase resistance to freezing and thawing
- improve workability
- decrease strength
Which of these statements are correct?
(a) 1 and 2 (b) 1 and 3
(c) 1 alone (d) 1, 2 and 3
- The optimum number of revolutions over which concrete is required to be mixed in a
mixer machine is
(a) 10 (b) 20
(c) 50 (d) 100 - Match List-I with List-II and select the correct answer using the codes given below the
lists:
List-I List-II
(Workability test)(Measurements)
A. Slump test 1. 300 mm to 500 mm
B. Compacting factor 2. 75 mm to 125 mm
C. Vee Bee test 3. 0.80 to 0.98
D. Flow test 4. zero to 10 s
Codes:
(a)ABCD (b)ABCD
2431 1342
(c)ABCD (d)ABCD
1432 2341 - Consider the following statements:
Curing of concrete by steam under pressure- increases the compressive strength of concrete
- reduces the shear strength of concrete
- increases the speed of chemical reaction
Select the correct answer using the codes given below:
(a) 1, 2 and 3 (b) 1 alone
(c) 2 and 3 (d) 3 alone
- The length of time for which a concrete mixture will remain plastic is usually more
dependent on
(a) the setting time of cement than on the amount of mixing water and atmospheric
temperature
(b) the atmospheric temperature than on the amount of mixing water and the setting time
of cement