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- The approximate ratio between the strengths of cement concrete at 7 days and 28 days is
(a) 3/4 (b) 2/3
(c) l/2 (d) l/3 - The approximate ratio of strength of 15 cm × 30 cm concrete cylinder to that of 15 cm cube
of the same concrete is
(a) 1.25 (b) 1.00
(c) 0.85 (d) 0.50 - Tensile strength of concrete is measured by
(a) direct tension test in the universal testing machine
(b) applying compressive load along the diameter of the cylinder
(c) applying third point loading on a prism
(d) applying tensile load along the diameter of the cylinder - Consider the following statements:
Higher water cement ratio in concrete results in- stronger mix 2. better workable mix
- a weak mix 4. less bleeding
Of these statements
(a) 1 and 2 are correct (b) 2 and 3 are correct
(c) 3 and 4 are correct (d) l and 4 are correct
- Consider the following strengths of concrete:
- Cube strength 2. Cylinder strength
- Split-tensile strength 4. Modulus of rupture
The correct sequence in increasing order of these strengths is:
(a) 3, 4, 2, 1 (b) 3, 4, 1, 2
(c) 4, 3, 2, 1 (d) 4, 3, l, 2
- A splitting tensile test is performed on a cylinder of diameter ‘D’ and length ‘L’ if the
ultimate load is ‘P’, then the splitting tensile strength of concrete is given by
(a) P/ DL (b) 2P/ DL
(c) 4PL/ D^3 (d) 2PD/ L^3 - The compacting factor test of cement concrete determines its
(a) strength (b) porosity
(c) degree of compaction under loads(d) workability - The split tensile strength of M 15 grade concrete when expressed as a percentage of its
compressive strength is
(a) 10 to 15% (b) 15 to 20%
(c) 20 to 25% (d) 25 to 30% - Consider the following statements:
Shrinkage af concrete depends upon the- relative humidity of the atmosphere
- passage of time
- applied stress
Which of these statements is/are correct?
(a) 1 and 2 (b) 2 and 3
(c) 1 alone (d) 1, 2 and 3