8. The grade of concrete generally not used in the rein-forced concrete, is
B. M 15
C. M 20
D. M 40.
9. The characteristic strength of concrete is the strength of material if its test result is not less than
10. If fck is characteristic compressive strength of concrete, the flexural and split tensile strength fr = a .Nifek N/mm2 where the value of a is
11. If fah is the characteristic cube strength of concrete in N/mm2, the modulus of elasticity of structural concrete E =coffii; where the value of a, is
12. Creep of concrete is assumed proportional to the stress if the stress does not exceed ..... of the characteristic compressive strength
13. The creep coefficient i.e. the ratio of ultimate creep and elastic strain after
A. 7 days is 2.2
B. 28 days is 1.6
C. 365 days is 1.1
D. all the above.
14. For concreting of heavily reinforced sections without vibration, the workability of concrete should be
A. very low
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