A. 24 to 48 hours
B. 3 days
C. 7 days
D. 14 days
✅ The correct answer is option A.
Design of Concrete Structures MCQs
32. According to ISI recommendations, the maximum depth of stress block for balanced section of a beam of effective depth d is__________________?
A. 0.43 d
B. 0.55 d
C. 0.68 d
D. 0.85 d
✅ The correct answer is option A.
33. Modulus of rupture of concrete is a measure of_______________?
A. flexural tensile strength
B. direct tensile strength
C. compressive strength
D. split tensile strength
✅ The correct answer is option A.
34. The fineness modulus of fine aggregate is in the range of______________?
A. 2.0 to 3.5
B. 3.5 to 5.0
C. 5.0 to 7.0
D. 6.0 to 8.5
✅ The correct answer is option A.
35. According to IS : 456 -1978, the modulus of elasticity of concrete Ec (in N/mm2) can be taken as______________?
A. Ec = = 5700
B. Ec = = 570
C. Ec = = 5700fck
D. Ec = where fck N/mm2 = 700 is the characteristic strength in
✅ The correct answer is option A.
36. If the depth of neutral axis for a singly reinforced rectangular section is represented by kd in working stress design, then the value of k for balanced section_______________?
A. depends on as, only
B. depends on aCbC only
C. depends on both crst and acbc
D. is independant of both ast and acbc where d is the effective depth, ast is per-missible stress in steel in tension and ocbc is permissible stress in concrete in bend¬ing compression
✅ The correct answer is option A.
37. Minimum grade of concrete to be used in reinforced concrete as per IS:456-1978 is_____________?
A. M15
B. M20
C. M 10
D. M25
✅ The correct answer is option A.
38. As compared to ordinary portland cement, high alumina cement has______________?
A. higher initial setting time but lower final setting time
B. lower initial setting time but higher final setting time
C. higher initial and final setting times
D. lower initial and final setting times
✅ The correct answer is option A.
39. Minimum thickness of load bearing RCC wall should be_____________?
A. 50 mm
B. 100 mm
C. 150 mm
D. 200 mm
✅ The correct answer is option B.
40. The relation between modulus of rupture fcr, splitting strength fcs and direct tensile strength fcl is given by_______________?
A. tcr – rcs = tct
B. fcr>fcs>fc
C. fcr
D. fc5>fcr>fC
✅ The correct answer is option B.