A. fcr=0.35Vf7
B. fcr=0.57f7
C. fcr=0.7Vf7
D. fcr=1.2Vf7
where fcr and fck are in N/mm2′
Related Mcqs:
- 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<fcs
D. fc5>fcr>fC - The strength of concrete after one year as compared to 28 days strength is about_______________?
A. 10 to 15% more
B. 15 to 20% more
C. 20 to 25% more
D. 25 to 50% more - 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 - Modulus of rupture of concrete is a measure of_______________?
A. flexural tensile strength
B. direct tensile strength
C. compressive strength
D. split tensile strength - 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 approximate value of the ratio between direct tensile strength and flexural strength is_____________?
A. 0.33
B. 0.5
C. 0.75
D. 1.0 - Strength of concrete increases with________________?
A. increase in water-cement ratio
B. increase in fineness of cement
C. decrease in curing time
D. decrease in size of aggregate - 1% of voids in a concrete mix would reduce its strength by about______________?
A. 5%
B. 10 %
C. 15%
D. 20% - If nominal shear stress tv exceeds the design shear strength of concrete xc, the nominal shear reinforcement as per IS : 456-1978 shall be provided for carrying a shear stress equal to__________________?
A. xv
B. xc
C. xv – TC
D. Tv + Tc - Cube strength of controlled concrete to be used for pretensioned and post-tensioned work respectively should not be less than__________________?
A. 35 MPa and 42 MPa
B. 42 MPa and 35 MPa
C. 42 MPa and 53 MPa
D. 53 MPa and 42 MPa
