Question

Consider the following statements:

1. Modulus of Elasticity of concrete increases with increase in compressive strength of concrete.

2. Brittleness of concrete increases with decrease in compressive strength of concrete.

3. Shear strength of concrete increase with increase in compressive strength of concrete.

Which of the above statements are correct?
1. 1 and 2 only 
2. 1, 2 and 3
3. 1 and 3 only 
4. 2 and 3 only

Answer 1

Correct Answer - Option 3 : 1 and 3 only 

Concept:

Modulus of Elasticity of concrete (E_c) is given by\({E_c} = 5000√ {{f_{ck}}} \)

Where f_ck = Characteristics compressive strength of concrete

So Modulus of Elasticity of concrete increases with an increase in compressive strength of concrete as

∴ E_c is proportional to √f_ck

Brittleness of concrete increases with an increase in compressive strength of concrete. Brittleness of high strength concrete is generally very high. Low strength concrete is less brittle than high strength concrete.

Similarly, shear strength of concrete is given by, τcmax = 0.628 √fck 

∴ Shear strength is proportional to √f_ck

So shear strength of concrete increases with an increase in compressive strength of concrete.