SSC JE Civil Engineering 23-Mar-2021 Shift 1 Paper

Concept:
As per IS 456:2000, the modulus of elasticity of concrete is given by:
$\mathrm{E}=5000\sqrt{{\mathrm{f}}_{\mathrm{ck}}}$
Where,
${\mathrm{f}}_{\mathrm{ck}}=$ characteristic strength of concrete $\left(\frac{\mathrm{N}}{{\mathrm{mm}}^2}\right)$ and $\mathrm{E}=$ Modulus of elasticity of concrete $\left(\mathrm{MPa}\right)$
Long term elastic modulus of concrete is given by:
Effective modulus $\mathrm{left}\left({\mathrm{E}}_{\mathrm{c}}\right)$ of elasticity is given by: $\frac{{\mathrm{E}}_{\mathrm{c}}}{1+\mathrm{\theta }}$
Where $\mathrm{theta}$ is the creep coefficient depending upon the age of the concrete.

Age at loading	Value of creep coefficient θ
7 days	2.2
28 days	1.6
1 year	1.1