Question

Stress-strain curve of concrete is

• A. A perfect straight line upto failure
• B. Straight line upto 0.002 strain value and then parabolic upto failure.
• C. Nearly parabolic upto 0.002 strain value and then a straight line upto failure
• D. Hyperbolic upto 0.002 strain value and then a straight line upto failure

Answer 1

The correct option is C Nearly parabolic upto 0.002 strain value and then a straight line upto failure

The characteristic and design stress-strain curves specified by the Code for concrete in flexural compression are depicted in Figure below. The maximum stress in the concrete in the structure is restricted to $0.67f_{ck}$. The curves consist of a parabola in the initial region upto a strain of 0.002 (where the slope becomes zero), and a straight line thereafter, at a constant stress level up to an ultimate strain of 0.0035.