The Rheological behaviour of concrete, when represented by shear stress vs rate of shear, is characterized asWhere : τ shear stress,Τ0 = (initial) yield value,μ = at-point plastic viscosity,γ̇ = at point rate of shear.

• A. τ = τ0 + μ . γ̇
• B. τ0 = τ + μ . γ̇
• C. \(\frac{\tau }{{{\tau _0}}} = \mu .\dot \gamma\)
• D. τ = μ . γ̇