Correct Answer - Option 1 : 10.86%
Explanation:
Given,
Case - I: Bulk density = 20.1 kN/m3, water content = 15%
Case II: Dry Density = 19.4 kN/m3 ⇒ water content = ??
No change in void ratio.
As, dry unit weight (γd) = γ/(1 + w)
\(\begin{array}{l} {γ_d} = \frac{γ}{{1 + w}} = \frac{{20.1}}{{1 + 0.15}} = 17.478\; kN/{m^3}\\ {γ_d} = \frac{{{γ_w}.G}}{{1 + e}} \end{array}\)
If void ratio 'e' remains unchanged during drying, \(γ_d\) also remains unchanged.
\(\begin{array}{l} {γ_d} = \frac{γ}{{1 + w}}\\ 17.478 = \frac{{19.4}}{{1 + w}} \end{array}\)
w = 10.99 %