Question

The bulk specific gravity of a bituminous mix is $2.35$ and the theoretical specific gravity is $2.43$. The percentage of bitumen in the mix is $4$% by weight with specific gravity $1.03$. Then voids is bitumen (VFB) are _____ %.

• A. 73.5

Answer 1

The correct option is A 73.5
Given,

Bulk specific gravity,

$G_m=2.35$

Theoretical specif gravity, $G_t=1.03$

We know,

$V_a\%=(1-\frac{G_m}{G_s})\times 100=(1-\frac{2.35}{2.43})\times 100=3.29\%$

$V_b\%=\left(\frac{W_b}{W}\right)\times \left(\frac{G_m}{G_b}\right)=\frac{4\times 2.35}{1.03}=9.126\%$

Percentage voids in mineral aggregate (VMA) $=3.29+9.126$
$=12.416$%
$\therefore$ Percentage void filled in bitumen (VFB)$\frac{100V_b}{VMA}=\frac{9.126\times 100}{12.416}$
$=73.502$

$\approx 73.5$%