Question

In a Marshall sample, the bulk specific gravity of mix and aggregates are 2.202 and 2.541 respectively. The sample includes 5% of bitumen (by total weight of mix) of specific gravity 1.10. The theoretical maximum specific gravity of the mix is 2.504. The voids filled with bitumen (VFB) in the Marshall sample (in %) is _________

• A. 45.36
• B. 38.48
• C. 51.75
• D. 30.24

Answer 1

The correct option is A 45.36

Percent air voids,
$V_v=\frac{G_t-G_m}{G_t}\times 100$
$=\frac{2.504-2.202}{2.504}\times 100=12.06\%$

Percentage volume of bitumen,
$V_b=\frac{G_m}{G_b}\times W_b=\frac{2.202}{1.1}\times 5=10.01\%$

$VMA=V_v+V_b=12.06+10.01=22.07\%$

$\therefore VFB=\frac{V_b}{VMA}\times 100=\frac{10.01}{22.07}\times 100=45.36\%$