Question

A cohesive soil yields a maximum dry density of 1.8 g/cc at an OMC of 16% during a Standard Proctor test. If the value of G is 2.65, the maximum dry density it can be further compacted to is ____ g/cc

• A. 1.86

Answer 1

The correct option is A 1.86
${\gamma }_{dmax}=1.8g/cc$

At OMC, w = 0.16

Specific gravity, G = 2.65

Now, we have

${\gamma }_{dmax}=\frac{G{\gamma }_w}{1+e}$

$\Rightarrow 1.8=\frac{2.65\times 1}{1+e}$

$\Rightarrow 1.8(1+e)=2.65$

or e = 0.472

$\therefore S=\frac{wG}{e}=\frac{0.16\times 2.65}{0.472}$

$\Rightarrow S=0.8983$

= 89.83%

The maximum dry density it can be further compacted to, is the theoretical dry density at OMC corresponding to zero air content.

At zero air content, soil is fully saturated

S = 1

$\Rightarrow e=\frac{wG}{S}=\frac{0.16\times 2.65}{1}$

= 0.424

$Now,{\gamma }_{dtheo}=\frac{G{\gamma }_w}{1+e}=\frac{2.65\times 1}{1+0.424}$

$or{\gamma }_{d\_theo}=1.86g/cc$