A soil sample, taken from a borrow pit has a specific gravity of soil solids of 2.66. The sample was taken to a materials laboratory and tested. The results of a standard Proctor test are tabulated below. Weight of Soil (lb) Moisture Content (%)
3.20 12.8
3.78 13.9
4.40 15.0
4.10 15.7
3.70 16.6
3.30 18.1

The maximum dry density in lb/ft3 is most nearly:

115 Ib/ft^3

Explanation:

To determine the maximum dry density in Ib/ft3 we have to calculate :

Bulk unit weight ( yb ) ; W / v

Dry unit weight ( yd. ) :  yb / ( 1 + w )

For every set of data given

assuming  v = 1/30 ft^3

calculating for the 3 data set ( maximum dry density )

weight of soil (W) = 4.40

moisture content (%) (w) = 15.0 = 0.15

Bulk unit weight (yb) = 4.40 / (1/30)  = 132 Ib/ft^3

Dry unit weight ( yd. ) = 132 / ( 1 + 0.15 ) = 114.702 Ib/ft^3

therefore after calculations the maximum dry density in Ib/ft^3 ≈ 115 Ib/ft^3

diy

explanation: