1. (10 pts) The results of a standard Proctor test are given in the following table.

a. Complete the table, assuming Gs = 2.6. Show one sample calculation on how you obtain

the three unit weights (Y. Ya, and yz). Note that the standard mold volume is 1/30 ft³.

Compaction

Trial No.

1

2

3

4

5

6

Weight of

moist soil in

the mold (lb)

3.65

4.12

4.48

4.38

3.91

3.63

Water Content

(%)

7.2

9.5

12.5

14.9

17.1

18.1

(Moist) Unit

Weight (lb/ft³)

Dry Unit Weight

(lb/ft³)

Dry Unit Weight

w/ Zero Air Void

(lb/ft³)

b. Plot the dry unit weight data vs. water content and determine the maximum dry unit weight

and optimum water content. Also, add the Zero Air Void curve in the plot. When plotting,

use an MS Excel chart option (Scatter with Smooth Lines and Markers). Attach your plot

(an MS Excel file) indicating the OMC and max dry unit weight.

c. Determine the degree of saturation at OMC you determined (i.e., the water content and dry

unit weight are known) Hint: Recall Se=wGs and ya=Gryw/(1+e)

d. If the dry unit weight you achieved in the field is 105 lb/ft³, what is the relative compaction

(%) of the compacted soil?/nCENG 3232

Soil Mechanics

Compaction

e. If the construction specification requires the field compaction to be 95% of the maximum

dry unit weight, what is the range of water content that can be referenced in the field?

f. As a field civil engineer, what would you do to increase the degree of compaction?