Question

Laboratory compaction test results for a cohesive soil are given in the following table:

Water Content (%)	Dry Density (pcf)
12.0	116.2
13.6	117.6
14.8	117.9
16.1	116.5
17.2	113.6

                                                                                                              

Plot Diagram with labels and sample test labels

Specifications call for a fill dry density of 114 pcf and further require that the fill be compacted at optimum water content for the field compactive effort. For the following field density test results on a fill, explain how you alter the field placement operation:

1. ?_d = 115 pcf ; ? = 12.5 percent

2. ?_d = 112.5 pcf ; ? = 13.5 percent

3. ?_d = 110 pcf ; ? = 14.5 percent

4. ?_d = 111 pcf; ? = 17.3 percent

Answer 1

The main aim to find the Optimum moisture content of compacted soil

First of all we need to draw the Graph as per the Dry density vs water content

As per the Graph the Max dry density is 118 pcf and Optimum moisture content is 15%

We need to finalise the value as per the 114 pcf

in that Small Mathamatical caluclation i was did, in that we know 116.5 Pcf od water content is 16.1 and same like dry density of 113.6 pcf of water content is 17.2 and we need to find the 114 pcf of how much water was there

and small caluclation was did and based on the calculation the water content is 17.078% at 114 pcf

similarily

the filed test values all plotted graph Dry density vs Water content

As per the graph Max dry density is 110 pcf and optimum water conetnt is 14.5%