ntroduction ............................................................................................................................ 3
Sample Calculations ............................................................
...
ntroduction ............................................................................................................................ 3
Sample Calculations ............................................................................................................... 5
Results .................................................................................................................................... 6
Discussion ............................................................................................................................. 8
Conclusion ............................................................................................................................ 9
References ............................................................................................................................ 10
Appendix ............................................................................................................................. 11
(Attached Sheet)
Introduction
The standard proctor compacting test is used to determine the soil compaction properties,
as well as to determine the optimal moisture content at which soil can reach its maximum dry
density, therefore; it is necessary to compact soil to improve its strength. The degree of
compaction is measured by its dry unit weight gd. Soil has a lot of different particles with
different shapes; so when compacting dry soil there is a lot of friction with the soil particles
against each other, therefore; it is difficult for them to maneuver into the soil voids. When water
is introduced to the soil it almost acts like a lubricant and reduces the friction on the soil particles
against each other. Through this process, the particles have an easier time sliding into the soil
voids when compacted. Although water makes compaction easier, too much water can also be
bad for compaction. Through the standard proctor test the goal is to find the optimum moisture
content of the soil, wopt. This point is where water changes from helping compaction to hurting it.
When there is too much water added to the soil it starts becoming too saturated and the water
fills in the soil voids. With the voids filled up there is nowhere for the soil particles to go. Instead
of the soil condensing it just moves thus not compacting.
Sample Calculations (From trial 1)
Weight of moist soil
W2 – W1 = 13.01 lb – 9.26 lb = 3.75 lb
Moist unit weight
(W 2– W 1)
(1/30) =
(13.01– 9.26)
(1/30)
= 112.5 lb/ft3
Moisture content w (%)
(M 4 – M 5)
(M 5 – M 3)
x 100 =
(53.4 –52.37)
(52.37 – 29.87)
x 100 = 4.6 %
Dry unit weight of compaction,
gd =
γ
1+(w()/100) =
112.5
1+(4.6/100) = 107.6 lb/ft3
Zero-air-void unit weight
gzav =
γ w
(
w( )
100 )+(1 /Gs
) =
62.4
4
100
+
1
2.812
= 157.73 lb/ft3
[Show More]
.png)
.png)
.png)
.png)
