CV311 Geotechnical Engineering
Year III– Bachelor in Civil Engineering
Experiment 3: Standard Proctor Compaction
Test
Date performed: 19/04/22
Due date: 26/04/22
Jacob T.N. Ketewai
S11155373
Group 3
Unit Lecturer: Thomas Kishore
Introduction
The Proctor Compaction Test establishes the maximum unit weight that a particular type of soil can be
compacted to using a controlled compactive force at an optimum water content. This is the most common
laboratory soil test and the basis for all engineered compacted soil placements for embankments,
pavements, and structural fills. (Gilson Company Inc.). In-place measured densities of the compacted fill
are compared to the Proctor test results to determine the degree of soil density.
It has long been known that the moisture content of soils, particularly cohesive soils, has a direct impact
on how efficiently they can be compacted by construction equipment. But because the soil is a natural
material and the ideal moisture content and maximum dry weight varies for each soil type, the questions
of the best unit weight and ideal moisture content couldn’t be answered.
This is how the proctor test came into existence, to answer this essential engineering question.
Aim
The aim of this experiment is to find the optimum moisture content and maximum dry weight at which
the soil sample can be compacted at for the best possible results.
Apparatus








Compaction mold
Standard Proctor Rammer (2.5kg)
Vanier Caliper
Balance
Sample Extruder
Graduated Cylinder
Moisture Cans
Tray
Procedure

Initially, soil taken was weighed 2kg on a tray thoroughly mixed with water to make it dampen
with 10% moisture content.

The weight of Proctor Mould + Base plate (without extension) was recorded as W1 (kg).

The moisture soil is poured into the mold and divided into 3 layers.

For each of the layers that was put in the compaction mold, the moist soil was compacted with 25
blows from the hammer.

The weight of Proctor Mould + Base plate + Compacted moist soil was recorded as W2 (kg).

After completion of compaction, weight of soil in mold is determined. Now:
𝑑𝑒𝑛𝑠𝑖𝑡𝑦 𝑜𝑓 𝑠𝑜𝑖𝑙 =
𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑜𝑖𝑙 𝑖𝑛 𝑚𝑜𝑙𝑑
𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑚𝑜𝑙𝑑
,𝛾=
𝜔
𝑣
.

The compacted soil was extruded from the mold using the extruder and weight of the empty
moisture can with lid was recorded as W3 (kg).

Some soil from the extruded soil sample was collected into a moisture can and weighed, recorded
as W4 (kg), before oven dry method.

Steps 4-10 was repeated, since in this process there will be an increase in W2 with the increase in
moisture content.

The oven dried soil was recorded the next day as W5 (kg).
Results
Determination of bulk density
Test no:
Volume of mould
V(m3)
Mass of mould +base +compacted soil
W2(kg)
Mass of mould +base
W1(kg)
Mass of compacted soil
W2-W1 (kg)
𝑊 −𝑊
Bulk density 𝛾 = 2 𝑉 1
kg/m3
Determination of water content:
Container no.
Mass of container
W3 (kg)
Mass of container and wet soil
W4(kg)
Mass of container and dry soil
W5(kg)
Mass of water
W4 - W3 (kg)
Mass of dried soil
W5 - W3 (kg)
W5− W3
Water content 𝑤 = W4− W3 × 100
%
Dry density 𝛾𝑑 =
100𝛾
100+𝑤
1
9.68x10-4
6.02
4.78
1.24
1280.99
2
9.68x10-4
6.42
4.78
1.64
1694.21
3
9.68x10-4
6.58
4.76
1.82
1880.17
4
9.68x10-4
6.53
4.78
1.75
1807.85
D5
0.02
0.044
0.042
0.024
0.022
91.67
D3
0.02
0.06
0.052
0.04
0.032
80
M1
0.02
0.048
0.042
0.028
0.022
78.57
LM5
0.02
0.056
0.048
0.036
0.028
77.77
668.33
941.23
1052.9
1016.96
kg/m3
Water Content vs Dry Density
1200
Dry Density kg/m^3
1000
800
600
400
200
0
76
78
80
82
84
86
Water Content %
Maximum dry density: 1052.9 kg/m3
Optimum Water Content: 78.57%
88
90
92
94
Sample Calculations:
Bulk Density:
𝛾=
𝛾=
𝑊2 − 𝑊1
𝑉
6.02 − 4.78
9.68x10−4
𝛾 = 1.24
Water content:
𝑤=
𝑤=
𝑊5 − 𝑊3
× 100
𝑊4 − 𝑊3
0.042 − 0,02
× 100
0.044 − 0.02
𝑤 = 91.67%
Dry Density:
𝛾𝑑 =
𝛾𝑑 =
100𝛾
100 + 𝑤
100(1.24)
100 + 91.67
𝛾𝑑 = 668.33
Discussion
Comparing the graph obtained from the results with the above image, it must be stated outright that the
graph obtained, while not atypical, is still reasonable and can be used to obtain the values that need to be
found, the maximum dry density and optimum water content, which were 1052.9 kg/m3 and 78.57%
respectively. These values are important because, The ability to attain acceptable levels of compaction is
reliant on the moisture content of the soil being placed along with the compactive effort achievable from
the plant used ( Nicholls Colton Group Ltd, 2021). In simple terms, for the soil sample used, if the site
from which it was obtained were to be compacted, the water content at time of compaction would need to
be 78.57% and it would then need to be compacted to a density of 1052.9kg/m3 in order to get the best
results.
Conclusion
In summation, this experiment and lab repot basically outline the process of the proctor compaction test,
showed how to interpret the data for which the results obtained for maximum dry density and optimum
water content were found to be1052.9 kg/m3 and 78.57% respectively, and finally showed what these
values meant.
Reference
Nicholls Colton Group Ltd. (2021). Optimum Moisture Content/Maximum Dry Density (OMC/MDD):
Nicholls Colton Group. Retrieved April 25, 2022, from Nicholls Colton Group Web Site:
http://nicholls-colton.co.uk/optimum-moisture-content-maximum-dry-densityomcmdd/#:~:text=(OMC%2FMDD),Optimum%20moisture%20content%2Fmaximum%20dry%20density%20(OMC%2FMDD),of%20
a%20soil%20to%20settlement.
Gilson Company Inc. (n.d.). Proctor Compaction Test: Gilson Company Inc. Retrieved April 25, 2022, from
Gilson Company Company Web Site: https://www.globalgilson.com/blog/proctor-compactiontest-a-basic-guide