UNIVERSITY OF DAR ES SALAAM (UDSM)

COLLEGE OF ENGINEERING AND TECHNOLOGY (CoET)

DEPARTMENT OF GEOTECHNICHAL ENGINEERING AND TRANSPORTATION (TGE)

HIGHWAY MATERIALS (TR 331)

PRACTICAL REPORT No. 1

COMPACTION TEST AND THE FIELD DENSITY TEST

NAME: SAINOCK, TIMOTHY

REGISTRATION NO. 2014 - 04 -02597

DEGREE PROGRAM: Bachelor of Science in CIVIL ENGINEERING

GROUP: E

YEAR OF STUDY: 2016/2017

COURSE INSTRUCTOR: Dr P. M. BUJULU

DATE OF PRACTICAL: 09th November, 2016, Wednesday

DATE OF SUBMISSION: 16th November, 2016, Wednesday

 PROCTOR COMPACTION TEST (Moisture Density Relationship Of Soils)

Chapter 01; Introduction

Soil compaction is the mechanical densification of soils by pressing soil particles to park more
closely together, through reduction of air voids. Proctor compaction test is the test which use the
methodology developed by R.R Proctor in 1933, therefore, the test is known as proctor test. There
are basically two types of proctor compaction test which are routinely performed (1) The standard
proctor test using 2.5 kg rammer, 3 layers and 30.5cm drop of rammer and (2) Modified proctor test
using 4.5 kg rammer, 5 layers and 45.8cm hammer drop.

The dry density which can be achieved for soil depends on the degree of compaction applied and the
moisture content. The moisture content which gives the highest dry density is called Optimum
moisture content for that point of compaction. In general the optimum moisture content is less than
plastic limit.

Chapter 02; Objective

The main objective of the test was

 To determine the relationship between the moisture content and dry density of a
specified compactive effort, the test is used to provide a guide for specifications
on field compaction.
 To determine the maximum dry density (MDD) of the soil type.
 To determine the optimum moisture content (OMC) for attaining the maximum
densification of the soil type.
Through compaction engineering properties of soil mass like compressibility and
permeability are reduced while shear strength is increased. Compaction is particularly important
when soil is used as foundation material for road or as construction material for embankment.
 Chapter 03; Apparatus and the materials used

 A cylindrical compaction mould; used for putting soil for compaction, It supports the
sample volume of about 942 cm3.
 The extension collar; Used for the prevention of the sample from leaving the mould
during the compaction process.
 A 4.5 kg metal rammer; used to compact soil in the mould as the source of the
compaction energy. Each layer with 25 blows.

 An electronic balance; used to measure soil and mould weights before and after the
compaction of the soil sample.
 Scoop; used to hold soil from the tray to the compaction mould into three different
layers.
 A large metal tray; used for mixing soil with water.
 A straight edge; assists the trimming of the sample after the compaction when the collar
is removed.
 The measuring cylinder; used for the measurement of the mixing water.
 Chisel; used for the assistance of the removal of the compacted mould from the
compaction mould.
 Chapter 04; Sample preparation

 Soil mass is air dried first.

 Sieve the materials through 20mm sieve according to BS & CML standard for
942 cc mould.
 Obtain the sample from quartering so as to maintain particle size distribution and
to get required representative soil.
 On sieving when 5% by mass of the material is retained in 20mm sieve we have
to do replacement to compensate.
 For the 942cc mould 3kg of sieved soil is required for the test.
 Five representative samples of the soil material passing on 20 mm test sieve were
prepared. The sample was mixed with water for the range of 2%, 4%, 6%, 8% and
10% of a weight of sample in order to give different moisture content .Each 5
portion of sample was sealed in an airtight container and allowed to cure for
minimum of 4 hours.
 Chapter 05; Experimental Procedures
 The compaction mould and base plate was weighed to obtain its mass, the weight
was recorded as 5574g.
 The mould and the base plate was placed on the floor and sample was poured into
the mould, the test which modified proctor test requires 5 layers of soil sample in
the mould. Each layer should occupy 1/5 of height of mould in order to allow 5
layers on the mould to fit.
 The rammer was placed with the casing on material and lifted until it reaches the
top of the casing and the allowed to fall freely under the influence of gravity at the
dropping height of 45.8cm on the sample, each layer was striked by 25 blows.
 After all 5 layers were compacted the extension collar was removed and the
excess soil was striked and leveled using a straight edge.
 Then the levelled soil sample with the compaction mould was weighed and the
value was recorded, in which the weight of the compacted sample was computed
and the density of the soil sample was computed.
 The soil was removed from the mould with the assistance of the chisel, small
portion of the compacted soil was taken for moisture content determination.
 All the procedures above were repeated until all 5 samples were compacted and
the weight were recorded.
 After 24 hrs. the moisture content was determined, then the dry density of the soil
samples were computed and the graph of the dry density against the moisture
content was plotted
 Chapter 06; Computations

 Bulk density (r)

𝑴𝟏 − 𝑴𝟐
Bulk density = g/ cm3 Where M1 = Mass of the mould + sample
𝑽

M2 = Mass of the mould

V = volume of mould
 Dry density (rd )
𝐁𝐮𝐥𝐤 𝐝𝐞𝐧𝐬𝐢𝐭𝐲
Dry density = Where w = Water content (In fractions)
𝟏+𝐰

 Moisture content (w)

𝐰𝐞𝐢𝐠𝐡𝐭 𝐨𝐟 𝐦𝐨𝐢𝐬𝐭𝐮𝐫𝐞(𝑴 )
𝒘
Moisture content = 𝒘𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝒔𝒐𝒍𝒊𝒅 𝒔𝒂𝒎𝒑𝒍𝒆(𝑴 x 100%
𝒔)

 Zero air void (ZAV) line

𝒘 𝑷 ∗𝑮
𝒔
Zero dry density = 𝟏+𝒘𝑮 g/ cm3 Where Gs = specific gravity of the soil sample
𝑺

The data were calculated and collected according to the sheet provided and graph of dry densities
against moisture content was plotted to obtain optimum moisture content and corresponding
maximum dry density (MDD)

Number of layers 5 5 5 5 5 5
Number of blows/layer No 25 25 25 25 25 25
Wt. of mould + wet g 6905 7125 7280 7363 7258 7020
Wt. of mould
ssssssssssssssoilsoil g 5627 5627 5627 5627 5627 5628
Wt. of wet soil g 1278 1498 1653 1736 1631 1392
Volume of mould Cc 942 942 942 942 942 943
Wet density g/cm3 1.356 1.590 1.755 1.843 1.731 1.476
Dry density g/cm3 1.274 1.440 1.589 1.638 1.514 1.267
Zero air void density g/cm3 2.266 2.166 2.075 1.991 1.919 1.845
CONT.NUMBER K10 K27 K4 K15 K333 K30
Wt. of wet soil + cont. g 148.89 124.89 156.23 131.46 161.619 150.79
Wt. of dry soil+ cont. g 141.36 117.06 143.77 119.61 144.37 132.90
Wt. of cont. g 24.33 24.44 24.46 24.71 24.15 24.25
Wt. of water g 7.53 7.83 12.46 11.85 17.25 17.89
Dry soil g 117.03 92.62 119.31 94.9 120.22 108.65

Moisture content % 6.4 8.44 10.44 12.49 14.35 16.46

THE GRAPH OF DRY DENSITY VS MOISTURE

CONTENT
2500

2300

2100

1900
DRY EDNSITY kg/m3

1700

1500

1300

1100

900

700

500
4 6 8 10 12 14 16 18
MOISTURE CONTENT %
 Chapter 07; Sources of errors

The following are some of the errors that occurred during the conduction of the experiment;
 Error due to unequal compactive effort on the application of the blows
 Errors due to the climatically changes as increase in temperature of the surrounding.
 Errors due to the computations
 Errors due to the calibration of the electronic balances.

Chapter 08; conclusion

 The experiment was the success since the required values were obtained and the standards
was accepted, From the graph the standard modified maximum dry density was 1.638g/cm3
and the optimum moisture content was 12.15%

Chapter 09; Recommendations

 The compactive energy should remain constant throughout the experiment in order to
obtain a more accurate results
 The replacement is required if the retained material on the 20 mm sieve are greater than
5% of the selected sample.
 The soil shouldn’t be reused for different moisture content, sufficient sample should be
prepared to ensure that the same soil sample is not used for different moisture content this
is because during the test the is a possibility for the degrading/breaking the soil particles.
 FIELD DENSITY BY THE SAND REPLACEMENT METHOD

Chapter 01; Introduction

Compaction is the process whereby soil particles are forced more closely together
through reduction in the volume of the pore spaces. This increases the density of the soil since,
for a given weight of soil volume is decreased.
Field density is the density of soil obtained in situ, this is achieved through the use of
variety of compacting equipment. No one particular type of compaction equipment suits every
soil since soils differ from one another by size and shape of particles, gradation, and moisture
content and chemical composition. Different types of equipment have been using different forces
to move the soils particles close together. The compacting forces are.
 Pressure
 Impact
 Vibration
The material compacted at site need to be checked if the compaction reach the
requirements as directed by the standards. The soil is excavated from the compacted pavement
and sent to the laboratory for testing requirement in order to find the field control specification
for the specific soil sample. This can be achieved using two methods
1. Balloon method
2. Sand replacement method
Both methods assists the test in determination of the volume of the hole from which the
material has been excavated in the pavement. The basic principle of sand replacement is to
measure the insitu volume of the hole from which the material was excavated, and a sand with
known weight and density filling the hole.

Chapter 02; Objective

The main objective of the test was

 To obtain the field density.as the control for the in situ compaction.
 To determine the degree of compaction achieved.
 Chapter 03; Apparatus and the materials used

 Cylindrical calibrating container with a cone; for the calibration of the volume of the
soil extracted by the use of the sand.
 Feet or ruler; used for the measurement of the height of the excavated hole.
 Scoop; used to hold soil from the holes to the airtight containers.
 A large metal tray with the circular hole of about 150 mm in diameter; used as the
 Chisel and the scrapper; used for the excavation process of the hole.
 Mallet; used as the source of the energy during the excavation of the material in the hole.
 Nails; used for fixing the metal plate during excavation of the material in the hole.
 Sand; dry and clean test sand of uniform gradation passing 1mm and retained 600 µm
sieve.
 Brush; used for removing small soil material remained in the hole before the calibration
of the volume of the hole.
 An electronic balance; used to measure soil sample from the holes and the sand before
and after filling the hole.
 Plastic airtight containers; used as the container of the excavated materials so as to
retain the moisture content as it was in situ.
 Cylindrical calibrating container with a cone; for the calibration of the volume of the
soil extracted by the use of the sand.
 Feet or ruler; used for the measurement of the height of the excavated hole.
 Scoop; used to hold soil from the holes to the airtight containers.
 A large metal tray with the circular hole of about 150 mm in diameter
 Chapter 04; Sample preparation

Sample to be dug is selected at randomly it may be either at the Centre, left or right of the
compacted soil pavement. The standard height of the hole for density determination is
150mm.The excavated material should be kept in an air & water tight container ready for the
laboratory tests.

Chapter 05; Experimental Procedures

1. Expose an area of about 450mm square on the surface of the soil mass. Trim the surface
down to a level surface of the soil mass using a scrapper tool.
2. Place the metal tray on the leveled surface.
3. Excavate the soil through the central hole of the tray, using the hole in the tray as a
pattern. The depth of excavated hole should be about 150mm.
4. Collect all the excavated soil in a metal container, and determine the mass of the soil.
5. Remove the metal tray from the excavated hole.
6. Fill the sand pouring cylinder within 10mm of its top determine it’s mass.
7. Place the cylinder directly over the excavated hole. Allow the sand to run out the cylinder
by opening the shutter. Close the shutter when the hole is completely filed and no
movement of sand is observed.
8. Remove the cylinder from the filled hole. Determine its water content.
9. The two tins with the sample was then shifted to the oven and the temperature was set at
105oC for at least 16 hours.
10. After 24 hrs the moisture content was determined, then the dry density of the soil samples
were computed. Also the degree of the compaction was also computed.

Chapter 06; Computations

 Volume of the hole

𝑴𝑺+𝒄𝒃 −𝑴𝑺+𝒄𝒂 − 𝑴𝒔𝒄
V= Where; 𝑴𝑺+𝒄𝒃 = Mass of sand and the cylinder before pouring
𝒑

𝑴𝑺+𝒄𝒂 = Mass of sand and the cylinder after pouring

𝑴sc= Mass of sand in cone
r= Bulk Density of the sand = 1.351 g/cm3

 Bulk density (r)

𝑴 𝟏 − 𝑴𝟐
Bulk density = g/ cm3 Where M1 = Mass of the container + sample
𝑽

M2 = Mass of the Container

V = volume of the hole
 Dry density (rd )
𝐁𝐮𝐥𝐤 𝐝𝐞𝐧𝐬𝐢𝐭𝐲
Dry density = Where w = Water content (In fractions)
𝟏+𝐰

 Moisture content (w)

𝐰𝐞𝐢𝐠𝐡𝐭 𝐨𝐟 𝐦𝐨𝐢𝐬𝐭𝐮𝐫𝐞(𝑴 )
𝒘
Moisture content = 𝒘𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝒔𝒐𝒍𝒊𝒅 𝒔𝒂𝒎𝒑𝒍𝒆(𝑴 x 100%
𝒔)

 Degree of Compaction (DC)

𝐅𝐢𝐞𝐥𝐝 𝐝𝐫𝐲 𝐝𝐞𝐧𝐬𝐢𝐭𝐲 (𝐃𝐃)
Degree of compaction = 𝑴𝒂𝒙𝒊𝒎𝒖𝒎 𝑫𝒓𝒚 𝑫𝒆𝒏𝒔𝒊𝒕𝒚 (𝑴𝑫𝑫)
 Chapter 07; Data presentation

DRY DENSITY OF SOIL

Sample No 1 2
Mass of sample + container Ms1 g 4647.7 4652.7
Mass of container Ms2 g 0 0
Mass of sample (MS1 –MS2) Ms g 4647.7 4652.7
Mass of sand + cylinder before pouring M1 g 9013.6 9193.6
Mass of sand +cylinder after pouring M2 g 3862.3 3992.3
Mass of sand in a cone M3 g 1651 1651
Mass of sand in Hole Mh g/cm3 3500.3 3550.3
Bulk density of sample (Ms/Mh x density of sand) 1.794 1.770
Moisture content container No g K16 H18
Mass of Wet sample + container Mwet g 4647.7 4745.6
Mass of dry sample + container Mdry g 4368.7 4493.5
Mass of container Mcont g 0 0
Mass of water Mw g 279 252.1
Mass of dry sample Md g 4368.7 4493.5
Moisture content W % 6.4 5.6
Dry density ((bulk density)/(1 +w)) g/cm3 1.690 1.676
Maximum dry density (proctor) g/cm3 2 2
Optimum moisture content % 10.2 10.2
Degree of compaction % 84.5 83.8
 Chapter 08; Analysis of results

The specifications usually ranges from 95-100% of MDD when 4.5kg hammer is used the
field control. The experiment failed because the values of dry field density and moisture content
are out of the ranges

In Tanzania (Pavement material design manual) suggests that

Acceptable variation of field MDD =±5% of lab (specified) MDD
Acceptable variation of field OMC = ±2% of lab (specified) OMC

Thus

Bulk density=2±0.1 g/cm3 (MDD±5% OF MDD)

Field moisture content = 10.2± 0.204 (OMC±2%)

 The obtained field density for samples K16 and H18 are 1.690g/cm3 and 1.676g/cm3
respectively.
 The obtained moisture content for sample K16 and H18 are 6.4% and 5.6% respectively.

The compaction is termed as a poor compaction the compacted soil having low moisture
content than required OMC the particles are not lubricated and thus friction between soil
particles prevents densification and hence low values of dry density.

Chapter 09; Sources of errors

The following are some of the errors encountered during the conduction of the field density test;
 Error due to poor removal of the soil sample remained after the excavation of the hole.
 Errors due to the climatically changes as increase in temperature of the surrounding.
 Errors due to the computations estimations
 Errors due to the calibration of the electronic balances.
 Chapter 10; conclusion

In order to reach the maximum dry density specified in the laboratory, moisture content
should be increased to OMC this will create a film of water around soil particles which will
reduce friction and increase compactibility and hence density.
Caution should be taken not to increase further moisture far from OMC this will create
pore water pressure and hence on compacting gives lower density.