Road Engineering & Geotechnical Branch, JKR

Ir. Liew Shaw Shong

22 September 2014

Section 71 of the Street, Drainage & Building

Act, 1974

Misconstruction / Lack of Supervision

RM500,000 / 10 Years Imprisonment

Engineering Purposes
Strength to take imposed static & dynamic
Stresses
Stiffness to control Deformation
Permeability Characteristics
Collapsibility of Soil Matrix Structure
Erodibility
Availability of Materials
Efforts needed for Economical & Efficient
Compaction

What is Compaction?

Terminology

(3rd Layer or 3rd Lift)

(2nd Layer or 2nd Lift)
(1st Layer or 1st Lift)

Lift (Max.
thickness per
lift subject to
materials and
compaction
equipment)

Suitability of Fill Materials

Availability of Materials & Engineering solutions
Engineering Characteristics of Materials
Strength, Stiffness, Permeability, Collapsibility &
Erodibility
Particle sizes, Grading, Plastic Index, Liquid Limit,
Slakability, Toughness, Hardness

Efforts needed for Economical & Efficient

Compaction

Type of Fill

Minimum Minimum
Dry Density Density
Ratio*
Index

Residential Fill

95%

65%

Commercial Fill to support floor

loading up to 20kPa and isolated
pad footing to 100kPa

98%

70%

Road Embankment
(a) 0.3m below pavement
subgrade
(b) < 0.3m below pavement
subgrade

95%

65%

100%

80%

* Note : Standard Proctor Compaction (AS 1289)

Method Specifications

End Product Specifications

Performance Specifications

Too Wet
- Excessive Consolidation Settlement
- Low Strength
- Plastic Fill

Too Dry
- Vulnerable to Collapse Settlement
- Brittle Fill

Objective - Ensure Uniform Compaction Energy

within compacted layers

Scope of Earthworks

Frequency of Field
Density Tests

Large Scale Operation

(Industrial lots, Road
embankment)

One test per 500m3

Small Scale Operation

(Residential lots)

One test per 200m3

Concentrated Operation
(Gullies filling, Farm dam)

One test per 100m3

Confined Operation
(Filling behind structures)

One test per 2 layers per 50m2

Trenches

One test per 2 layers per 40m

Note : AS 3798:1990

Whenever soil is placed as an engineering fill, it

is normally compacted to a dense state, so as to
obtain satisfactory engineering properties
Control of the degree of compaction is
necessary to achieve a satisfactory result at
reasonable cost
Laboratory compaction tests provide the basis
for procedures used on site

Laboratory and Field Tests

Stage

Tests

Purpose

Stage 1

Proctor Test or Vibrating

Hammer

To obtain maximum dry density

and optimum moisture content
of fill soil material

Stage 2

Trial Compaction

(First time trial and error of

FDT test at site to determine
compaction effort)

Stage 3

Field Density Tests (FDT Compare compacted field dry

- Sand replacement method)
density to maximum dry
& Moisture Content
density

Laboratory and Field Tests

Proctor Tests by R.R. Proctor (1920)

Compaction effort (energy)
Soil types
Water content
Dry unit weight

Adopted Standards for Compaction Tests

Standard Proctor
Test OR Modified
Proctor Test?
1)Standard Proctor
Test(2.5 kg rammer)
2)Modified Proctor
Test(4.5 kg rammer)

2.5 kg or 4.5 kg rammer? (BS 1377-4:1990)

Maximum size of bulk soil

particle?
Fine grain
Medium-gravel size
Coarse-gravel size

Percentage (%) of passing

37.5mm sieve and 20mm
sieve?

Size of Mould?

1L mould or CBR mould? (BS 1377-4:1990)

1L mould
Mould Volume =1000 mm3

CBR mould
Mould Volume = 2305 mm3

Soil particles susceptible to crushing

(deform)during compaction?
Grading
Zone

Minimum percentage
passing test sieves
20 mm

37.5 mm

(1)

100 %

100 %

(2)

95 %

100 %

(3)

70 %

100 %

(4)

70 %

95 %

(5)

70 %

90 %

(X)

< 70 %

< 70 %

Minimum mass of
prepared soil required

Type of
mould used

NO

YES

6 kg

15 kg

1L

15 kg

40 kg

CBR

TEST NO APPLICABLE

NO

Soil particles not susceptible to crushing during

compaction.

YES

Soil particles susceptible to crushing during compaction.

Soil particles susceptible to crushing (deform)

during compaction? (BS 1377-4:1990)

of
of
of

of

NO

Soil particles not susceptible to crushing during compaction.

YES

Soil particles susceptible to crushing during compaction.

BS 1377-4:1990: Summary of Preparation Method

for Compaction Tests

Layers and time of rammer blows? (BS 13774:1990)

Layers and time of rammer blows? (BS 13774:1990)

Distribution of rammer blows during free fall

rammer compaction)

Cautious notes
> 6 mm on top of mould
after compaction

REJECT

Void in the mould after

compaction

REJECT

< 6 mm on top of mould

after compaction

OK

Repeat minimum 5 times whole mould

compaction.
Obtain moisture content of each soil samples
Compute the bulk density, (in Mg/m3), of each
compacted specimen:-

Compute the dry density, d (in Mg/m3), of each

compacted specimen

2.8

2.4

d = w Gs(1 - A)/(1 + w Gs)

2
4.5kg Rammer

2.5kg Rammer

1.6

1.2
0

10
20
Moisture Content, w (%)

30

Plot Dry Density vs

Moisture Content curve
Plot 0%, 5%, 10% of
Saturation Line

Determine:1) Maximum Dry

Density (Mg/m3)
2) Optimum
moisture
Content (%)

Source: ELE
International

IMPORTANT NOTE :
Always check the
moisture content(s)
are in acceptable
range?

Comparison of compaction on dry side .vs. wet side

Factors considered
Characteristic of compaction equipment
Weight and size
Operation frequency and frequency range

Soil Characteristic
Initial density
Soil type
Size and shape of soil particle
Moisture Content

Compaction Procedure
No. of passes of the roller
Layer thickness
Frequency of operation of vibrator
Towing speed

Scale of compaction?
Large earthwork platform ?
Beside Retaining Structures?
Confined space?

Source of bulk filling material?

Imported bulk filling material?
Cut material (borrow pit) within
site?

Compaction equipment
Smooth wheel roller (400kPa)
Rubber tire roller (700kPa)
Sheepsfoot roller (1.4 to 7MPa)
Tamping foot roller (1.4 to
8.4MPa)
Grid roller (1.4 to 6.2 MPa)
Vibrating plate
Dynamic compaction
Vibrocompaction

To determine the compaction effort (no of

passes) and loose lift thickness for compaction
at site.
Description

Compactor Capacity

No of passes

20-30 tonne roller

compactor

start 6 passes (e.g.: 6,

8,10, 12, 14 passes)

1 tonne roller compactor

Start 20 passes (e.g.:

20, 22, 25 passes)

Loose lift
thickness

Typical value

20-30 tonne roller

compactor

400 mm

500 mm

1 tonne roller compactor

200 mm

300 mm

Trial Compaction
Dry
Test no. Density
(Mg/m3)

Maximum
Moisture
Dry
Compaction
No. of Thickness
Content
Density Achieved (%)
Passes of Fill, (mm)
(%)*
(Mg/m3)

FD1

1.527

1.734

88.1

16.29

6 passes

500

FD2

1.443

1.734

83.2

16.81

8 passes

500

FD3

1.433

1.734

82.6

17.1

10 passes

500

FD4

1.659

1.736

95.6

14.67

6 passes

450

FD5

1.641

1.736

94.5

15.45

8 passes

450

FD6

1.63

1.736

93.9

16.48

10 passes

450

8 passes with maximum loose lift thickness of 450mm are

established from Trial Compaction

To obtain field dry density after compaction.

Verification test / control test for quality of

compaction.

Determine moisture content at laboratory (Oven or

Microwave Oven)

Determine moisture content at field (Speedy Tester)

Scope of Earthworks

Frequency of Field
Density Tests

Large Scale Operation

(Industrial lots, Road
embankment)

One test per 500m3

Small Scale Operation

(Residential lots)

One test per 200m3

Concentrated Operation
(Gullies filling, Farm dam)

One test per 100m3

Confined Operation
(Filling behind structures)

One test per 2 layers per 50m2

Trenches

One test per 2 layers per 40m

Note : AS 3798:1990

Numbering sequence of FDT (no repeat of naming)

Reduced level (Important: to check thickness
of lift)
Moisture Content (Important: must be in the
reasonable range of fill soil type)
Passed 95% of relative density of Standard
Proctor Test?
Sieve analysis should be included together with
Proctor Test (for soil with gravels).
Plasticity Index to test for clay existence in bulk
soil as fill material.

Standard Proctor Test Results

Some results

95.2

96.0

95.5

95.2

95.2

95.2

95.3

95.1

95.3

95.3

95.4

95.0

Summary of compaction test :2010 Nos of FDT done.

FDT test generally consistence.
Good record of FDT points (Zoning, etc) except
for typo error.
Only issue - Crusher run with higher moisture
content redo Standard Proctor Test to verify
moisture content by independent laboratory.

Backfilling works at RC Retaining Wall

(Inverted-L)

Summary of Compaction tests issue:Late submission of FDT results

Modified Proctor Test instead of Standard
Proctor Test was submitted.
QS did not capture Compaction Test for
backfilling- became VO works.
Moisture content varies.
Solution reject FDT points with moisture
content >20% and do Mackintosh Probe (MP)
Test for correlation.

Landfill cover project at Johor

Compaction to 90% of standard Proctor Density

Summary of Compaction tests issue:Submit doubtful FDT result.

result and submit to us).
Moisture content not acceptable (8% to 22%)
compacted to OMC compared with optimum
moisture content in Modified Proctor Test (i.e.
13.16%)

Solution:Do trial pit and re-do FDT test.

Do Mackintosh Probe Test for correlation.

So can it be the same recipes for different moisture

content and the density is same?

Weak Strength

Tension
Cracks

Tilting

3m

Distortion

Leaking Pipe

Lateral Movement
Settlement
1.5
1

Leaking Water

1
Original Ground

Leaking Water
Instability (Creeping Movement)

1.5

Total/Differential Platform Settlement

Gap (75mm)
Void (150mm)
Differential Settlement

Depressions

Differential Settlement

Shear Cracks

Differential Settlement
Sagging

Shear Cracks

Shear Cracks

Cast-In-Situ
R.C. Monsoon
Drain
Weep Hole
Drain

Fill Settlement

Excessive Fill
Settlement

Fill Settlement

Poor Compaction

Very Poor Compaction

Poor Compaction

or Thin Fill

or Thick Fill

or Thin Fill

Collapse Settlement of New Fill

Collapse Settlement of New Fill

Downdrag on Pile
Structural Cracks

Downdrag from Piles

Erosion of Drain
High Permeability of Poorly Compacted
Soil by Surface Runoff

Consideration of compaction pressure in a

restrained condition
h

Ka

Earth Pressure
Envelope without
Compaction Effort

ka

Earth Pressure
Envelope including
Compaction Effort

Retaining Structure

Retaining Structure

Distance from Wall

Resultant
Pressure
Distribution from
Compaction
Effort

Retaining Structure

Minimum 1.5 m away

from face of wall

Distance
from Wall

Retaining Structure

Each fill material shall have own compaction

test as reference
Only specify the actual required compaction
effort or reasonable compaction practice
Controls on loose lift thickness, moisture
content at placement & particle size
Field tests with sufficient statistics
Light compaction on last layer to prevent rain
water ingression
Compaction pressure
Supervision

BEFORE Compaction

After Compaction
(>95% rice + water ,
< 5% air void)