Compaction is a ground improvement technique that densifies soil through external effort like rolling, ramming, or vibration. Rolling uses heavy cylinders to compact soil surfaces like sports pitches. Ramming involves dropping a heavy block or mechanical rammer onto soil. Vibration compactors include vibratory rollers, plates, and tampers used in confined areas. Laboratory tests determine optimum water content and maximum dry density for different soils and compactive efforts like standard and modified Proctor tests.

1. What is compaction?
 A simple ground improvement
technique, where the soil is densified through
external compactive effort.
COMPACTION
Compactive effort
+ water =

2.  There are three method in field compaction
 Rolling
 Ramming
 Vibration

3.  Rolling - a heavy cylinder is rolled over the
surface of the soil. Commonly used on sports
pitches. Roller-compactors are often fitted
with vibratory devices to enhance their ability.
 Different types of rollers are used for
Compaction. which are depend on following
factors
 Contact pressure
 Number of passes(normally 5 to 15)
 Layer thickness (less than 15 cm)
 Speed of roller

4.  A hand operated rammer consist of a block of
iron,about 3 to 5 kg in mass,attached to a wooden
rod.the rammer is lifted for about 0.30 m and dropped
on the soil to be compacted
 A mechanical rammer is operated by compressed air or
gasoline power.it is much heavier about 30 to 150 kg.
mechanical rammers have been used up to a mass of
1000 kg in some special cases.
 Tampers are used to compact soil adjecent to
existing structures or confined area as
trenches,within plinth of building.

5.  Vibration are induced in the soil during compaction.the
compactors are available in a variety of forms.when the
vibrator is mounted on adrum,it is called a vibratory roller.
these rollers are available both as pneumatic type and the
smooth wheel type.in a smooth wheel type, a separate motor
drives an arrangement of eccentric weights to create high
frequency,low-amplitude,up and down osicillations of the
drum.
 These rollers are suitable for compacting granular soils.
 Another form of vibratory compactor is a vibrating plate
compactor. hand operated vibrating plates are also available.

6. Instrument of Filed Compaction
 Different types of rollers (clockwise
from right):
 Vibratory roller
Pneumatic rubber tired roller  Smooth-wheel roller
 Sheepsfoot roller

7. Smooth Wheeled Roller
Compacts effectively only to 200-300 mm;
therefore, place the soil in shallow
layers (lifts)

8. Vibrating Plates
 for compacting very small areas
effective for granular soils

9. Sheepsfoot Roller
 Provides kneading action; “walks out” after
compaction
Very effective on clays

10. Impact Roller
 Provides deeper (2-3m) compaction. e.g., air
field

11. Laboratory Compaction Test
- to obtain the compaction curve and define
the optimum water content and maximum
dry density for a specific compactive effort.
hammer
Modified Proctor
Standard Proctor
•5 layers
•3 layers
• 25 blows per
• 25 blows per layer layer
•4.9 kg hammer
•2.7 kg hammer
• 450 mm drop
• 300 mm drop
1000 ml compaction mould