Construction Practices (CE-211)

Compaction Equipment

Engr. Dr. Muhammad Haseeb Alvi

Assistant Professor
Department of Civil Engineering

UNIVERSITY OF MANAGEMENT
AND TECHNOLOGY LAHORE
 Compaction of Soil and Rock
With time, the material will settle or compact itself naturally, but
compaction aims to achieve the required density quickly. Obtaining a
greater soil unit weight is not the direct objective of compaction. The
reason for compaction is to improve soil properties to

1. Reduce or prevent settlements

2. Increase strength

3. Improve bearing capacity

4. Control volume changes

5. Lower permeability
 Compaction Equipment
• Compaction equipment is available in several types, each with
different features for handling specific applications.

• The best compactor depends on the material needing

compaction, the area size, and other project-specific factors.

• Although there are multiple kinds of compaction machines,

they all apply downward pressure on a material to compress it
and fill in empty spaces.

• Compaction equipment can also help create an even, level

surface so bringing other equipment into the area is safe.
 Purpose of Compaction Equipment
• Compaction equipment compresses substrate materials
like soil, gravel, and asphalt to make them denser and
more stable. Reducing air voids within a base material
prevents future settling and keeps groundwater from
seeping up through the substrate.

• It also increases its durability, strength, and load-bearing

ability. Compaction is essential for creating strong, stable
foundations for various projects.
 Purpose of Compaction Equipment
• In general, granular soil, gravel, and sand are best
compacted with vibratory equipment, which lets the
particles bounce, twist, and fall into a position that allows
the least movement. However, cohesive soil, clay, and silt
compress better with impact force, which pushes out air
and water between the small particles.
 Purpose of Compaction Equipment
• Using heavy equipment allows efficient compaction with
minimal effort from workers. Some of the many uses of
compaction equipment include:

• Grading

• Utility work

• Landscaping

• Landfill compacting

• Construction projects

• Road and rail construction

 Types of Soil Compaction Equipment
The compaction equipment for soil can be categorized into
two types based on their mass.
• Light soil compaction equipment
• Heavy soil compaction equipment
Light Soil Compaction Equipment
These types of equipment are used particularly for
compacting small areas, which require less compaction effort
(force). The following equipment falls under the category of
Light compaction equipment.
• Rammers
• Vibratory tampers
• Vibratory plate compactors
 Types of Soil Compaction Equipment
Rammers
Rammers are machine-powered
and hand-steered small
machines used for compacting
small areas by providing an
impact on the soil. Rammers
are lighter in weight so they
can be handled by a single
person.
 Types of Soil Compaction Equipment
• The base size of the rammers is usually smaller in area ranging
from 15 x 15 cm2 to 20 x 20 cm2. Usually, their weights are in
the range of 30 kg to 10 tons.

• In the case of rock compaction, these rammers can weigh up to

two or three tons and can fall freely from heights of 1 or 2 m to
crush the rock underneath them.

• Rammers are particularly suitable for compacting cohesive

soils like clays located in small areas like trenches and
building foundations.
 Types of Soil Compaction Equipment
Vibratory Tampers
• The base plate installed on
vibratory tampers is spring-
activated by an alternative
mechanism driven by a motor.
• Vibratory tampers are also
ideal to be used in smaller
areas in confined zones. They
can even be used to compact
all types of soils using the
vibrations.
• They are usually manually
guided like rammers and
weigh between 50 and 100 kg.
 Types of Soil Compaction Equipment
Vibratory Plate Compactors

• Vibratory plate compactors are particularly used on coarse

soils like sand containing four to eight percent fine particles
like clay.

• In contrast to rammers, which compact soil by producing an

impact, vibratory plate compactors compact the soil by
producing vibrations.

• The weight of these machines can range between 100 kg and 2

tons. The plate areas are also bigger in contrast to rammers,
with areas ranging from 0.16 to 1.6 square meters.
Types of Soil Compaction Equipment
 Types of Soil Compaction Equipment
Heavy Soil Compaction Equipment

• These types of equipment are used particularly for

compacting larger areas with different types of soils,
which may require less or larger compaction effort (force).

• Heavy compaction equipment is selected based on the

amount of moisture content in the soil and the type of soil.
 Types of Soil Compaction Equipment
Heavy Soil Compaction Equipment
The following equipment falls under the category of Heavy
compaction equipment.
• Smooth wheels rollers
• Sheep foot rollers
• Elephant foot rollers
• Pneumatic tired rollers
• Wobble wheel roller
• Impact roller
• Grid rolls
• Pad foot/ presser rollers
 Types of Soil Compaction Equipment
Smooth Wheel Rollers
• These types of rollers apply static compression on the soil
underneath their rolls. These machines are triple-wheeled
vehicles. The front wheel is made of one large drum, while
on the rear side, there are two large drum wheels.
• The static compression is applied through these drum-
shaped wheels. These machines are used with granular
soils. Most commonly they are used in compacting the
base course of roads and paving highways and airfields.
• These machines are propelled by a diesel engine. The
weights of the drum wheels can be altered by adding
ballast or other heavy materials inside the drums.
 Types of Soil Compaction Equipment
Smooth Wheel Rollers
• Their weight can range from 10 to 200 kg per drum. As a
result, the pressure exerted by them is in the order of 300 N,
which of course can be varied by adding more ballast into the
drums.
 Types of Soil Compaction Equipment
Sheep Foot Rollers
• The sheep foot roller is also a vehicle similar to smooth wheel
rollers. However, in contrast to a smooth drum used in smooth
wheel rollers, these machines have a sheep’s foot or tamping
roller in front. While on the rear side, they have tires.

• Sheep’s foot or tamping roller consists of a hollow steel

cylindrical drum made with steel projections or feet extending
in a radial direction on the front. These projections of feet are
extended outward from the cylinder surface.
 Types of Soil Compaction Equipment
Sheep Foot Rollers

• The dimensions of the roller can be varied to get different

soil compaction capacities. These dimensions include the
diameter and width of the drum and the length and shape
of the feet of the rollers. Usually, the feet are 15 to 20 cm
long and placed in staggered rows around the drum. This
allows to obtain a contact of about two tamping feet per
square foot of tamped area. The weight of the drums can
also be varied in a way similar to smooth wheel rollers.
 Types of Soil Compaction Equipment
Sheep Foot Rollers

• Sheep foot rollers are particularly suitable for cohesive

soils. This is due to the smaller width of loaded areas
under their feet. Sometimes sheep foot rollers are also
employed in the compaction phase on the areas with soil
fragments of rock soils. They break down these soft rock
fragments. They are also used to pulverize hard dry soil
and can also help in the mixing of soils.
 Types of Soil Compaction Equipment
Sheep Foot Rollers

• Sometimes, these rollers are also towed by a tractor. This

also allows compaction through vibration. Especially in
sandy soils, mixing large quantities of water and using a
towing tractor will couple the benefits of vibrations to
achieve much better compaction.
Types of Soil Compaction Equipment
 Types of Soil Compaction Equipment
Elephant Foot Roller

• A sheep foot roller is sometimes also termed an elephant

foot roller if some of the feet are removed from the drum
and are replaced with 20 to 25-cm wide flat plated welded
on the remaining feet of the drum.

• Elephant rollers are useful for silty soils of low cohesion.

This is due to the increased widths of the loaded area,
which produces greater confinement.
 Types of Soil Compaction Equipment
Pneumatic Tired Rollers

• The pneumatic tired roller is ideal for compaction of

cohesion-less or slightly cohesive soils. These soils
include gravels, sands, clayey sands, silty sands, and even
sandy clays. The pressure applied by them is distributed
over relatively larger areas, which prevents the soil from
collapsing.
 Types of Soil Compaction Equipment
Pneumatic Tired Rollers

• Pneumatic tired rollers consist of a platform mounted on

two axles. The rear axle has one more wheel compared
with the front axle. The total width of all the inflated tires
is approximately equal to 80% width of the rollers.

• They are not commonly used on soils. Instead, their best

use can be found in the area where the surface to be rolled
is not rough or steep like the asphalt of the roads.
Types of Soil Compaction Equipment
 Types of Soil Compaction Equipment
Wobble Wheel Roller

• Wobble wheel rollers are similar to pneumatic tired rollers

except that their wheels are mounted at a slight angle with
respect to their axle. This also allows to achieve slight
kneading action.
Types of Soil Compaction Equipment
 Types of Soil Compaction Equipment
Impact Roller

• In impact rollers, a tractor pulls a prism-shaped mass,

made of steel or concrete. As a result of the rotation of
prism-shaped mass, an impact is generated, which
transfers sufficient energy to achieve medium compaction
to a depth of several meters.

• This type of roller can be used for granular soils including

gravels and rock fills.
Types of Soil Compaction Equipment
 Types of Soil Compaction Equipment
Grid Rollers

• These rollers are made of cylindrical surfaces of a steel grid

formed by a network of steel bars. The grid is made of square
holes. The weight of the grid can be achieved by adding ballast
to the cylinder. Usually, their weight ranges from 5.5 tons to 15
tons with ballast added.

• Grid rollers are used for compacting weathered rocks and thick
soils. On the other hand, they are not suitable for clayey soils,
silty soils, and uniform soils. They are mainly used in subbase
construction in road projects.
Types of Soil Compaction Equipment
 Types of Soil Compaction Equipment
Pad Foot/Slash Presser Rollers

• The roller is similar to a sheep foot roller. However, they have

lugs on their cylinders, which have larger areas than the feet of
sheep foot rollers.

• They are also sometimes termed as tamping rollers having

static weight in the range of 15 to 40 tons. They can achieve
more degree of compaction than sheep foot rollers. They also
operate at high speeds and can break down large lumps of soil.
They are best suitable for compacting cohesive soils.
Types of Soil Compaction Equipment