4. Bull dozer
A bulldozer is a crawler (continuous tracked tractor) equipped with a
substantial metal plate (known as a blade) used to push large
quantities of soil, sand, rubble, or other such material during
construction or conversion work and typically equipped at the rear
with a claw-like device (known as a ripper) to loosen densely
compacted materials.
Bulldozers can be found on a wide range of sites, mines and quarries,
military bases, heavy industry factories, engineering projects and farms.
5. Most often bulldozers are large and powerful tracked heavy equipment. The
tracks give them excellent ground holding capability and mobility through very
rough terrain. Wide tracks help distribute the bulldozer's weight over a large area
(decreasing ground pressure), thus preventing it from sinking in sandy/muddy
ground. Extra wide tracks are known as swamp tracks or LGP (low ground
pressure) tracks.
Because of these attributes, bulldozers are often used in road building,
construction, mining, forestry, land clearing, infrastructure development, and any
other projects requiring highly mobile, powerful, and stable earth-moving
equipment.
6. Components of bulldozer
The bulldozer's primary tools are the blade and the ripper.
1. BLADE - The bulldozer blade is a heavy metal plate on the front of the tractor,
used to push objects, and shove sand, soil, debris, and sometimes snow. Dozer
blades usually come in three varieties:
a) A straight blade ("S blade") which is short and has no lateral curve and no side
wings and can be used for fine grading.
b) A universal blade ("U blade") which is tall and very curved, and has large side
wings to carry more material.
c) An "S-U" (semi-U) combination blade which is shorter, has less curvature, and
smaller side wings. This blade is typically used for pushing piles of large rocks,
such as at a quarry.
7. Ripper
The ripper is the long claw-like device on the back of the bulldozer. Rippers can come as a single
shank/giant ripper or in groups of two or more multi shank rippers.
Usually, a single shank is preferred for heavy ripping. The ripper shank is fitted with a replaceable
tungsten steel alloy tip, referred to as a 'boot’. Ripping rock breaks the ground surface rock or
pavement into small rubble easy to handle and transport, with agricultural ripping, a farmer breaks up
rocky or very hard earth, which is otherwise unploughable, in order to farm it.
Some bulldozer have less common attachment known as
stumpbuster. A stumpbuster is used to split a tree stump. A
bulldozer with a stumpbuster is used for land clearing
operations, and is often equipped with a brush-rake blade.
Multi-shank ripper
8. Types of Ripper
1. Ripping rock – it can break big rocks. It is easy to handle and easily transportable.
2. Agricultural ripping – it is used by farmers , in case of the soil is very hard for use
in agricultural, farmers use it to excavate the hard top soil.
3. Ripper / Rooter – it may be fitted on tyre or carried by tractor .it has 2 or more
teeth which penetrate in the soil and loosen the soil and rips the plant out of the
ground. It is used to ripe plant off the ground.
9. Scraper
In civil engineering, a wheel tractor-scraper is a piece of heavy equipment used for earthmoving.
The rear part of the scraper has a vertically moveable hopper with a sharp horizontal front edge
which can be raised or lowered. The front edge cuts into the soil, like a carpenter's plane cutting wood,
and fills the hopper. When the hopper is full it is raised, closed, and the scraper can transport its load to
the fill area where it is dumped. With a type called an 'elevating scraper’ a conveyor belt moves material
from the cutting edge into the hopper.
10. Crane
A crane is a type of machine, generally equipped with a hoist rope,
wire ropes or chains, and sheaves, that can be used both to lift and
lower materials and to move them horizontally. It is mainly used for
lifting heavy things and transporting them to other places. The
device uses one or more simple machines to create mechanical
advantage and thus move loads beyond the normal capability of a
human. Cranes are commonly employed in the transport industry
for the loading and unloading of freight, in the construction industry
for the movement of materials, and in the manufacturing industry
for the assembling of heavy equipment.
11. Loaders
A loader is a heavy equipment machine used in construction to move aside or
load materials such as asphalt, demolition debris, dirt, snow, feed, gravel, logs,
raw minerals, recycled material, rock, sand, woodchips, etc. into or onto another
type of machinery such as a dump truck, conveyor belt, feed-hopper.
There are many types of loader, which, depending on design and application, are
called by various names, including bucket loader, front loader, front-end loader,
payloader, scoop, shovel, skip loader, wheel loader, or skid-steer.
12. Excavator
Excavators are heavy construction equipment consisting of a boom, dipper (or stick),
bucket and cab on a rotating platform known as the "house“.
The house sits atop an undercarriage with tracks or wheels. They are a natural
progression from the steam shovels and often mistakenly called power shovels.
All movement and functions of a hydraulic excavator are accomplished through the
use of hydraulic fluid, with hydraulic cylinders and hydraulic motors.
Due to the linear actuation of hydraulic cylinders, their mode of operation is
fundamentally different from cable-operated excavators which use winches and steel
ropes to accomplish the movements.
13. Excavators are used in many ways:
1. Digging of trenches, holes, foundations
2. Material handling
3. Brush cutting with hydraulic saw and mower attachments
4. Forestry work
5. Forestry mulching
14. 6. Construction
7. General grading/landscaping
8. Mining, especially, but not only open-pit mining
9. River dredging
10. Driving piles, in conjunction with a pile driver
11. Drilling shafts for footings and rock blasting, by use of an auger or hydraulic drill
attachment
12. Snow removal with snowplow and snow blower attachments
15. Shovels
A shovel is a tool for digging, lifting, and moving bulk materials, such as soil, coal,
gravel, snow, sand, or ore.
Most shovels are hand tools consisting of a broad blade fixed to a medium-
length handle. Shovel blades are usually made of sheet steel/hard plastics and are
very strong. Shovel handles are usually made of wood or glass-reinforced plastic.
Hand shovel blades made of sheet steel usually have a folded seam/hem at the
back to make a socket for the handle. This fold also commonly provides extra
rigidity to the blade. The handles are usually riveted in place. A T-piece is
commonly fitted to the end of the handle to aid grip and control where the
shovel is designed for moving soil and heavy materials.
16. Grader
A grader, also commonly referred to as a road grader or a motor grader, is a
construction machine with a long blade used to create a flat surface during the
grading process. Typical models have three axles, with the engine and cab
situated above the rear axles at one end of the vehicle and a third axle at the
front end of the vehicle, with the blade in between.
17. In civil engineering, the grader's purpose is to "finish grade" (to refine or set
precisely). The "rough grading" is performed by heavy equipment or
engineering vehicles such as scrapers and bulldozers .
Graders are commonly used in the construction and maintenance of dirt roads
and gravel roads. In the construction of paved roads they are used to prepare
the base course to create a wide flat surface upon which to place the asphalt.
Graders are also used
to set native soil foundation pads to finish grade prior
to the construction of large buildings.
18. Road roller
A road roller is a compactor type engineering vehicle used to compact soil,
gravel, concrete, or asphalt in the construction of roads and foundations.
Type of roller –
1. Hand roller/ cylindrical roller
2. Pneumatic roller
3. Sheep footing roller
4. flat wheeler roller
19. Types of Roller
1. HAND ROLLER - This is a light roller of iron, concrete or stone; drawn by hand or
bullocks. The size varies, but it is generally about 1 meter in dia. and about 1.5 meter
long.
This ground pressure generated by this type of roller is about 7 kg/cm2.
2. SHEEPSFOOT ROLLER- As the name indicates, this type of roller consists of a drum
having many round or rectangular shaped protrusions or “feet” on it. These rollers are
also called tamping rollers.
Various types are available having different diameters and widths of drum and
different lengths and shapes of feet. The most common type is the one having two
drums 1.22 meters wide and 1.06 either as taper-foot or club-foot rollers according to
the shape of the feet.
Suitable for cohesive soil only.
20. Types of Roller
Area of each protrusion can vary from 30 to 80 cm2.
The soil is supposed to be consolidated when the impression by the projecting teeth is not more
than 12 mm deep or when the surface has been rolled 16 to 20 times.
Various types are available having different diameters and widths of drum and different lengths and
shapes of feet. The most common type is the one having two drums 1.22 meters wide and 1.06
either as taper-foot or club-foot rollers according to the shape of the feet.
The factors that governs the amount of compaction of soil are as follow:
1. Gross weight of the roller
2. Area of each feet
3. No of feet in contact with ground
4. Total no of feet per drum.
Maximum pressure is exerted on soil when a foot is vertical.
21. PNEUMATIC TYRED ROLLERS
This type of roller consists of a heavily loaded wagon with several rows of four to
six closely spaced tyres. This is also called rubber tyred roller.
These have kneading action and these can convert flocculated structure into
dispersed structure.
Suitable for cohesive soil, however may be used for all type of soil.
It provided uniform pressure throughout the width.
factors governing the amount of compaction are as follow
1. Tyre pressure
2. Area of contact
Tyre pressure may be up to about 7 kg/cm2
22. PNEUMATIC TYRED ROLLERS
The coverage area is about 80%.
The gross weight of the roller is about 6 to 10 tonnes which can be increased to
25 tonnes by ballasting with steel section or other means.
The maximum density can be achieved by 8 passes of the roller. The optimum
speed of roller is between 6 to 24 km/h.
Used for compacting cold laid bituminous pavements, soft base course materials
or layers of loose soil.
These rollers are also suitable for compacting closely graded sands, and fine-
grained cohesive soils at moisture content approaching their plastic limits,
though the compaction is not as high as that with the smooth wheel roller.
23. Smooth wheeled roller
This type of roller consists of a large steel drum in front and one or two wheels or
drum on the rear end.
Depending upon the number of wheels on the rear, it can be of following two
types:
1. Tandem rollers (having one wheel at rear and one wheel in front)
2. Three wheeled rollers (having two wheel at rear and one in front)
The weight of tandem roller varies from 2 to 8 tonnes and that of two wheeled
roller varies from 8 to 10 tonnes.
24. Smooth wheeled roller
It is suitable for gravel and boulders . But may b e used for silts and clay.
It ground coverage provided by smooth wheeled roller is 100%.
The weight of the roller can be increased by filling the inside space of the drum with
water or wet sand. This is called ballasting.
The ground pressure exerted by tandem rollers is about 10 to 17 kg/cm2.
Performance of smooth wheel roller depend upon it load per cm width and diameter
of the roll.
The speed and number of passes of a smooth wheeled roller depends on the type of
soil to be compacted and project requirements. The optimum working speed has
found to be 3 to 6 km/h and about 8 passes are adequate for compacting 20 cm
layer.
25. Vibratory Compaction Equipment
In vibratory compaction, A stress is applied repeatedly and rapidly via a mechanically
driven plate or hammer. Often combined with rolling compaction.
Vibratory compaction are suitable for cohesion less soil, especially under confined
condition.
TYPES –
1. Vibratory roller – In this, the vibrator is mounted on a drum. These are available as
pneumatic type and smooth-wheel type.
2. Vibrating plate compactor – In this, there are number of small plates, each plate is
operated by a separate, vibrating unit.
Hand operated vibratory plate are also available. The effect of vibrating plate is limited to a
small depth. Their main use is to compact granular base course for highway and runways
where thickness of layer is small.
It can compact granular soil to a very high maximum dry density.
