1.1: General Introduction
Road construction is very tedious work. To make the construction process easier there are many tools and equipment in practice. Every tool has its advantages and disadvantages. The construction process can be either labour intensive or capital intensive (i.e equipment base).
1.2: Labour intensive and capital intensive work.
1.2.1: Labour intensive work.
Method of road construction in which human resources are used instead of equipment is known as labour intensive work.
1. It gives employment opportunities.
2. In areas such as mountains where it is difficult to carry heavy equipment, labour intensive work may be advantageous.
3. It is advantageous if labour is available at low cost.
4. It is advantageous to bring economic stability.
5. It is suitable in case if the soil is highly constable.
1. It is costly if labours are not available at a low cost.
2. It is a time-consuming process of construction.
3.Chances of an accident of labours.
4. Affected by emotional factors (i.e Strike).
5.Difficult to work in adverse climate.
6.Less uniform work.
1.2.2: Capital intensive work
Method of road construction in which machines or equipment are used instead of human resources is known as capital intensive work.
1. It is a faster process.
2. Economical if labour charge is higher.
3. It is a highly safe and sophisticated method of road construction.
4. Quality of work is consistent (uniform).
5.No need for stage construction.
6. It can work in an adverse climate.
7. It is not affected by the emotional factor.
1. The high initial investment is required.
2.Difficult to transport the equipment in a rural area.
3. It takes away the employment opportunities of labours.
4. Trained or skilled manpower is required.
5. Reselling or disposing of construction equipment is difficult.
1.3: Construction equipment type and user
There are several types of equipment used in road construction. Some of them are described below:
These are large excavating machines with excavating bucket. This bucket is used for loading the materials to trucks or tipper. It is used to excavate natural surface of the ground, excavating trenches and for construction of basement in general grading work which requires precise control of depth.
It is also called Drag shovel/ Back shovel or Truck hoes. It has a gooseneck to increase the depth of digging.
They are used to excavate below ground level. They are useful in digging trenches, pits, whenever sloring is not required.
It performs various functions such as cleaning and preparing the land, opening the tracks, moving the earth, spreading and drilling the earth. This equipment is useful for pushing with high force. It may be
It contains excavator along with the mover. They can excavate, haul and discharge materials. It is also of two types:-
These excavate the earth and load in transporting equipment or deposit it on leeve damp or spoil, banks.
Power shovels are of smaller size while draglines are of large size and are advantageous if we have to do the large earth excavation.
A grader is used in road and air-filled construction. These are mostly used for levelling and finishing the earthwork.
1.4: Transporting equipment
Equipment which is used to transport the road material from one place to another place is known as transporting materials.
1)Dumping Truck (Tipper)
-used to shift the materials.
-No need for manpower to unload.
-use to shift the construction material in large quantity.
-It needs manpower in loading and unloading of materials.
3)Mini dumpers (Mini Tippers)
-It is used to shift the construction materials in smaller quantity.
-Need manpower in loading but not in unloading.
-It is used to shift the materials in rough tracks.
-It needs manpower in loading and unloading.
-It is suitable for shifting materials in smaller quantity for a smaller distance.
-It is used in labour intensive work generally.
Along with this above equipment, there are other equipments also used as transporting equipment
1.5: Compacting equipment
Equipment which is used to throughout the air from the soil mass to reduce the void ratio and density of soil is known as compacting equipment.
It increases the density and stability, reduce the settlement and reduce or lower the adverse effect of moisture contents.
Various equipment used for compaction of the road are as follows:-
1)Smooth wheel roller
Three wheel roller is the conventional type of smooth wheel roller used in road compaction. In this type of roller, compaction efficiency depends upon the diameter, width and weight of the compactor.
It is most suitable for gravel, sand, crushed rocks, and any materials where crushing is needed.
Effectiveness is limited because of static compressive loading rather than compression supplemented by vibration and tamping.
2)Sheep foot roller
This type of roller consists of a hollow steel cylinder with projecting feet. The weight of the roller can be control by filling the cylinder with soil or water. It is useful in clay soil. During rolling operation soil under projecting feet get compacted well.
In this type, the number of pneumatic wheels is mounted on two or more axles under a load platform. This roller is pulled by tractors and is considered as most suitable for compaction of non-plastic silts and film sands.
These roller compact soil by kneading action of space between two wheels.
4)Vibrating rollers (vibrators)
These compactors have one smooth vibrating steel wheel and two pneumatic wheels. The most common type of vibrating roller has front steel wheel vibrating. The application of vibrator is still experimental stage due to its poor output.
1.6: Watering Equipment
Equipment which is used to apply water all over the pavement surface thereby spreading in controlled quantity is known as watering equipment. These are of two types:-
In this type of watering equipment water is filled on a truck and is spread over the pavement surface by using a porous pipe across its width.
These are similar to scraper but instead excavating arrangement longitudinal porous pipe is fitted along with the drum of water so, that water could be spread easily all over the pavement surface in control quantity.
1.7: Aggregate Production
After receiving the stones or boulder from the quarry they are crushed into smaller size and the sieved into different size. The process of crossing is done in three stages:-
At this stage, stones are directly received from the quarry and therefore a reduction in size is carried out with the help of following equipment:-
The crushed stones receive from primary crusher are put into following crushers:-
This is the final stage of crushing the required size of aggregates are obtained by crushing aggregates in the following equipment:-
c)Ball roller or ball mill
1.8: Rock Excavating Equipment
These are the instruments used to construct the road in rocky terrain. Following equipment are used during construction of a road in the rocky area.