Compaction is the process of mechanically increasing the density of soil. It is the simple way of increasing the stability and supporting capacity of the soil. Compaction is one kind of densification that is realised by rearrangement of soil particles without a flow of water.
Major reasons for compaction of soil:
- Reduction of air-voids content in Soil
- Increasing load bearing capacities
- Providing Stability
- Reducing water seepage, contraction and swelling
- Prevent frost damages and soil settlement
There are two principal types of compaction force :
01. Static Force:
It is simply the dead weight of the equipment. This is done by applying the downward force on the soil surface and compressing the soil particles. Static force is confined to upper soil layers and limited to the appreciable depth. Kneading and Pressure are two basic mechanisms of static compaction.
02. Vibratory Force:
It is usually an engine drive to create the downward force in addition to the weight of the machine. The vibrating mechanism is usually a rotating eccentric weight of the machine or piston combination. The compactors deliver a rapid sequence of blows to the surfaces, thereby affecting the top layers as well as deeper layers. Vibrations move the material, setting particles in motions and moves them close together for highest density possible.
The different types of compaction equipment used in compaction project depend on the scope of work. The compaction equipment to be used can either be used for some situations or can be a special type which meets the requirements of the particular project.
- Smooth Wheeled Roller
- Sheepsfoot Roller
- Pneumatic Roller
- Vibratory Roller
- Vibratory Plate Compactor
The various types of compaction equipment used in building projects include:
01. Smooth Wheeled Rollers:
It is an important equipment for compaction. It consist large steel drum in front and one or two wheel on rear end.
02. Sheepsfoot Rollers:
Sheepsfoot rollers also known as a tamping roller. Steel drum of sheepsfoot roller consist of many rectangular shaped boots of equal sizes fixed in hexagonal pattern.
03. Pneumatic Roller:
Pneumatic roller is also called rubber tyres roller. Pneumatic roller has number of tyres at the front and at the rear end.
04. Vibratory Roller:
Vibratory roller consist two smooth drums with the vibrator. One is fixed at front and other one on rear side of vibratory roller. Both drums are of the same diameter, length and same weight.
Rammer compactor is used for compacting small area and providing impact load to soil. This equipment is light weight and can be hand or machine operated.
06. Vibratory Plate Compactor:
Vibratory plate compactor is used for compacting different types of soils in narrow and conjusted area where it is not possible to use large equipment.
The selection of compaction equipment for building projects depend upon the nature of the mechanical, job size, distance, method of disposal, and construction time assigned, volume and depth of soil to be compacted, type of soil, loads on compacted surface, etc.