ROAD PAVEMENT

Pavement is a sort of hard surface comprised of durable surface material that is placed down on an area meant to carry automobile or pedestrian activity. 

Its primary role is to disperse applied vehicle loads to the sub-grade via several layers. The road pavement should provide enough skid resistance, good riding quality, good light reflecting properties, and low noise pollution. 

Its purpose is to lower the vehicle’s transmitted load so that it does not exceed the sub-bearing grade’s capability. Road pavements play an important function in the development of any structure. There are two types of road pavements: flexible and rigid pavements.

Types of Pavement

  • Flexible pavement
  • Rigid Pavement
FLEXIBLE PAVEMENT

In flexible pavements, vehicle stress is conveyed to the subgrade via gain to gain contact of the aggregate via the granular structure. These roads have reduced flexural strength and act like a flexible sheet (e.g. bituminous road).

Types of Flexible Pavement

  • Full-depth asphalt pavement
  • CRAM (Contained rock asphalt mat), and
  • Conventional layered flexible pavement.

Full –depth Asphalt Pavement

They are constructed by laying down bituminous layers directly on the soil sub-grade. This is more appropriate whenever there is a significant volume of traffic and local resources are unavailable.

 

Contained rock asphalt mats

Contained rock asphalt mats are made by layering dense and open-ranked mixture layers between two asphalt layers. When dense ranked asphalt concrete is laid on top of the sub-grade, it may greatly reduce vertical compressive strain on the soil sub-grade and protect it from surface water.

 

Conventional flexible pavements

They are layered systems with high-quality, costly materials placed at the high points whenever stresses are high, and quality, low-cost materials placed at the lower levels.

RIGID PAVEMENT

Rigid pavements are constructed of reinforced cement concrete slabs that rest on a hard prepared subgrade or directly on a granular subgrade. Rigid pavements have high flexural strength and are utilized to disperse wheel weight across a wider surface area.

 

Types Rigid Pavement

  • JPCP (Jointed plain concrete pavement),
  • JRCP (Jointed reinforced concrete pavement)
  • CRCP (Continuous reinforced concrete pavement), and
  • PCP (Pre-stressed concrete pavement)

1. Jointed Plain Concrete Pavement

Plain cement concrete is used to create this firm pavement that has contraction joints that are tightly spaced. For weight transmission between joints in this design, steel bars are commonly utilized. It has a 5 to 10 meter joint spacing.

2.Jointed Reinforced Concrete Pavement

Reinforcement in a rigid pavement does not improve structural stability, but it can increase joint spacing by 10 to 30 meters. The dowel bar’s primary function is to transfer weight only, with reinforcing employed in the slab to hold the pavement together even after fractures appear.

3.Continuous Reinforced Concrete Pavement

There are no joints between them in this form, and it is done by providing reinforcement.

4.PCP (Pre-stressed concrete pavement)

PCP are designed and produced to withstand tensile stresses generated by external loads such as automobiles on the road or planes at airports. Despite their relatively thin construction, prestressed concrete pavements provide acceptable performance.

RIGID PAVEMENT FLEXIBLE PAVEMENT
High initial cost.
Low initial cost.
More robust.
Less robust.
Joints are essentially required.
Joints aren't necessary.
Use only one layer.
There are several layers of materials.
It is made of Portland cement.
It is built with bituminous materials like asphalt.
Curing is required, which delays the opening to traffic.
Can be opened to traffic soon after construction.
The slab action mechanism distributes the load.
Grain to grain transmission is used to transfer the wheel weight.
Have sufficient flexural strength.
They have low flexural strength.
The thickness is less.
The thickness is greater.
More than 30 years of long-term service life.
15 years is a typical length of service.
Low maintenance and repair costs.
High repair and maintenance costs.
Temperature variations cause significant stress.
Temperature variations do not cause in stresses.
They do not need to be repaired frequently.
It requires regular maintenance.
Design based on flexural strength.
Design based on subgrade strength.
Concrete provides good night visibility.
Due to the colour of the asphalt, it provides poor night visibility.
No damage from oil and other chemicals like grease.
Damaged by chemicals and oil.
Deformation in the subgrade is transmitted to the subsequence layers.
Deformation in the subgrade is transmitted to the top layers.
Noisy due to iron-wheeled traffic.
Suitable for all sorts of traffic.
Corrugations do not form.
Corrugations are formed.
Underground pipes beneath rigid pavements are difficult to replace.
Underground pipes beneath flexible pavements are simple to lay, locate, and repair.
The least resilient to vehicle loads.
Greater resilience to vehicle loads.
Skilled workers are required.
Normal skills with little supervision are required.
Stages of development are not practicable.
Stages of development are practicable.
A good grade is required.
A good grade is not required.
Flexible pavement has low tractive resistance.
More tractable resistance is provided.
Glare caused by reflected sunlight.
There is no glare caused by sunlight.

Surface courseSurface or Wearing Course. These are the topmost layers of road pavement that are directly exposed to vehicles. It has properties like friction, smoothness, noise management, rut resistance, and drainage.

Parts of pavement: Base CourseBase Course– A layer of broken stones or brick provided over the subbase course or, in the absence of a subbase, directly over the subgrade in a road surface.

Parts of pavement: Granular Sub baseGranular Sub-base -The layer of granular material placed between the sub-grade and base course of a road pavement, such as burned clinker, gravel, or slag.

Parts of pavement: Compacted subgradeCompacted Subgrade-The act of grading, shaping, and compacting natural subgrade materials preparatory to laying an aggregate base or pavement is known as subgrade compaction.

Parts of pavement: Natural subgradeNatural Subgrade– A subgrade is a layer of natural soil that has been compacted to withstand the weights that have been placed on top of it. Despite the fact that it must have certain features, it is a layer that is required in various constructions such as pavements and slabs.