Types of pavement are mainly four. I will show you each of them in detail with the advantages and disadvantages.
Before we begin, let’s look into what a pavement is.
What is pavement?
The pavement is a hard surface that’s built with concrete or asphalt, like a road or a driveway.
Based on the structural behavior, road pavements are classified as
- Flexible pavement
- Rigid pavement
- Semi-rigid pavements
- Interlocking cement concrete block pavement (ICBP)
Without any due, let’s jump onto the first type of pavement.
Flexible pavement is the pavement which possess negligible flexural strength. And,
- The flexible pavement layer may reflect the non recoverable as well as recoverable deformations of the lower layer including sub grade on the upper layers and also to the pavement surface.
- The vertical compressive stress is maximum on the pavement surface directly under the wheel load and is equal to the contact pressure under the wheel
- The lower layers of pavement has to take up only lesser magnitudes of stresses and there is no direct wearing action due to traffic loads and weathering action due to environmental factors. Therefore inferior materials with lower cost can be used in the lower layers.
- In flexible pavement layers, top layer has to be the strongest as the highest compressive stresses are to be sustained by this layer, in addition to the wear and tear due to the moving traffic and varying factors due to weather.
Next, let’s peep into advantages and disadvantages of flexible pavements.
Advantages of flexible pavement
- Initial cost can be reduced by constructing thin bituminous surface layer
- Standard design load in terms of CSA (Cumulative Standard Axles)
- Functional deterioration
- Strengthening by overlay
- High salvage value
- Can be open to traffic after 24 hours
Disadvantages of flexible pavements
- Deterioration under stagnant water
- Periodic maintenance
- Patching of pot holes is expensive
- Thickness is very high
- Night visibility is very low
That’s it about flexible pavement. Let’s move onto the next type of pavement.
Rigid pavements are those which possess noteworthy flexural strength of flexural strength or flexural rigidity.
See more details below.
- Rigid pavements are generally made of Portland cement concrete hence known as ‘cc pavement’
- Construction of rigid pavement using high quality plane cement concrete known as ‘pavement quality concrete (PQC)
- The CC pavement made of PQC are generally expected to sustain up to 45kg/cm2 of flexural stresses
- In rigid pavements, the stresses are not transferred from grain to grain to the lower layers as in the case of flexible pavement layers.
- Slab action is capable of transmitting the wheel load cases through a much wide area below pavement slab
Having the details in back pack, ready to know the advantages and disadvantages of rigid pavements?
Advantages of rigid pavement
- No deterioration under stagnant water
- Thickness is less
- Service life 30 years
- Life cycle cost is very less
- Night visibility is high
Disadvantages of rigid pavement
- Axle load study is required
- Design should be for 30 years
- Possible to restore the pavements under crack
- Surface may become smooth or slippery
- Long period of 28 days is required to open traffic
Let’s conclude the section with a comparison.
Comparison between flexible and rigid pavements
|Flexible pavement||Rigid pavement|
|Bitumen is mostly used for construction||Otherwise called concrete pavements|
|Bitumen becomes soft due to low temperature and bleeds leading to failure of pavement||Have longer life and is practically maintenance- free|
|When water enters the pavement during raining, resulting in potholes||Can withstand extreme weather conditions|
|Due to low temperature in winter season, bitumen becomes brittle leading to cracking of pavement||Initial cost higher comparatively, but economical in long term|
Now, you know about flexible and rigid pavement. Time to meet some not-so-famous type of pavement.
Semi rigid/ composite pavements
Semi-rigid pavements are an intermediate state between the Flexible and the Rigid pavement. The flexural strength of the pavement is less than a concrete slab. Nevertheless, it finds support by the lateral distribution of loads through the pavement depth as in flexible pavement.
When the intermediate class of semi-rigid materials like soil cement, lean cement concrete are used in the sub-base or base course of layers of pavements, they are called semi-rigid pavement.
Pavement consisting of both flexible pavement layers and one or more semi rigid pavement layers are called composite pavements.
The last member is ICBP or Interlocking concrete block pavement.
Interlocking Concrete Block Pavement (ICBP)
Interlocking Concrete Block Pavement (ICBP) has been extensively used in a number of countries for quite sometime as a specialized problem-solving technique for providing pavement in areas where conventional types of construction are less durable due to many operational and environmental constraints
That was the trip through the types of pavement. Have any doubts regarding this? Just drop it in comments.
See you there. Happy learning!