The pavements having high flexural strength is called rigid pavement. It is simply a concrete road that may be either RCC or PCC.
Rigid Pavement is divided into different slabs during construction and a small gap is provided between the slabs so that concrete doesn’t crack during expansion in summer days. Unlike flexible pavements; rigid pavement acts as a slab and is capable of transmitting wheel load stresses to a wider area beneath by the slab action.
These pavements do not show deformation on the pavement surface or deformation of lower layers due to the rigidity of the cement concrete slab. Some examples of this pavement are PCC pavements, RCC pavements and Prestressed concrete pavement.
There are two types of rigid pavement. They are:
1. Un-Reinforced Concrete Pavement (URCP)
a. Jointed Dowelled Concrete Pavements(JDCP)
b. Jointed Un-Dowelled Concrete Pavements(JUDCP)
2. Reinforced Concrete Pavement(RCP)
a. Jointed Reinforced Concrete Pavements(JRCP)
b.Continuous Reinforced Concrete Pavements(CRCP)
For the complete explanation of types: Click Here
Requirements of Good Rigid Pavement
~ It should have a long-life design with low maintenance cost.
~ It should be impervious enough to protect sub-grade soil.
~ It should have a high coefficient of friction to resist skidding.
~ It should be smooth enough to provide comfort to the users.
~ It should be structurally strong to withstand all types of loads.
Construction Steps of Rigid Pavement
a. Preparation of subgrade
~ The first step of rigid pavement construction is the preparation of subgrade.
~ Cutting and Filling work is done according to the requirement and compaction work is carried out. The light application of water should be done during the compaction work.
b. Provision of sub-base course
~ Sub-base course is provided when the subgrade is weak. In the case of strong sub-grade; there is no need for the sub-base course.
~ Sub-base course is a mixture of soil & small stone pieces. After the provision of sub-base; it should be compacted.
c. Preparation of Base Course
~ Then built non-erosive base coarse with boulders and stones maintaining slopes for water disposal purpose.
~ Voids and gaps between the boulders or big stones are filled with small stones.
~ Strong stones with irregular shape are generally prefered.
~ Thickness of base course should be a minimum of 6 inches.
d. Surface Course Preparation
~ Construct the slab of concrete above the base course (either with RCC or PCC ).
~ For high traffic road; its thickness should not be less than 12 inches.
~ For low traffic road; its thickness should not be less than 6 inches.
Facts of Rigid Pavement
1. They are also called single layer pavement.
2. They may last up to 50-60 years if timely maintenance and care are done.
3. They may require asphalt for toping to reduce the noise during vehicle operation.
4. The vehicle operation cost of rigid pavement is low.
5. They are cheaper while considering the life-cycling cost.
6. Deflection is very low. so, it is called rigid pavement.
7. Maintenance cost is very low.
Advantages of Rigid Pavement
~ Low maintenance and operation cost.
~ Higher life span ( Life span may be up to 40 years whereas flexible pavement has a life span of only 10-20 years).
~ It has high flexural strength.
~ It has good resistance to petroleum products, oils and chemicals.
~ More environment-friendly than flexible pavement.
~ It distributes loads in a wider area and can bear a large amount of load due to slab action.
Disadvantages of Rigid Pavement
~ High initial cost required for construction.
~ Maintenance is difficult than flexible pavement.
~ Requires at least 28 days of curing before high traffic movement because concrete gains its 99% efficiency/strength in 28 days.
~ Any excessive deformations occurring due to heavier wheel loads are not recoverable in this pavement type( settlement is permanent).
Read More: Flexible Pavement