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What is flexible pavement in road construction?

In simple terms, a flexible pavement can be defined as a pavement layer comprising of a mixture of aggregates and bitumen, heated and mixed properly and then laid and compacted on a bed of granular layer.

What is flexible pavement?

Flexible pavements are those which are surfaced with bituminous (or asphalt) materials. These types of pavements are called “flexible” since the total pavement structure “bends” or “deflects” due to traffic loads.

Why the flexible pavements are constructed in different layers?

The wheel load acting on the pavement will be distributed to a wider area, and the stress decreases with the depth. Taking advantage of this stress distribution characteristic, flexible pavements normally has many layers. Hence, the design of flexible pavement uses the concept of layered system.

What are the three layers of a flexible pavement?

A typical flexible pavement structure (see Figure 2) consists of:

• Surface Course. The layer in contact with traffic loads.
• Base Course. The layer immediately beneath the surface course.
• Subbase Course. The layer between the base course and subgrade.

How is flexible pavement made?

Flexible Pavements are constructed from bituminous or unbound material and the stress is transmitted to the sub-grade through the lateral distribution of the applied load with depth. Most asphalt surfaces are built on a gravel base, although some ‘full depth’ asphalt surfaces are built directly on the subgrade.

What is the uses of flexible pavement?

Around the world flexible pavement is the most favored pavement structure to build road and highways. A massive amount of non-renewable materials and industrial products like aggregates, bitumen, cement, lime, and other additives are consumed during construction and maintenance of this pavement system.

What is the importance of flexible pavement?

Flexible pavements are preferred over rigid concrete roads because of their certain advantages, such as they can be strengthened and improved in stages with the growth of traffic. Flexible pavements are less expensive in regards to their initial cost and maintenance.

What is the difference between flexible and rigid pavement?

Flexible pavements tend to have more layers and are therefore much thicker by default. Rigid pavements have fewer layers and are thinner than flexible pavements, which makes them susceptible to more repairs over time.

How do you make flexible pavements?

(i) The flexible pavement is designed as a four- layer structure – bituminous surfacing consisting of two courses -wearing course and binder course, granular base and granular sub-base over the soil subgrade. (ii) Soils having CBR-values in the range of 2 to 10\% are covered.

What are the components of flexible pavement?

The composition and structure of flexible pavement consists of surface course, binder course, base course, subbase course, frost protection course, subgrade. Flexible pavements contain bitumen or asphalt layer as wearing course and supports loads through bearing. They have low flexural strength.

How many layers are in flexible pavement?

Lastly, it is important to protect the lower pavement layers and subgrade from any of the weakening effects of water. There are actually typically five or six layers in a flexible pavement, divided into two overlapping sections: the pavement section and the foundation section.

What are the materials of each layer of a flexible pavement?

Frost Protection Layer The function of frost protection layer is to prevent damage of pavement from frost heaves, which are formed by freezing of groundwater. A good quality base course and Sub-base courses provided can also serves frost protection layer.

What is flexflexible pavement?

Flexible Pavement – Introduction The type of highway pavement that transmits the imposed wheel load to the underlying layers by grain-to-grain transfer mechanism is known as flexible pavement. In simple terms, these are the pavements that transfer the wheel load to a wider area beneath by grain-to-grain contact.

What is the difference between subgrade and flexible pavement?

It transmits load to the subgrade through a combination of layers. Flexible pavement distributes load over a relatively smaller area of the subgrade beneath. The initial installation cost of a flexible pavement is quite low which is why this type of pavement is more commonly seen universally.

Which type of pavement is used in road construction?

A combined pavement also used which is known as semi-rigid pavement. In this, a rigid pavement is provided with a thin layer of flexible pavement over it and is an ideal pavement with most desirable characteristics.

How are wheel loads transferred in flexible pavement?

In Flexible Pavement, wheel loads are transferred to subgrade by grain-to-grain transfer through the points of contact in the granular structure. The wheel load stresses acting on the pavement are distributed to a larger area and the stress decreases with the depth.