Flexible pavements are those pavements which reflect the deformation of subgrade and the subsequent layers to the surface. The load is distributed by the slab action mechanism. Considering the stage of construction, flexible pavement is preferred to the rigid pavement.
Flexible andrigidpavements
Difference between flexible and rigid pavement:
In flexible pavements, underlying layers play very important role.
Variation among rigid pavement and flexible pavement. In rigid pavement, load is distributed by the slab. Types of road pavement pdf. Because of its lower flexural strength, the flexible pavement works like a flexible sheet (e.g.
Than compared to flexible pavements.
The wheel load is transferred by grain to grain mechanism. Modulus of elasticity of rigid pavement is very high, because of high strength concrete and more load bearing capacity of the pavement itself. The slab action in the rigid pavement can distribute the heavy loads over the whole area and below the courses of pavement Thus the strength of subgrade primarily influences the thickness of the flexible pavement.
Flexible pavements can be defined as one consisting of a mixture of asphaltic or bituminous materials and aggregate placed on a bed of compacted granular material of appropriate quality in layers over the subgrade.
In case of the flexible pavement the loads are deflected from grain to grain but in case of rigid pavement the deflection is not so appreciable, but the load is distributed over a large are underneath the surface course. Maintenance of well deigned rigid pavement is practically very small, whereas the bituminous surface of flexible pavement needs frequent maintenance. The pavement design is also one major factor, with flexible pavements reliant on subgrade strength and rigid pavement dependent on the flexural strength of concrete. It should contain adequate friction keeping the power of the vehicle unchanged.
Pavement design methods, developing guidelines with a protocol for considering rigid versus flexible pavement designs when allowed alternate bids, and developing the alternate pavement design analysis tool (apdat) for pavement type analysis.
Flexible pavement has very low modulus of elasticity (less strength). Other flexible pavement characteristics include: Flexible pavements typically distribute wheel loads to lower layers of the pavement section as shown on the right side of the exhibit below and consists generally of bituminous material. The concrete slab itself supplies most of a rigid.
25 rows the lifespan of flexible pavement is approximately 15 years.
Rigid pavements are constructed from cement. Since the top layer alone does not have to bear the entire load of traffic (weight is distributed amongst all the layers), flexible pavement are more structurally sound and much less likely to collapse due to heavyweight. Life of rigid pavement is more than the flexible one. Rigid pavements are constructed of portland cement concrete slabs resting on a prepared subbase of granular material or directly on a granular subgrade.
Therefore, more role are playing only underlying layers.
It should be rigid 4. Rigid pavement are difficult to install and maintain. The rigid characteristic of the pavement are associated with rigidity or flexural strength or slab action so the load is distributed over a wide area of subgrade soil. The main difference between the flexible and rigid pavements is based on the manner in which the loads are distributed to the subgrade.
Short service life, usually 15 years.
The following are two major pavement types used in road construction, flexible pavement; Flexible pavement and rigid pavement contain superior riding quality 2. It should be less slippery 3. Rigid pavements a rigid pavement is constructed from cement concrete or reinforced concrete slabs.
Long service life, more than 30 years.
Flexible pavements, vehicular stress is transferred to subgrade through gain to gain contact of the aggregate through the granular structure.these types of roads have less flexural strength, act like a flexible sheet (e.g. The initial cost of rigid pavement is much more than the flexible one. The rigid pavements can be analyzed by the plate theory. Load is transmitted through the slabs to the underlying subgrade by flexure of the slabs.
