Road Engineering

enas saleh

5 months ago

Rigid pavement and Flexible pavement

1
/
1

 


1.Composition



  • Flexible pavement are composed of properly graded aggregate with bitumen/ tar as binder.

  • Rigid pavements are constructed by using PCC- cement, aggregate, water and dowel bars (for joints).


2. Stability


Rigid pavement



  • Strength depends upon interlocking of aggregates, friction and cohesion.


Flexible pavement



  • strength depends upon the flexural strength of place concrete


3. Design



  • Flexible materials are constructed in numbers of layers.

  • Flexible road and flex asphalt are these having multi layer of poured concrete, rock and asphelt


4 . Joints



  • Flexible Pavement are laid continuously, hence there are no joints.

  • Rigid Pavements are constructed in bays , hence joints and present


5. Cost



  • (Flexible Pavement) initial cost is less and maintenance cost is more.

  • (Rigid Pavements) initial cost are high and low maintenance costs.


6. Load Distribution



  • (Flexible Pavement) load are distributed to underlying layers by grain to grain action.

  • (Rigid Pavements) load is distributed over a wider area of sub-grade due to its rigidity and high elastic modulus.


7. Thermal Stress



  • (Flexible Pavement) No thermal stresses developed due to temperature variation.

  • (Rigid Pavement) thermal stresses developed leading to warping.


8. Traffic



  • (Flexible Pavement) can be open to traffic after 24 hours.

  • (Rigid Pavement) cab be open to traffic after minimum 14 days.