Presentation

1. FAILURES OF FLEXIBLE
PAVEMANT
PRESENTED BY
RANDHIR KUMAR
14-CE-84
CIVIL ENGINEERING
HALDIA INSTITUTE OF TECHNOLOGY

2. FUNDAMENTAL DEFINITION
Types of highway pavement:
(a) flexible pavement
(b) rigid pavement
(c) others
FLEXIBLE PAVEMENT: Flexible pavement are those, which on the whole have low or negligible flexural strength and are
rather flexible in their structural action under the loads.
RIGID PAVEMENT: Rigid pavement are those which possess noteworthy flexural strength or flexural rigidity.
The rigid pavements are generally made of Portland Cement Concrete(cc) and are therefore called ‘CC
pavement’.
Others Type of pavements include (a) ‘Semi-rigid pavements’ or ‘composite pavements’
(b) Interlocking Cement Concrete Block pavements

3. DIFFERENT LAYERS OF FLEXIBLE PAVEMENT

4. DIFFERENT TYPES OF FAILURES IN FLEXIBLE PAVEMENT
1. Alligator cracking or Map cracking (Fatigue)
2. Consolidation of pavement layers (Rutting)
3. Shear failure cracking
4. Longitudinal cracking
5. Frost heaving
6. Lack of binding to the lower course
7. Reflection cracking
8. Formation of waves and corrugation
9. Bleeding
10. Pumping

5. CAUSES OF FAILURES
1. ALLIGATOR OR MAP CRACKING
 Relative movement of pavement layer material
 Repeated application of heavy wheel loads
 Swelling and shrinkage of subgrade or others layers
due to moisture variations
Primary causes of this type of failure are:

6. 2.CONSOLIDATION OF PAVEMENT LAYERS 3. SHEAR FAILURE CRACKING
 Repeated application of load along same wheel
path resulting longitudinal ruts
 Wearing of surface course along the wheel path
resulting the shallow ruts
 Excessive wheel loading
 Low shearing resistance of pavement materials

7. 4. LONGITUDINAL CRACKING 5.FROST HEAVING
 Differential volume change in subgrade soil
 Settlement of fill material
 Sliding of side slope
It depends upon:
 ground water table conditions
 Climatic conditions
Primary causes of this type of failure are:

8. 6.LACK OF BINDING WITH LOWER LAYER 7.REFLECTION CRACKING
 Lack of prime coat or tack coat in between two
layers is the primary reason behind this type of
failure.
 Differential movement across the underlying
crack or joint
Potholes

9. 8.FORMATION OF WAVES AND CORRUGATION
 Transverse undulations appear at regular interval due to the
unstable surface course caused by stop-and-go traffic.

10. 9.BLEEDING 10.PUMPING
 Excess bituminous binder occurring on the
pavement surface causes bleeding. Bleeding causes
a shiny, glass-like, reflection surface that may be
tacky to the touch.
 Seeping or ejection of water and fines
from beneath the pavement through
cracks.