This document summarizes flexible pavement design and common types of distress that can occur. Flexible pavement is designed based on a layered system to distribute loads through the subgrade. It has advantages like adaptability and ease of repair but higher maintenance costs and shorter lifespan than rigid pavement. Distress in flexible pavement includes surface defects like fatty, smooth or streaked surfaces; cracks like block, alligator or edge cracks; deformation like rutting or corrugation; and disintegration like pumping or potholes. Causes of distress can be environmental factors, heavy traffic loads, or issues with material quality.

1. National Institute of technology, Patna
GUIDED BY_
RANJA BANDYOPADHYAYA
ASSISTANT PROFESSOR
DEPARTMENT OF CIVIL ENGG.
PRESENTED BY –
DEVRAJ REGAR (1724013)
M.TECH 2nd SEM
Transportation Engineering
Study of Distress in flexible pavement

2. Introduction:_ Pavement
Rigid Pavement_
The design of Rigid pavement is
based on providing a structural
cement concrete slab of sufficient
strength to resists the loads from traffic.
Flexible Pavement_
The flexible pavement design is
based on the load distributing
characteristics of a layered system

3. Flexible pavements consist of a series of layers, with the highest quality materials at
or near the surface. The strength of a flexible pavement is a result of building up thick
layers and thereby distributing the load over the sub grade; the surface material does not
assume the structural strengths as with rigid pavements.
Advantage
• Adaptability to stage construction
• Availability of low-cost types that can be
easily built
• Ability to be easily opened and patched
• Easy to repair frost heave and settlement
• Resistance to the formation of ice glaze
Disadvantage
• Higher maintenance costs
• Shorter life span under heavy use
• Damage by oils and certain chemicals
• Weak edges that may require curbs or
edge devices

4. Distress in Flexible Pavement
• Surface Defects
Fatty surface
Smooth surface
Streaking Surface
hungry surface
• Cracks
Block Cracks
Alligator Cracks
Edge cracks
Longitudinal and transvers cracks
• Deformation
Rutting
Corrugation
Shoving
Settlement and upheavals
• Disintegration
Pumping
reveling
Pot holes
Polished Aggregate

5. Fatty surface Smooth surface
Streaking Surface Hungry surface
Surface Defects

6. Block Cracks Alligator Cracks
Edge cracks Longitudinal cracks
Cracks

7. Rutting Corrugation
Shoving Settlement and upheavals
Deformation

8. Pumping Raveling
Pot holes Polished Aggregate
Disintegration

9. Cause of Distress
Environmental
Cause
Traffic Cause Material Cause
These stress come under
pavement due to Env. factor
like moisture
These stress come under
pavement due to traffic like-
heavy load or high volume
traffic
These stress come under pavement
due to material quality Like low CBR
value, Optimum bitumen content
(OBC)