Flexible Pavement: Click To Edit Master Title Style
Flexible Pavement: Click To Edit Master Title Style
Flexible Pavement: Click To Edit Master Title Style
Flexible Pavement
• Types, causes and maintenance
of its failure
1
Click toofedit
Types Master
failures title style
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
11. Edge cracking and shoulder drop off
12. Slippage Cracks
2 2
Click toand
Types edit Master
Causes oftitle stylein Flexible Pavement
failures
3 3
2. Consolidation of pavement layers:
Click toof ruts
• Formation editfalls inMaster title
this type of failure. A rutstyle
is a depression or
groove worn into a road by the travel of wheels.
• This type of failure is caused due to following reasons.
• Repeated application of load along the same wheel path resulting
longitudinal ruts.
• Wearing of the surface course along the wheel path resulting shallow
ruts.
• Repair - Minor surface rutting can be filled with micro paving or paver
placed surface treatment deeper ruts may be shimmed with a truing
and levelling course, with an overlay placed over the shim.
4 4
Click to edit Master title style
3. Shear failure cracking
• If the shearing resistance of the pavement is low, the shear
4. Longitudinal cracking
• This types of cracks extents to the full
failure cracking occurs, as shown in fig. 9. The upheaval of thickness of pavement.
pavement materials is caused by the formation of cracks. The
inadequate stability or excessively heavy loading contributes to • The following are the primary causes of
the poor shear resistance of the pavement mixture. longitudinal cracking.
5 5
5. Frost Heaving
Click to edit Master title style
• Depending upon the groundwater and climatic conditions, a localized heaving up of a portion of pavement takes place
due to the action of frost, as shown in fig.
6 6
7. Reflection cracking:
Click to edit Master title style
• When a bituminous overlay is provided over the existing cement concrete pavement and if due to some reason, the cement
concrete pavement fails, the same pattern of cracks in the form of reflection cracks is seen on the bituminous overlay, as
shown in fig.
Corrugation 7 7
9. Bleeding
Click tobituminous
• Excess edit Master title style
binder occurring on
the pavement surface causes bleeding.
Bleeding causes a shiny, glass-like,
reflective surface that may be tacky to
the touch. Usually found in the wheel
paths.
• Repair- Minor bleeding can often be
corrected by applying coarse sand to
blot up the excess asphalt binders.
• Major bleeding can be corrected by
cutting off excess asphalt with a motor
grader or removing at with a heater
planer.
Water Bleeding
8 8
10. Pumping 11. Edge cracking and shoulder drop off
Click tooredit
• Seeping Master
ejection title
of water and finesstyle • Edge Cracks travel along the inside
from beneath the pavement through edge of a pavement surface within one
cracks is called pumping. or two feet.
• The most common cause for this type of
crack is poor drainage conditions and
lack of support at the pavement edge.
• As a result underlying base materials
settle and become weakened.
Water Pumping
9 9
12. Slippage Cracks
Click to edit Master title style
• Slippage cracks are crescent-shaped or horse shoe shaped cracks or tears in the
surface layer.
• It is the asphalt where the new material has slipped over the underlying course.
• It is caused by a lack of bonding between layers.
• Acceleration, deceleration and sudden brakes on the road are leads to slippage
cracks.
• Repair - The most common repair for these issues are full depth asphalt
replacement.
1010
Click to edit Master
Maintenance title style
and Repair of failures in pavement
2. Asphalt Overlay
1. Bituminous Surface treatment:- • Asphalt overlay is a paving method of
• Also known as a seal coat or chip seal, is a thin protective wearing applying a new layer of asphalt to a
surface that is applied to a pavement or base course. deteriorating surface.
• An asphalt overlay project will use the
• It is provided to protect the underlying pavements, improved skid
resistances etc. existing layers as a base for the new
asphalt pavement.
• A BST offers preventive maintenance from the effects of sun and • Some asphalt surfaces with severe
water, both of which may deteriorate the road.
damage like rutting, potholes, large
cracks, and expansions will need to be
milled before an overlay is applied.
1111
Click to edit Master title style
3. Slurry Seals 4. Crack Seals
• Slurry seals is a homogenous mixture of • Crack seal products are used to fill
emulsified asphalt, water, well-graded individual pavement cracks.
fine aggregate and mineral filler that has • It is used to prevent entry of water or
a creamy fluid-like appearance when other noncompressible substances such
applied. as sand, dirt, rocks or weeds.
• Slurry seals are used to fill existing • Crack sealant is typically used on early
pavement surface defects as either a
stage longitudinal cracks, transverse
preparatory treatment for other
cracks, reflection cracks and block cracks.
maintenance treatments or as a wearing
course. • Crack filler material is typically some form
of rubberized asphalt or sand slurry
1212
Click to edit Master title style
Thank You
13