This document discusses bridge defects and maintenance. It covers topics like acoustic emission testing of concrete bridges, common bridge defects like corrosion, and methods to protect bridges. Bridge deck waterproofing is also discussed, noting the two main types of waterproofing systems used are sheet and liquid sprayed systems. The document emphasizes the importance of maintenance to enhance bridge durability and extend lifespan.

1. 011
BRIDGE
DEFECTS &
MAINTENANCE
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3. BRIDGE DEFECTS AND MAINTENANCE
Bridge defects
and
maintenance
• Acoustic Emission
(AE) studies of
concrete structures
• Most concrete
bridges and other
structures are still
inspected using
traditional methods

4. BRIDGE DEFECTS AND MAINTENANCE
Bridge defects
and
maintenance
• Conventional
testing methods for
concrete structures
do not provide the
full information
about the severity
of defects

5. PHILOSOPHY OF TESTING CONCRETE BRIDGES BY
ACOUSTIC EMISSION
Bridge defects
and
maintenance
• It is necessary to
perform a series of
measurements on
model elements and
full-scale structures
under controlled
loading condition.

6. PHILOSOPHY OF TESTING CONCRETE BRIDGES BY
ACOUSTIC EMISSION
Bridge defects
and
maintenance
• Testing elements in
a laboratory enables
researchers to learn
more about the
features of the
observed
phenomenon.

7. PHILOSOPHY OF TESTING CONCRETE BRIDGES BY
AE.

8. BRIDGE DEFECTS AND MAINTENANCE
• The model tests
generated useful
information about the
wave propagation and
attenuation in concrete,
• helpful for setting up the
measuring equipment.

9. BRIDGE DEFECTS AND MAINTENANCE
• The attenuation has a
critical influence on the
values of AE signal
parameters: amplitude,
duration and energy,
which are the most
important in evaluating the

10. MONITORED BRIDGE BUILT OF POST-TENSIONED
BEAMS

11. NEW BRIDGE BUILT OF PRE-STRESSED BEAMS

12. BRIDGE DEFECTS AND MAINTENANCE

13. BRIDGE DEFECTS AND MAINTENANCE

14. MEASURING AREAS WITH DIFFERENT LEVEL OF
AE INTENSITY

18. NEW STEEL-CONCRETE BRIDGE TESTED BY AE.

19. Steel reinforcement in
concrete is well
protected against
corrosion due to the
highly alkaline
environment
generated from the
hydration of cement

20. BRIDGE DEFECTS AND MAINTENANCE
Environment
al factors
key
circumstances
that reduce the
passivation of
steel are:
-carbonation
-chloride

21. BRIDGE DEFECTS AND MAINTENANCE
Other factors which
may influence either
the initiation or rate
of reinforcement
corrosion include:

22. BRIDGE DEFECTS AND MAINTENANCE
cracks in concrete,
temperature,
moisture,
Oxygen,
inadequate concrete
quality or cover

23. BRIDGE DEFECTS AND MAINTENANCE
Bridge defects
and
maintenance
• Steel reinforcement
protection- due to
high alkalinity-
presence of the
hydroxides of
sodium, potassium
and calcium
produced during the
hydration reactions

24. BRIDGE DEFECTS AND MAINTENANCE
Bridge defects
and
maintenance
•The
surrounding
concrete acts
as a barrier to
many of the
steel's
aggressors

25. PROCESS OF CORROSION
Steel, once
corroded,
causes crack
on the
surface of the
concrete
cover
The
presence of
corrosion
activity is
not
detected till
such cracks
become
visible

26. PROCESS OF CORROSION
PROCESS OF
CORROSION
• These cracks
then help in
conduction of
oxygen and
moisture which
act as
accelerators for
corrosion
PROCESS OF
CORROSION
• Corrosion also
causes the
effective steel
cross section
to increase
initially

27. BRIDGE DECK WATERPROOFING
Bridge defects
and
maintenance
• Waterproofing of
bridge decks is vital
and necessary
operation to
enhance the
durability of the
bridge

28. BRIDGE DECK WATERPROOFING
Bridge
defects and
maintenance
•It also
improve the
life span of
the bridge

29. BRIDGE DECK WATERPROOFING SYSTEMS
Bridge defects
and
maintenance
• Two types of Bridge Deck
Waterproofing Systems
are available for use:
Bridge defects
and
maintenance
• Sheet Systems-These are
Polymer Modified
Bituminous sheets bonded
to the bridge deck

30. BRIDGE DEFECTS AND MAINTENANCE
Bridge defects
and
maintenance
• Manufacturers have
developed various
systems that would
satisfy the enhanced
requirements of the
bridge deck
waterproofing
market.

31. BRIDGE DEFECTS AND MAINTENANCE
Bridge
defects and
maintenance
•Another
method is-
Liquid
(Sprayed)
Systems

32. BRIDGE DEFECTS AND MAINTENANCE
These systems largely
fall into acrylics and
polyurethanes and
consist of three
Elements.

33. BRIDGE DEFECTS AND MAINTENANCE
1-Primer
2-Membrane (applied in
one or two coats)
3-Tack Coat specially
developed to enhance the
bond of the membrane to
the surfacing mix

34. BRIDGE DEFECTS AND MAINTENANCE
1-Impermeability to water
under all conditions
2-Good adhesion to deck
3-Good
adhesion to
surfacing
4-Capability of
bridging
shrinkage cracks
in concrete

35. HOW TO PROTECT BRIDGES
The damage to concrete may include:
* Carbonation of the concrete causing
corrosion of the reinforcing steel
* Spalling due to corrosion of reinforcing
steel
* Cracking caused by wetting and drying
* Rust Stains and other stains
* Salt penetration from marine rain
causing salt erosion and spalling

36. BRIDGE DEFECTS AND MAINTENANCE
Impregnation:
Water and chloride ion can be
excluded by the practice of
Impregnation.
Anti-Carbonation:
Carbon dioxide and
carbonation can be specifically
practice of Coating with an Anti-
Carbonation Coating.

37. BRIDGE DEFECTS AND MAINTENANCE
Surface coatings
are used on
concrete
structures to
provide
additional
protection
against ingress
of water, water
soluble salts and
atmospheric
gases.
In addition they
enhance the
aesthetic
appearance and
help in hiding the
patchy
appearance of
concrete that has
been repaired in
different places.

38. BRIDGE DEFECTS AND MAINTENANCE
there
are two
types of
protecti
ve
coatings
:
• Film forming –
relying on
adhesion over
concrete.
• Non-film forming
– that penetrate
into the concrete
surface.