The document discusses cracks in buildings, including the types, causes, effects, and methods for repairing cracks. It identifies two main types of cracks: structural cracks that could endanger safety, and non-structural cracks caused by factors like moisture, temperature changes, or chemical reactions. Left unaddressed, cracks can accelerate concrete deterioration and carbonation, compromise waterproofing, and affect building appearance and durability. The document outlines various techniques for repairing cracks, such as epoxy injection, routing and sealing, stitching, drilling and plugging, and gravity filling. It emphasizes the importance of both preventing cracks and properly repairing existing cracks to maintain building integrity.
2. Contents
1. Introduction
2. Dangers & affects of cracks
3. TYPES OF CRACKS
4. Causes & Preventive measures
5. Techniques to cure cracks
6. conclusion
7. REFERENCES
www.CIVILSCHOLAR.com
3. 1. Introduction
A crack is a complete or incomplete separation of
concrete into two or more parts produced by breaking or
fracturing.
Cracks are one kind of universal problems of concrete
construction as it affects the building artistic and it also
destroys the wall’s integrity, affects the structure safety
and even reduce the durability of structure
www.CIVILSCHOLAR.com
5. 2. Dangers & affects of cracks
Carbon dioxide penetrates into the concrete through the
cracks and speed up carbonation around the cracks, thus
shortening the structure usage.
The cracks in the concrete wall would cause the leakage
of the building; it reduces the stiffness, durability and
seismic performance of buildings.
Cracks on the wall surface damage to the later
rendering, will affect to the appearance.
www.CIVILSCHOLAR.com
6. Cracking due to corrosion of reinforcement
www.CIVILSCHOLAR.com
7. 3. TYPES OF CRACKS
I. Structural Cracks: These cracks occur due to
incorrect design, faulty construction or overloading
and these may endanger the safety of a building.
II. Non-Structural Cracks: They are due to internal
forces developed in materials due to moisture
variations, temperature variation, crazing, effects of
gases, liquids etc.
III. Based On Width:
a) Thin - less than 1mm in width
b) Medium - 1 to 2mm in width
c) Wide - more than 2mm in widthwww.CIVILSCHOLAR.com
8. cracks around window opening cracks around drilled hole
cracks on the columnwww.CIVILSCHOLAR.com
10. 4. Causes & Preventive measures
A. Elastic Deformation
B. Thermal Movement
C. Chemical Reaction
D. Shrinkage
E. Foundation Movement and Settlement of Soil
F. Earthquake
G. Vegetation
H. Poor Construction practices
www.CIVILSCHOLAR.com
11. Effect of variation in water content of concrete on
drying shrinkage
www.CIVILSCHOLAR.com
12. Relation between mix proportion and drying shrinkage
of cement concrete mortar
www.CIVILSCHOLAR.com
13. Roots of Fast
Growing Tree Under
the Foundation of
Compound Wall
www.CIVILSCHOLAR.com
14. 5. Techniques to cure cracks
i. Epoxy injection:
Cracks as narrow as 0.002 in. (0.05 mm) can be
bonded by the injection of epoxy.
The technique generally consists of establishing
entry and venting ports at close intervals along the
cracks, sealing the crack on exposed surfaces and
injecting the epoxy under pressure.
However, unless the cause of the cracking has been
corrected, it will probably recur near the original crack.www.CIVILSCHOLAR.com
17. ii. Routing and sealing:
This method involves enlarging the crack along its
exposed face and filling and sealing it with a suitable
joint sealant.
The procedure is most applicable to approximately
flat horizontal surfaces such as floors and pavements.
However, routing and sealing can be accomplished
on curved surfaces (pipes, piles and pole).
www.CIVILSCHOLAR.com
18. iii. Stitching:
The stitching procedure consists of drilling holes on
both sides of the crack, cleaning the holes and anchoring
the legs of the staples in the holes, with either a non-
shrink grout or an epoxy resin-based bonding system.
Stitching may be used when tensile strength must be
reestablished across major cracks.
www.CIVILSCHOLAR.com
20. iv. Drilling and plugging :
Drilling and plugging a crack consists of drilling down
the length of the crack and grouting it to form a key.
This technique is only applicable when cracks run in
reasonable straight lines and are accessible at one end.
This method is most often used to repair vertical cracks
in retaining walls.
www.CIVILSCHOLAR.com
22. v. Gravity Filling:
Low viscosity monomers and resins can be used to
seal cracks with surface widths of 0.001 to 0.08 in. (0.03
to 2 mm) by gravity filling.
High-molecular- weight methacrylate, urethanes, and
some low viscosity epoxies have been used successfully.
The lower the viscosity, the finer the cracks that can be
filled.
Wet surfaces should be permitted to dry several days
to obtain the best crack filling.www.CIVILSCHOLAR.com
23. 6. conclusion
Though it is impossible to guarantee against cracking
yet attempts can be made to minimize development of
crack.
In case of existing cracks, after detail study and
analysis of crack parameters, most appropriate method
of correction should be adopted for effective and
efficient repair of crack.
www.CIVILSCHOLAR.com