BAHIR DAR UNIVERSITY

BAHIR DAR INSTITUTION OF

TECHNOLOGY
FACULITY OF CIVIL AND WATER RESOURCE
ENGINEERING
DEPARTMENT OF CIVIL ENGINEERING
Title: CAUSE, PREVENTION AND REPAIR OF CRACK IN BUILDINGS
GROUP 12

SN NAME ID NUMBER
1 Barudin Mohammed 0500488
2 Biniam Mengistu 0500626
3 Dawit Tesfaye 0500790
4 Dawit W. Giorgis 0500791
5 Zerihun Ephrem 0500815
6 Dereje Asnakew 0500822

January 2017
 Bahir Dar Institute Of Technology

SUMMARY
This proposal is intended to serve as a tool in the process of crack evaluation and repair of
buildings. The causes of cracks in buildings are summarized along with the principal procedures
used for crack control. The techniques and methodology for crack evaluation are described. The
need to determine the causes of cracking as a necessary prerequisite to repair is emphasized. The
selection of successful repair techniques should consider the causes of, whether the cracks are
active or dormant, and the need for repair. Criteria for the selection of crack repair procedures
are based on the desired outcome.

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Table of Contents
SUMMARY................................................................................................................................................ii
List of figures.............................................................................................................................................iii
List of tables...............................................................................................................................................iii
1 INTRODUCTION...............................................................................................................................1
1.1 BACKGROUND.........................................................................................................................1
1.2 STATEMENT OF THE PROBLEM...........................................................................................2
1.3 OBJECTIVES..............................................................................................................................2
1.4 LITERATURE REVIEW............................................................................................................3
2 MATERIALS AND METHOD...........................................................................................................4
2.1 SITE DESCRIPTION..................................................................................................................4
2.2 METHOD OF DATA COLLECTION........................................................................................7
2.2.1 PRIMARY DATA...............................................................................................................7
2.2.2 SECONDARY DATA.........................................................................................................7
2.3 METHOD OF DATA ANALYSIS..............................................................................................9
2.3.1 GENERAL METHODOLOGY...........................................................................................9
FLOW CHART...................................................................................................................................9
3 EXPECTED OUTCOMES................................................................................................................14
4 TIME SCHEDULE............................................................................................................................15
5 BUDGET REQUIRED......................................................................................................................16
6 REFERENCES..................................................................................................................................17
List of figures

Figure 1: location of research site................................................................................................................5

Figure 2: Building cracks at Bahir Dar, Kebele 04 and 05...........................................................................6

List of tables
Table 1: Crack width limit.........................................................................................................................11
Table 2: Time schedule..............................................................................................................................15
Table 3: Budget required...........................................................................................................................16

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1 INTRODUCTION
1.1 BACKGROUND
Cracks are one kind of universal problem of building construction as it affects the
building aesthetically and also it destroys the wall integrity, affect the structure safety even
reduce the durability and serviceability of structure. Cracks in concrete have many causes. They
may affect appearance only, or they may indicate significant structural distress or a lack of
durability. Cracks may represent the total extent of the damage, or they may point to problems of
greater magnitude. Their significance depends on the type of structure, as well as the nature of
the cracking.

Buildings in Ethiopia are comparatively tall and slender, have thin walls, are designed for
higher stresses and are built at fast pace. These structures are, therefore, more crack prone as
compared with old structures which used to low, had thick walls, where lightly stressed and were
built at a slow pace.

Buildings around Bahir Dar are affected by cracks as they are designed for higher stresses
and built at a fast pace. For instance Class Rooms, and Dormitory at Bahir Dar University have
cracking problem.

This proposal conducted to show the methods of prevention and repair of cracks in
building. It will use data from EBCS-2, Internet and direct observation in order to know the
cause and the type of crack for determination of the remedies.

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1.2 STATEMENT OF THE PROBLEM

Building cracks are most common type of problem in any type of building. So, it is
important to understand the cause and the measures to be taken for prevention. Though cracks in
concrete cannot be prevented entirely but they can be controlled by using adequate material and
technique of construction and considering design criteria. We all dream of a house structurally
safe and aesthetically beautiful but it is not so easy. Due to some faulty steps during construction
or some unavoidable reasons different type of cracks starts to appear on various structural and
non- structural parts of the building with the passage of time.

Many of clients request a survey of a building due to cracking that they have seen in the
render of their property, sometimes when they live in it but most frequently when they are about
to purchase a new property such as a new house or a new business premises. Cracks are one of
the key things that we are asked to look out for when carrying out a building survey or structural
survey.

This project proposal will try to minimize the problem for the appearance of cracks in
building by preventing before the appearance and to provide a feasible method of maintenance.

1.3 OBJECTIVES
The proposal aims to determine the feasible method of prevention and maintenances of
cracks in buildings.

Specific objective of this project are:

 To identify the main causes of cracks in building

 To identify the types of cracks occurred
 To identify their type of cracks and what type of prevention

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1.4 LITERATURE REVIEW

Some researchers already worked on related types of causes and remedies of cracks such as
study type of cracks in building and its controlling done by [K.R Kashyzadeh and N.A Kasheh
2012]; It shortly describes about what every civil engineer should know about face of the
building i.e. cracking causes and evaluation of cracks done in concrete structures by [S.M
Mehndi et al. 2014] ; they explained about the evaluation of cracks that can be done by different
techniques like crack compactor and ultrasonic testing; Buildings crack causes and remedies by
[Goushma T. 2014], from this research it is found that building cracks has direct and indirect
impact and building cracks do not cause structural problem in direct way but it facilitates the
activities which ultimately cause the problem; prevention and repair of cracks in concrete
structures by [B.B Gant et al. 2014], they broadly classified about the structural and non-
structural cracks that occurs in building along with their causes and remedy.

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2 MATERIALS AND METHOD

2.1 SITE DESCRIPTION
The project site is located at Bahir Dar city at 1800 m above mean sea level and which
encompass Kebele 4 and 5 regions. In this site the proposal conducted to determine the cause,
prevention and repair of cracks on mixed use buildings such as commercial centers, pension and
Hotels, office and café buildings. Those buildings are highly affected by non-structural type of
crack. These cracks are occurred on the non- structural parts of the building.

Mostly the non-structural cracks on the site are occurred due to fast pace construction of
the buildings, poor quality of material used and thermal shrinkage.

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Figure 1: location of research site

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Figure 2: Building cracks at Bahir Dar, Kebele 04 and 05

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2.2 METHOD OF DATA COLLECTION

Some of the data for the proposal is collected by making direct interview with the
professionals and some clients & building service users. Most of the data for this proposal is
collected from Books, researches, Internet and some images and from Ethiopian Building
Construction Codes (EBCS).

This proposal collects data for analysis by applying primary and secondary methods of data
collection.

2.2.1 PRIMARY DATA

The project site is located at Bahir Dar city at 11.5742º N, 37.3614º E. It includes Kebele
4 and 5 regions. In this region the buildings are affected by non-structural type of crack but most
of them are dormant cracks. These crack types are determined by making direct observation on
the project site, and taking measurements using tape which is used to know crack width.

From professionals point of view cracks are classified as non-structural crack and
structural cracks. In building cracks are mostly occurred due to the usage of poor quality of
material, incorrect construction method such as mix design, water cement ratio, method of
concrete casting, thermal expansion and also due to shrinkage effect.

There is prevention methods provided by the professionals which are commonly used in
Bahir Dar, the first one is providing construction joints as per specification. Secondly using the
recommended type of construction method and conducting high supervision on the quality of
construction material used.

Generally in Ethiopia the construction industry used sealant and admixtures for repairing
cracks formed on the buildings. These repairing materials are used in sealing and injecting
method of repair. The commonly used repairing admixture materials are Sika and Hydraulic
cement.

In Bahir Dar city cracks on buildings are repaired by using mortar which is a mixture of
sand, cement and water as a repairing material and repairing is applied by the routing and sealing
method.

From the Clients and users point of view cracks on buildings are occurred due to use of
unskilled labor, quality of construction material and less or lack of supervision during
construction of the building.

2.2.2 SECONDARY DATA

Most of the data for this proposal is collected from Books, researches, Internet and some
images and from Ethiopian Building Construction Codes (EBCS).

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From Ethiopian Building Construction Codes this proposal uses data on the determination
of crack width. From this code the building needs maintenance of the crack width exceeds 0.2
mm. From Books, Researches, Internet and Images this proposal determine the methods of
repairing of cracks on buildings. Such as if the cracks are formed in brick walls or hollow
concrete blocks the stitching repair method is the recommended one. If the crack is formed on
the concrete floors, walls, beams and columns routing and sealing method of repair is applicable.

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2.3 METHOD OF DATA ANALYSIS

2.3.1 GENERAL METHODOLOGY

In this project the method of studying the preventing and repairing cracks starts from
determining the cause of the cracks then find out the methodology for prevention. And the next
concept is check the existing crack is within the safe limit, if not describe the feasible methods
for maintenance.

FLOW CHART

Condition survey
Nonstructural cracks

Yes
Connection type Structural cracks Potential to become
Structural crack

Beam, column or slab

Cosmetic cracks

Select method and

material Apply sealant

Application of crack
repair

Major causes of cracks in building and their preventive methods:

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1) Thermal expansion: it is one of the most potent causes of cracking in buildings. All
materials more or less expand on heating and contract on cooling. The thermal expansion
in a component depends on a number of factors such as temperature variations, dimension,
and coefficient of thermal expansion and some other physical properties of materials.

Prevention method

Thermal expansion can be avoided by introducing expansion joints and control

joints. In structures having rigid frames, thermal stresses have to be taken into account in
the structural design itself to withstand undesirable cracks.

2) Permeability of concrete: it is a direct function of the porosity and interconnection of

pores of the cement paste.
Prevention method

Concrete permeability is controlled by good proportioning of water cement ratio,

enough curing, high degree of compaction.
3) Moisture movement: most of the building materials with pores in their structure in the
form intermolecular space expand on absorbing moisture and shrink on drying.

Prevention method

Shrinkage cracks are controlled by using temperature reinforcement plaster with coarse
well graded sand or stone chip will suffer less from shrinkage cracks and is preferred for
plastering for external face of walls.

4) Corrosion of reinforcement: a properly designed and constructed concrete is initially

water tight and the reinforcement steel within it is well protected by a physical barrier of
concrete cover which has low permeability and high density. Corrosion causes loss of
mass, stiffness and bond and therefore concrete repair becomes inevitable.

Prevention method

The feasible prevention measure against corrosion is the use of concrete with low
permeability. Increased concrete cover over the reinforcing bar is effective in delaying the
corrosion process and also in resisting the splitting.

5) Poor construction process: there is a general lack of good construction practices either
due to ignorance, carelessness greed or lack of knowledge or worse still, a combination of
all of these.
Prevention method

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In order to avoid poor construction practices, taking measures against improper

selection of materials, selection of poor quality cheap materials, inadequate supervision.

6) Poor design and specification: it is crucial that the designer and specifier must first
consider the environmental conditions existing around the building site. It is also equally
important to do soil investigations to determine the type of foundations, the type of
concrete materials to be used in concrete and the grade of concrete depending on the
bearing capacity of the soil near to the site.

Prevention method
Poor design and specification can be controlled by providing proper specification
for concrete, proper specification and design considering the site environment,
constructible and adequate structural design and finally selecting proper contractor to
construct their design.

REPAIR METHODOLOGY

First before repairing any cracks in building, the provided limit of cracks will be checked
from Ethiopian Building Construction Code 2 (EBCS 2) code book. If the existing crack is
exceeding the provided limit, it should be repaired with the best suited method.

The provided crack width in buildings is as follows:

Table 1: Crack width limit

Type of exposure Provided crack width (mm)

Dry environment 0.4
Humid environment 0.2
Sea water or aggressive chemical
environment 0.1

Major crack repairing methods

a) Routing and sealing: it is mostly practiced in Ethiopia. It can be used in conditions

requiring remedial repair and where structural repair is not necessary. This method
involves enlarging the crack along its exposed face and filling and sealing it with a
suitable joint sealant. The enlarging process does not have to be perpendicular to the
crack rather it has to be slant with some degree. This is common technique for crack
treatment and is relatively simple from other repairing methods.
Routing and sealing is used to treat both fine pattern cracks and larger, isolated
cracks. A common and effective use is for waterproofing by sealing cracks on the

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concrete surface where water stands, or where hydrostatic pressure is applied. This
treatment reduces the ability of moisture to reach the reinforcing steel or pass through the
concrete, causing surface stains other problems.
The procedure consists of preparing a groove at the surface ranging in depth,
typically, from 6 to 25 mm. A concrete saw, hand tools or pneumatic tools may be used.
The groove is then cleaned by air blasting, sandblasting, or water blasting, and dried. A
sealant is placed into the dry groove and allowed to cure. A bond breaker may be
provided at the bottom of the groove to allow the sealant to change shape, without a
concentration of stress on the bottom.

b) Epoxy injection: this technique is 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. It requires a high degree of skill for satisfactory
execution.

Procedure

1. Cleaning the cracks; the first step is to clean any cracks that have been
contaminated (to the extent this is possible and practical). Contaminants, such as
oil, grease, dirt, or fine particles of concrete, prevent epoxy penetration and
bonding, and reduce the effectiveness of repairs. Preferably, contamination should
be removed by vacuuming or flushing with water or other effective cleaning
solutions.

2. Sealing the surfaces; Surface cracks should be sealed to keep the epoxy from
leaking out before it has gelled. Where the crack face cannot be reached, but
where there is backfill or where a slab-on-ground is being repaired, the backfill
material or sub base material is sometimes an adequate seal.
3. Installing the entry and venting ports; Three methods are in general use:

a) Fittings inserted into drilled holes. This method entails drilling a hole
into the crack, approximately 3/4 in.(20 mm) in diameter and 1/2 to 1 in.
(13 to 25 mm)below the apex of the V-grooved section, into which a
fitting such as a pipe nipple or tire valve stem is usually bonded with an
epoxy adhesive. A vacuum chuck and bit, or a water-cooled core bit, is
useful in preventing the cracks from being plugged with drilling dust.
b) Bonded flush fitting. An alternative method that is frequently used to
provide an entry port is to bond a fitting flush with the concrete face over

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the crack. The flush fitting has an opening at the top for the adhesive to
enter and a flange at the bottom that is bonded to the concrete.
c) Interruption in seal. Another system of providing entry is to omit the seal
from a portion of the crack. This method can be used when special gasket
devices are available that cover the unsealed portion of the crack and
allow injection of the adhesive directly into the crack without leaking.

4. Mixing the epoxy; Mixing is done by batch or continuous methods. In batch

mixing, the adhesive components are premixed according to the manufacturer’s
instructions, usually with the use of a mechanical stirrer, like a paint mixing
paddle.

5. Injecting the epoxy; Hydraulic pumps, paint pressure pots, or air-actuated

caulking guns may be used. The pressure used for injection should be selected
carefully. Increased pressure often does little to accelerate the rate of injection. In
fact, the use of excessive pressure can propagate the existing cracks, causing
additional damage.

6. Removing the surface seal; after the injected epoxy has cured, the surface seal
should be removed by grinding or other means as appropriate.

c) Stitching: it involves drilling holes on both sides of the crack and grouting in U shaped
metal units with short legs (staples or stitching dogs). Stitching may be used when tensile
strength must be reestablished across major cracks. 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.

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3 EXPECTED OUTCOMES
This research project expects to have the following outcomes by the end of this project.

a) Provide an economical and suitable method of preventing and maintaining cracks.

b) Avoiding any misunderstandings with the causes of cracks in building.

4 TIME SCHEDULE
The work should be conducted in accordance with the following schedule. It can be
updated during the work and may shorten the total time needed for the completion of the
research.
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Table 2: Time schedule

Components of
works Months
February March April May June
Preparatory works
 Literature 
review
Data collection
 Primary data
collection  
 Secondary
data

collection

Data analysis
 Describe
cause of
crack
 
 Describe
preventive
methods
 Describe
repair
methods
Conclusion 
Printing and
submitting final 
research
Preparation for
presentation 
Research
presentation 

5 BUDGET REQUIRED
It is the fund of financial requirement for each and individual actions conducted in the
progress of doing the project.

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Table 3: Budget required

Unit cost Total cost

no Item Unit Quantity (birr) (birr)
1 Service cost
1.1 Print Pages 250 1 250
1.2 Color print Pages 20 5 100
1.3 Binding Pcs. 5 10 50
2 Consumable goods
2.1 Print paper Pack. 2 120 240
2.2 Pen Pack. 1 210 210
2.3 Note book Pcs. 6 25 150
2.4 Staples Pack. 1 10 10
3 Permanent goods
3.1 16GB flash disk Pcs. 1 180 180
3.2 4GB SD card Pcs. 1 60 60
3.3 Stapler Pcs. 1 90 90
4 Perdiem Day
4.1 Experts Day 4 100 400
4.2 Transportation cost Trip 20 15 300
Total 2040

6 REFERENCES
1) EBCS 2 1995, pp. 58&59
2) Kazem Reza Kashyzadeh, Neda Aghli Kesheh. Study type of cracks in construction and
its controlling volume 2 issue 8, August 2012, pp. 528 ~531

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3) Rajat Srivastava , study on causes of cracks and its prevention measures in concrete
structures.
4) Grishma Thagunna. Building cracks, causes and remwdies. 3rd world conference on
applied sciences, Engineering and Technology at Basha research centre.

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