1 nrrnrrni 0000073620

EXPERIMENTAL~-~~ ... ~·· ~----· ............. ~ ........ RACKED CONCRETE

COLUMN REPAIRED BY JACKETING METHOD

MUHAMMAD ZULIIlLMI BIN ALI

A report submitted in partial f ulf'dment of the

Requirements for the award of the degree of

Bachelor of Civil Engineering

Faculty of Civil Engineering and Earth of Resources

University Malaysia Pahang

JUNE2012

ii

vi

ABSTRACT

This study is to investigate the strength, crack pattern, and failure pattern in

crack concrete colmnn repair by jacketing method. The scope of this research is

limited to overloading load and the sample is made using concrete G25. The

reinforcement concrete has been design and analyse according to BS5950 with T12

for main bar and R6 for shear link. Two samples with colmnn size of 125 mm x 125

mm x 1500 mm was prepared for repair method, and the structural test is carried out

after reach 28 days strength using strong floor machine with rate 0.55 mm per

minute. The samples were preloaded under axial compression to its ultimate load;

repair using jacketing method in grouting mortar and then retested to failure. The

result show that the original maximum load indicate highest value compare to

maximum load after repaired by jacketing method. Diagonal crack is observed in

original colmnn and transverse crack is observed in colmnn after repaired. As

conclusion, the jacketing method used in this study failed to restore the strength of

cracked concrete colmnn.

vii

ABSTRAK

Kajian ini adalah untuk menyiasat kekuatan, corak retak, dan corak kegagalan

untuk tiang konkrit yang retak menggunakan kaedah jacketing. Skop untuk: kajian ini

adalah terhad disebabkan beban muatan yang berlebihan dan sampel itu dibuat

menggunakan konkrit 025. Konkrit tetulang telah direka bentuk dan dianalisa

berdasarkan kepada BS5950 dengan Tl2 bar utama dan R6 bar ricih. Dua sampel

dengan saiz 125 mm x 125 mm x 1500 mm telah disediakan bagi kaedah pembaikan,

dan ujian struktur dijalankan selepas kekuatan 28 hari jangkauan yang menggunakan

mesin lantai yang kukuh dengan kadar 0.55 mm seminit. Sampel yang telah dimuat

mampatan paksi kepada beban muktama; pembaikan jacketing dengan menggunakan

kaedah Grouting mortar dan kemudian diuji semula sehingga kegagalan. Hasilnya

menunjukkan bahawa beban maksimum asal menunjukkan nilai tertinggi berbanding

dengan beban maksimum selepas dibaiki oleh kaedah jacketing. Retak pepenjuru

diperhatikan dalam ruang asal dan retak melintang diperhatikan dalam ruang selepas

dibaiki. Sebagai kesimpulan, kaedah jacketing yang digunakan dalam kajian ini

gagal untuk mengembalikan kekuatan konkrit tiang yang retak.

I

viii

TABLE OF CONTENTS

CHAPTER TITLE PAGE

CERTIFICATION OF THESIS CERTIFICATION BY SUPERVISOR I

TITLE PAGE 11

AUTHOR'S DECLARATION lll

DEDICATION IV

ACKNOWLEDGEMENTS v ABSTRACT VI

ABSTRAK Vll

TABLE OF CONTENTS viii LIST OF TABLES IX

LIST OF FIGURES x LIST OF ABBREVIATIONS XI

LIST OF SYSBOLS Xll

CHAPTER I INTRODUCTION

1.1 Introduction 1 1.2 Problem statement 2 1.3 objective 3 1.4 Scope of study 3 1.5 Significance of study 3

CHAPTER2 LITERITURE REVIEW

2.1 Introduction 4 2.2 Type of repair column 5 2.3 Crack 5 2.4 Method of concrete repair 6

2.4.1 Jacketing technique 6 2.4.2 Epoxy resin injection technique 6

CHAPTER3 METHODOLOGY

3.1 Introduction 7 3.2 Analysis of reinforcement concrete column 7

3.2.1 Introduction 7 3.2.2 Design column specimen 8

I

3.3 Concrete 9 3.3.1 Introduction 9 3.3.2 Aggregate 9 3.3.3 Cement 9 3.3.4 Water 10 3.3.5 Steel Bar 10

3.4 Formwork 11 3.5 Concrete mix design 12

3.5.1 Mixing concrete process 12 3.6 Curing 14 3.7 Column crack 14 3.8 Repair method 15

3.8.1 Jacketing technique 15 3.9 Quality control of concrete 16

3.9.1 Introduction 16 3.9.2 Workability 16 3.9.3 Slump test 16 3.9.4 Concrete compression test 17

3.10 Test for column crack 19 3. I l Analysis of data 20

3. I I . I .Analysis crack pattern 20 3.I 1.2.Strength of column crack 20

CHAPTER4 RESULT AND DISCUSSION

4.1 Introduction 21 4.2 Cube test result 2I 4.3 Expected result 22 4.4 Maximum load for structure test 22

4.4.1 Original column specimen l 22 4.4.2 Specimen 1 repair using jacketing 23

method 4.4.3 Original column specimen 2 25 4.4.4 Specimen 2 repair using jacketing 26

method 4.4.5 Maximum loading result comparison and 28

analysis

4.5 Crack pattern 30 4.5.1 Original column specimen 1 & 2 30 4.5.2 Specimen 1 & 2 repair using jacketing 31

method 4.5.3 Crack pattern comparison and analysis 32

CHAPTERS CONCLUTION AND RECOMMENDATION

5.1 Introduction 33 5.2 Brief conclusion 33

5.2.l Comparison the Strength Produce 33 Between Original Column Specimen and

after Repairing using Jacketing Method 5 .2.2 The Type of Crack Due to Load between 34

Original Specimen and After Repair Using Jacketing Method

5 .3 Recommendation 34

REFERENCES 36

APPENDIX A B c D

Column design calculation Mix design Compression test Result

37 38 39 40

TABLE NO. 3.1 4.1 5.1

LIST OFT ABLES

Ratio of concrete Cube test result Result

TITLE

ix

PAGE 12 39 40

x

LIST OF FIGURES

FIGURE NO TITLE PAGE 1.1 Column crack on site 2 3.1 Square section of column 8 3.2 Dimension of column 8 3.3 Cross section column 10 3.4 Side view of column 11 3.5 Formwork 12 3.6 Concrete mixer 13 3.7 Curing process 14 3.8 Additional of reinforcement 15 3.9 Pour grouting mortar into formwork 15 3.10 Slump test apparatus 17 3.11 Compression test machine 18 3.12 Strong floor 19 3.13 Loading arrangement 20 4.1 Arrangement of column inside the strong floor specimen 22

1 4.2 Load versus displacement specimen 1 23 4.3 Situation of the column after the maximum load is 24

applied specimen 1 4.4 Load versus displacement after re-test specimen 1 24 4.5 Arrangement of column inside the strong floor specimen 25

2 4.6 Load versus displacement specimen 2 26 4.7 Situation of column after the maximum load is applied 27

specimen2 4.8 Load versus displacement after re-test specimen 2 27 4.9 Load versus displacement for specimen 1 29 4.10 Load versus displacement for specimen 2 29 4.11 The crack pattern at top of column 30 4.12 The crack pattern at bottom of column 30 4.13 The pattern crack at top of column after repair 31 4.14 The pattern crack at bottom of column after repair 31 5.1 Enlargement column 34 5.2 Jacketing with steel plate 35

RC

C35

G25

ACI

BS

ASTM

MS

LIST OF ABBREVIATIONS

Reinforcement concrete

Column 35

Grade 25

American concrete institute

British Standard

America Society for Testing and Material

Malaysia Standard

xi

xii

LIST OF SYMBOLS

% Percent

0 Degree

mm Millimetre

N Newton

fy Reinforcement characteristic strength

kN Kilo Newton

Po Ultimate strength

fc Concrete characteristic strength

Ac Area of concrete

Ast Area of steel

1

CHAPTER I

INTRODUCTION

1.1 Introduction

Industrial training is a valuable expenence for every student. Whether

consultant, contractor or developer, the experience only have in industrial training.

I 00% experience on site will be having in contractor. Experience on site different

from what we learn in university. In site, we exposed more toward on installation of

every each structure element such as slab precast, RC beam, and enlargement

column.

Various problems occur at site whether problem in architect drawing not

same with structure drawing. This entire problem can disturb the project progress.

The major problem that gives the critical problem on site is crack in structure

element. Many damaged concrete structure with various types of crack were

repaired. For economic concern, this damage was repaired with some technique and '

method better than construct new building. This technique can restore strength of the

structure that applies.

2

1.2 Problem statement

In my industrial training, there is one problem that occurs during

construction. One of column C35 was crack during construction. Because of this

column, some activity cannot run as schedule. It gives us problem to complete that

project as planning before.

As solution on this problem, the contractor comes out with their solution to

rectification this problem. There are methods that were suggested from contractor is

jacketing technique. This method can restore the strength the column.

Figure 1.1: column crack on site

3

1.3 Objective

The objectives of the study are:

I. To compare the strength produce between original column specimen

and after repair using jacketing method.

2. To study the type of crack due to load between original specimen and

after repair using jacketing.

1.4 Scope of study

The scope of this research is the column crack due to overloading load. There

is one type of rectification that used to restore the strength of column cracked. The

maximum loading after repair using the jacketing technique will compare with the

maximum loading for the column without repair using jacketing method. This

method just for study there effect of strength to that column crack. The concrete

grade which will be used to make the sample for testing to be carried out is concrete

G25. This sample must create a crack after 28 day. Cube test will be carried out on 7,

14 and 28 day age of concrete.

1.5 Significance of study

This study is to investigate type of method use to rectification the column

crack until their strength restore. For technical and financial reason, these methods

which are times saving, have more simple procedure to carry out and required lower

cost are more appealing to the industry.

4

CHAPTER2

LITERATURE REVIEW

2.1 Introduction

Reinforcement concrete is one of the most widely used modem buildings.

Concrete is combination by mixing cement, sand, and aggregates with water.

Reinforcement concrete is a strong building material that is formed into many shapes

and sizes ranging. It almost common used in construction work compare to the

reinforcing steel in worldwide. Reinforcing steel require expensive manufacturing

mills compare to the concrete production. The extensive use of reinforced concrete

construction its relatively low cost compare to other materials such as steel.

5

2.2 Type of repair column

The main cause for RC column with the need to undergo rectification are

large spacing of tie in columns, the use of 90° hooks, close tie spacing, and to meet

stringent existing building code requirement. (Abdullah, and K.Takiguchi, 2011)

Column which need to undergo rectification usually have insufficient ductility due to

improper transverse confinement, and insufficient shear strength. (Abdullah, and co,

2011). There is various type of rectification method for RC column. Some of the

method use to rectify RC column is: (a) Ferrocement jacket, (b) high performance

fibre-reinforce concrete jacket.

2.3 Crack

Crack in concrete have many causes. They may affect appearance only, or

they may indicate significant structural distress or lack of durability (Camille A. Issa,

Pauls Debs.2005). Crack always occurs before a concrete structure achieves their

strength or fails. Crack an important role in concrete response to load in both tension

and compression. It very important to first identify the location and extent of

cracking when anticipating repair of crack in concrete (reported by ACI committee

224, ACI 224.lR-93). Crack can be categorized in three groups: cracks due to

inadequate structural performance, cracks due to inadequate material performance,

and acceptable cracks (Tsiatas, 2002). Structural cracks are caused primarily by

overloading; material related cracks are due to shrinkage and chemical reaction; and

acceptable cracks are those that develop due to service level for tensile stresses to be

distributed properly along the length of the material (Tsiatas, 2002).

6

2.4 Method of concrete repair

There many researchers about concrete repair such as seismic performance of

repaired RC column (K.-S. Yown, H.-E. Lee and S.choi, 2006). The restoration of

the strength of cracked concrete was measured for various conditions of the concrete

surfaces (Hindo, K. R., 1990). Repair and rehabilitation work for concrete structures

can broadly be classified into two main categories: (i) repair in which the damage

due to deterioration and cracking is corrected to restore the original structural

capacity and (ii) repair that is necessary to strengthen the structural capacity of a

member whose load carrying capacity has either been inadequate or whose strength

has been severely impaired (Al-Gadhib AH,2003).

2.4.1 Jacketing technique

Jacketing is the most popularly used method for strengthening of building

columns. The common types of jackets are steel jacket, reinforced concrete jacket,

fibre reinforced polymer composite jacket, jacket with high tension materials like

carbon fibre. Jacketing serves to improve the lateral strength and ductility by

confinement of compression concrete. The jacketing of columns is generally carried

out by two methods (i) reinforced concrete column jacketing and (ii) steel jacketing

(Shri, Pravin B, W aghmare, 2011 ).

2.4.2 Epoxy resin injection technique

Epoxy resin is a common used in rehabilitation work. According to ACI

224.lR-93, epoxy resins are commonly used repair materials that generally have very

good bonding and durability characteristics. Structural performance of RC slabs

repaired using epoxy resin injection performed best compared to other repair material

(Calder and Thompson, 1998). The bond between concrete and the injection material

is very critical; a good bond may restore the original stiffuess of the repaired material

and prevent further penetration of chloride ions and water (Minoru et al, 2001). The

crack must be clean and dry prior if not the epoxy resin not applicable.

7

CHAPTER3

METHODOLOGY

3.1 Introduction

In this chapter, vanous aspect of preparation of material, apparatus and

testing sample will be explained. All the aspect will be follow according to the

specification.

3.2 Analysis of Reinforcement Concrete Column

3.2.1 Introduction

Analysis of RC column is an important in this research. It is important to

analysis the strength of RC column before construct the column. It is to ensure that

the design of the column is follow the specification required according to BS 8110-

1 : 1997. The column design calculations refer in appendix A.

8

3.2.2 Design column specimen

For this research, the analysis based on short column with square section. The

column is single reinforcement column.

Figure 3.1: Square section of column

L

Figure 3.2: 3 dimension of column

Dimension of column

b= 125 mm

h= 125 mm

L= 1500 mm

9

3.3 Concrete

3.3.1 Introduction

Concrete is a composed mainly of three materials, namely, cement, water

aggregate, and an additional material, known as an admixture. The selection of

concrete proportions involves a balance between economy and requirements of

placeability, strength, durability, density, and appearance.

3.3.2 Aggregate

The coarse and fine aggregate will be used in this research. There are between

ranging from 10 mm to 20 mm for coarse and less than 5 mm for fine aggregate. The

standard specification for concrete aggregate is described in ASTM C33-03 (ASTM

2003).the aggregate will be air dried to ensure that are no moisture content in

aggregate. This is because the moisture content of the aggregate can affect the

performance of the concrete. Aggregate also considerably improves both the volume

stability and the durability of the resulting concrete.

3.3.3 Cement

Cement is a material that has adhesive and cohesive properties enabling it to

bond mineral fragments into a solid mass. The different cements used for making

concrete are finely ground powders and all have the important property that when

mixed with water a chemical reaction take place which, in time, produces a very hard

and strong binding medium for the aggregate particles. The cement used in this study

is ordinary Portland cement. Type 1 Portland cement as in ASTM C150-05 (ASTM

2005c) was used throughout the study.

10

3.3.4 Water

Water used in concrete in addition to reacting with cement and thus causing it

to set and harden, also facilitates mixing, placing and compacting of the fresh

concrete. It is also used for washing the aggregates and for curing purposes. The

clean water in accordance to MS 28 is used.

3.3.5 Steel bar

Both mild steel (fy = 250 N mm2) and high strength steel (fy = 460 Nmm2

) will

be used in this research. The high strength steel will be used as main bar whereas the

mild steel will be used as bent-up links. The dimension of steel are selected while

design the reinforcement according to BS 8110.

Ill .. 125 mm

• •

125mm

Figure 3.3: Cross section column

11

2T12 ii\

1 ~ -, ..... R 6 - 200

_, 125mm

~ -'

~,.

1500 mm \ ,,

2T12

Figure 3.4: Side view of column

3.4 Formwork

In this research, timber formworks were used to mould the column having

size of 125 x 125 x 1500 mm. The advantage of using plywood formwork over other

type is that it can mould bigger and produce smooth surface concrete. So that, the

timber formwork is the best choice due to its flexibility and cost.

Prepare formwork

a) Determine and calculate the quantity of plywood required for the

structure.

b) Measured and draw line or mark on the plywood according to the

required dimension. This step is repeated for supporting member and

braces.

c) Using sawing cut the plywood based on the line done in step 2.

d) Using sand paper, clean the plywood to ensure that the plywood is free of

dust and other debris.

e) Nails the plywood together using hammer.

f) Place supporting member and braces to secure the formwork.

12

Figure 3.5: form.work

3.5 Concrete Mix Design

The column were used concrete grade 25 will be used for column in this

research. The dimension of the column is the same as the design that is 125 x 125 x

1500 mm. The column casting in horizontal same as beam casting. Mix design table

refer appendix B.

Cement Water Fine agg. Coarse agg.

I column 11.76 kg 5.88 kg 19.32 kg 30.24 kg

Table 3.1: Ratio of concrete

3.5.1 Mixing Concrete Process

Procedure for mixing concrete is followed by BS 1881: Part 125-1989

(Testing concrete. Methods for mixing and sampling fresh concrete in the

laboratory). Procedures for mixing concrete are as below:

13

a) Prepare the mixer before mixing concrete. be sure the surface of the mixer is

wet.

b) Put the coarse and fine aggregate in the mixer.

c) Star the mixer. Let it mix for 15 minutes.

d) Add about haft of the water in the mixer and mix it for 2 minutes.

e) Carefully add all the cement with the mixer running and mix it for 30 seconds

until all the cement is blended in.

f) Add enough water from the final half of the water to produce a workable mix

and mix it for 2 minutes.

g) Perform a slump test (BS 1881: Part 102, method of determination of slump).

h) Cast the cube in order to determine the compressive strength of the concrete

and out of the mix or column casting.

i) After 24 hours, the cube and column should be stripped and cured in the

water tank (BS 1881: Part 111: 1983, method of normal curing of test

specimen.

Figure 3.6: Concrete mixer

14

3.6 Curing

The purpose of curing is to promote the hydration of cement, thus the

development of strength and durability of concrete. It also controls the temperature

and moisture movement from and into the concrete. While the column samples it

take 28 days to achieve good strength for concrete. Cure the sample by cover it with

jute and water is spray at the interval of 1 hour.

Figure 3.7: Curing process

3. 7 Column crack

Column crack for this research is due to overloading load. The crack of

column was using strong floor equipment.

Step of produce column crack:

a) Setup the column on the equipment.