DURABILITY of CONCRETE STRUCTURES PART...

DURABILITY of CONCRETE STRUCTURES

PART 5

Prof. Dr. Halit YAZICI

1

REPAIR

REHABILITATION &

MAINTENANCE

2

Causes of Damage

EARTHQUAKES

design and application faults

Potential danger !

3

Causes of Damage

DURABILITY

PROBLEMS

Corrosion

Sulfate Attack

Carbonation

Freeze-Thaw

ASR

Hazardous

chemicals, etc.

4

CORRECT DIAGNOSIS

PROPER REHABILATION DECISION

(Strengthening, renewal, repair)

5

INSPECTION AND DETERMINING DEGREE OF DAMAGE

Site inspections Detailed survey, determining the reasons of deteriorations & environmental aggressivitiy Tests on concrete and reinforcement Project control with new material properties

CHOOSING OF PROPER MATERIALS & METHOD FOR REPAIR

CLEANING OF DETERIORATED PARTS OF CONCRETE

CLEANING AND COATING (IF NECESSARY) OF REINFORCEMENT OR PLACEMENT OF NEW REINFORCEMENT

COVERING OF REPAIRED PARTS WITH SPECIAL MORTARS

INSULATION OF FINISHED SURFACES

DEMOLITION and RECONSTRUCTIO

N

CONSTRUCTIONAL INTEGRITY CAN BE REGAINED, SERVICE LIFE CAN BE EXTENDED

SOUND

APPRAISALS, MAJOR REPAIRS, STRENGTHENING,

UPGRADING

MINOR REPAIRS &

MAINTENANCE

DECISION

REPAIR & MAINTENANCE

6

DETECTION OF CRACKS

BY WETTING OF SURFACE

CHECKING THE SURFACE

CONDITION BY ADHESIVE BANDS

(DUST, LOOSE PARTICLES, ETC.)


7

INSPECTION of CONCRETE

1) TAKING CORES (FROM DAMAGED & UNDAMAGED REGIONS)

2) EXAMINATION of AVALIABLE DATA RELATED with THE

CONCRETE

•Concrete Structure (Design, dimensions, loading background)

•Specifications

•Concrete design

•Previous test results on materials used in production

•Quality control of fresh concrete

•The method and frequency of taking specimens

•Test results of specimens cured in the laboratory

•Test results of specimens cured in situ

•The strength of concrete in the actual structure

•Information on curing conditions & curing time

•The age of the concrete when the damage had occurred

8

DESTRUCTIVE TEST (CORE)

TROUBLESOME , EXPENSIVE, SIZE and AGE EFFECT

RELIABLE RESULTS

NON-DESTRUCTIVE TESTS (REBOUND HAMMER, ULTRASOUND)

APPLICATION ALONE IS NOT ADVISABLE, CORRELATION

WITH CORES IS NECESSARY, ERROR RATIO is HIGH

(ESPECIALLY FOR OLD BUILDINGS)

* THE NUMBER of TEST DATA must be SUFFICIENT for REPRESENTATION

* STATISTICAL METHODS MUST BE USED in EVALUATION

CONCRETE STRENGTH

9

CORE

FACTORS EFFECTING THE TEST RESULTS

•SLENDERNESS RATIO of SPECIMEN

•EMBEDDED STEEL

•DRILLING DIRECTION of CORE

•RATE of APPLICATION of LOAD

•DRILLING LOCATION of CORE

•AGE of THE CONCRETE

•HUMIDITY of CORE

•etc.

•THE CALIBRATION & SENSITIVITY of TESTING MACHINE 10

CONCRETE REBOUND HAMMERS

For

CONCRETE

(Narrow

elements)

For LOW

STRENGTH

MATERIALS

(Plaster, etc.)

FOR MASS

CONCRETE 11

FACTORS EFFECTING THE TEST RESULTS

•SURFACE CONDITION of CONCRETE

•LOCAL VARIATIONS

•HUMIDITY CONTENT at the SURFACE

•CARBONATION at the SURFACE

•APPLICATION POSITION (DEGREE) of HAMMER

•CALIBRATION of HAMMER

•AGE of CONCRETE

•etc.

•EXISTANCE of STEEL REINFORCEMENT

•SURFACE HARDENERS

CONCRETE REBOUND HAMMER

12

CARBONATION

ACID + ALKALI SALT + WATER

Ca(OH)2

CO2

Ca(OH)2+CO2 CaCO3+H2O

pH12.6 pH8.3

IF pH<9.5-11.5

Initiation of Corrosion

(In Presence of O2 & H2O)

tKC C : CARBONATION DEPTH (mm)

K : COEFFICIENT of CARBONATION (mm/year0.5)

t : TIME (year)

LOW STRENGTH

CONCRETE W/C>0.6 K >3-4 mm/year0.5

15 mm OF CARBONATION DEPTH CAN BE REACHED IN 15 YEARS!

13

SCHMIDT HAMMER TEST ON CARBONATED

SURFACES

CARBONATED

CONCRETE SURFACE HARDENING

BIG ERRORS ON OLD STRUCTURES !!! EXAMPLE:

TEST RESULTS OF TWO BUILDINGS

(a. 25 YEARS OLD b. 50 DAYS OLD)

HAMMER RESULTS : fck = 16.9 MPa !

CORE RESULTS : fck = 4.8 MPa AGE OF CONCRETE 25 YEARS

HAMMER RESULTS : fck = 25.1 MPa !

CORE RESULTS : fck = 18.0 MPa AGE OF CONCRETE 50 DAYS

14

STEEL REINFORCEMENT

VISUAL

INSPECTION

NON-

DESTRUCTIVE

TESTS (Electrical

measurements,

metal detectors -

pundit)

•Location

•Number

•Distance

•Diameter

•Corrosion

condition

of the

reinforcement

DESTRUCTIVE

TESTS

LABORATORY

TESTS

Sampling

Tensile Test

Chemical Analysis

Other Tests

(energy

absorption

capacity,

Workability vb.)

Stress-Strain

Relationship

•Corrosion

•Rust Stains

•Cover Cracks

•Pop-out

Removal of

concrete cover

•Location

•Number

•Distance

•Diameter

•Corrosion

condition

of the

reinforcement 15

TENSILE TEST

16

CuSO4 crytals

Copper

(Cu)

Saturated copper

sulfate solution

(CuSO4)

Permeable

end

Wet Sponge

Millivoltmeter Corrosion

measuring

system –

(electrical)

17

STRUCTURAL INSPECTION

Architectural Survey

The Survey of Load Carrying System (Determination of dimensions &

locations of Column-Shell-Beam-Curtains)

Determination of Location, diameter and number of Reinforcement

Determination of width and direction of cracks

Determination of other damage types if exists (Buckling, X cracks on

walls, Settlement etc.)

Noting of application faults

Determination of elements that are heavily damaged, that threats the

structural safety in order to take urgent measures

etc.

INSPECTION OF PROJECTS & SPECIFICATIONS

THE CALCULATION of LOAD BEARING CAPACITY OF

STRUCTURE BY MEANS of DATA EVALUATED

COMPARISON of RESULTS WITH PROJECTS & AVALIABLE SPECIFICATIONS 18

FACTORS ON DECISION MAKING

•ECONOMICAL (Feasibility Study) –

Cost of Repair 0.5 Cost of Reconstruction ?

•Technological possibilities

•Service life

•Historical & Artistic worth

•Commercial aspect

•Political aspect

•The effect of Strengthening on building functions

•The applicability and Reliability of Repair-

Strengthening methods

•Demolition, Reconstruction opportunities

19

EVALUATION OF OBTAINED

DATA

STATISTICAL METHODS

INCLUDING PROBABILITY &

RISK CONCEPTS SHOULD

BE USED

BEING CONTENTED WITH THE AVERAGE

of INSUFFICIENT NUMBER of TEST DATA

REAL SITUATION OF STRUCTURE CAN NOT BE

REPRESENTED

BIG MISTAKES 20

SOUND

•There is no

necessity

MINOR

REPAIRING IS

NEEDED

•Simple Repairs

•Measures that

should prevent

repetation of

damage etc.

LOAD BEARING

CAPACITY SUFFICIENT

LOAD BEARING CAPACITY

UNSUFFICIENT

STRENGTHENING

IS NEEDED

REPAIR

STRENTENING IS

NEEDED

DECISION

OTHER FACTORS EFFECTING DECISION

STRENGTHENING

PROJECT 21

INCORRECT STRENGTHENING PROJECT AND APPLICATION

WEAKENING AND FAILURE OF THE STRUCTURE

22

PREPARATION BEFORE REPAIR

THE CONCRETE THAT WILL BE REPAIRED

HAVE TO CONTAIN CERTAIN PROPERTIES

SURFACE MUST BE SOUND & DURABLE,

SHOULD NOT CONTAIN

* LOOSE OR DECOMPOSED PARTICALS,

* FAULTS & CRACKS (HONEY COMBED REGIONS)

* DUST, DIRT, OIL, PAINT, CURING MATERIALS THAT

WEAKENS THE ADHERENCE BETWEEN THE OLD & NEW

CONCRETE

* DETRIMENTAL MATTERS THAT CAUSE CORROSION

TO REACH THE SOUND CONCRETE LAYERS

DETORIATED CONCRETE LAYER SHOULD BE

REMOVED & SURFACE PREPATION OPERATIONS

SHOULD BE PERFORMED 23

REMOVAL of DAMAGED

CONCRETE

IMPACT HAMMERS

FREQUENTLY USED

METHOD

RISK OF FORMATION

of MICROCRACKS on

SOUND CONCRETE

THE TYPE of CRUSHER is

IMPORTANT EXTRA OPERATIONS might be

NECESSARY IN CASE of DAMAGE

in SOUND LAYERS 24

REMOVAL of DAMAGED

REGIONS

CUTTING by SAWS

CUTTING DEPTH CAN BE

ADJUSTED

CUTTING PROCEDURE

SHOULD NOT PENETRATE

TO SOUND LAYER

SAWS THAT MAY CUT & STRIP THE

CONCRETE COVER (ALSO OPERABLE

ON VERTICAL SURFACES) 25

REMOVAL of DAMAGED

CONCRETE

SAND BLASTING

LOOSE PARTICLES and DIRTY

MATERIAL MAY BE CLEANED

FROM SURFACE

REMOVAL of THICK LAYERS is

NOT POSSIBLE

ECONOMICAL on LARGE

SURFACES

TOO MUCH DUST !!!

ADDITIONAL IMPROVEMENT

METHOD for OTHER REMOVAL

APPLICATIONS

26

REMOVAL of DAMAGED

CONCRETE

WATER

JET

REMOVAL of LOOSE &

POLLUTED MATERIAL FROM

the SURFACE

REMOVAL of THICK LAYERS is

NOT POSSIBLE

SANDY WATER

JET

MOST ECONOMICAL METHOD

in CASE of USING CEMENT

BASED REPAIRING MORTARS

NOT ADVISABLE FOR POLYMER

BASED MORTARS DUE to WET

SURFACES

USED as ADDITIONAL CLEANING

METHOD 27

REMOVAL of DAMAGED

CONCRETE

OTHER METHODS

BLASTING PROPER for LARGE

SCALE WORKS

APLLICATION RISKS,

SPECIALIST TEAM

NECESSARY

BURNING

CLEANING of

PAINTS, FOREIGN

MATERIALS FROM

THE SURFACE

NOT ADVISABLE FOR

STRUCTURAL ELEMENTS

WITH INSUFFICIENT

CONCRETE COVER

THICKNESS

28

REMOVAL of DAMAGED

CONCRETE

OTHER METHODS

ACID

APPLICATION

APPLICATION of 5-

10% PHOSPHORIC

ACID SOLUTION MAY

LOOSEN WEAK &

DIRTY LAYER

NOT ADVISABLE

METHOD.

CLEANING is

NECESSARY after

IMPLEMENTATION

AIR

BLOWING

PRESSURE of AIR

MAY BLOW AWAY

DUST etc. FROM

SURFACE

LAST APPLIED METHOD

(i.e. AFTER SAND BLASTING)

29

REMOVAL of DAMAGED

CONCRETE

OTHER METHODS CHISEL, HAMMER,

SAND PAPER,

ELECTRICAL SURFACE

WEARING DEVICES

PROPER FOR CLEANING

of SURFACE AND

REINFORCEMENT

MORE THAN ONE METHOD SHOULD be

IMPLEMENTED

MINIMUM DAMAGE SHOULD be EXPECTED on

SOUND CONCRETE SURFACES

EXCESS HEAT & VIBRATION SHOULD NOT CAUSE PROBLEMS

on REINFORCEMENT or R.F + CONCRETE BOND 30

STRENGTHENING & IMPROVEMENT MATERIALS

VOLUME of WORKS

APPLICATION POSSIBILITIES

BONDING PROPERTIES (STEEL & CONCRETE)

ADHERENCE to OLD CONCRETE (DIMENSIONAL STABILITY)

SELECTION of MATERIALS

ENVIRONMENTAL PROPERTIES

(TEMPERATURE, HUMIDITY, WIND, etc.)

ECONOMICAL FACTORS

SERVICE CONDITIONS & EXPECTED SERVICE LIFE

31

STRENGTHENING & IMPROVEMENT MATERIALS

RENEWAL of CONCRETE

EPOXY or POLYESTER BASED REPAIR MORTARS

STEEL PROFILES

CEMENT BASED REPAIR MORTAR

SELF – COMPACTING CONCRETE (SCC)

SHOTCRETE - GUNITE

FIBER REINFORCED CONCRETE (Steel, Polypropilen, Glass, etc.)

FIBER REINFORCED SCC

FIBER REINFORCED POLYMERS (FRP)

NON-SHRINKING MORTARS (GROUT)

CEMENT PASTE

SLURRY INFILTRATED CONCRETE (SIFCON)

REACTIVE POWDER CONCRETE (RPC) 32

RENEWAL of CONCRETE

PROPER for LARGE SCALE WORKS for STRENGTHENING PURPOSES

HONEY COMBED PARTS IN NEW CONSTRUCTIONS must be

RENEWED IMMEDIATELY

33

RENEWAL of CONCRETE

USUALLY NEW FORMS ARE NECESSARY

IF

REINFORCEMENT

IS DEFECTIVE; IT

SHOULD BE CUT

AWAY & NEW

REINFORCEMENT

SHOULD BE

PLACED with

NECESSARY

BONDING LENGTH

34

Photographs : Çelik MATER

WRAPPING

35

ADDITIONAL LOAD –BEARING ELEMENTS

ANCHORAGE OF REBARS

SURFACE PREPARATION

ADHESION OF NEW AND OLD CONCRETE

***

36

t1 t2 t

1

2

OLD

CONCRETE

NEW

CONCRETE

0

SHRINKAGE of NEW CONCRETE

– SHRINKAGE of OLD CONCRETE

--------------------------------------------------

= RELATIVE SHRINKAGE

2 -1 -------- =

if is HIGH

RISK of CRACKING !!!!

DIFFERENTIAL SHRINKAGE PROBLEMS

37

SHRINKAGE

THERMAL EXPANSION

E

EXTRA

TENSILE

STRESS

Tensile

stresses Cracks

Before casting

sP sT <

NO CRACKS

SUFFICIENT MECHANICAL PROPERTIES

(FLEXURAL, TENSILE, COMPRESSIVE STR.)

E1, 1

E2, 2

E1 E2

1 2

constraints

constraints

38

Max 2 cm

0.5 cm

Subsurface should be clean and rough enough to provide

sufficient frictional resistance

< 3 cm mortar

> 3 cm concrete

ADHERENCE

Very low viscosity, low yield value Segregation

susceptible

Mechanical blocking

Cement paste migration due to low viscosity

Segregation resistant

Self levelling cement mortar with optimum viscosity and low yield value

high viscosity repair mortar

Low pore filling capacity due to high viscosity

Low adhesion performance due to empty

pores

39

Properties of repair materials

Classification of repair materials

Class 40 Class 25 Class 15

Compressive strength- 28 d. (MPa) 30-60 20-40 10-30

Min. Tensile strength- 7 d. (MPa) 2 1.5 1

Modulus of Elasticity - 28 d. (GPa) 15-25 9-15 5-9

Min. Adherence strength- 28d. (MPa) 2 1.5 1

Max. Coeff. of thermal expansion (1/oC) 8-12x10-6

Max. Drying shrinkage -28d 400x10-6

Max. Drying shrinkage -1 year 1000x10-6

Manual of structural maintenance, Hong Kong Housing

Department, 1987

Dimensional stability – Mechanical properties – Adherence

40

Flowable

sticky

sprayable

APPLICATION EASINESS

41

MAINTENANCE AND PROTECTION

42

Emulsion applications

(resin, paraffin and

acrylic)

Water and

solvent based

hydrophobic

materials

43

FRP

CARBON – GLASS FIBER REINFORCED COMPOSITES

VERY HIGH TENSILE STRENGTH

APPLICATION EASE

DURABILITY AGAINST CHEMICAL ATTACK (NO CORROSION RISK)

LIGHT WEIGHT MATERIAL

EASE of STORAGE (ROLLS, BANDS)

CONCRETE

EPOXY BASED BINDER

EPOXY BASED PUTTY

EPOXY BASED ADHESIVE

LAMINATE

EPOXY BASED ADHESIVE

UV RESISTANT PAINT

44

FRP LOW RESISTANCE to HIGH TEMPERATURES

DIRECTION of FIBERS is IMPORTANT

LOW UV RESISTANCE

HIGH CREEP DEFORMATIONS

LONG-TERM PERFORMANCE is NOT CLEAR

RELATIVELY EXPENSIVE MATERIAL

min. CONCRETE CLASS C16

APPLICATION DIFFICULTIES at JOINTS

45

E fy ft u

STEEL

Fe B 44K

STRAND

206000

206000

7850

7850

440

1200

550

1900

> 20

> 5

MBrace FIBRE C1-30

(High strength Carbon)

Mbrace FIBRE C5-30

(High Modulus Carbon)

MBrace FIBRE C8-30

(Very High Modulus carbon)

230000

390000

640000

1820

1820

2100

-----

-----

------

3430

3000

1900

1.5

0.8

0.3

MBraceFIBRE G-60AR

(AR Glass)

65000 2600 ----- 1700 2.8

E fy ft u

STEEL

Fe B 44K

STRAND

206000

206000

7850

7850

440

1200

550

1900

> 20

> 5

MBrace FIBRE C1-30

(High strength Carbon)

Mbrace FIBRE C5-30

(High Modulus Carbon)

MBrace FIBRE C8-30

(Very High Modulus carbon)

230000

390000

640000

1820

1820

2100

-----

-----

------

3430

3000

1900

1.5

0.8

0.3

MBraceFIBRE G-60AR

(AR Glass)

65000 2600 ----- 1700 2.8

FRP

46


APPLICATION OF

FIBER

REINFORCED

POLYMERS

FOR

STRENGTHENING

PURPOSES

AT COLUMN-BEAM

JOINTS & AT

GIRDERS

47

APPLICATION

OF FRP’s ON

TEST

SPECIMENS


48

FRP LABORATORY STUDIES

15 cm CUBES & 10/20; 15/30

cm CYLINDER SPECIMENS

WRAPPED BY ONE AND

TWO LAYERS OF FRP

RELATIVE STRENGTH IN CUBES

CONTROL(100) ONE LAYER OF

FRP (121)

TWO LAYERS OF FRP (142)

RELATIVE STRENGTH IN CYLINDERS 10/20 cm

CONTROL (100) ONE LAYER OF FRP (180)

TWO LAYERS OF FRP (242)

15/30 cm CYLINDER

CONTROL (100) ONE LAYER OF FRP (132)

49

FRP LABORATORY STUDIES

10 X 10 X 60 cm CONCRETE SPECIMEN

CONTROL SPECIMEN (100)

LAMINATED SPECIMEN (372)

REPAIRED BROKEN SPECIMEN (262)

ADHESION OF LAMINATE TO TENSILE ZONE

APPLICATION OF LAMINATE TO TENSILE ZONE

OF BROKEN BEAM THAT HAS BEEN BONDED

BY EPOXY

WRAPPING OF FRP

LAMINATED AND WRAPPED SPECIMEN (859)

BEAM BEHAVED LIKE A RFC ELEMENT

RELATIVE FLEXURAL STRENGTH

50

FRP

51

Strengthening against flexural and shear stresses 52

DIFFERENT APPLICATIONS OF FRP

53

MBrace FRP” Wet Lay Up”

MASONRY PANELS

HIGH STRENGTH CARBON AND AR GLASS FIBER 54

FRP EASE OF

APPLICATION

55

FRP EASE OF APPLICATION

56

BEAM-COLUMN JOINT ?

current research topic

(Ghobarah and Said 2002)

Alper İlki

İTÜ, 2007

57

1- SELF LEVELLING CONCRETE

(SLC) 2- SELF COMPACTING CONCRETE

(SCC) 3- SELF CONSOLIDATING CONCRETE

(SCC)

- NO VIBRATION

- NO SEGREGATION

IDEAL MATERIAL

for REPAIRING

SCC

58

SCC

59

Different

workability

tests:

V – Funnel

Test

SCC

60

SCC

L – Box

Test

61

HIGH MECHANICAL

PROPERTIES

HIGH DURABILITY

MAXIMUM

COMPACTION

LOW W/C

RATIO

QUALITY of

CONCRETE

COVER

IMPERMEABILITY

HIGH PERFORMANCE CONCRETE

SCC

62

SHORTER CONSTRUCTION PERIOD

LOWER LABOR COSTS

BETTER CONCRETE QUALITY (STRENGTH & DURABILITY)

EASE OF PUMPING

SEGREGATION RESISTANCE

FLUIDITY

But RESISTANCE to SEGREGATION

Reological behavior is being changed by introduction of new

chemical admixtures

SCC

63

* EXTRA HYDRAULIC PRESSURE (STRONGER FORMS)

SCC

* CASTING PROBLEMS in SOME CONSTRUCTION ELEMENTS

* DIFFERENT PHYSICAL & MECHANICAL PROPERTIES

* COST of MIX

* ABSENCE of STANDART PRODUCTION TECHNICS & TESTS

64

SCC

65

SCC

66

SCC

67

* SUITABLE FOR REPAIRING & STRENGHTENING JOBS

(Especially in cases where vibration is not possible)

SCC

68

(GUNITE, PNEOCRETE, PLASCRETE,

LETCRETE) SHOTCRETE

Aggregate

Cement

Water

Accelerator

Conveying in

pipes by

pressured air

Placing by

Blowing

WET METHOD

DRY METHOD

69

(Transportation + Placing + Compaction) simultaneously

No formwork, Less labor force

High application speed

Special team & equipmnet

Loss of material by bouncing

70

(GUNITE, PNEOCRETE, PLASCRETE,

LETCRETE) SHOTCRETE

71

RE-CONSTITUTION OF FREEZE-THAW SURFACES

BY SHOTCRETE


72

FIBER REINFORCED CONCRETE

Aggregate

Cement

Water

Admİxture

Randomly

distributed

fibers

fiber fiber

fiber

matrix Matris Matris

Crack Crack Crack

Function:

Control of crack propogation

73

(Lofgren 2005)

Different fiber types

74

CARBON FIBERS

STEEL FIBERS POLYPROPILEN FIBERS

GLASS FIBERS

TYPES of CONCRETE FIBER

75

INCREASE in

ENERGY ABSORBTION

CAPACITY

FIBER REINFORCED CONCRETE

76

SFRC

Plain concrete Plain concrete

Plain concrete

strain

strain

SFRC

SFRC

Com

pre

ssiv

e s

tr.

Tensile s

tr.

Load

deflection

77

Parameters that affect the mechanical performance of

fiber reinforced concrete

• Fiber type

• Fiber content

• Aspect ratio of fiber

• Tensile strength of fiber, mechanical conformity with

matrix

• Orientation of fibers

• Homogeneous dispersion of fibers in matrix phase

DECREASE IN WORKABILITY

DECREASE IN COMPRESSIVE STRENGTH DUE TO FORMATION OF POROUS ZONES AT FIBER OVER DOSAGES

REQUIREMENT OF BETTER CASTING PLANNING AND WORKMANSHIP

DISADVANTAGES

78

40 kg/m3 ZP305 40 kg/m3 RC80/60

60 kg/m3 RC80/60

STEEL FIBER REINFORCED SELF LEVELLING

CONCRETE

79

STEEL FIBER REINFORCED SELF LEVELLING

CONCRETE

80

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 5

Deplasman (mm)

Yü

k (

N)

plain

60 kg/m3 ZP305

40 kg/m3 ZP305

20 kg/m3 ZP305

plain 20 kg/m3 40 kg/m3 60 kg/m3

Flow diameter (mm) 775 755 710 640

Comp.str (MPa) 65.1 68 68.1 62.9

Flexural str. (MPa) 5.1 5.4 6.6 10

Fracture en. (N/m) 51 873 2138 3138

Mix properties

Powder content: 580 kg/m3

Water/binder: 0.32

fine/coarse agr: 1.72

Load (N

)

Deflection (mm)

Increase in energy absorbtion capacity 61.5 times !!!

81

STEEL FIBROUS SHOTCRETE

RAILROAD TUNNEL REPAIRING / UŞAK 82

SIFCON

STEEL FIBER (% 4-20 by VOLUME) HIGH REINFORCEMENT CONTENT

HIGH DEFORMATION CAPACITY,

% 10 – 15

HIGH COMPRESSIVE STRENGTH

120 – 140 MPa

(SLURRY INFILTRATED CONCRETE)

CEMENT

SILICA FUME

WATER

SUPERPLASTICIZER

VERY FINE AGGREGATE

83

SIFCON

85

REPAIRING & STRENGTHENING with SIFCON

IMPROVING SHEAR RESISTANCE (dimensions:mm)

SIFCON COVER LOAD (P/2)

a

d=

20

0

onarılmış 50 100 50

25

150

25

150 25 25 REPAIRED

PORTION

100 50 50

86

REACTIVE POWDER CONCRETE (RPC)

* SILICA FUME

* REACTIVE SiO2 (300 m)

(REPLACING FINE & COARSE AGGREGATE)

* HIGH COMPRESSIVE STRENGTH : 200 – 800 MPa

* MODULUS OF ELASTICITY : 41 000 – 76 000 MPa

* WATER VAPOUR CURING UNDER ATMOSPHERIC

or HIGH PRESSURE

* STEEL MICRO FIBERS

* HIGH COMPACTION (GRADATION is VERY IMPORTANT)

87

R.F. BEAM

RPC

STRENGTHENING by RPC

REACTIVE POWDER CONCRETE (RPC)

88

BINDING MATERIALS

OLD

PRACTICES

CEMENT PASTE

CEMENT MORTARS

SUCCESFULL

APPLICATIONS

RECENT

PRACTICE

EPOXY RESINES

POLYVINYL ACETATE

STYRENE BUTADYNE

ACYRILIC

SUCCESFULL

APPLICATIONS

HIGH COMPRESSIVE, TENSILE, SHEAR STRESSES

IMPERMEABILITY

CHEMICAL DURABILITY

EXPENSIVE

TOXIC PROPERTIES

SHORT STORAGE TIME

89

EPOXY & POLYESTER BASED REPAIR MORTARS

MORE THAN

1 COMPONENT

EPOXY RESIN

PLASTICIZER

PIGMENTS

SUSPENSION COMPOUNDS

SOLVENT

SAND COMPOSITIONS

BINDER

FILLER

RAPID STRENGTH GAIN (MAX. STR. 2 hours – 2 days)

HIGH BINDING PROPERTY

EXPENSIVE MATERIAL

IMPERMEABILITY

LOW RESISTANCE to HIGH TEMPERATURES

DURABILITY AGAINST CHEMICAL ATTACK

DRY SURFACE APPLICATIONS

EXOTHERMIC REACTION (HIGH HEAT)

LONG TERM RESISTANCE ???

PETROCHEMICAL PRODUCTS

90

Mechanical and physical properties

of typical epoxy based repair mortar

Loss in mechanical properties over 80oC !!!

Basınç dayanımı, DIN 53454 110-120 MPa

Eğilme dayanımı, ASTM C580-74 30-35 MPa

Elastisite modülü, ASTM C580-74 18-20 GPa

Çeliğe aderansı, DIN ISO 4626 > 30 MPa

Betona aderansı, DIN ISO 4624 > 3 MPa

Termal genleşme katsayısı, ASTM C531-81 (20-100 °C) 2110-6

°C-1

Rötre, ASTM D 2566-79 0.0017 %

Compressive Str.

Flexural Strength

Modulus of Elasticity

Adhesion str. (steel)

Adhesion str. (concrete)

Coefficient of thermal expansion

Shrinkage ASTM D 2566-79

91

SMALL SCALE REPAIR JOBS

(FILLING BINDING)

GLASS FIBER REINFORCED

EPOXY BASED REPAIR MORTAR

92

CEMENT BASED REPAIR MORTARS

HIGH THERMAL RESISTANCE

SIMILAR PHYSICAL & MECHANICAL PROPERTIES with CONCRETE

SATURATED DRY SURFACE APPLICATIONS (?)

IMPERMEABILITY

LONGER CURING PERIOD

RELATIVELY LOW COST

PORTLAND CEMENT

MINERAL ADDITIVES

EXPANDING CEMENT (GROUT)

PLASTICIZERS

RETARDERS or ACCELARATORS

COMPONENTS

SAND

RELATIVELY SLOW STRENGTH GAIN

FIBER (POLYPROPILEN, STEEL, CARBON,

GLASS etc.)

93

LARGE SCALE

REPAIR WORKS

94

GROUT

* LARGE VOIDS can be FILLED by AGGREGATE

* FILLING of PORES & CRACKS by INJECTION

* IMPERMEABILITY PROBLEMS

* HIGH FLOWABILITY

* CHEMICAL & MINERAL ADDITIVES

* SULFO-ALUMINATE BASED COMPOUNDS

(for swelling)

* LOWEST POSSIBLE W/C RATIO FOR HIGHER STRENGTH

* PREFABRICATED COLUMN SOCKETS

SHRINKAGE is COMPENSATED

by EXPANDING COMPOUNDS

95

OPENING OF

CRACKS DRILLING OF

INJECTION HOLES


96

CLEANING OF

DUST & LOOSE

MATERIAL

CLEANING OF

SURFACE BY

PRESSURED WATER

OR BY SAND BLAST


97

FIXING OF

CUPPER

TUBES

PLASTERING

OF CRACKS


98

INJECTION FROM LOWEST

TUBE TO UPPER HOLES BY

PUMP


99

CLOSING OF

INJECTION HOLES


100

INJECTION PUMPING


101

STRENGTHENING BY STEEL

EASE OF APPLICATION BY THE USE OF EPOXY BASED BINDERS

102

. 50.10/30 lama

L100.100.10

1

L100.100.10

3 mm kaynak

18 10 1810

366 mm

300 mm

12/t=15 cm ilave

mesnet donatısı 80.10 saç

kiriş boyunca sürekli

Bulon

450 mm

2

18/t=30 cm

etriye (üstten bulonlu)

Eski kiriş

30/60

Pul

80.10 , etriye başlığı


Additional support RF 12/15

Bolt

washer Cont. Steel plate over the beam

Stirrup base

beam

Welding (3mm)

Steel plate

Stirrup (bolted)

103

Typical joint failure

Wrapping by steel plates

Double Wrapping by steel plates

Typical joint failure

Wrapping by steel plates

Double Wrapping by steel plates

Str. at corner joints Str. at front joints

104

photos by Hayri ÜN


105

CASE STUDY OF SULFATE ATTACK

106

SMALL BUSHES

SOUND SURFACES

DETERIORATED SURFACES (WHITE STAINS, SOFT, FRIABLE, CRACKED SURFACES)

WHITE SALT ACCUMULATED NATURAL SOIL

INDUSTRIAL (WASTE WATER) POOL


107

UNDERGROUND WATER

AGGRESSIVE

(SULFATE) SOIL

SOUND

ZONES

DETERIORATED

SURFACES

OPENING OF INSPECTION

HOLE & REMOVAL OF

AGGRESSIVE SOIL SOUND

CONCRETE

DETERIORATED

CONCRETE


108

SOUND

CONCRETE

REMOVAL OF

COVER

STEEL

REINFORCEMENT

COVER

REMOVED

ZONE

SOUND

CONCRETE


DIAMETER CONTROL, RUST

CLEANING & PAINTING

WITH ANTICORROSIVE

MATERIALS 109

PLASTERING

WITH

SPECIAL

FINISHING

MORTAR

SULFATE RESISTANT

INSULATION OVER

CONCRETE COVER


APPLICATION OF

REPAIRING

MORTAR

SOUND

CONCRETE

110

GRAVEL

FILLING

INCLINED SIDE WALKS

FOR RAIN (SULFATE

RESISTANT CEMENT)


DRAINAGE PIPES

(LOWERING OF

WATER LEVEL)

111

DURABILITY of CONCRETE STRUCTURES

PART 5

Prof. Dr. Halit YAZICI

112

DURABILITY of CONCRETE STRUCTURES PART...

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