CEM V - Concrete Properties

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26 Νοε 2013 (πριν από 4 χρόνια και 9 μήνες)

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1

CEM V
-

Concrete Properties
evaluated

by

ESPI

Universität für Bodenkultur Wien,

Institut für Konstruktiven Ingenieurbau

Klaus Voit, Konrad
Bergmeister

ENVIZEO 3
rd

Workshop, 07.12.2011, Vienna

2

Content

I)
Introduction
:

What

is

ESPI
and

what

is

it

capable

of
?

II)
Compression

Test
(
Test Set
-
up

&
Performance)


II
-
1)
Complete

Cubes


II
-
2) Cubes
cut

in Half


II
-
3) Single
Grains


II
-
4)
Verification

of

Measurements

via
Strain

Gauges

III)
Flexural

Tension Test
(Test Set
-
up

& Performance)

IV) Summary

3


ESPI = Electronic Speckle Pattern Interferometry


Measuring +
Visualisation

of Displacement / Deformation


using Laser Light
+
Video Detection


Area Measurement


Measurement of different Directions


Contact
-
free


Sensitivity up to 10 to 100 nm

I)
Introduction


4


Laser Beam
splitted

into

2 Laser
beams





1
st

Laser Wave
goes

to

a
Mirror
:
Reflected

unchanged




2
nd

Laser Wave
goes

to

Sample:
experiences

Shift

of

Phase


Both

Laser
Beams

reflected

to

a
Camera



Interference


Design
of

ESPI


5


Constructive

Interference
: Swing in Phase,
no

Phase
Shift






Destructive

Interference
:
O
ut
of

Phase

Interference

of

2
Waves

Speckle Pattern

=

fingerprint

of


the

surface

at

current

state

high
luminosity

low

luminosity

white

dot

black

dot

6


Speckle Pattern
of



Speckle Pattern after



Initial Position:



Deformation
(
Increase

of

Load
):







ESPI
calculates

Difference

Picture:

(=
Stripes

and

Fringes
)


Along

1
Stripe
: same
Displacement


1

Stripe

= ca. 3

m


Speckle Pattern

Deformation

ca.

3

m

7


=
Visualization

of

Deformation:
Visualization

of

Cracks






After
Data
P
rocessing
:

Calculation

of

Strain
,
Shear
, etc.

Difference

Picture


Stripe

Developing

Crack

Extension

Shortening

Example
: 3
-
Point
-
Flexural
-

Tension
Test:

Strain

Map

in x
-
Direction

(CEM I)


[

m/mm]

8


Visualization

of

Force Transmission


Visualization

of

Strain

Distribution
in Sample
itself


Measurement
of

Deformation
and

Extension


Independently

in
3 different
Directions

(x, y, z)


Visualization

of

Crack Development


Direct

Measuring

of

Crack
Opening

Width


Weakness
:


Only

Surface

Analysis (2D)


Sensitive
and

Demagable


Crack
throughout

field

of

View


Application

Limitation

Strengths

&
Weakness

of

ESPI

9

II)
Compression

Tests


1
st

Test Setup
:

Complete

Concrete Cubes
:

150x150x150 mm



2
nd

Test Setup
:

Half Concrete Cubes
(Cut in Half):

150x150x75 mm
considered

as

a
Whole



3
rd

Test Setup
:

Half
Concrete Cubes
(Cut in Half):

150x150x75 mm,
Examination

of


Single
Grains

10

Compression

Tests


Behavoir

of

CEM V


Concretes

under

Compression


Charakterization

of

Deformation Properties


Characterization

of

first

Crack Development


Calculation

of

Crack
Widths


Calculation

of

Elastic

Modulus



Verification

of

ESPI
Deformations

via
Strain

Gauges

11

II
-
1)
Complete

Cubes


Test Setup:

Spider Computer
for

Measuring

Strain

Gauges

&
Displacement

Sensors

Illumination

Press

ESPI Sensor

Sample
under

Test

Sample
under

Test:

ESPI
-
Computer

12

Experimentation

of

Complete

Cubes


Successive

Increase

of

Load



In
Load

Steps

of

ca. 30 kN


After
each

Load

Step
:
Stop

Press + ESPI
Measuring



Results

presented

at

CCC
Congress

2011 in
Balatonfüred

Testing

Complete

Concrete Cubes

13

Example
: AT V/A


Displacement


Stripes

in
x
-
Direction

at


Load

Step

8 (
630,5 kN
)





Stripes

in
y
-
Direction

at


Load

Step

8
(
630,5 kN
)





Stripes

in
z
-
Direction

at


Load

Step

8
(
630,5 kN
)

14

Example
:
AT V/A


Deformation


Analysis Load steps 14
-
16:
630,5
-

758,9
kN
(
F
max
: 1152,8 kN)


Qualitative Analysis of Displacement:

Extension (in x
-
Direction) and Shortening (in y
-
Direction)

Displacement

with

Direction

Vectors

Extension in x
-
Direction

via Crack

Shortening

in y
-
Direction

at

distinct

Layers

15

Example
: SK
V/A


Crack Width


Development of a Crack in the
Central
leftern

Part


Crack Width
Load steps
10
-
20:
333,8


887,1 kN in

m
:

Deformation in x
-
Direction

(

m)

3,7

m

㈬㌠

m

Cross
Sections

over

Crack

Stripes

Picture

Crack

16

II
-
2) Cubes
C
ut in Half


For

Testing

the

Interior

of

the

Concrete Samples


Not
only

outer

Cement


Paste
coating


Smoother
Surface


Visual Determination
between


Grain

and

Cement

Matrix


Same Test Setup
as


Complete

Cubes


Directly

before

test
: Samples

sprayed

for

uniform

Reflection

Intensity

Half Cube

17

Sample
Preparation



Concrete Cubes
were

cut

in Half

18

Example
: CEM I 6 (Sample 2)


Observation:
Load

transmission

via Corners


Samples
not
perfectly

cubic
, but
higher

in
Edges


Expected

in y
-
Dir.
Actually

in y
-
Dir.









Along

every

Fringe

same
Displacement





Formwork

not
perfectly

cubic

19

Example
: CEM I 6 (Sample 2)

Analysis Load steps
10
-
18:
54,6


226,7
kN


Dislacement




Strain



Shear


(

m)
(Colors in x
-
Dir.)




(

m/mm) in
x
-
Dir.


(

m/mm) in
y
-
Dir.





(Extension in Cracks)

(
Load

Transmission via Corners)








20

Statistic

Evaluation


Compressive

Strength
:







0
10
20
30
40
50
60
CEM I
AT V/A
AT V/B
SK V/A
SK V/B
N/mm²

Compressive Strength
Half Cubes
-

Mean
(
Age ca. 160d)

0
10
20
30
40
50
60
CEM I
AT V/A
AT V/B
SK V/A
SK V/B
N/mm²

Compressive Strength
Complete Cubes
-

Mean
(
Age ca. 60d)

21

Analyzation

of

Crack Development


Determination
of
:


Load

at

primary

Crack & Crack
Opening

Width










AT V/B
develops

Central Cracks
at

very

late

Stage



H
igth

tensile

Capacity
/
Fracture

Energy







0
5
10
15
20
25
30
35
40
45
50
CEM I
AT V/A
AT V/B
SK V/A
SK V/B
N/mm²

Strength at
primary Crack
Development

Half Cubes
-

Average Values (Age: ca. 160 days)

Peripheral Cracks
Central Cracks
Max. Strength
0
10
20
30
40
50
60
70
80
CEM I
AT V/A
AT V/B
SK V/A
SK V/B
%

Primary Crack in %
of

Maximum
Strength

22

Elasticity

Modulus


ESPI
didn
´
t

provide

plausible Data
concerning

E
-
Modulus



Probable
Reasons
:


Measurement
of

Deformation
only

on
one

Side
of

Cube


Only

Surface

Measurement


Force
Transmissions

via Corners (not all
over

Section
)


Shape
of

Specimen


Increase

Of

Load

Step

by

Step

(
including

Rest
Periods
)







23

II
-
3) Single
Grains


Visualization

of

the

Difference

Grain



Cement

Matrix


Testing

of

Adhesion

Grain

-

Cement


Was
only

possible
/
visible

for

SK V/B
Cement


Example
: SK V/B 7:

Recognizable

Grains
:
Grain

Boundary

Considered

Section

24

Single
Grains

-

Analysis


Analysis Load steps
21
-
25:
332,4
-

363,6 kN


Grain Boundaries visible trough Compression Test:



Displacement

in x
-
Direction

(

m)

25

Strain







Strain




(

m/mm) in
x
-
Direction



(

m/mm)
in y
-
Direction





Single
Grains

-

Analysis



Maximum
Strain

in
Grain

Boundaries


26

Shear





Shear

(

m/mm) in
x
-
Direction




(

m/mm)
in y
-
Direction



Single
Grains

-

Analysis



Maximum
Shear

in
Grain

Boundaries


27


Cross
Section
:
Strain

in y
-
Direction

(

m/mm)













Crack
between

Grain

and

Cement



Negative
Strain

(
Shortening
) in
Cement




Single
Grains

-

Analysis

Cement

28

II
-
4)
Verification

of

Measurements


Verification

of

ESPI
Measurements

With

Strain

Gauges


Measuring

Deformation
between

Load

Steps

simultanously

with

Strain

Gauges

and

ESPI


Comparison


Gauge
Length
: 70 mm

Strain

Gauge in x
-
Direction

Strain

Gauge in y
-
Direction

29

Verification

of

Measurements


Comparison

ESPI


Strain

Gauges
:










High
Correlation
;

Divergence

from

0,8%
to

max. 11,7%

Sample
SG H
[mm/mm]
ESPI H
[mm/mm]
|%|-Divergence
Horizontal
SG V
[mm/mm]
ESPI V
[mm/mm]
|%|-Divergence
Vertical
Specimen 1 run1
0,074
0,068
8,62
0,429
0,461
7,40
Specimen 1 run2
0,071
0,072
0,80
0,517
0,560
8,27
Specimen 2 run2
0,121
0,135
11,67
0,619
0,670
8,32
Specimen 3 run1
0,180
0,188
4,28
0,928
0,977
5,27
Specimen 3 run2
0,139
0,153
10,30
0,709
0,735
3,60
30

III)
Flexural

Tension Test


Behavoir

under

Flexural

Tension


Identification

of

Tensile

Strength


Calculation

of

Flexural

Modulus


Primary
Crack Development
(
When
,
How
)


Comparison

regarding

Crack Width


31

Test Setup


Test Setup:

ESPI

Sample
under

Test

32

ESPI
Measurements


Strain

in x
-
Direction


Strain

in y
-
Direction

CEM I, Sample 2:
Load

Steps

15
-
18 (830
-
1440 N)

Tension Zone

Compressions

Zone

at

Bearing

33

Tensile

Strength
/Extension
Diagrams



Maximum
Strength

34

First Crack Development

First Crack
Identified

by

ESPI

(@ 5,25 N/mm²)



Load

at

First Crack in
Percentage

of

Maximum
Strength



35

Calculation

of

Flexural

Modulus


Flexural

Modulus

between

1/5
F
max

and

F
max

36

Crack Width


From

Initial Crack
until

Break:
Cross
section

across

Crack

ca. 12

m

37

Crack Development


Across

or

Around

Grain
:

Type

Crack

Development

CEM I

Both

AT V/A

Both
, Trend
across

Grain

AT V/B

Mainly

around

Grain

SK V/A

Both

SK V/B

Both
, Trend
around

Grain

CEM I

AT V/A

AT V/B

SK V/A

SK V/B

38

Statistic

Evaluation
Flexural

Tension Test


Tensile

Strength
:

0
1
2
3
4
5
6
7
8
9
CEM I
AT V/A
AT V/B
SK V/A
SK V/B
Tensile Strength (N/mm²)

Tensile Strength
-

Mean

0
1
2
3
4
5
6
7
8
CEM I
AT V/A
AT V/B
SK V/A
SK V/B
Tensile Strength (N/mm²)

Tensile Strength
-

5%
-
Fractile

39

Statistic

Evaluation
Flexural

Tension Test


Flexural

Modulus
:

0
50
100
150
200
250
300
CEM I
AT V/A
AT V/B
SK V/A
SK V/B
Flexural Modulus (N/mm²)

Flexural Modulus
-

Mean

0
50
100
150
200
250
CEM I
AT V/A
AT V/B
SK V/A
SK V/B
Flexural Modulus (N/mm²)

Flexural Modulus

-

5%
-
Fractile

40

Statistic

Evaluation
Flexural

Tension Test


Load

at

First Crack (
E
valuated

by

ESPI) :

0
1
2
3
4
5
6
7
CEM I
AT V/A
AT V/B
SK V/A
SK V/B
N/mm²

First Crack ESPI
-

Mean

0
10
20
30
40
50
60
70
80
90
100
CEM I
AT V/A
AT V/B
SK V/A
SK V/B
%

Load at First Crack (ESPI) in % of
Maximum Tensile Strength
-

Mean

41

Statistic

Evaluation
Flexural

Tension Test


Crack Width (
Evaluated

by

ESPI) :

0
2
4
6
8
10
12
14
16
18
CEM I
AT V/A
AT V/B
SK V/A
SK V/B
Crack
width (

m
)

Crack Width
from

first

Crack
until

Break
(

m
)

42

IV) Summary



CEM I
(Reference)

AT V/A

AT V/B

SK V/A

SK V/B


Compressive

Strength



(
after 60d
)

51 N/mm²

+

-

+

-


Tensile

Strength

7,8 N/mm²

+

-

-

-


Crack
Development
at

5,5 N/mm²

+

-

0

-


Crack
Width

8,9

m

-

0

0

-


Failure
Mode


(
around or across Grain)

Both

Across

Around

Both

Around

+
better


-

worse


0
same

43

Summary

ESPI:


ESPI
Measurements

validated

by

Strain

Gauges


Calculation

of

Deformation,
Strain
, Crack Width

CONCRETE


COMPRESSIVE TEST:


AT V/A, SK V/A
better

than

CEM
I (after
ca.
60d)

CONCRETE


FLEXURAL TESTS:


Tensile

Strength

highest

for

AT
V/A, same Level
as

CEM
I


Flexural

Modulus

highest

for

AT
V/A




V/A
Cements

equivalent

and

better

than

CEM I



44

The End

THANKS FOR YOUR ATTENTION