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National Institute of Building Sciences Provider #G168

BEST4 Conference

Nibsbest4 April 13-15, 2015

Credit(s) earned on completion of this course will be reported to AIA

CES for AIA members. Certificates of Completion for both AIA

members and non-AIA members are available upon request.

This course is registered with AIA CES for continuing professional

education. As such, it does not include content that may be deemed or

construed to be an approval or endorsement by the AIA of any

material of construction or any method or manner of handling, using,

distributing, or dealing in any material or product.___________________________________________

Questions related to specific materials, methods, and services will be addressed at the

conclusion of this presentation.

Participants will :

1. Learn how to link the performance of individual building enclosure components in a holistic framework to achieve high-performance buildings.

2. Explore, through built case studies, how building envelope design determines overall energy conservation and sustainability capabilities

3. Learn innovative practices for avoiding heat loss as well as moisture and air infiltration in enclosure design for healthy new and existing buildings.

4. Understand the role of building enclosure commission-ing in the design, construction, and operation and maintenance of commercial facilities.

Learning Objectives

State of the Art in Evaluation Durability of Exterior Plasters

Dariusz Gawin

with Marcin Koniorczyk, Piotr Konca

Department of Building Physics & Building Materials, Lodz University of Technology, Poland

Acknowledgements:

K. Witczak1, W. Grymin1, A. Marciniak1, M. Wyrzykowski1,2

1 Lodz University of Technology, Poland; 2 EMPA, Zurich, Switzerland

F. Pesavento, B.A. Schrefler*

University of Padova, Italy

Layout/1 Durability of exterior plasters - introduction: - Role of exterior plaster in a wall;

- Modes of plaster degradation in different climates;

Factors influencing durability of plasters - Inner structure (porosity, pore size distribution);

- Moisture retention (sorption isotherm);

- Hygro-thermal properties (capillary suction, permeability, thermalconductivity & capacity);

- Thermal expansion;

- Moisture induced expansion (shrinkage & swelling);

- Chemical composition;

Durability of plasters in standards & recomendations - Cyclic freezing/thawing test;

- Mechanical strength test & pull off test;

- Shrinkage & thermal dilatation test;

- Salt crystallization tests;

- Accelerated calcium leaching test;

> 5

Layout/2

Damage due to hygro-thermal expansion/shrinkage - Physical mechanisms of degradation;

- Methods of experimental testing;

- Numerical modeling;

- Preventing hygro-thermally induced damage.

Frost damage - Physical mechanisms of degradation;



- Preventing frost damage.

Damage due to calcium dissolution/leaching - Physical mechanisms of degradation;



- Preventing degradation due to chemicals dissolution.

> 6

Layout/3

Damage due to salt crystallization - Physical mechanisms of degradation;



- Preventing damage due to expanding-salts.

Conclusions & Final Remarks

0.45

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

0 60 120 180 240 300 360

CZAS [dni]

WIL

GO

TN

OŚ

Ć W

ZG

L.

[-]

pow . w ew środek pow . zew

RE

LA

TIV

E H

UM

IDIT

Y

[ -

]

TIME [day]

255

260

265

270

275

280

285

290

295

300

0 60 120 180 240 300 360

CZAS [dni]

TE

MP

ER

AT

UR

A

[K]

pow . w ew środek pow . zew

TE

MP

ER

AT

UR

E

[K]

TIME [day]

IntroductionDegradation due to variable hygrothemal conditions

Frost degradation of the plaster in the climatic conditions of Poland,

due to excessive moisture content and negative temperatures.

IntroductionFrost damage due to water freezing / thawing

Introduction

Frost and moisture damage

IntroductionLeaching of cement based materials

(dissolution of calcium)

De

min

era

lize

dw

ate

r

Picture of a leached cement paste sample, obtained by means of microscopic analysis in a fluorescent light.

Introduction

Salt crystallisation & material damaging

Efflorescence on a wall surface

> 11 / 42

Pore size distribution curves for the IMTZ

Exterior plaster

Functions in a wall

External finishing and aesthetic role

Protection and buffer layer for moisture

Attenuation of temperature variations

Protection against deteriorating factors

Bridge at the 6th Street,Los Angeles, USA

The Greensbono Dam, North Carolina, USA

> 13

Porous materialsInner structure of porosity

Scanning Electron Microscopy

100 x 10 000 x

Moisture in porous materialsPhases of water

Critical temperature & critical point Phases of water & triple point

Phases of moisture Scanning Electron Microscopy

10 000 x

Mechanics of multiphase porous media

Porous materialsMulti-phase porous materials

R

cp

1 1 1

' "R r r

1.0E+05

1.0E+06

1.0E+07

1.0E+08

1.0E+09

1.0E+10

1.E-10 1.E-09 1.E-08 1.E-07 1.E-06

PROMIEŃ KAPILARY [m]

CIŚ

NIE

NIE

KA

PIL

AR

NE

[P

a]

273.15 K

373.15 K

CA

PIL

LA

RY

PR

ES

SU

RE

[P

a]

CAPILLARY RADIUS [mm]

Moisture in porous materialsInner structure of porosity

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.E-10 1.E-09 1.E-08 1.E-07 1.E-06

PROMIEŃ KAPILARY [m]

WIL

GO

TN

OŚ

Ć W

ZG

L.

[-]

273.15 K

293.15 K

373.15 K

RE

LA

TIV

E H

UM

IDIT

Y [

-]

CAPILLARY RADIUS [m]

Laplace equation

– relative humidity .pv – vapor pressure pvs – saturated vapor pressure .

RT

Mp

p

pw

w

c

vs

v

exp

Kelvin equation

pc – capillary pressure .R – meniscus curvature.

Pendular saturation Funicular saturation Insular air saturation

Increasing moisture content

Moisture in porous materialsMoisture content vs. pore size

Concrete w/c=0.4 (exp.)

0

20

40

60

80

100

120

0 0.2 0.4 0.6 0.8 1

WILGOTNOŚĆ WZGL. [-]

ZA

W.

WIL

GO

CI

[kg

/m3]

RELATIVE HUMIDITY [-]

Moisture in porous media Sorption isotherms

MO

IST

UR

E C

ON

T.

[kg

/m3]

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0% 20% 40% 60% 80% 100%

Relative humidity [%]

Sa

tura

tio

n d

eg

ree

[%

]

Ordinary Concrete

at T=20°C

Concrete (math. model)

Structure of porous materials Simplified models of porosity

Physical reality Simplified model

Cumulative & differential pore size distribution curve

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.001 0.01 0.1 1 10 100 1000

ŚREDNICA PORÓW [mm]

LO

G. R

ÓŻ

N. O

BJ

.

PO

RÓ

W [m

l/g

]

PORE SIZE [mm]

DIF

F. P

OR

E V

OL

UM

E

[ml/

g]

0

0.1

0.2

0.3

0.4

0.5

0.6

0 0.01 0.1 1 10 100 1000


SK

UM

UL

. O

BJ

. P

OR

ÓW

[ml/g

]

CU

MU

L. P

OR

E V

OL

UM

E

[ml/

g]

PORE SIZE [mm]

Structure of porous materials Mercury Intrusion Porosimetry

Description of porosity structure Pores clasiffication

Gel pores

Moist material as multi-phase medium Phases & constituents

solid matrix

chemically bound water

physically adsorbed water

capillary water (free water) Liquid phases

Gas phase = moist air water vapour dry air

Solid phase


Inter-Material Transition Zone

Experimental Study

Exterior plaster

Inter-material transition zone

Wall material (ceramic brick, concrete blocks



Experimental Study

0

0,01

0,02

0,03

0,04

0,05

0,06

0,07

0,001 0,01 0,1 1 10 100 1000

PORE DIMENSION [mm]

CU

MU

LA

TIV

E V

OL

UM

E [

ml/g

] .

mortar matured at RH= 75%

mortar matured in water

IMTZ - stucco at a ceramic brick

IMTZ - stucco at a AAC brick

Inter-material transition zone

SEM of the cement

stucco/ceramic brick interface

2-D EDS analysis of Ca content at

the stucco/ceramic brick interface


Experimental Study

Scanning Optical Microscopy analysis of the porosity for the

stucco/material IMTZ (based on the EN 480 - 11)


Experimental Study

Scanning Optical Microscopy analysis of the porosity at

the stucco/AAC IMTZ (based on the EN 480 - 11)

0

10

20

30

40

50

60

70

80

0 4 8 12 16 20 24 28 32

DISTANCE [mm]

PO

RO

SIT

Y [

%]

Total 'optical' porosity

porosity < 300 microns

Surface layer:14mm IMTZ: 2mm


Experimental Study

Material propertiesDifferent properties of the materials & IMTZ

Material Total

porosity [%]

Apparent density [kg/m

3]

Intrinsic permeability

[m2]

Thermal conductivity

[W/m·K] AAC 70 400 5.0 × 10

-16 0.14

Stucco 17 2200 9.0 × 10-19

0.80 IMTZ 25 1990 2.4 × 10

-18 0.80

Material Young

modulus [GPa]

Poisson ratio [-]

Compressive strength [MPa]

Tensile strength [MPa]

AAC 2.4 0.20 4.50 0.50 Stucco 8.0 0.175 7.40 0.82 IMTZ 7.8 0.175 7.04 0.78

Durability of exterior plasterPull off test

Freezing of water in porous materialsCyclic freezing /thawing test

Phenomenological approach

- description of the final results of the process only, without

profound entering into details of the physico-chemical phenomena involved and their interactions

- usually based on Thermodynamics (of Irreversible Processes)

- often uses inverse solution technique

(assumed model vs. experimental results model parameters)

Mechanistic approach

- description of the physical processes involved, taking into

account their complicated interactions, effect of the material structure, phase changes of particular constituents etc.

ModelingPhenomenological & mechanistic approach

Phenomenological approach

Luikov - 1966

Harmathy - 1969

Bazant et al. – 1971-2006

Krischer - 1978

Huang – 1979

Bazant & Wittmann - 1982

Gawin - 1991

Coussy – 1995, 2004, 2010

Ulm & Coussy - 1995

Sercombe, Hellmich, Ulm, Mang

– 2000

Mechanistic approach

Slattery - 1967

Whitaker - 1977

Hassanizadeh & Gray - 1979, 1990

Bear, Bachmat - 1986

Nasrallah & Perre - 1988

Gawin & Schrefler – 1996, 1999

Lewis & Schrefler – 1998

Gawin - 2000

Gawin, Pesavento, Schrefler

– 2003-2012

Modeling

Modeling coupled heat, air, moisture & chemicals

transport (CHAMCT) in porous materials

Modeling

Modeling calcium leaching

Adenot and Buil - 1992

Gerard - 1996

Ulm, Torrenti, Adenot - 1999

Kuhl, Bangert, Meschke - 2004

Kuhl & Meschke – 2007

Nonequil. Calcium leaching

Gawin, Pesavento & Schrefler

-2008, 2009

Frost damage

Bazant – 1998

Scherer – 1999, 2005, 2010

Setzer – 2001

Coussy – 2005, 2006, 2007

Pentalla – 1998, 2002, 2006

Modeling material degradation

- damage theory:

Mazars - 1984

Pijaudier-Cabot & Mazars - 1989

Pijaudier-Cabot, Gerard, Molez– 1998

- chemo-poro-plasticity:

Ulm, Torrenti, Adenot - 1999

- theory of reactive porous media:

Kuhl, Bangert, Meschke - 2004

Modeling salt transport & precipitation

Samson et al. - 2007

Koniorczyk & Gawin –2008, 2011, 2012

Koniorczyk – 2009, 2010, 2012

Modeling material degradation (cracking + chemical)

Dry air mass balance

Water species mass balance

Salt mass balance

Multiphase medium energy balance

Electrical charge balance equation

Multiphase medium momentum balance

Multiphase medium angular momentum balance

Second law of Thermodynamics for multiphase medium

Evolution equation for deterioration (chemical, thermal…)

Evolution equation for damage (cracking)

Evolution equation for chemical reaction / phase change

Modeling

Balance equations & evolution equation

Dry air – gas pressure

Water – moisture content, capillary pressure, relative humidity

Salt – salt concentration

Heat – temperature

Electrical charge – electrical pptential

Mechanical equilibrium – strain tensor, displacement vector

Angular momentum – summetry of stress tensor

2nd law of Thermodynamics – restrictions for constitutive relations

Damage (mechanical, chemical, thermal, …) parameter

Mechanical damage parameter

Chemical reaction / phase change – degree of advancement

Modeling

State variables & internal variables

Less more wetting phases: vapour, ice, water

MLMSMV

from nonwetting

to wetting phase

Stable phase

change at equil.

conditions:

[Setzer – 2001]

ModelingPhase changes in porous materials

- Condensation of vapor

- Thawing of ice

Less more wetting phases: vapour, ice, water

MLMSMV

from wetting

to nonwetting phase

Unstable phase

change below equil.

conditions:

ModelingPhase changes in porous materials

- Evaporation of water

- Freezing of ice

[Setzer – 2001]

Modeling

Mass transport mechanisms

Capillary water (free water):

advective flow (water pressure gradient)

Physically adsorbed water:

diffusive flow (water concentration gradient)

Chemically bound water:

no transport

Water vapour:

advective flow (gas pressure gradient)

diffusive flow (water vapour concentration gradient)

Dry air:

advective flow (gas pressure gradient)

diffusive flow (dry air concentration gradient)

1) 0% < < 20% 2) vapour + mono-layer of physically adsorbed water

3) adsorption desorption 4) diffusion and advective flow of vapour + surface diffusion in adsorbed water film

1) 20% < < 60% 2) vapour + poly-layer of physically adsorbed water

3) adsorption desorption 4) diffusion and advective flow of vapour + surface diffusion in adsorbed water film

1) 60% < < 95% 2) capillary water + vapour + poly-layer of physically adsorbed water

3) capillary condensation evaporation & adsorption desorption 4) „condensation – capillary flow - evaporation” + diffusion and advective flow of vapour + ( surface diffusion in adsorbed water film )

1) Relative humidity, 2) moisture forms, 3) phase changes, 4) mechanisms of moisture transfer, ( phenomenon of less importance )

ModelingMoisture trnasport in porous materials - summary

1) 95% < < 99% 2) capillary water + vapour (+ poly-layer of physically adsorbed water)

3) capillary condensation evaporation & (adsorption desorption) 4) capillary & advective flow of capillary water +„condensation – capillary flow - evaporation” + (diffusion of vapour in air)

1) 99% < < 100% 2) free water + vapour

3) capillary condensation evaporation 4) capillary & advective flow of free water + (diffusion of vapour in air)

1) = 100% 2) free water 3) - 4) advective flow of free water

1) Relative humidity, 2) moisture forms, 3) phase changes, 4) mechanisms of moisture transfer, ( phenomenon of less importance )

ModelingMoisture trnasport in porous materials - summary

Thawing: ice + energy capillary water

Freezing: capillary water ice + energy

Evaporation: capillary water + energy water vapor

Condensation: water vapor capillary water + energy

Desorption: phys. adsorbed water + energy water vapor

Adsorption: water vapor phys. adsorbed water + energy

Modeling

Phase changes of water

Macroscopic balance equations

(differential equations)

Microscopic balance equations

(differential equations)

Spatial averaging

F.E. model

(algebraic equations)

Weighted residual method

& time discretisation

microscopic view

macroscopic view of

averaged overlapping

continua

Modeling

Phase changes of water

> 43 / 42

g cg c

gg gc gs gt gu gg gc gs gt g

c Cag c Ca

cc cs ct cu cg cc gs ct c

c Cag c Ca

tc ts tt tu tg tc ts tt t

c

sc

t t t t t

t t t t

t t t t

t

CaCa

p p c T uC C C C C K p K p K c K T f

p c T uC C C C K p K p K c K T f

p c T uC C C C K p K p K c K T f

pC C

Cag c Ca

ss st su sg sc ss st s

g c Ca

ug uc us ut uu uu u

t t t

t t t t t

c T uC C K p K p K c K T f

p p c T uC C C C C K u f

where Kij - related to the primary variables

Cij - related to the time derivative of the primary variables

fi - related to the other terms, eg. BCs (i,j=g,c,t,s,u)

Modeling

Numerical solution

Forces:

in water

Capillary pressure

Disjoining pressure

in skeleton

Capillary pressure

Disjoining pressure

Modeling

Physical origins of shrinkage

ch ch chem ε I

free thermal strain

chemical strain

creep strain

mechanical strain (caused by mechanical load and shrinkage)

Shrinkage strain

Chemical strain

Free thermal strain strain

t s T ε I 3

ws csh

T

pK

ε I

mech tot c th ch

Modeling

Material strain decomposition

sh sh ε I

or

> 46

where is the solid surface fraction in contact with the wetting film,

I - unit, second order tensor, - Biot’s coefficient,

ps - pressure in the solid phase and pc is given by

with - disjoining pressure

s g ws csp p p

ws

sx

Coefficient x

0,0E+00

5,0E-02

1,0E-01

1,5E-01

2,0E-01

2,5E-01

3,0E-01

3,5E-01

0,0 0,2 0,4 0,6 0,8 1,0

Saturation [-][Gray & Schrefler, 2001]

[Gray & Schrefler 2006]

s s se p σ σ I

c f wg wwgp s J

f

0

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

0.0007

0.0008

0% 20% 40% 60% 80% 100%

Relative humidity [% RH]S

hri

nkag

e s

train

[m

/m]

experimental results

theory by Coussy

theory by Schrefler & Gray

Modeling

Shrinkage / swelling strains

Effective stress principle:

Non-local isotropic damage theory

[Mazars & Pijaudier-Cabot, 1989]

2

2( ) exp

2o

c

x sx s

l

1( ) ( ) ( )

( )r V

x x s s dvV x

3

2

1

i

i

Ko

Koc

Fct

Fcc

max

t t c cd d d

Modeling

Material damage (cracking)

Joint effect of mechanical and chemical damage

[Pijaudier-Cabot, Gerard, Molez – 1998]

0 0(1 )(1 ) : (1 ) :e ed V D

)0(

)(1

0

0

leach

leach

E

EV

VdE

E

E

E

E

ED

leach

leach

leach

leach

leach

leach

111

)0(

)(

)(

)(1

)0(

)(1

0

0

00

Modeling

Chemical deterioration and Total damage

> 49 / 42

0

CaD

2,0E-10

3,0E-10

4,0E-10

5,0E-10

6,0E-10

7,0E-10

8,0E-10

9,0E-10

0 2 4 6 8 10 12 14 16 18 20 22 24

Ca++

IONS CONCENTRATION [mol/m3]

Ca

++ IO

NS

DIF

FU

SIV

ITY

[m

2/s

]

T= 298.15 K

T= 283.15 K

T= 313.15 K

0,0E+00

1,0E-10

2,0E-10

3,0E-10

4,0E-10

5,0E-10

0 2 4 6 8 10 12 14 16 18 20 22

Ca++

IONS CONCENTRATION [mol/m3]

Ca

++ I

ON

S T

HE

RM

OD

IFF

. [

m2/s

]

T= 298.15 K

T= 283.15 K

T= 313.15 K

Ions thermo-diffusionIons diffusion

0 expCa Ca Ca CaT T w T T refD

cnS D T T

T

D I I

[Samson et al. - 2007]

0 4expCa Ca Ca

d d w d refD nS D A T T

D I I

Modeling

Chemical deterioration and Total damage

Slab – thickness=30 cm

Material: concrete C50 final porosity: 0.122, density: = 1900 kg/m3,

intrinsic permeability: ko= 5·10-19 m2,

Young modulus: E= 49.2 GPa,

water/cement ratio w/c=0.45.

Initial conditions: To= 293.15 K, o= 99.8% RH, hydr=0.3;

Boundary conditions:

Shrinkage (from day 7)

convective heat exchange: c=5W/m2K; Tamb=293.15K;

convective moisture exchange: c=0.002m/s; RHamb=60%

surface mechanical load: unloaded or load=7 MPa at 8,28,84,182 days

Sealed (for the first 7 days and basic creep)

convective heat and mass exchange: c=5W/m2K; sealed

surface mechanical load: unloaded or load=7 MPa at 8,28,84,182 days

Material shrinkage

Tests of Bryant and Vadhanavikkit (1987)

Drying & Load

-2.0E-03

-1.8E-03

-1.6E-03

-1.4E-03

-1.2E-03

-1.0E-03

-8.0E-04

-6.0E-04

-4.0E-04

-2.0E-04

0.0E+00

1 10 100 1000

TIME [days]S

TR

AIN

[-]

exp. Sealed - load sealed - loadexp. shrinkageshrinkageexp. total creepdrying & load

Pickett’s effect (8 days)

Material shrinkage

Tests of Bryant and Vadhanavikkit (1987)

-1.8E-03

-1.6E-03

-1.4E-03

-1.2E-03

-1.0E-03

-8.0E-04

-6.0E-04

-4.0E-04

-2.0E-04

0.0E+00

1 10 100 1000

TIME [days]

TO

TA

L S

TR

AIN

[-

]

exp. shrinkageshrinkageexp. 8 daystotal 8 daysexp. 28 daystotal 28 daysexp. 84 daystot. 84 daysexp. 182 daystot. 182 days


41 cm

Initial conditions: RH =50%; T= 20oC;

e= 0,023 m/s

he= 23.3 W/(m2K)

Te= TMY (incl. solarrad.)

RHe= TMY (incl. rain)

i= 0,008 m/s

hi= 7.7 W/(m2K)

Ti= 20oC

RHi= EN-13788

Considered cases:

AAC wall with external stucco and internal plaster;

Brick wall with external stucco and internal plaster;

Two levels of internal air humidity

Considering & neglecting IMTZ in the stucco & plaster

Climatic data of Warsaw, Cracow & Kolobrzeg

Material hygro-thermal strains

AAC wall exposed to the climatic conditions of Poland

Climatic data & location

Warsaw:

central part

of Poland

Cracow:

foreland of the

Tatra Montains

Kolobrzeg: at the seaside of the Baltic Sea

Material hygro-thermal strainsWall exposed to the climatic conditions of Poland

Total solar energy [kWh/m2year] and wind driven rain [mm/m2year] (from WUFI)

Warsaw Kolobrzeg Cracow


Warsaw

western façade

-20

-10

0

10

20

30

40

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]

TE

MP

ER

AT

UR

E [

oC

]

stucco / AAC interface at x = 0,401m

80

100

120

140

160

180

200

220

240

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]W

AT

ER

CO

NT

EN

T [

kg

/m3]


-1,2

-0,8

-0,4

0,0

0,4

0,8

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]

ST

RE

SS

[M

Pa

]



Cracow

western façade

-20

-10

0

10

20

30

40

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]

TE

MP

ER

AT

UR

E [

oC

]


60

80

100

120

140

160

180

200

220

240

260

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]

WA

TE

R C

ON

TE

NT

[k

g/m

3]


-1,5

-1,0

-0,5

0,0

0,5

1,0

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]

ST

RE

SS

11

[M

Pa

]



Kolobrzeg

western façade

-20

-10

0

10

20

30

40

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]

TE

MP

ER

AT

UR

E [

oC

]


80

100

120

140

160

180

200

220

240

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]

WA

TE

R C

ON

TE

NT

[k

g/m

3]


-1,2

-0,8

-0,4

0,0

0,4

0,8

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]

ST

RE

SS

[M

Pa

]



Warsaw

western vs. southern façade

-20

-10

0

10

20

30

40

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]

TE

MP

ER

AT

UR

E [

oC

]

S - stucco / AAC interface at x = 0,401m

W - stucco / AAC interface at x = 0,401m

60

80

100

120

140

160

180

200

220

240

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]

WA

TE

R C

ON

TE

NT

[k

g/m

3]



-1,5

-1,0

-0,5

0,0

0,5

1,0

0 30 60 90 120 150 180 210 240 270 300 330 360

TIME [day]

ST

RE

SS

11

[M

Pa

]




Warsaw: southern vs. western façade of the building

model considering vs. neglecting IMTZ (on western façade)

Simulations

100

120

140

160

180

200

220

240

260

90 100 110 120 130 140 150 160 170 180 190

TIME [day]

WA

TE

R C

ON

TE

NT

[k

g/m

3] W - no IMTZ, x= 0,401m

W - with IMTZ, x= 0,401m

100

120

140

160

180

200

220

240

260

90 100 110 120 130 140 150 160 170 180 190

TIME [day]

WA

TE

R C

ON

TE

NT

[k

g/m

3] S - no IMTZ at x = 0,401m

S - with IMTZ at x = 0,401m


Simulations

-1,0

-0,8

-0,6

-0,4

-0,2

0,0

0,2

0,4

30 35 40 45 50 55 60

TIME [day]

ST

RE

SS

11

[M

Pa

]

W - no IMTZ at x = 0,401m

W - with IMTZ at x = 0,401m

-1,0

-0,8

-0,6

-0,4

-0,2

0,0

0,2

0,4

30 35 40 45 50 55 60

TIME [day]

ST

RE

SS

11

[M

Pa

]

S - no ITZ at x = 0,401m

S - with IMTZ, x = 0,401m

Warsaw: southern vs. western façade of the building

model considering vs. neglecting IMTZ (on western façade)


Simulations

Location Orientation max

[MPa] min

[MPa] Nfr [h]

Warsaw S 0.60 -1.21 0 Warsaw W 0.76 -1.17 0 Cracow S 0.65 -1.33 0 Cracow W 0.70 -1.35 58 Kolobrzeg S 0,45 -1.18 0 Kolobrzeg W 0.48 -1.14 0

the highest tensile stresses on the W-façade

the highest tensile stresses on the S-façade

possible frost damage


Correlation of stresses & temperature (western façade):

Warsaw Cracow

Kolobrzeg

y = -0,0396x + 0,2629

R2 = 0,9438

-1,5

-1

-0,5

0

0,5

1

-20 0 20 40

TEMPERATURE [oC]

ST

RE

SS

[M

Pa

]

y = -0,0397x + 0,2457

R2 = 0,9302

-1,2

-0,8

-0,4

0

0,4

0,8

-10 0 10 20 30 40

TEMPERATURE [oC]

ST

RE

SS

[M

Pa

]

y = -0,0369x + 0,2258

R2 = 0,9411

-1,5

-1

-0,5

0

0,5

1

-20 -10 0 10 20 30 40

TEMPERATURE [oC]

ST

RE

SS

[M

Pa

]


Correlation of stresses & capillary pressures (western façade):

Warsaw Cracow

Kolobrzeg

y = -0,0476x + 0,253

R2 = 0,1634

-1,5

-1

-0,5

0

0,5

1

2 4 6 8 10 12 14 16

CAPILLARY PRESSURE [MPa]

ST

RE

SS

[M

Pa

]

y = -0,0762x + 0,4822

R2 = 0,4418

-1,5

-1

-0,5

0

0,5

1

0 4 8 12 16


ST

RE

SS

[M

Pa

]

y = -0,054x + 0,3088

R2 = 0,34

-1,2

-0,8

-0,4

0

0,4

0,8

2 6 10 14


ST

RE

SS

[M

Pa

]


ww

w

v

v

w

w

vg xM

RT

p

p

M

RTpp

r

lnln

)cos(2

00

Maximum radius

of saturated pores

(Laplace’ equation)

0

0,2

0,4

0,6

0,8

1

0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1

Wilgotność wzgl. [-]

Nasycenie

[-]

Relative humidity [-]

Sat

ura

tio

n [

-]

Clay brick [ P.K. Larsen]

alternatively: Raoult’s law

Kwx

Salt crystallizationEffect of salt on sorption isotherms

SEM photographs and EDS analysis Pore size distribution curves

0

0,02

0,04

0,06

0,08

0,1

0,12

0,14

0,001 0,01 0,1 1 10 100 1000

Średnica porów [mm]S

kum

ul. o

bję

t. p

oró

w [

ml/g]

Stężenie soli 25%

Stężenie soli 20%

Stężenie soli 15%

Stężenie soli 0 %

SPECIF

IC

PO

RE V

OLU

ME [

ml/g]

PORE SIZE [mm]

1,E-22

1,E-21

1,E-20

1,E-19

1,E-18

0 0,2 0,4 0,6 0,8 1

PREC. SALT REL. VOLUME [-]

PE

RM

EA

BIL

ITY

[m

2]

Salt crystallizationEffect of salt on permeability

sc RT

The Van’t Hoff equation:(for dilute solutions)

pp +

Semipermeable membrane

– osmotic pressurecs - salt molar concentration

mequilibriu at

pp ss mm *

Semipermeable membrane

"' ss cc

Osmotic flow of solvent

Salt crystallizationOsmotic pressure & osmotic flow

Capillary suction experiment:[Rucker, Krus, Holm - 2003]

Initial conditions:

Sw = 0,068;

T = 23 oC;

Capillary forces

Sandstone sample

= 0,26 [kg/kg].

Salt crystallizationEffect of material microstructure

(wide pores = no osmosis)

Water content Salt content

0

1

2

3

4

5

6

0 0,02 0,04 0,06 0,08 0,1

Distance [m]

Wa

ter

co

nte

nt [M

%]

8 h [exp]

22 h [exp]

32 h [exp]

46 h [exp]

8 h

22 h

32 h

46 h

0

0,4

0,8

1,2

1,6

2

2,4

0 0,02 0,04 0,06 0,08 0,1

Distance [m]

Sa

lt c

on

ten

t [M

%]

8 h [exp]

22 h [exp]

32 h [exp]

46 h [exp]

8 h

22 h

32 h

46 h


(wide pores = no osmosis)

material with very fine pores (e.g. gel pores) = semipermeable membrane

(lower permeability for the solvated ion groups than for water due to the „double layer” effect)

0

0

Distance [m]

Wa

ter

co

nte

nt

[M %

]

0

0

Distance [m]

Salt

co

nte

nt

[M %

]

Osmotic water flow Salt „flow” due to osmosis

Capillary water flow

Dispersive & advectivesalt flow

-membrane)


(narrow pores = osmosis)

Capillary suction experiment:[Cerny, Pavlik, Rovniakova - 2004]

umax= 0,007 [kg/kg]max 0,003 [kg/kg]

Cement mortar sample

(CEM I 42.5 R Lafarge)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.001 0.01 0.1 1 10 100 1000


LO

G. R

ÓŻ

N. O

BJ

.

PO

RÓ

W [

ml/g

]

PORE SIZE [mm]DIF

F. P

OR

E V

OL

UM

E

[m

l/g

]

water flow

salt flow



The results with and without osmosis

Water content Salt content

Reflection coefficients =0.4 (osmosis) and =0.0 (no osmosis.

0

1

2

3

4

5

6

7

8

0 0,02 0,04 0,06 0,08 0,1 0,12 0,14

Distance [m]

Wa

ter

co

nte

nt

[M %

]

no osmosis

with osmosis

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0 0,02 0,04 0,06 0,08 0,1 0,12 0,14

Distance [m]

Salt

co

nte

nt

[M %

]

no osmosis

with osmosis




10 cm

Initial conditions:

Sw = 0,108;

T = 10 oC;

= 0,08 [kg/kg].

e= 0,023 m/s

he= 23 W/(m2K)

Te= TMY (Warsaw)

RHe= TMY (Warsaw)

i= 0,008 m/s

hi= 8 W/(m2K)

Ti= 20oC

RHi= 50%

Considered cases:

no salt effects (pure water);

effect of prec. salt on permeability (Sp);

effect of prec. salt on permeability and sorption isotherms (Sp + Sw)

2 cases of the salt (NaCl) binding isotherms of the Freundlich type: Sp= A4

4 and Sp= A8 8

0

0,05

0,1

0,15

0,2

0,25

0,3

0 0,05 0,1 0,15 0,2

[kg/kg]

Sp [-]

Salt crystallizationEffect of salt presence on wall drying

7

7,5

8

8,5

9

9,5

10

10,5

11

0 200 400 600 800 1000

TIME [days]

TO

TA

L M

AS

S O

F W

AT

ER

[kg

/m2]

Pure w ater

Solution Sp(w 4)

Solution Sw +Sp(w 4)

Solution Sp(w 8)

Solution Sw +Sp(w 8)


0

5

10

15

20

25

30

35

0 200 400 600 800 1000

TIME [days]

PP

RE

CIP

ITA

TE

D S

AL

T [

kg

/m3]

Inner surface

Outer surface


Rate type model

0,|'|

,)'(

maxmax

maxmax

p

p

w

p

wp

SAKS

AKS

dt

dS

-Primary crystallization A’ 1- Further crystallization A’ = 1

(salt present in the pores)whereA’ – the supersaturation parameter;max – maximum salt concentr. at temp. T;p – process order ;a - equilibrium activity of a salt crystal;cl - mean surface free energy of the crystal-

liquid interface;m/m0 - relative molality

dV

dA

a

a

V

RTp cl

m

ln

Crystalization pressure

Salt crystallizationKinetics & crystallization pressure


Initial conditions:

RH = 0,99;

T = 20 oC;

w = 0,15 [kg/kg].

c= 0,008 m/s

hc= 8 W/(m2K)

T= 20oC

RH= 60% for concrete wall

RH= 85% for brick wall

Considered cases:

brick wall

concrete wall

½ of the wall = symmetry


Moisture content

Brick wall vs. Concrete wall


> 78 / 42

Salt supersaturation degree



Salt content (degree of saturation with salt)



Salt crystallization pressure)



4 cosd

P

Washburn equation:

Material deterioration

Mercury Intrusion Porosimetry tests

First intrusion Extrusion Second intrusion


Two-cycle MIP tests

> 83

Cement mortar composition

Symbol CM0 CM0.1 CM0.2

CEM I 32.5 [g] 450 450 450

Sand [g] 1350 1350 1350

Water [g] 203 203 203

AEA [g] 0 0,45 0,9

Contribution of ink-bottle type pores

2.int

0

0 1.int

0

1por

ink bottle

por

V rC r r

V r


Two-cycle MIP tests

Samples initially saturated with 25% Na2SO4 water solution

Crystallization pressure

ln cl

m

RT a dAp

V a dV

x10

Temperature cycles


Sodium Sulphate crystallization

Microstructure change due to salt crystallization of CM0



Microstructure change due to salt crystallization of CM0.2



Experimental setup for capillary suction test



cap

mC t

A

Δm - mass change of sample sample

A - area of the cross-section of the sample

Ccap - capillary suction coefficient

t - time

Capillary suction coefficient

cap

mC t

A



The coefficient of capillary

suction 𝐶𝑐𝑎𝑝

CM0

AEA=0.0%

[kg/(h0.5m2)]

CM0.1

AEA=0.1%

[kg/(h0.5m2)]

CM0.2

AEA=0.2%

[kg/(h0.5m2)]

Before crystallization test 0.484 0.463 0.424

After 10 crystallization cycles 0.570 0.514 0.465

Increase 18% 10% 9%

Pore microstructure



Material parameter

CM0

AEA=0.0%

CM0.1

AEA=0.1%

CM0.2

AEA=0.2%

Before AfterBefor

eAfter Before After

Total pore area [m2/g] 8.98 8.93 7.43 6.99 7.03 8.59

Bulk density [g/ml] 2.20 2.10 2.22 2.25 2.21 2.18

Apparent density [g/ml] 2.53 2.43 2.61 2.61 2.68 2.63

Porosity [%] 13.10 13.80 14.74 13.99 17.52 17.35

Freezing of water in porous materialsEquilibrium during freezing/thawing

/2 w gweqw w eq

fr

S T Sr T

/

*

2 w iceeqfr

fr m

r TT T

- equilibrium water saturation𝑆𝑤𝑒𝑞

𝑟𝑓𝑟𝑒𝑞

- pore radius where water is in equilibrium with ice

𝛾 𝑤 𝑖𝑐𝑒 - surface tension at water-ice interface

𝛴𝑓𝑟 - entropy of water freezing

Freezing of water in porous materialsEquilibrium during freezing/thawing

/2 w gweqice ice eq

fr

S T Sr T

- equilibrium ice saturation𝑆𝑤

𝑒𝑞

𝑟𝑓𝑟𝑒𝑞

- pore radius where water is in equilibrium with ice at temp. T

𝛾 𝑤 𝑖𝑐𝑒 - surface tension at water-ice interface

Experimental data

from DSC calorimeter

Freezing of water in porous materialsKinetics of freezing/thawing

𝐴𝑓𝑟 - chem. affinity for water freezing

1fr fr

fr

ART

,c cfr fr eqw

fr

fr

p pv

RT

,

,

ice wc cfr

w g

p p

𝜏𝑓𝑟

*,

cfr eq m mp T T

- characteristic time of water freezing

𝛴𝑓𝑟 - entropy of water freezing

Freezing of water in porous materialsEquilibrium crystallization pressure

- curvature of pore interior

/ //

/

2 21 1ice w ice wcryst c

ice w pore

pore pore vap w

p pr r

, 1 /

2 / 2 /

mice w B

w

pore E

rS

r r

𝜅𝑖𝑐𝑒,𝑤𝑚 𝑟𝐸 - pore entrance radius

Freezing of water in porous materialsAverage pore crystallization pressure

- water saturation, sorption isotherm of a material cwS p

1/

1/

1c

w

ice w wcrystcryst c cw ice cS p

vap w

SS S p p dp

p

Freezing of water in porous materialsEffect of the pore structure on the crystallization pressure

0,0E+00

1,0E-01

2,0E-01

3,0E-01

4,0E-01

5,0E-01

6,0E-01

7,0E-01

8,0E-01

9,0E-01

1,0E+00

1,0E+03 1,0E+04 1,0E+05 1,0E+06 1,0E+07 1,0E+08

SATU

RA

TIO

N [

-]

CAPILLARY PRESSURE [Pa]

Cement paste - EXP

Acon=2.0E+6, Bcon= 3.0



0,0E+00

2,0E+05

4,0E+05

6,0E+05

8,0E+05

1,0E+06

1,2E+06

1,4E+06

1,6E+06

1,8E+06

0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1

AV

ER. C

RY

STA

L. P

RES

SUR

E [P

a]

WATER SATURATION DEGREE [-]

Acon=2.0E+6, Bcon= 3.0, λ= 0.5

Acon=5.0E+6, Bcon= 2.0, λ= 0.5

Acon=5.0E+5, Bcon= 5.0, λ= 0.5

Sorption isotherm

Sw(pc)

Crystallization pressure

<pcryst>(Sw)

Freezing of water in porous materialsDeterioration of pore structure

d – damage parameter (= % decrease of compresive strength)

Experimental data

from MIP porosimeter

Freezing of water in porous materialsCrystallization pressure in deteriorated material

d – damage parameter (= % decrease of compresive strength)

Calculated with using

pore size distribution

from MIP porosimeter

d=0 – undamaged mat.

d=0.55 – after 25 cycles

d=0.72 – after 50 cycles

Freezing of water in porous materialsModel validation

Experimental data

from DSC calorimeter

Freezing of water in porous materialsModel application – concrete wall cyclic freezing /thawing

Temperature & Ice content vs. Time

during cyclic freezing / thawing

Freezing of water in porous materialsModel application – concrete wall cyclic freezing /thawing

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

0 50 100 150 200

DA

MA

GE

CO

EF

ICIE

NT

[-]

TIME [hours]

THICKNESS 0.0;p_cryst(T,d)

THICKNESS 0.07;p_cryst(T,d)

Crystallization pressure & Frsot damage vs. Time

during cyclic freezing / thawing

Casting

Water storage (28 days)

Drying until constant mass

Freeze/thaw cycles

Drying until constant mass

MIP

MIP

The samples of series F-01,F-02,F-05 and F-06 after 100 freeze-thawing cycles


Cyclic freezing / thawing tests

Material parameter

F-01 (w/c=0.5) F-05 (AEA=0.1%)

0c. 25c. 50c. 0c. 25c. 50c. 100c.

Total pore area [m2/g] 5.94 8.75 8.44 5.93 7.91 6.93 8.04

Bulk density [g/ml] 2.03 2.04 1.88 2.10 2.04 2.05 1.87

Apparent density [g/ml] 2.51 2.57 2.49 2.53 2.58 2.52 2.52

Porosity [%] 19.04 20.70 24.51 16.93 21.02 18.90 25.95

Material parameter

F-02 (AEA=0.0%) F-06 (AEA=0.2%)

0c. 25c. 50c. 0c. 25c. 50c. 100c.

Total pore area [m2/g] 5.67 6.01 7.21 5.78 7.87 8.26 8.02

Bulk density [g/ml] 2.10 2.20 2.04 1.81 1.79 1.84 1.80

Apparent density [g/ml] 2.51 2.56 2.52 2.60 2.57 2.51 2.56

Porosity [%] 16.44 14.11 18.93 27.49 30.38 26.68 29.36



> 104

w/c=0.5

AEA=0.0%

w/c=0.4

AEA=0.0%

w/c=0.4

AEA=0.1%

w/c=0.4

AEA=0.2%



> 105

w/c=0.5

AEA=0.0%

w/c=0.4

AEA=0.0%

w/c=0.4

AEA=0.1%

w/c=0.4

AEA=0.2%



Materialparameter

UnitF-01 (w/c=0.5) F-05 (AEA=0.1%)

0c. 25c. 50c. 0c. 25c. 50c. 100c.

𝐶𝑐𝑎𝑝 [kg/(h0.5m2)] 1.983 2.723 8.254 1.01 1.176 1.879 4.847

Materialparameter

UnitF-02 (AEA=0.0%) F-06(AEA=0.2%)

0c. 25c. 50c. 0c. 25c. 50c. 100c.

𝐶𝑐𝑎𝑝 [kg/(h0.5m2)] 1.119 1.543 1.699 0.55 0.730 0.747 0.767



Capillary suction coefficient

cap

mC t

A

Portlandite dissolution (calcium hydroxide)

OHCaOHCa 2)( 2

2

Ettringite dissolution

dissolution of different phases of CSH gel

OHOHSOOHAlCaOHSOOAlCa 2

2

44

2

234626 2643)(2632)(

OHnSiOHnCaOnHSiOnCaO 243

2

22 12

diffusion

water

Calcium leaching in cement pasteChemical reactions leading to calcium leaching process

Calcium conc. in the pore solution [mol/m3]

Ca

lciu

m c

on

cte

nt

in t

he

so

lid

sk

ele

ton

[k

mo

l/m

3]

Calcium leaching

> 109 / 42

RTs

- characteristic time

R – universal constant of gas,

– process equilibrium const.,

- parameter dependent on

micro-diffusion of, Ca2+

Calcium leaching in cement pasteKinetics of calcium leaching process

s

s

sdsccRTdt

ds

0

0/ln1

[Gawin, Pesavento, Schrefler – J. Solids Struct. 2008]

Specimen (bar, 16 cm) – uniform temperature

Diffusive flow of ions

cini= cequil [mol/m3]Temperature fixed on the surface:Tsup =25°C=const

ORTsup=60°C= const

- Initial porosity = 12.2%- Material properties according to [Kuhl, Bangert, Meschke, 2004]

- Characteristic time of the process: ts= 2 hours

Convective ions exchange with the environment:

c = cequil 1 [mol/m3] in Tleach =1000 days;dc=10-5 kg/m2s, tend =10000 daysTemperature fixed on the surface:T sup=25°C = const OR Tsup= 60°C= const

Calcium leaching in cement pasteEffect of temperature

0

2

4

6

8

10

12

14

16

0 2 4 6 8 10 12 14 16 18 20 22

Ca ions concentr. [mol/m3]

So

lid

Ca c

on

cen

tr.

[km

ol/

m3]

0.00E+00

5.00E-07

1.00E-06

1.50E-06

2.00E-06

2.50E-06

3.00E-06

So

urc

e [

mo

l/m

3s

]

SCa-Ca,T=25°C

SCa-Ca,T=60°C

source,T= 25°C

source,T= 60 C

Equilibrium curves at different temperatures


[Gawin, Pesavento, Schrefler – J. Solids Struct. 2008]

9

10

11

12

13

14

15

16

17

18

19

20

21

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08

DISTANCE [m]

Ca

IO

NS

CO

NC

EN

TR

AT

ION

[m

ol/

m3]

t= 2 t= 2 [10 3̂ days]

t= 6 t= 6

t= 10 t= 10

t= 14 t= 14

t= 20 t= 20

Liquid calcium concentr.

Red: T=60°CBlue:T=25°C

7

8

9

10

11

12

13

14

15

0 0.01 0.02 0.03 0.04 0.05 0.06

DISTANCE [m]

Ca

CO

NT

EN

T I

N S

KE

LE

TO

N

[km

ol/

m3]

t= 2 [10 3̂ days] t= 2

t= 6 t= 6

t= 10 t= 10

t= 14 t= 14

t= 20 t= 20

Solid calcium content


9

10

11

12

13

14

15

16

17

18

19

20

21

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08

DISTANCE [m]

Ca

IO

NS

CO

NC

EN

TR

AT

ION

[m

ol/

m3]

t= 2 t= 2 [10 3̂ days]

t= 6 t= 6

t= 10 t= 10

t= 14 t= 14

t= 20 t= 20

Liquid calcium concentr.

Red: T=60°CBlue:T=25°C

7

8

9

10

11

12

13

14

15

0 0.01 0.02 0.03 0.04 0.05 0.06

DISTANCE [m]

Ca

CO

NT

EN

T I

N S

KE

LE

TO

N

[km

ol/

m3]

t= 2 [10 3̂ days] t= 2

t= 6 t= 6

t= 10 t= 10

t= 14 t= 14

t= 20 t= 20

Solid calcium content


R2 = 0.9952

R2 = 0.9993

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

12500 17500 22500 27500 32500 37500 42500 47500

TIME0.5

[s0.5

]

FR

ON

T P

OS

ITIO

N

[m]

T= 60°C, linear, alfa=10-5

T= 25°C, linear, alfa=10-5

Linear (T= 60°C, linear, alfa=10-5)

Linear (T= 25°C, linear, alfa=10-5)

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