woody ash in cement-based materials:a case study anali… · conclusion sadrŽaj 1) introduction 2)...

WOODY ASH IN CEMENT-BASED MATERIALS: A CASE STUDY

DRVNI PEPEO U CEMENTNIM MATERIJALIMA:

DETALJNA ANALIZA JEDNOG IZVORA PEPELA

NEVEN UKRAINCZYK

Institute of Construction and Building Materials, TU Darmstadt

1.RADIONICA „Transformacija pepela iz drvene biomase u građevne kompozite s dodanomvrijednošću“,

Hrvatska gospodarska komora, 20. listopada 2017.

1

Introduction

SADRŽAJ1) Introduction2) Experimental3) Results

� Freshconcrete

� Mechanicalproperties

� Durability

Increased use of biomass as renewable source of energy

• releases less CO2 by burning than it absorbs while growing

•15.5 million tons of BA in the EU by 2020. (will double)

2

� Durability4) Conclusion • Reuse of BA in Concrete

Variety of Bioashes:

• type of biomass feed stock,

• geographical location (collection and handling process)

• combustion technology:

e.g. fixed bed (grate), pulverized fuel or fluidized bed boilers

Experimental: materials


� WAcharacter.

� Hydration� Mechanical

properties

Woody Ash (Lika Eko-Energo d.o.o., Udbina, Croatia )

• 1MWe co-generation plant

• a fixed bad (moving grate) furnace (1050oC)

• Fueled by forest residues and waste wood from

timber industry (bark, …): beech and fir

3

properties4) Conclusion

timber industry (bark, …): beech and fir

• Cyclone fly ash

Cem II 42.5N (Nexe)

Standard sand 0-2mm

Experimental


� WAcharacter.


properties

WA characterisation:

- chemical composition (XRF, ...), physical (PSD), mineralogical (XRD), morphological (SEM)

WA and cement Hydration:

- Pastes:

- XRD, TG, soundness (Le Chatelier), reaction calorimetry

4


- XRD, TG, soundness (Le Chatelier), reaction calorimetry

- Mortars:

- packing density, workability, mechanical properties

Experimental


� WAcharacter.


properties

Experimental plan: 'pastes'

Sample

name

cement

replacement

with WA, %

water:binder

mass ratio

Workability, flow

table, mm

Cem II 0

0.5!

0.300#

(150 ± 5mm)#

WA10 10 0.308#

WA15 15 0.316#

WA20 20 0.324#

5


0.5! (150 ± 5mm)#WA20 20 0.324#

WA30 30 0.339#

WA 100 0.310#*

! calorimetric, XRD and TG tests; # volume stability (soundness)

and water requirement tests for fixed workability; * flow table test not applicable

Experimental


� WAcharacter.


properties

Experimental plan: Mortars

Sample

name

Stand.

Sand, g

Cement,

g

WA,

g

WA/binder,

%

w/b Sand

replacement,

Cem.

repl., %

Workability,

mm

6


name Sand, g g g % replacement,

%

repl., % mm

M 1350 450 0 0 0.50 0 0 160

M10 1317 438 45 10 0.50 2.5 2.7 155 (130)

M15 1301 432 67.5 15 0.51 3.7 4.1 150 (100)

M20 1284 426 90 20 0.52 4.9 6.4 150 (100)

Results: WA characterisation chemical composition (mas. %)


� WAcharacter.


properties

SiO2 CaO K2O P2O5 Al2O3 MgO Fe2O3 SO3 Na2O TiO2

26.7 41.3 7.86 1.46 4.72 7.5 2.04 0.68 1.95 0.34

Cr2O3 ZnO MnO BaO SrO CuO SnO2 Rb2O ZrO2 Y2O3

0.037 0.045 0.63 0.127 0.073 0.032 0.053 0.056 0.100 0.010

XRF

7


Cl- Total (Volhard) 0.054

Cl- water soluble 0.037

L.O.I 4.92

C (EN15104) 1.87

H (EN15104) 0.52

N (EN15104) 0.19

Results: WA characterisation mineralogical (XRD)


� WAcharacter.


properties 600

800

1000

Rela

tive inte

nzity

WA

CaO

β-C2S

MgO

CaCO3

SiO2

C AF

Free CaO

(qxrd)

4.5%

8


10 20 30 40 50 60

0

200

400

600

Rela

tive inte

nzity

C4AF

C2AS

2Θ (CuKα1,2

)

(qxrd)

Free MgO

(qxrd)

2.5%

Results: WA characterisationmorphological (SEM)


� WAcharacter.


properties

Element Norm.

wt.%

Ca 59.81

O 34.68

C 2.54

Mg 1.6

9


ElementNorm.

wt.%

O 45.1

Si 36.5

Na 8.8

Ca 5.8

Mg 2.2

K 1.8

Mg 1.6

K 1.6

Si 0.5

Results: WA characterisationphysical (PSD): 27 mas. % < 80 µm


� WAcharacter.


properties 8

10

12

14

16 Cement:

d50

= 24.5 µm

dmode

= 33.0 µm

d3.2

= 15.8 µm

wood ash:

d50

= 146.3 µm

dmode

= 238.9 µm

d3.2

= 36.4 µm

Dif

eren

tial

volu

me

frac

tion, dQ

3(d

), %

10


0.1 1 10 100 1000

0

2

4

6

8

Dif

eren

tial

volu

me

frac

tion, d

d, µm

Results: WA characterisationsoundness


� WAcharacter.


properties

Vol. stability (soundness):CaO/MgO topochemical reaction

100

, m

m

normal WA

pre-treatment:

grinded: <80µm

weted and dried

standard limit

d

11


0 10 20 30 100

0.1

1

10

Le C

hatile

r expansio

n, d

2-d

1, m

m

cement replacement = WA/(WA + cem), %

f(grinding, pre-wetting/carbonation)

Results: WA characterisationcalorimetry


� WAcharacter.


properties0,2

0,3

0,4

0 1 2 3 40 .0

0 .2

0 .4

0 .6

0 .8

P

P 1 0

P 2 0

P 3 0

F A∆T

, K

Cem II

WA10

WA20

WA30

WA

∆T

, K

100

120

140

160

180

200

J/g

bin

der

12


0 10 20 30 400,0

0,1

0 1 2 3 4

H y d r a tio n t im e , h

Hydration time, h

∆

0 10 20 30 40

0

20

40

60

80 Cem II

WA10

WA20

WA30

WA

Hydration time, h

Q, J/g

bin

der

Results: WA characterisationportlandite by TG


� WAcharacter.


properties12

14

16

18

20

, %

(g /

10

0g

pow

de

r)

Ca(OH)2: mas.% per powder

13


0 5 10 15 20 25 300

2

4

6

8

10

Ca(O

H) 2

, %

(g /

10

0g

pow

de

r)

Hydration time, days

Cem II

WA10

WA20

WA30

WA



� WAcharacter.


properties

Ca(OH)2: mas.% per binder (cem +27% of WA)

14

16

18

20

, %

(g

/10

0g

bin

de

r)

Cem II

14

16

18

20

, %

(g

/g b

inde

r)

Cem I

cem I + WAcem II + WA

14


0 5 10 15 20 25 300

2

4

6

8

10

12

Ca

(OH

) 2,

% (

g/1

00

g b

ind

er)


Cem II

WA10

WA20

WA30

WA

0 5 10 15 20 25 30

0

2

4

6

8

10

12

Ca

(OH

) 2, %

(g

/g b

inde

r)


Cem I

WA10

WA15

WA20

WA



� WAcharacter.


properties

Ca(OH)2: Effect of grinding

10

12

14

16

, %

(g

/g b

inde

r)

15


0 5 10 15 20 25 30

0

2

4

6

8

10

Ca

(OH

) 2, %

(g

/g b

inde

r)

H ydra tion tim e, h

W A as rec ieved

P

P10

W A

G rinded W A<80µm

P10<80µm

W A<80µm

Results: WA characterisationXRD


� WAcharacter.


properties

Re

lative in

tesity E

trin

git

Etr

ingit

C a (O H )2

CaC

O3+

CS

H

AF

m

SiO

2

C3S

/C2S

C a (O H )2

P C 3 0

P C 2 0

H y d ra t io n t im e = 1 D a y

16


1 0 2 0 3 0 4 0 5 0

Re

lative in

tesity

2 Θ (C u K α1 , 2

)

P C 2 0

P C 1 d

W A 1 d

P C 1 0



� WAcharacter.


properties 4000

6000

8000

Ettringite

Re

lative

in

ten

zity

Ca(O

H) 2

Ca(O

H) 2

+ C

3S

/C2S

Ettringite

Ca(OH)2

CaC

O3+

CS

H

AF

m S/C

2S

AS

H8

17


5 10 15 20 25 30 35 40 45 50 55

0

2000

4000

Ettringite

P30 28D

P20 28D

Re

lative

in

ten

zity

Ca(O

H)

2Θ (CuKα1,2

)

Ettringite

CaC

O

AF

m

SiO

2

C3S

/C

P 28D

W A 28D

P10 28D

C2A

SH



� WAcharacter.


properties

XRD: grinded WA<80µm, t =7, 200 days

1500

2000R

ela

tive

in

ten

zity

W A 200d <80µm

W A 7d <80µm

W A 7d orig ina lC2A

SH

8 / C

SH

?

Ca

(OH

) 2

C aC O3+C S H

A Fm

Ca

(OH

) 2

S iO

18


5 10 15 20 25 30 35 40 45 50 55 60

0

500

1000

P 10 <80µm , 200d

2Θ , oC uK α

Re

lative

in

ten

zity

W A 7d orig ina l

Ca

(OH

)

S iO2

Etr

ing

it

Results: WA characterisationMechanical properties


� WAcharacter.


properties40

50

60

Com

pre

ssiv

e s

tre

ng

th, M

Pa

cem II + WA

19


0 20 40 60 80 100 120 140

0

10

20

30


Com

pre

ssiv

e s

tre

ng

th, M

Pa

M

M10

M15

M20

Results: WA characterisationParticle packing model


� WAcharacter.


properties

Particle packing density:– in house Matlab modelacc. de Larrard (1999) and Fennis (2011, 2013)

0.58

0.60

0.62

Packin

g d

ensity, vol. fra

ction o

f part

icle

s Model

Measured

20


0 20 40 60 80 100

0.48

0.50

0.52

0.54

0.56

0.58

Packin

g d

ensity, vol. fra

ction o

f part

icle

s

Cem. replacement, WA/(cem + WA), vol. %,

Conclusion


� WAcharacter.


properties

•EN 450-1 (year 2012):

•coarse particle size: 27% < 80um

•Low in pozzolan oxides

•excessive in K+Na and CaO/MgO

•> 15% WA -> expansions due to a delayed hydration of free CaO/MgO

•WA retards hydration

•initially more Ca(OH)2 is produced, but later increased pozzolanic reaction

21


•initially more Ca(OH)2 is produced, but later increased pozzolanic reaction

•Hydration of ash/blends shows development of AFm and CSH / C2ASH8

•strength and workability reduces

•15% dosage of ash (~4% cem +sand replacement) - acceptable workability and mechanical properties

•The 15% dosage corresponds also to the optimal particle packing (acc. to de Larrard-Fennis model)

N. Ukrainczyk et al., Reuse of Woody Biomass Ash Waste in Cementitious Materials, Chem. Biochem. Eng. Q., 30 (2) 137–148 (2016)

HVALA NA POZORNOSTI!

22

Mail: [email protected]

www.grad.hr/tarec

Projekt „Transformacija pepela iz drvene biomase u građevne kompozite s dodanom vrijednošću - TAREC2” (IP-06-2016) je financiran od strane Hrvatske zaklade za znanost.

woody ash in cement-based materials:a case study anali… · conclusion sadrŽaj 1) introduction 2)...

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