Physical and chemical characteristics of natural limestone fillers: mix properties and packing density

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Physical and chemical characteristics of

natural limestone fillers: mix properties

and packing density

Luc COURARD, Eric PIRARD and Huan HE

Université de Liège, Belgium

TC-SCM WORKSHOP, CYPRUS, 29-30 MARCH 2012

Introduction

Materials

Physico-chemical characteristics

Packing properties

Conclusions

Outline

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Specific requirements for fresh SCC : high workability and good

resistance to segregation.

Amount of coarse aggregate reduced and replaced by fine

material.

In Belgium, local available materials = limestone fillers.

Introduction

Production process of limestone fillers

Aggregate and lime production industry (quarrying operations)

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Production process of limestone fillers

Ornamental stones industry (sawing operations)

Materials

Limestone filler

reference Production process Industrial sector

F1

Dry process Crushing Lime

F2

F3 Drying / crushing Aggregates

F4 Wet process Sawing Ornamental stones F5 Washing Aggregates F6

Ordinary Portland Cement (PC) CEM I 42,5 R HES

Six limestone fillers collected in Belgium (F1 to F6)

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Physical characterization (Laser diffraction)

0 10 20 30 40 50 60 70 80 90 100 0,1 1 10 100 1000 Particle diameter [µm] C u m u la ti v e [ % ] F1 F2 F3 F4 F5 F6 PC F1 F2 F3 F4 F5 F6 PC d50(µm) 13.6 9.4 8.8 7.1 9.0 14.8 16.6 SS,BET[m2/g] 1.3 1.2 5.5 4.0 5.7 3.7 –

Mineralogical and chemical characterization

F1 F2 F3 F4 F5 F6

Calcite CaCO3[%] 99.5 99.5 82.0 94.5 86.0 75.0

Quartz SiO2[%] 0.0 0.0 15.5 1.8 6.5 2.0

Dolomite Ca(Mg,Fe)(CO₃)₂[%] 0.5 0.5 2.5 3.7 7.5 23.0

Methylene Blue Adsorption MBA [g/kg filler] 0.7 0.7 4.0 1.3 5.0 3.3

Fillers coming from lime production (F1, F2) and ornamental stones

sawing (F4) : high CaCO

₃

content.

Fillers produced in limestone quarries (F3, F6) : large amounts of

impurities.

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Bêta-P: spread measurement for different W/P

y = 0,049x + 1,0734 R2_{= 0,9551} 0,00 0,20 0,40 0,60 0,80 1,00 1,20 1,40 0 1 2 3 4 5 ττττP E /P 1 ) 2 ( 2 0 2 1+ − = D D Dm m p

τ

Avec Dm [140 - 250 mm]

2

2 1 2

D

_m

=

+

2

2 1 1

D

m

+

=

à t + 5min à t D2 D1 D0= 100 mm 70 mm 60 mm

Smooth Paste test (Legrand, 1971)

Modification of the paste appearance

VE

… correlated with threshold value of dilantancy (rheological behaviour)

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R2_{= 0,8412} R2 = 0,8174 0 1 2 3 4 5 6 160 170 180 190 200 210 220 230 Flow [mm] M B A [ g /k g f il le r] 0 0,25 0,5 0,75 1 1,25 1,5 ββββ p MBA value Bp value

Relationship between mortar flowability and MBA or b

_P

of limestone fillers

Physico-chemical characteristics

0 1 2 3 4 5 6 F1 F2 F3 F4 F5 F6 SS ,B E T [ m ²/ g ] 0 1 2 3 4 5 6 M B A [ g /k g f il le r ] SS,BET MBA

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Materials

CEM I 42.5 CEM I 52.5

Limestone Filler

Standard sand EN196-1:2005 (0~2 mm)

Size and shape characterization

OCCHIO 500Nano (0.5µm~2 mm)

Vacuum dispersion

Image analysis

Equipments

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Particle size

Traditional equivalent volume (area) diameter Maximum inscribed diameter

0 20 40 60 80 100 0.1 1 10 100 Size [µµµµm] P a s s in g f ra c ti o n [ % ] LF CEM I 52.5 CEM I 42.5 PSD: 0 0.2 0.4 0.6 0.8 1 D im e n s io n a l v a lu e

Circularity LF Circularity CEM I 52.5 Circularity CEM I 42.5 LF Elongation LF Elongation CEM I 52.5 Elongation CEM I 42.5

Particle shape

100 µm 100 µm 100 µm 100 µm LF CEM I 52.5 CEM I 42.5

1 b

Elongation

a

= −

2

4 A

Circularity

P

π

=

Particles >6 µm (>500 pixels/ particle):

Length (a) Width (b)

χFmax

Holzer et al., 2010 byµCT &FIB-NT

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χFmax 2 max 4 F A Roundness

πχ

=

Particle shape

Solidity =A/Ac χFmax Convex hull χFmax 0 0.2 0.4 0.6 0.8 1 5.00 15.00 25.00 35.00 45.00

Ave rage inne r diam ete r [µµµµm ]

D im e n s io n v a lu e

Solidity LF Solidity CEM I 52.5

Solidity CEM I 42.5 Roundness LF

Roundness CEM I 52.5 Roundness CEM I 42.5

A Ac

1

1 Bluntness

V

=

−

2 max

1 (1

)

N i i

r

V

N

r

=

∑

+

In which:

Bluntness describes the maturity of the particle in the abrasion process. Krumbein’s chart Calypter tools ri 0.2 0.4 0.6 0.8 1 D im e n s io n v a lu e [-] Bluntness LF Bluntness CEM I 52.5 Bluntness CEM I 42.5

Physico-chemical characteristics

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Dry packing (direct) methods, e.g.

BS 812:Part 2:1995

For aggregate

For fillers

Wet packing (indirect) methods:

Standard consistence test,

BS EN 196:part 3, 1995

the wet packing method

(Wong & Kwan, 2008)

Influences of inter-particle forces? Standard of compaction level?

Standard consistence test:

The wet packing method

(Wong & Kwan, 2008)

( ) b b b w w b V M M V V V u φ ρ ρ ρ = = = + Packing density:

The voids ratio (u): 1 1 b b V V u V

φ

− = = −

Packing properties

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The wet packing method

(Wong & Kwan, 2008)

The dry packing method

Concrete vibration table Compaction cylinder

Influences of inter-particle forces? Standard of compaction level?

Packing tests

The dry packing method

0.3 0.4 0.5 0.6 0.7 0.8 0 30 60 90 120 150 180 Vibration tim e [s] P a c k in g d e n s it y ( P D ) [-] Sand LF CEM I 52.5 CEM I 42.5 PSD? Shape? Inter-particle forces?

Packing properties

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The dry packing method

0 10 20 30 40 50 60 0 30 60 90 120 150 180 Vibration tim e [s] Im p ro v e d P D p e rc e n ta g e [ % ] Sand LF CEM I 52.5 CEM I 42.5 0 2 4 6 8 7.5 22.5 37.5 52.5 75 105 135 165

Vibration tim e (average in each range) [s]

In c re a s in g r a te o f P D [ X 1 0 3 s -1] Sand LF CEM I 52.5 CEM I 42.5

The wet packing method

0 0.3 0.6 0.9 1.2 1.5 0 0.2 0.4 0.6 0.8 1 1.2 uw [-] V o id r a ti o [-] LF CEM I 52.5 CEM I 42.5 Nominal 0.3 0.4 0.5 0.6 0.7 0.8 0 0.3 0.6 0.9 1.2 1.5 uw [-] P a c k in g d e n s it y ( P D ) [-] LF CEM I 52.5 CEM I 42.5 Nominal Influence of entrapped air

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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Limestone fillers (LF) CEM I 52.5 CEM I 42.5

Powder types P a c k in g d e n s ity ( -)

Wet packing Dry Packing

Discussion on the wet packing method

Limitations in the wet packing method manual effects on M-V evaluation

Cement hydration

Mixing efficiency (e.g. LF) Superplasticizer ( ) b b b w w b V M M V V V u φ= = _ρ = _ρ _ρ +

₍

₎

b w w b SP SP

V

M

V

V u

u

φ

ρ

=

+

0.5 0.6 0.7 0.8 g d e n s it y ( P D ) [-] 2 3 4 5 r p e rc e n ta g e [ % ] Real values Nominal values Error percentage

Packing properties

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Results on blended cement (total replacement and coarse replacement)

0.4 0.45 0.5 0.55 0.6 0 10 20 30 Volum e fraction of LF (%) P a c k in g d e n s it y ( P D ) (-) CEM I 42.5 +LF CEM I 52.5+LF

CEM I 42.5+LF coarse replacemen

Numerical simulations

PSD simulations

0 0.2 0.4 0.6 0.8 1 0.1 1 10 100 Sieve size (_µµµµm) P a s s in g f ra c ti o n ( -) CEM I 42.5 exp. CEM I 42.5 simul. CEM I 52.5 exp. CEM I 52.5 simul. LF exp. LF simul.

Packing properties

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CEM I 42.5 CEM I 52.5 LF CEM I 42.5 CEM I 52.5 LF 0.72 0.68 0.716 0.674 0.658 0.695 Periodical boundaries: Rigid boundaries:

Maximum packing density

0.4 0.5 0.6 0.7 0.8 0.9 Limestone fillers (LF) CEM I 52.5 CEM I 42.5 P o w d e r t y p e s Simulation periodical Simulation rigid Dry Packing Wet packing

Packing properties

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Surface to surface nearest neighboring distance (NND)

0 0.05 0.1 0.15 0.2 0.25 0 0.5 1 1.5 2 Surface-to-surface NND (µµµµm) P ro b a b il it y ( -) CEM I 42.5 CEM I 52.5 LF 0 0.2 0.4 0.6 0.8 1 0 10 20 30 40 50

Distance to surface of aggregate (µµµµm)

V v ( -) 0 0.2 0.4 0.6 0.8 1 S v (µµµµ m -1) Sv CEM I 42.5 Vv CEM I 42.5 Sv LF Vv LF Sv CEM I 52.5 Vv CEM I 52.5

Surface area density (

S

_V

) and volume density (

V

_V

) in ITZ

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0 0.3 0.6 0.9 1.2 1.5 1.8 0 10 20 30 40 50

Distance to surface of aggregate (µµµµm)

N o rm a li z e d λλλλ -3 (µµµµ m ) -3 CEM I 42.5 CEM I 52.5 LF

1

4

V V

V

S

λ

=

−

Meaning free spacing:

A parameter proportional to global bonding capacity :

λ

−3 Stroeven & Stroeven 2001

Hu, 2004

Permeability

0 0.5 1 1.5 2 0 10 20 30 40 50 κ κ κ κ (µµµµ m ) 2 CEM I 42.5 CEM I 52.5 LF 2

(1

)

32 16

V V

V

λ

κ

=

−

+

Carman 1939Hu, 2004

Packing properties

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The limestone fillers collected in Belgium differ from each other

through their physico-chemical characteristics (impurities such as

clay, quartz and dolomite).

The water requirement of limestone fillers is mainly influenced by

their clay content (indicated by high MBA and S

_S,BET

values).

Size and shape characteristics of LF and OPC can be identified by an

advanced image analysis system.

With a proper replacement of cement by LF, packing density of the

mixture can be improved. Filler effect is significant as also illustrated

by the numerical simulation.

Conclusions

Influence of clay in limestone fillers for self-compacting cement based composites. L. Courard, F. Michel and J. Piérard. Construction Building Materials 25 (2011) 1356– 1361.

Influence of physico-chemical characteristics of limestone fillers on fresh and hardened mortar performances. F. Michel, J. Piérard, L. Courard and V. Pollet. In: 5th International RILEM Symposium on Self-Compacting Concrete, Proceedings PRO 54 (Eds. G. De Schutter and V. Boel, Rilem Publications), Gent, Belgium (September 3-5, 2007), pp. 205-210.

Characterization of fine aggregate in concrete by different experimental approaches (2011) He, H., Courard, L., Pirard, E. and Michel F. ICS-13, the 13th International

Congress of Stereology, Oct. 19-23, 2011, Beijing, China.

Particle packing density and limestone fillers for more sustainable cement (2011) He, H., Courard, L. and Pirard, E., 13th_{International Conference on Non-conventional} Materials and Technologies (13 NOCMAT 2011), Sep. 22-24, 2011, Changsha, China.