Assessment of calcined clays as SCMsdocuments.epfl.ch/users/s/st/ston/www/4 Assessment...

Assessment of calcined clays as SCMs

Prof. Adrian Alujas DíazUniversidad Central de las Villas. Cuba

adrianad@uclv.edu.cuaalujas@gmail.com

Doctoral School, Laboratory of Construction Materials

EPFL, June 26 – July 01, 2015

Studies

• 2001: Bachelor in Chemistry, UCLV, Cuba• 2010: PhD, UCLV, Cuba “Pozzolanic reactivity of low grade

clays”• 2011-2012: Swiss Government Research Scholarship, EPFL

“Rapid pozzolanic reactivity test”• 2013-now: Associate Professor, Centro de Estudios de

Química Aplicada, UCLV, Cuba

Research

• 2005-2008: Ecomaterials for Low Cost Housing• 2009-2012: Production of activated clays for low cost

building materials in developing countries“• 2014-now: LC3 / R&D of cementitious materials with a high

level of clinker replacement, based on the use of calcined clays and limestone

Adrian Alujas DiazAssociate Professor, Centro de Estudios de Quimica Aplicada,

Universidad Central de Las Villas, Cuba

Founded in1952 ~7000 students ~1200 docents 12 faculties 37 careers The largest university

campus in Cuba…

Group of ModelingModeling of cement hydration

Fac. of Mathematics, Physics and Computation

Group of MaterialsCementitious materialsRecycled aggregatesRheologyWalls and Red Ceramic

Group of StructuresConcrete fissurationStructural solutions

Group of ArchitectureMonitoring of impacts Environmental studiesArchitectonic and urban design

CIDEM – Faculty of ConstructionGroup of Inorg. Chem.

Hydration of cementitiousmaterialsDevelopment of pozzolanic materials Characterization of materials

Group of Org. Chem.Development of plasticizers Inhibitors of corrosion

Faculty of Chemistry

Group of CooperativesAlternatives for cooperatives at the housing sector

Group of EconomyEconomic and environmental feasibility studies

Faculty of EconomyGroup of CommunicationDevelopment of strategies for social and scientific communication

Group of CommunitiesCapacitation in actions at the scale of rural community

Fac. of Social Sciences

COLLABORATIVE NETWORK WITHIN THE UNIVERSITY

SCIENCE AND INNOVATION

Science & Innovation with a direct orientation topractice, through concrete, grassroots orientedprojects…

OUTLINE

• Brief introduction to clay and clay minerals• Selection and sampling of clay deposits• Characterization of raw clays• Assessment of calcined clays as SCMs

WHY CLAYS?

F.5 What does the way forward look like? Two options among many:Business as usual or aggressive mitigation

World Development Report 2010

Source: Clarke and others, forthcoming.

Note: The top band shows the range of estimates across models (GTEM, IMAGE, MESSAGE, MiniCAM) for emissions under a business-as-usual scenario. The lower band shows a trajectory that could yield a concentration of 450 ppm of CO2e (with a 50 percent chance of limiting warming to less than 2°C). Greenhouse gas emissions include CO2, CH4, and N2O. Negative emissions (eventually required by the 2°C path) imply that the annual rate of emissions is lower than the rate of uptake and storage of carbon through natural processes (for example, plant growth) and engineered processes (for example, growing biofuels and when burning them, sequestering the CO2 underground). GTEM, IMAGE, MESSAGE, and MiniCAM are the integrated assessment models of the Australian Bureau of Agricultural and Resource Economics, the Netherlands Environmental Assessment Agency, International Institute of Applied Systems Analysis, and Pacific Northwest National Laboratory.

Sustainable Development

9

“is development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (Bruntlandt)

There is a need to reconcile environmental, social equity and economic demands

Social

Environment Economic

EquitableBearable

Viable

Sustainable

Material Per year A = % of a CO2e / yr B = % of b

Concrete 17.1 GT 50.2% 2.6 GT 8.5%

Steel* 0.74 GT 2.4% 2.3 GT 8.1%

Timber 2.2 GT 6.5% 5.1 GT** 17%**

Figures for 2005 assembled by Dr Phil Purnell, U. Leeds, UK

Increase in clinker substitution!!!

Cement Production vs. Availability SCMs

Gobal cement production (109/yr)

Clinker factor, global average (%)

Global SCM volume (109/yr)

2006 2.6 79 0.5

2050 (CSI) 4.4 73 1.2

OUTLINE

• Brief introduction to clay and clay minerals• Selection and sampling of clay deposits• Characterization of raw clays• Assessment of calcined clays as SCMs

CLAY AND CLAY MINERALS

Clay is a fine-grained natural rock or soil material(ISO 14688 Ø≤2 µm) that combines one or moreclay minerals with traces of other minerals (oftenpredominantly clay minerals, but also fine-grainedquartz, feldspars) and organic matter. Clays areplastic at appropriate water content and becomehard, brittle and non–plastic upon drying or firing

Clay minerals are hydrated phyllosilicates minerals,typically smaller than 2 μm, mostly displaying foil-like morphology, which impart plasticity to clay andwhich harden upon drying or firing

STRUCTURE OF 1:1 CLAY MINERALSTetrahedral sheet

+

Octahedral sheet

Dioctahedral (gibbsite-like Al(OH)3)

Trioctahedral (brucite-like Mg(OH)2)

T

O

T

O

T

O

1:1 layer type: kaolinite (dioctahedral): Al2Si2O5(OH)4

STRUCTURE OF 2:1 CLAY MINERALSTetrahedral sheet

+

Octahedral sheet

Dioctahedral (gibbsite-like Al(OH)3)

Trioctahedral (brucite-like Mg(OH)2)

T

O

T

T

O

T

T

O

T

2:1 layer type: muscovite (dioctahedral): KAl2(AlSi3)O10(OH)2

STRUCTURE OF 2:1 CLAY MINERALSTetrahedral sheet

+

Octahedral sheet

Dioctahedral (gibbsite-like Al(OH)3)

Trioctahedral (brucite-like Mg(OH)2)

2:1 layer type: chlorite (trioctahedral): Mg5Al(AlSi3)O10(OH)8

Phyllosilicates – layer stacking• Imperfect fit between sheets results in structural

distortions and adjustments

STRUCTURE OF CLAY MINERALS

STRUCTURE OF CLAY MINERALS

CLASSIFICATION OF CLAY MINERALS - STRUCTURE

Division: Layer type (1:1, 2:1,…)Group: Charge per formula unit (z)Subgroup: di- or trioctahedral

Montmorillonite

[(Mx,·nH2O)(Al2-y,Mgy)Si4O10(OH)2]

2:1, smectite (z=0.2-0.6), dioctahedral

OUTLINE

• Brief introduction to clay and clay minerals• Selection and sampling of clay deposits• Characterization of raw clays• Assessment of calcined clays as SCMs

ORIGIN OF CLAY DEPOSITS

More than 90% on the crust is composed of silicate minerals. Only 8% of the crust is composed of non-silicates

39%

12%12%

11%

5%

5%

5%

3%

ORIGIN AND CLASSIFICATION OF CLAY DEPOSITS

Clay minerals get formed by transformation/neoformationof pre-existing rock-forming aluminosilicates minerals

CaAl2Si2O8 + H2O + 2H+ → Al2Si2O5(OH)4 + Ca2+

Primary deposits:In situ alteration of

aluminosilicates

Secondary deposits:Eroded, transported and

deposited sediments

Type of clays formed depends on (T,P, %RH, pH) and chemistry of the primary minerals

Kaolinite and smectite are most common in lower latitudes. Illite and chlorite dominate at higher latitudes

ORIGIN OF CLAY DEPOSITS - WEATHERING

Type of clays formed depends on (T,P, %RH, pH) and chemistry of the primary minerals

ORIGIN OF CLAY DEPOSITS - WEATHERING

Type of clays formed depends on (T,P, %RH, pH) and chemistry of the primary minerals

ORIGIN OF CLAY DEPOSITS - HYDROTHERMAL

In situ alteration of aluminosilicates

Hydrothermal alteration offeldspathic rocks

Heat source (magmatic,…) +acid fluids + fracture system

SAMPLING OF CLAY DEPOSITS

Representative sampling both in terms of surface and in terms of depth

Field recognition

Colour (off-white to reddish-pinkishdepending on impurities)

Slightly sticky feeling to the tongue; plasticity

SAMPLING OF CLAY DEPOSITS

Characterization at the laboratory

Chemical and mineralogical composition, particle size

Always save some samples!!!

SAMPLING OF CLAY DEPOSITS

CLASSIFICATION OF CLAY DEPOSITS BY ITS INDUSTRIAL USE

Industrial kaolins: contain relatively high amounts of kaolinite. The worldproduction of processed kaolins is about 20 million tons/year.

Bentonites: High montmorillonite (smectite) content. The worldproduction of bentonites is around 13 million tons/year

Palygorskite-sepiolite clays: Specifically used because of their surfaceproperties. The world production is around 2 million tons/year.

Common clays: contain mixtures of different clay and associated minerals,and enjoy the largest usage worldwide. The amount of common claysused worldwide it´s likely to exceed many hundreds of millions tons/year

www.LC3.ch

31

CLAYS Widely available all over the world

Proven pozzolanic properties when calcined under specific conditions (1:1 > 2:1)

High grade clay deposits

Cement industry + (Paper industry,

ceramics…)

MKHigh grade kaolinitic clays

Poor availability for raw materials and high demand from other industries

limit its massive use as SCMs

Multicomponent claydeposits (common clays)

Low grade kaolinitic clays ?

Widely available, specially in tropical and subtropical regions (developing

countries)

Poorly studied as a source of SCMs!!!

COMMON CLAYS VS HIGH GRADE CLAYS

OUTLINE

• Brief introduction to clay and clay minerals• Selection and sampling of clay deposits• Characterization of raw clays• Assessment of calcined clays as SCMs

CHARACTERIZATION OF RAW CLAYS

Separation of the clay fraction (optional)

Pour enough sample into the centrifuge tubes to fill the roundedpart of the bottom of the centrifuge tubes.

Add a small amount (about 0.25 g) of dispersant to thecentrifuge tubes.

Add distilled water to the bottom edge of the labeling tape. Placea cap on the centrifuge tube and shake the tube to homogenizethe suspension.

Disperse the sample for 15-20 seconds with the ultrasonic probe.

Check the water temperature and find centrifugation times inminutes and seconds from the prepared table.

Place the tubes in the centrifuge. Be sure that the centrifuge isbalanced by having opposite tubes filled equally.

Remove tubes from the centrifuge and pour the supernatantliquid into the plastic beakers. If the silt and clay fractions are tobe completely separated, repeat the centrifugation procedureuntil the supernatant is reasonably clear (4-5 times).

CHARACTERIZATION OF RAW CLAYS - XRD

Quantitative analysis requires an extensive sample preparation an careful data analysis, because preferred orientation is inevitable and stacking layer defaults in the structure

are difficult to predict from model structures

CHEMICAL CHARACTERIZATION OF RAW CLAYS

SiO2 Al2O3 Fe2O3 CaO MgO SO3 K2O MnO Na2O Others LOIClay 57.74 18.71 7.07 1.85 1.80 0.02 0.65 0.12 2.68 0.76 8.57

Clay fraction 43.89 24.73 11.13 1.38 2.63 0.08 1.10 0.14 1.99 3.11 9.81

% SiO2 %Al2O3 % OHFeldspar <69,00 <19,00Clay 2:1 <67,00 <28,00 <5,00Clay 1:1 <46,55 <39,50 <13,95

Clays are alumina rich minerals…but are not the only

ones…or the richest ones!!!

Bauxite: an aluminium ore, which consists mostly of the minerals gibbsite Al(OH)3, boehmite γ-AlO(OH) and diaspore α-AlO(OH), mixed with the iron oxides goethite and haematite, and the clay mineral kaolinite

TG

A

Wei

ght

(%)

Temperature (°C) D

TG

dm

/dT

(m

gs-1

)

Dehydrationrelease of free water

Dehydroxylationrelease of chemically bounded water

Decomposition Decarbonation

Sample heated in an oven at an specific heat rate, up to a defined temperatureand under a defined atmosphere

Measured the change in mass of the sample during heating∆m is plotted against temperature and/or time

Derivative DTG = dm(T)/dt is then calculated

TGA - BASICS

Microbalance surronded by a furnace

TGA - EQUIPMENT

• Furnace atmosphere• Reactive vs. inert atmosphere

• Sample grain size and packing density• Small grain sizes (<1μm)

→ lower peak temperatures• Increase in packing density

→ leads to sharper peaks

• Heating rate dT/dt• Peaks become larger, loss in resulution• Shift to higher temperatures if dT/dt increases

• Sample mass• Higher sample amount increases peak temperatures,

high temperature gradient inside the sample

Peaks are function of equipment, condition, reaction

TGA – EXPERIMENTAL CONDITIONS

TGA – DTG MEASUREMENTS

Resolution of the complex TG curves can be improved by plotting the derivative curves

(DTG) or second derivative curves (DDTG). Derivatives are taken as a function of time, not

temperature.

300 400 500 600 700 800 900

80

82

84

86

88

90

TGA

W

eight

(%)

Temperature (°C)

%Calcite

%Portlandite

TGA - MEASUREMENTS

For reactions with high stoichiometric factors, the small mass-change and the eventual measurement errors may reduce considerably the accuracy of the

measurement and in this case all we can obtain is a semi-quantitative estimation (phyllosilicates stoichiometric factors 7-20)

THERMAL ACTIVATION OF CLAYS

~ 5 %

~ 5 %

~ 14 %

TGA OF CLAYS – ADSORBED WATER

The binding energy of water on the external surfacesof clay minerals about 1.5±1 kJ/mol.

The binding energy of water in the interlayer space is afunction of the charge of the silicate and octahedrallayer and the size and charge of the interlayer cation(ion-water electrostatic interaction)

Montmorillonite (Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O

Nontronite Na0.3Fe2((Si,Al)4O10)(OH)2 · nH2O

Saponite Ca0.25(Mg,Fe)3((Si,Al)4O10)(OH)2 · nH2O

K - Montmorillonite Na - Montmorillonite

Chakchouk, A., B. Samet, and T. Mnif, Study onthe potential use of Tunisian clays as pozzolanicmaterial. Applied Clay Science, 2006. 33(2): p.79-88.

Samples which are rich inkaolinite present the bestpozzolanic activity.

KAOLINITIC CLAYS vs COMMON CLAYS

Habert, G., et al., Clay content of argillites: Influence on cement based mortars. Applied Clay Science, 2009. 43(3-4): p. 322-330.

Total clay content 29 45 28 73

Pozzolanic activity seemsto be more dependenton the clay mineralcontent rather than onthe clay mineral type (?)

KAOLINITIC CLAYS vs COMMON CLAYS

4

6

8

10

12

14

10 16 22 28 34 40

% Δ

m (O

H-)

% Al2O3

Pontezuela (PZ) Cayo Guam (CG) Castaño (CT)Kaolinite (KW) Carranchola (CM)

X ≥ 40% Kaolinite

Increasing % of potentially reactive Al2O3

Incr

easi

ng st

ruct

ural

dis

orde

r by

dehy

drox

ylat

ion

28d Comp Strengthrelative to OPC (%)

113.65

98.52

104.90114.07

CG PZ CM KWAl2O3 24.32 25.09 24.73 36.40

Al2O3 / SiO2 0.61 0.61 0.56 0.76Δm (OH-) 8.08 8.32 8.08 12.12

ASSESSMENT OF COMMON CLAYS AS A SOURCE OF SCM

5 10 15 20 25 30 35 40OH-

80

75

70

65

60

55

50

45

SiO2

50

45

40

35

30

25

20

15

Al2O3

CG

LL

LS

PZ

BE

SJ

SV

TQ

ZM

ZH

100% K

40% K + Q

ASSESSMENT OF COMMON CLAYS AS A SOURCE OF SCM

OUTLINE

• Brief introduction to clay and clay minerals• Selection and sampling of clay deposits• Characterization of raw clays• Assessment of calcined clays as SCMs

POZZOLANIC REACTIVITY OF CALCINED CLAYS

AS2 + 6CH + 9H → C4AH13 + 2CSH AS2 + 5CH + 3H → C3AH6 + 2CSH AS2 + 3CH + 6H → C2ASH8 + CSH

Al2O3 + SiO2 + Fe2O3 ≥ 70%High specific

surface

Glasser, D. et al, 1982; Baronio, B. et al; 1997

High degree of structural disorder

Through-solution process, involving dissolution of reactants, transport of dissolved reactants and nucleation and growth of reaction products

THERMAL ACTIVATION OF CLAYS

Dehydroxylation:Loss of structural OH-

Fernandez, R. et al; 2011

Increase of structural disorder

Pozzolanic reactivity of calcined clays is associated (but not only) with structuraldisorder caused by loss of structural hydroxyls during thermal activation

27Al NMR

THERMAL ACTIVATION OF CLAYS

~ 5 %

~ 5 %

~ 14 %

Pozzolanic reactivity

+++

+

++

THERMAL ACTIVATION OF CLAYS

TOH: Fe-OH < Al-OH < Mg-OH

• Diffusion of hydroxyls controls the rate of transformation

• Diffusion is favorable along defects created by stacking faults

• T of dehydroxylation (and reactivity) depends on structural disorder

THERMAL ACTIVATION OF CLAYS

-1.0x10-4

-8.0x10-5

-6.0x10-5

-4.0x10-5

-2.0x10-5

0.0

1/s

Temperature (°C)

DTG

0.0

0.1

0.2

0.3

0.4

0.5

0.6

mW/mgDTA

recrystallisation(exothermal)kaolinite

dehydroxilation

Optimum calcinationtemperature depends onclay mineral content and

structural features

0 200 400 600 800 1000

-9.0x10-5

-6.0x10-5

-3.0x10-5

0.0

25°C500°C550°C600°C650°C700°C750°C800°C1000°C

1/s

Temperatura (°C)

THERMAL ACTIVATION OF CLAYS

TECHNOLOGICAL ALTERNATIVES FOR THERMAL ACTIVATION

Flash Calciner

Rotatory kiln calcination

Flash calcination

PortlanditeM+; OH- ; SO4

2-Pozzolanic Material

Hydration Products

Direct MethodsConsumption of Portlandite

TGA, XRD, Conductivity, Wet Chemistry

Indirect MethodsCompressive strength

Released heatQuantification of hydration

productsChanges in volumeChanges in porosity

Mechanical tests, Isothermal Calorimetry, Chemical

Shrinkage, MIP, NMR, SEM-BSE

ASSESSMENT OF POZZOLANIC REACTIVITY OF CALCINED CLAYS

FILLER EFFECT

Direct methods may be disturbed when high cation exchange capacity clays, not properly calcined, are present in the sample

Fernández R. et al, C. 2009

ASSESSMENT OF POZZOLANIC REACTIVITY OF CALCINED CLAYS

100%OPC 100%

OPC - X

X% Pozzolan

Mechanical tests correlate well with the performance on realconditions but offers few insights about the nature of thepozzolanic reactivity

Results dependent of the OPC phase composition, degree ofreaction and level of substitution (Filler effect)

Long testing times are required

ASSESSMENT OF POZZOLANIC REACTIVITY OF CALCINED CLAYS

0

10

20

30

40

50

60

70

0 20 40 60 80 100

Re

sist

en

cia

a la

Co

mp

resi

ón

(M

Pa)

Tiempo (días)

00-N4-3 66-N4-3 86-N4-3 96-N4-3 MK-N4-3 F-N4-3

POZZOLANIC REACTIVITY - PERFORMANCE

INFLUENCE OF CALCINED CLAYS ON OPC HYDRATION

0 5 10 15 20 25 300

100

200

300

400

500

OPC Filler Cu8 MK

J / g

of c

emen

t

time (days)

Pozzolanic ReactionFiller Effect

(Cyr, Lawrence et al., 2005)

Clinker hydration is enhanced due to the filler effect

INFLUENCE OF CALCINED CLAYS ON OPC HYDRATION

0 5 10 15 20 25 30 35 400

2

4

6

8

10

12

14

16

18

MK Cu8 OPC Filler

mW

/ g

of c

emen

t

time (hours)

Aluminate rich pozzolanic materials may cause sulphate depletion and affectnormal hydration of OPC

INFLUENCE OF CALCINED CLAYS ON HYDRATION PRODUCTS

Aft - AfmEttringite forms early on in blended cementsTransforms into AFm phases depending on

SO42- and CO3

2- activity27Al NMR

INFLUENCE OF CALCINED CLAYS ON HYDRATION PRODUCTS

C-(A)-S-HC-S-H of low Ca:Si typically foundDecrease of Ca/(Si+Al) leads to

chain polymerization(Richardson, 2004)

29Si NMR

Q0 Cement

Q1

Q2

Calcium Silicate Hydrates

Q4Quartz

Q3

Rapid methods

Pozzolan

CH

Testing times could be greatly accelerated

Availability of CH and other chemical species is independent of the degree of hydration of OPC

Simplification of the chemical environment compared to OPC-Pozzolan pastes

Pure pozzolanic reaction approach, suitable to characterize pure pozzolanic reactivity

Experimental conditions are usually far from real conditions, but could be customized

ASSESSMENT OF POZZOLANIC REACTIVITY OF CALCINED CLAYS

Choosing the experimental parameters!!!

Proper Alkalinity

Room Temperature

Modified Chemical

EnvironmentCa2+; OH-; M+; SO4

2-

Decreasing testing time High Alkalinity

High Temperature

Simplified Chemical

EnvironmentCa2+; OH-

Closer to real conditions

Easier to analyze

Closer to real conditions

ASSESSMENT OF POZZOLANIC REACTIVITY OF CALCINED CLAYS

ASSESSMENT OF POZZOLANIC REACTIVITY OF CALCINED CLAYS

0

10

20

30

40

50

60

70

0 20 40 60 80 100

Re

sist

en

cia

a l

a C

om

pre

sió

n (

MP

a)

Tiempo (días)

00-N4-3 66-N4-3 86-N4-3 96-N4-3 MK-N4-3 F-N4-3

% d

Gd

d H

idió

l

28

dí

Isothermal Calorimetry60% Calcined Clay / 40% Ca(OH)2

w / s = 0.8 c(NaOH ) = 0.5 mol / L

0,00

0,05

0,10

0,15

0,20

0,25

0,30

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

SO3

/ Po

zzol

an

c (KOH) (mol/l)

Degree of pozzolanic reaction

Cumulative heatα

R3 POZZOLANIC REACTIVITY TEST

R3 POZZOLANIC REACTIVITY TEST

Calcined Clay (g) CH (g) K2SO4 (g) KOH (g) H2O (g)

12.50 37.50 1.47 0.32 60

Avet, F. ; 2014-2015

POZZOLANIC REACTIVITY OF CALCINED CLAYS

AS2 + 6CH + 9H → C4AH13 + 2CSH AS2 + 5CH + 3H → C3AH6 + 2CSH AS2 + 3CH + 6H → C2ASH8 + CSH

Al2O3 + SiO2 + Fe2O3 ≥ 70%High specific

surface

Glasser, D. et al, 1982; Baronio, B. et al; 1997

High degree of structural disorder

Through-solution process, involving dissolution of reactants, transport of dissolved reactants and nucleation and growth of reaction products

• Active silica and alumina: dissolution treatment of pozzolansMethod Dissolution procedure ReferenceHNO3/KOH 1. HNO3 concentrated

2. 10% KOH (12h)Rivot, 1862

HCl/KOH 1. 20% HCl (cold)2. 20% KOH (cold, 20h)3. 20% KOH (50-65 °C, 4h)

Baire, 1930

HCl/NaOH 1. 50% HCl (hot)2. NaOH (hot)

Malquori, 1935

NaOH/HCl 1. NaOH (1 N, hot, 0.5h)2. 50% HCl (hot) (2x)

ASTM C379-56T

HCl/Na2CO3 1. HCl (conc., heated)2. Na2CO3 +NaCl (hot, 15 min)

AFNOR P 15-301

Na2CO3 + NaOH 3.6% Na2CO3 + 1% NaOH (5 min, repeated X times)

Steopoe, 1956

Salicylic acid + methanol

Salicylic acid (25 g) in 300 ml methanol Takashima, 1958

HF + HNO3 2 M HF + 0.6 M HNO3 (1h)Heat evolution measured by calorimetry

Jambor, 1962

HF 1 M HF (10 min, 300 K)Solution conductivity measured

Rhaask and Bhaskar, 1975

ALKALI SOLUBILITY TEST

ALKALI SOLUBILITY TEST

He, C., Osbæck, B., Makovicky, E., 1995b. Pozzolanic reactivitys of six principal clay minerals: activation, reactivity assessments and technological properties. Cem. Concr. Res. 25 8.,1691–1702.

Alkaline solubility of calcined clays (0.5 mol/l NaOH, TPEA)

ALKALI SOLUBILITY TEST

Alkaline solubility of calcined clays (0.5 mol/l NaOH, 50°C)

0

50

100

150

200

250

MK CG 850 LS 850 PZ 850 LL 850 LL2 850

ppm

Alkali Solubility ppm (Al)

ppm (Si)

ALKALI SOLUBILITY TEST VS R3 TEST

R² = 0.9549

0

50

100

150

200

250

300

0 500 1000 1500 2000 2500 3000 3500

Solu

ble

Al (p

pm)

J / g Pozz

R3 vs. Soluble Al MK

CG 850

LS 850

PZ 850

LL 850

LL2 850

YG2 850

YG1 850

0

50

100

150

200

250

0 500 1000 1500 2000 2500 3000 3500

Solu

ble

Si (p

pm)

J / g Pozz

R3 vs. Soluble Si MK

CG 850

LS 850

PZ 850

LL 850

LL2 850

YG2 850

YG1 850

0 5 10 15 20 25 30 35 40 45 50 55

55

50

45

40

35

30

25

20

15

10

5

0100

95

90

85

80

75

70

65

60

55

50

45

LLLS

CG

% Al2O3

0

50

100

150

200

250

CG 850 LS 850 LL 850

c(Al

) ppm

Alkali Solubility Test (Al)

0

500

1000

1500

2000

2500

CG 850 LS 850 LL 850J /

g P

ozz

R3 Pozzolanic Test

0

10

20

30

40

50

OPC LC3 CG LC3 LS LC3 LL

Com

pres

sive

Str

engt

h (M

pa)

3 days 7 days 28 days

ALKALI SOLUBILITY TEST – R3 TEST – COMPRESSICE STRENGTH

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74

MUCHAS GRACIAS!!!