durable concrete: the future and use of supplementary ...density, and durability significantly...
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Durable Concrete:
The Future and Use of Supplementary
Cementitious Materials
METAKAOLIN
Presented By
A.J. Marisca, Regional Sales Manager, BASF KAOLIN
1 3/1/2017
Virginia Concrete Conference March 2-3, 2017
Today’s Objectives
What is a Pozzolan?
What is Metakaolin?
Why Metakaolin?
Durability
ASR
Aesthetic Effects
How to use Metakaolin
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Quick Survey
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Who is familiar with METAKAOLIN?
Who has tested METAKAOLIN?
Who has USED METAKAOLIN?
What is a Pozzolan?
Natural
Metakaolin
Rice Husk Ash
Pumice
Industrial
by-product
Fly Ash
Slag
Silica Fume
ASTM C 618 – Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use as a Mineral Admixture in Concrete states that:
Pozzolan are “siliceous or siliceous aluminous material which in itself possesses little or no cementitious value but will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds possessing cementitious properties”.
ACI Committee 240 - Natural Pozzolans
Committee Mission: Develop and report information on the use of natural pozzolans in concrete & mortar.
ACI Spring Convention 2017
– 3/27/2017 10:00 AM
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Metakaolin Is A Highly Reactive Pozzolan
Metakaolin reacts with the free lime in concrete to form additional calcium
silicate hydrate and other cementitious compounds.
Ca(OH)2 + (Al4Si4O10(OH)8)→ C-S-H
METAKAOLIN
The additional CSH increases the cementitious bonds within the concrete
to make it stronger. For this reason, pozzolans are classified as
supplementary cementitious materials.
At a 10% replacement rate dosage, High Reactivity Metakaolin (HRM)
consumes a large percentage of free lime in a mixture within seven days.
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High Reactivity Metakaolin (HRM ) creates a more dense concrete
What is Metakaolin?
Hydrated Aluminosilicate
Al4Si4O10(OH)8
Mined from high quality deposits along
the fall line in Georgia
Used in paper and architectural coatings,
inks, wire and cable, rubber and plastics,
catalytic converters
High Reactivity Metakaolin
Amorphous aluminosilicate formed by
calcination of kaolinite, a naturally
occurring crystalline mineral
Manufactured under controlled conditions
to provide consistent product
Very high pozzolanic activity due to
optimal thermal treatment
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Importance of Controlled Manufacturing
Calcined under optimal heat
treatment conditions to create
maximum pozzolanic activity
Consistent product quality
Not a by-product
Stable chemical composition
Narrow particle size distribution
High pozzolanic reactivity
Bright white color
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Comparing Three Important Pozzolans
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Characteristic Fly Ash Silica Fume Metakaolin
Particle Size (µm) 20 0.1 1.3
Total Reactive Oxide 86 85-97 >97
Reactivity
Early Strength
Concrete Durability
Concrete Workability
Appearance Water Demand
Metakaolin can improve critical properties of concrete mix
Where Can Metakaolin
Provide Benefit ?
Ready-mix concrete
Pre-cast concrete
High performance concrete
Glass fiber reinforced concrete (GFRC)
Mortars and Grouts
Shotcrete
Plaster and Stucco
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Key Benefits Achieved When Using Metakaolin
Increased strength,
density, and durability
Significantly improved
consolidation/placement
of concrete
Reduced dry shrinkage
Brightens and lightens
concrete
Improved chemical resistance of concrete by
densifying and reducing
free lime
Reduced chloride ion
permeability
Reduced alkali-silica
reactivity and thereby helps
reduce internal stresses
Reduced efflorescence
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Increased Early Strength with Metakaolin
Metakaolin can create concrete
compressive strengths as high as
18,000 psi.
Create longer spans, stronger
structures and smaller sections
for more efficient concrete
construction
Earlier removal of forms or
remove from molds for faster
construction cycles
Minimize need for shoring and
allow earlier loading of structure
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
7 28 365
Com
pre
ssiv
e St
ren
gth
Days
Control
Addition of 8% SF
8% Replacement with SF
Addition of 8% MK
8% Replacement with MK
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Financial savings by reducing construction time
Chemical Resistance and Durability
High Reactive Metakaolin
aggressively converts free lime
into cementitious CSH to achieve
higher strength and decreased
porosity and permeability resulting
in a significant reduction of
Chloride penetration
Alkali-silica reactivity (ASR)
Efflorescence
Sulfate attack
Properly-sized HRM particles act as a micro-fill to extend the cement paste
filling voids and increasing contact with aggregates in concrete
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Improving Class F Fly Ash Concrete with
Metakaolin
Compressive Strength
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200
Co
mp
ress
ive
Str
en
gth
(p
si)
DAYS
Control
7.5% MMX
7.5% Fly Ash
Rapid Chloride Penetration (AASHTO T-277-89)
0
1000
2000
3000
Control 7.5% MMX 7.5% Fly Ash
2500
800
1500
Ch
arg
e P
ass
ed
, C
ou
lom
bs
(ra
tin
g)
Mo
de
rate
L
ow
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Metakaolin reacts with residual alkali in fly ash which significantly increases early strength and results in a more dense concrete and provides enhanced durability
FM 578 -Florida Test Method For Concrete
Resistivity as an Electrical Indicator of its
Permeability Surface Resistivity
Non-destructive laboratory test method
measures the electrical resistivity of
water-saturated concrete and provides
an indication of its permeability.
The test result is a function of the
electrical resistance of the specimen.
Alternate to RCP
32.8
43.8 43.1
0
10
20
30
40
50
8% 10% 12%% Metakaolin
Kohm-cm PASS
RCP Test Surface
Resistivity Test
Chloride Ion
Permeability Charged Passed
(coulombs) 28 day test (kΩ−cm)
High > 4,000 < 12
Moderate 2,000-4,000 12 - 21
Low 1,000-2,000 21 - 37
Very Low 100-1,000 37 - 254
Negligible < 100 > 254
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Controlling Alkali-Silica Reaction
Expansion at 2 Years
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0 5 10 15 20
Metakaolin (%)
Exp
an
sio
n @
2 Y
ears
(%
)
Spratt
Sudbury
CSA Limit
ASR can be controlled by
limiting alkali content
restricting the use of reactive
aggregates
decreasing permeability
using a lithium admixture
using mitigating SCM (HRM)
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HRM reduces ASR by forming additional SCM which decreases permeability and
porosity limiting the intrusion of moisture into the concrete matrix
16.8%
10.1%
8.9% 9.0% 9.4%
8.6%
0.0%
2.0%
4.0%
6.0%
8.0%
10.0%
12.0%
14.0%
16.0%
18.0%
0
0.1
0.2
0.3
0.4
0.5
0.6
14 Days 1 Month 2 Months 3 Months 4 Months 6 Months
Expansio
n (
mm
)
Control (avg) MetaMax(avg) % Expansion of Control
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Metakaolin for Alkali Silica Reaction
ASTM C441 Test Method
Aesthetic Effects of Metakaolin
HRM can be used in
integrally colored
concrete to lighten and
intensify its color
HRM is used in white
portland cement concrete
without compromising
brilliance
Mixed into ordinary gray
portland cement, HRM
gives the concrete a
lighter value that can
create new aesthetic
opportunities
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Better Visibility for Improved Safety
New Jersey DOT
White concrete reflects more
than twice as much light as
gray concrete
Pennsylvania Turnpike
HRM improves visibility of light
colored concrete
– Especially significant during
wet conditions
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How to Formulate with Metakaolin
The addition of Metakaolin is based solely on the amount of Portland
cement or cementitious material that is being used in the system.
Recommend dose is 8 – 12% Metakaolin for general applications.
Can use up to 20% depending on required benefit, e.g. severe
efflorescence or ASR control.
Metakaolin will produce a cohesive mixture, use HRWR to adjust
workability instead of water.
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Order of Addition
The order of addition is very important when using Metakaolin
Metakaolin can bind with aggregate, therefore it is recommended that
it be added to a concrete batch after portland cement for optimum
performance and before any high-range water reducer
(superplasticizer) is added.
Add Metakaolin before color pigments, Metakaolin has the tendency to
lighten the final product and color addition may need adjusting
Add Metakaolin after calcium chloride – making sure the calcium
chloride is pre-dissolved if in pellet of flake form
If colorant is not being used, Metakaolin can be added as the last
ingredient
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SUMMARY
Why Use High Reactive Metakaolin?
High Reactivity Metakaolin possesses very high pozzolanic activity, converting free lime into more cementitious compounds
Strength
– High Pozzolanic Activity Increases Strength
Workability
– Excellent and Consistence Performance
Durability
– Control of Chemical Attacks & Reduced Permeability
– Sustainability
– Making the Structure More Green
Aesthetics
– Architecturally Appealing - No Darkening/Changing of Color
Controlled manufacturing provides consistent, reproducible results
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Visit our website for more information
http://www.kaolin.basf.com/metamax
22 3/1/2017
For more information
www.kaolin.basf.com
AJ Marisca
Regional Sales Manager, BASF Kaolin
Chuck Cleary
– Technical Specialist, BASF Kaolin
23 3/1/2017
Thank You
24 3/1/2017