CMIC 2012
B T (Tom) Benn – Adelaide Brighton Cement Ltd
Ass Prof Daksh Baweja – University of Technology Sydney
Prof Julie E Mills – University of South Australia

CMIC 2012
Mineral Additions & Chloride Ingress
Introduction
• Background to mineral additions
• Cements
• Limestone
• Cement kiln dust
• Supplementary cementitious materials
• General properties of concrete
• Durability
• Chloride ingress
• Transport mechanisms
• Conclusions & Research proposal

CMIC 2012
Mineral Additions & Chloride Ingress
Introduction
• Limestone addition first used 1965
• Heidelberg cement at 20%
• 5% mineral addition
• Europe in general early 1980’s
• South Africa 1982
• Canada 1983
• Australia 1991
• USA 2005
• Limestone cements (>5%) 1992 in ENV 197-1

CMIC 2012
Mineral Additions & Chloride Ingress
Comparison of cement properties
Property
Standard
Initial set
Units Type GP CEM I
– 32.5
CEM I
– 42.5
Minutes
AS 3972
≥ 45
EN 197-1
≥ 75
EN 197-1
≥ 75
Type I
ASTM C150
≥ 45
Final set
MgO
Chloride ion
SO
3
Loss on ignition
Strength 2-day
Strength 3-day
Strength 7-day
Strength 28-day
Hours
%
%
%
%
MPa
MPa
MPa
MPa
< 6
< 4.5
(clinker)
≤ 0.10
≤3.5
--
--
--
≥ 35
≥ 45
--
≤ 5.0
≤ 0.10
≤ 3.5
≤ 5.0
--
--
≥ 16.0
≥ 32.5 ≤ 52.5
--
≤ 5.0
≤ 0.10
≤ 3.5
≤ 5.0
≥ 10.0
--
--
≥ 42.5 ≤ 62.5
≤ 6.25
≤ 6.0
--
≤ 3.0 (C
3
A < 8%)
≤ 3.5 (C
3
A > 8%)
≤ 3.0
--
12.0 (cubes)
19.0
28.0

CMIC 2012
Mineral Additions & Chloride Ingress
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Limestone
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Australia & Europe
Natural inorganic mineral material
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CaO
3 not less than 75% by mass
If CaO
3 between 75% & 80% must be tested:
Clay content must be less than 1.20% (methylene blue test)
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Total organic test not greater 0.50% by mass
• CaO
3 content 80 % or greater no additional testing
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Canada
CaO
3 content at least 70% by mass
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USA
CaO
3 content at least 75% by mass

CMIC 2012
Mineral Additions & Chloride Ingress
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Cement Kiln Dust
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Dust created and extracted from kiln
Also known as by-pass dust
Typically between 7% – 15% of clinker
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Why removed
Causes build up and rings in kiln and preheater
Causes abnormal setting and strength characteristics in cement
If high in chlorides contributes to reinforcement corrosion
If high in alkalis contributes to ASR reaction
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Chemistry
Similar to raw materials for cement and clinker

CMIC 2012
Mineral Additions & Chloride Ingress
Cement kiln dust chemistry
Constituent
Silicon dioxide
Aluminium oxide
Iron oxide
Calcium oxide
Magnesium oxide
Sulphur trioxide
Chlorine
Potassium oxide
Sodium oxide
Long dry kilns
(U.S. EPA (1993)
ABC data
(07
– 10)
4.3 – 10.1
9.5 – 20.6
1.0 – 3.3
0.7 – 2.3
2.8 – 4.5
1.8 – 3.1
11.0 – 45.0
0.4 – 2.0
0.1 – 7.7
0.08 – 2.7
0.2
– 9.7
0.07 – 1.12
41.5
0.8
0.5
– 62.9
– 1.6
– 4.7
0.6 – 7.5
1.8
– 15.5
0.2 – 1.1

CMIC 2012
Mineral Additions & Chloride Ingress
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Supplementary Cementitious Materials
Fly ash, ground granulated blastfurnace slag, silica fume
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Advantages of using
Improved workability
Better cohesiveness and pumpability
Improved post 28-day strengths
Reduction in ASR with reactive aggregates
Reduced shrinkage (fly ash)
Reduced heat of hydration
Lower permeability (important for resistance to chloride ingress)
Improved resistance to chemical (sulphate) attack
Protection of steel in marine environments (GGBS)

CMIC 2012
Mineral Additions & Chloride Ingress
Strength of concrete Made with Portland Cement & Portland limestone cement
(from Hooton & Thomas 2010)
Limestone, %
Blaine, m
2
/kg
No Water Reducing Admixture With Water Reducing Admixture
PC-1 PLC-2 PC-2 PLC-4 PC-1 PLC-1 PLC-2 PLC-3 PC-2 PLC-4
4.8
380
12
500
4.8
380
12
500
4.8
380
12
450
12
500
12
580
4.8
380
12
500 w/c ratio 0.505 0.512 0.505 0.518 0.491 0.498 0.498 0.508 0.495 0.502
Slump, mm 115 110 115 110 110 110 110 80 105 105
1-day
7-day
19.2
33.5
21.4
32.7
18.5
32.3
18.9
31.6
21.8
35.3
21.9
34.4
23.6
35.2
24.6
36.7
21.0
35.6
22.0
35.0
28-day
56-day
41.1
43.8
39.8
43.3
39.3
44.0
39.9
43.0
42.2
45.2
40.3
43.6
41.9
44.7
42.5
46.6
42.3
45.2
41.5
45.8

CMIC 2012
Mineral Additions & Chloride Ingress
Compressive strengths of various grades of lab concrete
(Benn & Thomas 2012)

CMIC 2012
Mineral Additions & Chloride Ingress
Set times of various grades of lab concrete
(Benn & Thomas 2012)

CMIC 2012
Mineral Additions & Chloride Ingress
Drying shrinkage of various grades of lab concrete
(Benn & Thomas 2012)

CMIC 2012
Mineral Additions & Chloride Ingress
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Findings on properties in the literature
Voglis et al. (2 005) - for similar compressive strength in concrete limestone cement required a wider particle size distribution
Tsivilis et al. (1999a) – increasing tricalcium aluminate (C
3
A) and reducing the tricalcium silicate (C
3
S) increases compressive strength at all ages irrespective of the limestone between 10% and 35%.
Bonavetti et al. (2003) - the increased early hydration and strength due to formation of nucleation sites
Vogilis et al. (2005) - increased early hydration and strength dueto the early formation of calcium carboaluminates.

CMIC 2012
Mineral Additions & Chloride Ingress
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Findings on properties in the literature
Matthews (1994) - for the same slump
(w/c) ratio needs to increase by 0.01 for limestone up to 5% a further 0.01 when increased from 5% to 25%.
Schmidt (1993) - using cement from a different source, reported water demand for concrete could be reduced
• Hooton, Nokken & Thomas (2007) supported the statement by Tsivilis et al. (1999a) ‘… that the appropriate choice of clinker quality, limestone quality, percentage limestone content and cement fineness can lead to the production of
a limestone cement with the desired properties’.

CMIC 2012
Mineral Additions & Chloride Ingress
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Durability
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Durability can be different things to different people such as:
• Not having to repair a structure for 20 years or more,
• Able to cope with changes in use,
Able to cope with changes in loading,
Able to resist chemical attack e.g. acids, alkali-silica reaction,
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Able to prevent chloride ingress to prevent corrosion of reinforcement,
Having a classical façade that does not seem to age with changes in architectural fashions.

CMIC 2012
Mineral Additions & Chloride Ingress
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Description of ingress mechanisms
Diffusion – transfer free ions in the pore solution from high concentration to low concentration regions.
Capillary absorption – when moisture encounters the dry surface of the concrete, it will be drawn into the pores by capillary suction, this often happens with wetting and drying cycles.
Evaporative transport (also called wicking) – similar to absorption but where moisture, containing ions, is drawn from the wet surface through the matrix to the dry surface.
Hydrostatic pressure or permeation – where the hydraulic pressure on one side of the concrete forces the liquid, containing ions, into the concrete matrix.

CMIC 2012
Mineral Additions & Chloride Ingress
Exposure
Submerged
Tidal
Splash and spray
Coastal
Type of structure
Substructure below low tide
Primary chloride transport mode
Diffusion
Basement exterior walls or transport tunnel liners below low tide. Liquid containing structures
Permeation, diffusion and possibility wick action
Substructures and superstructures in tidal one.
Capillary absorption and diffusion
Superstructures about high tide in the open sea.
Capillary absorption and diffusion
(also carbonation)
Land based structures in coastal area or superstructures above high tide in river estuary or body of water in coastal area.
Capillary absorption (also carbonation)
Mechanism of chloride transport
(CCAA 2009)

CMIC 2012
Mineral Additions & Chloride Ingress
Findings reported in international literature
Property
Fineness (m
2
/kg)
Mortar: 28 day strength (MPa)
Concrete w/c
Concrete: 28 day strength (MPa)
Concrete: RCPT (Coulombs)
Percentage limestone
0
260
51.1
10
340
47.9
15
366
48.5
0.70
31.9
6100
27.4
5800
27.3
6000
20
470
48.1
28.0
6400
35
530
32.9
0.62
26.6
6600
Effect of limestone additions on the “chloride permeability’ of concrete
(Tsivilis et al. 2000)

CMIC 2012
Mineral Additions & Chloride Ingress
Findings reported in international literature
Effect of Limestone Additions on Chloride Penetration of Concrete –
Oxygen Permeability
(Matthews, 1994 )

CMIC 2012
Mineral Additions & Chloride Ingress
Findings reported in international literature
Effect of Limestone Addition on the Chloride Diffusion
Coefficient of Concrete by Initial Surface Absorption
(Dhir et al. 2007)

CMIC 2012
Mineral Additions & Chloride Ingress
Findings reported in international literature
Diffusion coefficients (x 10-12 m2/s) for concrete after 35 days immersion in 3% NaCl solution (Hooton, Ramezanianpour & Schutz, 2010)
GU
100%
PLC10
100%
PLC15
100%
GU 70%
GGBS 30%
PLC10 70%
GGBS 30%
PLC15 70%
GGBS 30%
C s
(% mass)
D a
(m
2
/s*10
-
0.73
15.9
0.84
15.6
0.8
22.5
1.1
8.07
1.07
6.11
(i) GU is general use Portland cement.
(ii) PLC is Portland limestone cement with either 10% or 15 % limestone.
(iii) The 70% implies 70 % cement and 30 % slag.
0.98
8.25

CMIC 2012
Mineral Additions & Chloride Ingress
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Conclusions
Some indication that without the inclusion of SCM the durability may be at risk (Irassar et al. 2001).
Literature supports the hypothesis that that the use of SCM will improve the durability even with high mineral additions(Thomas & Hooton 2010)
Previous research indicates that CKD can be added to cement
(Daugherty and Funnell 1983).
Gap in the data as no reference has been found relating to chloride ingress where CKD is added during the milling of the clinker and in particular where the CKD contains chlorides.
Gap in the knowledge on the effect of the inclusion of both higher limestone additions and CKD in cement on the chloride ingress into concrete, made with and without fly ash or slag.

CMIC 2012
Mineral Additions & Chloride Ingress
Proposed research
Mortar with w/c ratio ≈ 0.45 with following cementitious contents:
• Control - cement only mix, limestone additions = 5%, no CKD
• Experimental cement mixes, limestone additions = 10% & 15% + CKD.
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• Cement/fly ash mixes, fly ash replacement = 20% & 30%.
Cement/slag mixes, slag replacement = 30% and 50%.
Measure compressive strengths development for up to three years.
Measure chloride diffusion for up to three years (Nord Test NT 443 ?)
• Measure rapid chloride permeability (RCPT ASTM C 1202 ?)
Concrete with f’
C of 40 MPa to confirm mortar findings
Research will support sustainability as suggested by the Kevin Gluskie