2. Learning Outcomes
The learning outcomes from the p
g presentation are:
Understand what GGBS cement is
Understand the environmental, technical and architectural reasons why
environmental
you would specify GGBS cement
Know how to specify GGBS cement
Know the % of GGBS cement to specify for different results/applications
Understand the impact of specifying different % of GGBS cement
3. History of GGBS
1862: Hydraulic potential of
GGBS discovered in Germany
Early 1900’s - Portland Blast
Furnace Cements had an
established place in the concrete
market
2004: More than 5,000,000
tonnes of GGBS produced in
Germany
2006: Approximately
2,000,000 tonnes of GGBS
produced in UK
2008: Over 400,000 tonnes
available in Ireland
4. About Ecocem Ireland
Long term agreement
with partner companies
for
f supplying hi h
l i high
quality GBS
Can supply the Irish
pp y
market with
over350,000 tonnes
from Dublin
Provide technical back
up to specifiers and
concrete manufactures
5. GGBS Manufacture
Steel Manufacture Water to make GBS
Grind to make GGBS GBS
Store GGBS for
distribution
7. Ecocem Cement in Use
NRA, OPW B d Gái ESB C ill RPA B d N M
NRA OPW, Bord Gáis, ESB, Coillte, RPA, Bord Na Mona, Local Authorities
L lA h ii
Engineers, Architects, Developers, Precast, House builders, Farmers
9. GGBS and the Environment
CO2 emissions for Ecocem GGBS and cement production
Typical CO2 Emissions for Portland Cement and Ecocem GGBS Production
yp
(Figures in kg per tonne of output)
1000
900
800 Other Energy Used
700
Fossil Fuel Use
put
600
kg per Tonne of Outp
Process Emissions
500
400
300
200
100
0
CEM I CEM II/A GGBS (without offsets)
( ith t ff t )
10. GGBS and the Environment
CO2 emissions for Ecocem GGBS and cement production
Typical CO2 Emissions for Portland Cement and Ecocem GGBS Production
yp
(Figures in kg per tonne of output)
1000
900
800 Other Energy Used
700
Fossil Fuel Use
put
600
kg per Tonne of Outp
Process Emissions
500
400
300
200
100
0
CEM I CEM II/A Ecocem GGBS (without
E ( ith t
offsets)
11. GGBS and the Environment
CO2 emissions for Ecocem GGBS and cement production
Typical CO2 Emissions for Portland Cement and Ecocem GGBS Production
yp
(Figures in kg per tonne of output)
1000
900
800 Other Energy Used
700
Fossil Fuel Use
put
600
kg per Tonne of Outp
Process Emissions
500
400
300
200
100
0
CEM I CEM II/A Ecocem GGBS (with
E ( ith
offsets)
12. GGBS and the Environment
Depletion of natural
resources
For every tonne of Portland
cement produced, 1.6 tonnes
of limestone/shale are
removed from the landscape
GGBS production involves no
quarrying of limestone or
clay
13. GGBS and the
Environment
E i
Environmental
l
savings example
What is the impact of
replacing 50% of cement
with GGBS in an average
size shopping centre, using
5,000m
5 000m3 of concrete?
See calculator on:
www.ecocem.ie
15. Reduction in Embodied CO2 through the use of GGBS
3 bed Semi Detached House
Original
Embodied CO2
(38.7 tonnes)
Reduced
Embodied
E b di d CO2
(28.4 tonnes)
Larger embodied CO2 reductions are possible with increased replacement
rates of GGBS
ref: “Embodied CO2 of housing construction in Ireland” - Architecture Ireland – Jan/Feb 2010
16. GGBS and the Environment
Longer service life from GGBS concrete
Time to replacement extended
Specified by NRA on road bridges and structural concrete - 120 year
design life achieved
Reduced demand on natural resources for new concrete
Exposure to chloride attack:
17. Lighter colour - The Albedo Benefit
Solar radiation
is fl t d b
i reflected by This heat cannot
lighter coloured pass out of the
surfaces earth’s
atmosphere
through the
greenhouse gas
layer
Every 100m2 of
Darker coloured
GGBS concrete
surfaces absorb
pavement in
solar radiation
Ireland will offset
and re emit it as
6 tonnes of
heat
CO2/annum
18. Lighter colour - The Heat Island Benefit
Reduce heat island effect
Reduces air conditioning requirement; cost and environmental
benefit – studies have shown reductions of more than 20% in
building cooling costs whose albedo has been increased
(in the US potential saving of $1 billion per year)
Health benefit
19. Lighter colour – Reflectance Benefit
Reduces outdoor lighting requirements by enhancing
night time visibility
Saving money, energy and carbon emissions
Approx. 30% less lighting needed to achieve same
visibility for concrete as it does for asphalt
21. GGBS Chemical Composition
Same constituents as OPC
Different proportions
• Less CaO
• More Si02
• More Al2O3
22. Mix design using GGBS cement
GGBS cement replaces ordinary Portland cement on a
one for one
one-for-one basis
No change in any other element of the mix design:
• sand
• aggregates
• w/c ratio (can be reduced)
• Admixtures
Concrete manufacture
• Batch duration is the same
• Time to transport - may be appropriate to extend it
23. GGBS in Concrete
Engineering benefits start at 30%
Usage varies from 30 up to 85%
Most often specified at 50%
• Treated same as Portland cement concrete
No adjustment striking times
Placing, compacting and powerfloating
Concrete admixtures compatible.
24. Working with GGBS Concrete
Placing, compacting and pumping
eas e
easier:
• lower relative density
• smaller particle sizes
Powerfloating as normal
Setting times longer by 0.5 – 2 hrs
g g y
Slower rate of bleeding
Water demand 3% to 5% lower
W t d d t l
Compatible with admixtures
27. Strength – temperature effects
1.1 metres in depth
Foundation Slab: C40/50 @ 70% GGBS
50
45
40
Strength N/mm2
35
30
25
h
20
15
10
5
0
1 2 3 4
Day Age
Standard TMC
28. Strength – long term development
95
85
75
65 42.5 & 50%
GGBS
N/mm2
55
45
42.5
35
25
15
0 50 100 150 200
Days
29. Strength – long term development
C30/37 concrete, Greystones Marina
50% GGBS: 50% CEM II
45
Core Strength vs time
40
ength Mpa
35
Stre
30
25
1 month 6 Months 12 months 18 Months
30. Durability of GGBS Concrete - Chlorides
Chloride Penetration
Lower chloride ion diffusivity
L hl id i diff i it
Lower porosity/permeability
Applications: roads and bridges, car parks, sea defences,
marine structures.
31. Durability of GGBS Concrete - Chlorides
Effect of GGBS on chloride diffusion in concrete
16
CEM II/A-L 320 kg/m3
14
CEM II/A-V 320 kg/m3
icient 10-12 m2/s
/
12
CEM II/A-L 400 kg/m3
10 CEM II/A-V 400 kg/m3
8
iffusion coeffi
6
4
Di
2
0
0% GGBS 50% GGBS 70% GGBS
34. Durability of GGBS Concrete - Sulphates
Sulphate Resistance
Sulphates react with C3A and Ca(OH)2 to form
ettringite
Sulphate Resisting cement (SRPC) has reduced
C3A, but no reduced Ca(OH)2, and no reduced
porosity
SRPC cannot be used in marine environments
GGBS much lower price than SRPC
Note: In BS8500 the only
option recommended as
suitable for the most severe
sulphate exposure (Class DC-
l h (Cl C
4m) is concrete containing at
least 66% GGBS
Use of Sulphate resistant
cement is not permitted
35. Durability of GGBS Concrete - Sulphates
Aggressors:
Sulphates
S l h t
Sodium Sulphate Na2SO4
Magnesium Sulphate MgSO4
Acids
Sulphuric Acid H2SO4
36. Durability of GGBS Concrete - Sulphates
0.5
0.45 Masters
0.4
Study in
UCD, Dublin
0.35
sion
0.3
% Expans
CEM I
0.25 CEMII
SRPC
0.2 CEM I + 70% GGBS
CEM II + 50% GGBS
0.15 CEM II + 70% GGBS
0.1
01
0.05
0
Days Exposure
43. Heat of hydration - controlling thermal cracking
temperature differential – 2.5 metre deep slab
Basement slab with 70% GGBS
70.0 Top
Core
Bottom
60.0
Differential Top to Core
Differential B tt
Diff ti l Bottom to Core
t C
50.0
40.0
emperature (oC)
30.0
Te
20.0
10.0
0.0
0 21 28 33 46 58 70 77 92 99 118 139 164 189 234
Time after placing (hours)
44. Heat of hydration - controlling thermal cracking
Convention Centre, Dublin - basement
46. Architectural Qualities and Appearance
GGBS cement, and OPC GGBS is an off-white powder
Lighter, more even-coloured
concrete
Smoother, more defect-free
,
surface
Suppresses/Eliminates
efflorescence
Lower pigment requirements –
20% saving
GGBS can b used as partial
be d ti l
replacement for white cement,
up to 70%
55. Architectural Qualities and Appearance
2009 ICS Design and
ICS,
Construction Awards
Cable Stay Bridge, Waterford – 50% GGBS
56. Architectural Qualities and Appearance
Image courtesy of RPS
Mizen Head Bridge – 50% GGBS
- replacing first RC bridge constructed in Ireland in 1909
58. Carbon Neutral Concrete
The world’s first Carbon Neutral Building Material
launched in 2007 in partnership with the biggest
names i the Irish Construction Industry:
in th I i h C t ti I d t
Treasury Holdings
Pierse
Durkan Group
McNamara
JJ Rhatigan
Details on all prestigious projects can be found on
www.carbonneutralconcrete.ie
www carbonneutralconcrete ie
59. How to specify GGBS
COARSE & FINE AGGREGATES Coarse and fine aggregates shall comply with I.S. EN 12620.
CHLORIDE CONTENT The total chloride content of the concrete mix for reinforced concrete
shall not exceed 0.4% expressed as a percentage of chloride ion by weight of cement.
CEMENT Normal Portland cement (CEM I, CEM II/A) shall comply with the requirements of IS
EN 197 1 The cement shall be delivered to site in standard bags or in bulk containers and shall
197-1.
be stored under dry conditions.
CEMENT ADDITIONS Ground Granulated Blastfurnace Slag (GGBS) is permitted in I.S. EN
206-1 to be used as a Type II addition to CEM I or CEM II/A cements in concrete. Where GGBS
is added it replaces the CEM I or CEM II/A cement on a one-for-one basis; the total
cementitous material content of the concrete mix does not change, and the GGBS counts fully
towards the total cement content and water/cement ratio in concrete. GGBS shall comply I.S.
EN 15167-1 and be ground to a blaine of > 4000 cm2/g.
A cement combination comprising 50% GGBS and 50% CEM I or
CEM II/A is to be used in all concrete throughout the Project,
unless otherwise specified on the drawings or by the Engineer.
60. Multiple Benefits
Best durability (longer life)
• Factor of safety
• Reduce lifetime maintenance cost
Best sustainable material
• Reduces CO2 emissions
• Demonstrates commitment to a sustainable agenda
• Positive
P iti CSR
Best Architectural
• Whiter,
Whiter brighter concrete
Best value for money
61. Thank You
Thank you for your attention
y y
Should you have any questions in the future:
y yq
David O’Flynn; 087 965 4891
doflynn@ecocem.ie
d fl i
