Presented at the XXIV Nordic Concrete Research Symposium in Stockholm, August 17-19, 2022.

1. GREEN CONCRETE
Cement mixed with limestone and calcined
clay
Durability properties
Claus Vestergaard Nielsen, Ph.D.
XXIV NCR Symposium 2022,

2. Work presented from a Danish R&D collaboration
that took place from 2014 to 2019
• Danish parliament has issued a climate law to reduce CO2 emissions by 70% in 2030
• Danish building legislation is implementing CO2 limits on new large buildings in 2023
• Aalborg Portland has released a new cement called FutureCem with 30% reduction
compared to conventional CEM I
• In 2021-2024 a new R&D project is running in Denmark to develop further the
FutureCem technology. This is in order to obtain further CO2 reductions and in order
to spread the use from ready-mixed to precast.
The purpose of the project was to develop the next
generation of green concrete

3. Danish baseline
www.baeredygtigbeton.dk
2019 produktion data
10 million tonnes
RMC 50%
precast elements 20%
paving products 20%
Equals approximately
1.5 million tonnes
CO2e annually
From Roadmap towards 2030, 50% reduction of CO2
emissions from concrete
Production Emissions

4. Cement types used in Denmark
• Traditional “green concrete” in Denmark is based on CEM I mixed
with fly ash ( CEM II/A-V)
• Fly ash supply is challenged as power plants convert towards
bio fuels
• Precasters often use blended cement CEM II/A-LL with
limestone, having high early strength
• FutureCem is based on cement clinker mixed with limestone
filler and calcined clay. It is a Portland-composite cement
CEM II/B (Q-LL)
Embodied
CO2
[kgCO2e/t]
750
750
600

5. Demo structures
from 2016-2018

6. Field exposure sites
Marine exposure sites in
North Sea and in Baltic Sea.
Have been in operation for
more than 10 years.
Road exposure site in the
Copenhagen area established in 2018

7. Concrete types and binder combinations
CEM II/A-V
CEM II/B-V
CEM II/A-M (Q, LL) +
FA
CEM II/A-M (Q, LL)
CEM II/B_M (Q, LL)
Mix W is almost identical to the FutureCem cement released in

8. FutureCem CEM II/B-M (Q,LL) is allowed to all building
applications in Denmark, except
• XS2 and XS3, direct seawater exposure.
Mainly due to doubt about sulphate resistance.
• XF2 and XF4, freeze-thaw with chlorides.
Only accepted if the freeze-thaw resistance is documented with scaling test as
part of the initial pretesting.
• XA3, chemical exposure.
Due to doubt about the sulphate resistance.

9. Freeze-Thaw scaling tests
• Filled symbols =
Reference mixes
(normally score
“Very good”
• In Denmark the
concrete shall obtain
performance “Good”
to pass the test
• For low clinker ratios
(< 65%) this has been
difficult to fulfil
• In all cases the air
void structure is good

10. Challenges when introducing new cements
• The usual SCM’s used by the concrete producers are scarce now resources
that are being targeted by everyone in the cement and concrete industry.
Therefore, we need to look towards the natural pozzolans available regionally.
• The CO2 emission factors for SCM’s (FA, GGBFS, MS) and limestone filler are
subject to large scatter. Therefore, LCA results may not support the green
transition in a balanced way.
• Long-term durability properties are hard to investigate within the timeframe
available.

11. Final remarks
• The Green Project project running from 2014 to 2019 paved the way for the use of limestone –
calcined clay – Portland composite cements in Denmark
• FutureCem was introduced in 2021 and allowed for use in most exposure conditions.
FutureCem has 30% CO2 reduction compared with CEM I.
• New R&D project is running in Denmark in order to reduce CO2 further and in order to
document the durability properties further.
• Especially the sulphate resistance is being investigated
• Freeze-thaw performance is also being investigated
• More demo projects are in the pipeline

12. Thank you – Questions?
cln@teknologisk.dk