Presenting accelerated low carbon binder through formation of ettringite

1. low carbon rapid set cement binder
Quaternary Cement
The 9th International Drymix Mortar Conference
Nuremberg, Germany
27. March 2023

2. European Commission aims to make
the EU climate neutral by 2050
By 2030 - CO2 emissions should be reduced by at least 55 %
compared to 1990 !

3. mandatory reduction of

4. Cement clinker
• cement production contributes
7% of world wide CO2 emission
mainly through decarbonation of
limestone
• 1 ton of cement clinker emits
~ 800 kg of CO2
• carbon dioxide emissions tax
expected to double within next
decade
• currently ~ € 90,= per metric ton
• no free quota from 2030
• carbon dioxide emissions tripled in
last three decades to 3 billion tons /y.
• cement production consumes most
of natural resources

5. Clinker production
cement in making concrete world wide most abundant
building material
• quarrying, transport
• grinding, preparation
of raw materials
• cooling, grinding, mixing
Source:Chatham House

6. Source:McKinsey Laying the foundation for zero-carbon cement

7. actions
• replacing clinker amount by SCM’s – fillers
• using alternative binders like CSA cement or
geopolymers
• lowering cement amount by volume
concrete, mortar
• reduction concrete volume (3D-printing,GRC)
• improving efficiency of binder system
• re-use (concrete) scrap

8. Hybride cements
Replacement clinker amount by;
• Limestone filler
• GGBS
• Calcined clay
• Fly ash
• Pozzolanic and others
Standard in place
EN-197-1
• CEM II/B-S
• CEM II/A-LL
• CEM II/B-V
• CEM II/B-P

9. cement standard
calls for 2 day strength

10. EN 197-1 - compressive strength
Portland
cement
Portland
limestone
cement
Portland
slag
cement
Portland
cement
Portland
limestone
cement
Portland
slag
cement
Portland
cement
Portland
limestone
cement
Portland
slag
cement
CEM I
32,5 R
CEM II
A-LL 32,5 R
CEM II
B-S 32,5 N
CEM I
42,5 R
CEM II
A-LL 42,5 R
CEM II
B-S 42,5 N
CEM I
52,5 R
CEM II
A-LL 52,5 R
CEM II
B-S 52,5 N
MPa MPa MPa MPa MPa MPa MPa MPa MPa
2 days ≥ 10 ≥ 10 - ≥ 20 ≥ 20 ≥ 10,0 ≥ 30,0 ≥ 30,0 ≥ 30,0
7 days > 16,0
28 days ≥ 32,5 ≥ 32,5 ≥ 32,5 ≥ 42,5 ≥ 42,5 ≥ 42,5 ≥ 52,5 ≥ 52,5 ≥ 52,5

11. EN 197-1 - compressive strength
Portland
cement
Portland
limestone
cement
Portland
slag
cement
Portland
cement
Portland
limestone
cement
Portland
slag
cement
Portland
cement
Portland
limestone
cement
Portland
slag
cement
CEM I
32,5 R
CEM II
A-LL 32,5 R
CEM II
B-S 32,5 N
CEM I
42,5 R
CEM II
A-LL 42,5 R
CEM II
B-S 42,5 N
CEM I
52,5 R
CEM II
A-LL 52,5 R
CEM II
B-S 52,5 N
MPa MPa MPa MPa MPa MPa MPa MPa MPa
2 days ≥ 10 ≥ 10 - ≥ 20 ≥ 20 ≥ 10,0 ≥ 30,0 ≥ 30,0 ≥ 30,0
7 days > 16,0
28 days ≥ 32,5 ≥ 32,5 ≥ 32,5 ≥ 42,5 ≥ 42,5 ≥ 42,5 ≥ 52,5 ≥ 52,5 ≥ 52,5

12. own carbon footprint
availability of CEM I
price
interaction new binders with
additives
consistency
low reactivity
and slow hardening
DRYMIX
DRYMIX challenges

13. requirements drymix
• stable reactive binder
• low carbon footprint
• reduction binder content
• fast setting
• initial strength
• compensation of shrinkage
• low alkalinity
• high density

14. need to re-formulate
requirements drymix
• stable reactive binder
• low carbon footprint
• reduction binder content
• fast setting
• initial strength
• compensation of shrinkage
• low alkalinity
• high density

15. Low Carbon cement
Portland cement blended with two other materials, e.g. ground limestone, GGBS,
fly ash, silica fume, calcined clay, metakaolin etc.
Ternary cement
Quaternary Cement
Portland cement blended with at least three other materials e.g. ground limestone,
GGBS, fly ash, silica fume, calcined clay, metakaolin, gypsum, calcium aluminate
etc.
generally these binders are latent hydraulic and generate a lower initial strength
modified to ensure a stable binder to overcome slow hydration and loss of early strength

16. Quaternary Cement
study of the effect of early hydration of
ettringite on ternary mixtures
• shortening of setting time
• increase of early strength
Amorphous Calcium Aluminate

17. AFt (ettringite)
3CaO . Al2O3 . 2CaSO4 . 32H2O
AFm (mono sulfo aluminate)
3CaO . Al2O3 . CaSO4 . 12H2O 4CaO . Al2O3 . 19H2O
Solutions in the presence of lime, alumina, calcium
sulfate complex hydrates are formed ;
precipitation of ettringite

18. Amorphous Calcium Aluminate Cement
• one of the best precursors in forming AFt and AFm
• ground to high surface area to further improve
solubility and dissolution
• hydration of main phase C12A7 reacts quickly with
available sulphate to form ettringite and mono
calcium aluminate;
• account for high initial strength
• high density
• positive expansion, compensation of shrinkage
• bound excess water accelerate drying
Anhydrous Calcium Sulphate

19. investigating the effect of percipitation of ettringite in different blends of OPC and
SCM’s – and the effect on improving early strength and setting times
materials used
NHL 3,5
CEM I
52,5R
GGBS
META
KAOLINE
LIMESTONE
FILLER PCE
SCM

20. reference
GGBS
Metakaolin
CaCO3
CEM I 52,5R 23
NHL3,5 7
GGBS 55
CaCo3 15
PCE 0,15
CEM I 52,5R 23
NHL3,5 7
METAKAOLIN 55
CaCo3 15
PCE 0,15
CEM I 52,5R 23
NHL3,5 7
GGBS 15
CaCo3 55
PCE 0,15

21. GGBS
CEM I 52,5R 23
NHL 3,5 7
GGBS 50
CaCo3 12
ACA-XT-20 8
PCE 0,15
CEM I 52,5R 23
NHL 3,5 7
GGBS 54
CaCo3 12
ACA-XT-20 4
PCE 0,15
A
B
0 0
1,5
1,27
2,19
2,8
2,16
2,53
3,17
0
0,5
1
1,5
2
2,5
3
3,5
REFERENCE A B
MPa
6 hours 24 hours 72 hours
0 0
2,6
3,96
7,09
11,55
13,6
16
21,5
0
5
10
15
20
25
REFERENCE A B
MPa
6 hours 24 hours 72 hours
compressive strength
flexural strength

22. METAKAOLIN
CEM I 52,5R 23
NHL 3,5 7
METAKAOLIN 50
CaCo3 12
ACA-XT-20 8
PCE 0,15
CEM I 52,5R 23
NHL 3,5 7
METAKAOLIN 54
CaCo3 12
ACA-XT-20 4
PCE 0,15
A
B
0
0,8
1,65
0,9
1,83
3,36
3,14
2,8
3,93
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
REFERENCE A B
MPa
6 hours 24 hours 72 hours
flexural strength
0 0
2,6
3,96
7,09
11,55
13,6
16
21,5
0
5
10
15
20
25
REFERENCE A B
MPa
6 hours 24 hours 72 hours
compressive strength

23. CaCo3
CEM I 52,5R 23
NHL 3,5 7
GGBS 12
CaCo3 50
ACA-XT-20 8
PCE 0,15
CEM I 52,5R 23
NHL 3,5 7
GGBS 12
CaCo3 54
ACA-XT-20 4
PCE 0,15
A
B
0
0,51
1,2
1,04
2,01
2,83
2,56
2,94
3,87
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
REFERENCE A B
MPa
6 hours 24 hours 72 hours
flexural strength
0
1,07
3,02
2,95
5,32
9,1
7,49
10,71
15,49
0
2
4
6
8
10
12
14
16
18
REFERENCE A B
MPa
6 hours 24 hours 72 hours
compressive strength

24. CEM I 52,5R 31
GGBS 15
CaCo3 54
XT_20
PCE 0,15
reference II
leaving hydraulic calcium hydroxide out

25. Portlandcement
CEM I 52,5R 30
GGBS 12
CaCo3 50
ACA-XT-20 8
PCE 0,15
CEM I 52,5R 30
GGBS 12
CaCo3 54
ACA-XT-20 4
PCE 0,15
A
B
0 0
1,5
1,27
2,19
2,8
2,16
2,53
3,17
0
0,5
1
1,5
2
2,5
3
3,5
REFERENCE A B
MPa
6 hours 24 hours 72 hours
flexural strength
0 0
2,6
3,96
7,09
11,55
13,6
16
21,5
0
5
10
15
20
25
REFERENCE A B
MPa
6 hours 24 hours 72 hours
compressive strength

26. • it is shown that an addition of amorphous calcium aluminate XT-20 has a
significant impact on the early strength development of all binders
systems tested
• optimum dossage of Amorphous Calcium Aluminate XT-20 is ~ 8% by
weight
• XRD-testing confirms that it is in line with the amount of ettringite being
formed
• shortening of the setting time in all cases ;
20 ~ 40 minutes begin / final set of 30 ~50 minutes
• use of super plasticizing agent helped to keep water/binder ratio
• results show that formation of early ettringite improved the early strength
independently of other constituents
in conclusion

27. • hydraulic lime should have a positive effect on the percipation of
ettringite, shown is the effect is negligible
• calcium carbonate forms hemicarboaluminate, stabilize ettringite
• higher limestone addition contributed to early strength development,
filler effect
• higher amount of amorphous calcium aluminate XT-20 will increase
strength development / accelerate setting

28. • efficient low carbon binder system
• reduced use of Portland cement
• lower over all binder percentage
• allows considerable replacement
• indifferent of type and amount of SCM’s
• guaranteed fast set and hardening
• improves early strength
Amorphous Calcium Aluminate Cement
stable “fast set low carbon binder”

29. last note
further studies are being done to investigate the effect on other low
carbon/cement free hydraulic binder systems
more results will be presented next
hope to meet you all there