sustainable , robust cementious binder by blending Portlandcement calcium sulphate and calcium sulpho aluminate cement

2. So
called
ternary
systems
are
being
used
for
several
decades
by
the
construction
chemistry
predominantly
in
making
self-­‐leveling
screeds
,
under-­‐
and
over
layments
–
non
shrink
grouts
,
repair
mortars
etc.
They
are
based
on
mixing
calcium
,
alumina
and
sulphate
together
to
obtain;
ettringite
=
C4A3Š
3CaAl2O3
Ÿ
3CaSO4
Ÿ
32H2O
The
effect
on
the
binder;
• rapid
set
• high
early
strength
• shrinkage
compensation
• fast
drying
• low
alkali
• no
effluoresence
• improved
sulphate
resistance
what
is
needed
to
form
C4A3Š
?

3. what
is
needed
to
form
C4A3Š
?
• aluminium
• sulphate
• calcium
Calumex
Anhydrite,
hemi-­‐hydrate,
gypsum
Portlandcement,
calcium-­‐oxide/-­‐hydroxide
a
fibrous
needle
shaped
crystal
,
holding
32
water
molecules

4. what
is
to
be
considered
?
PORTLANDCEMENT
Content
of
• C3A
tri-­‐calcium
aluminate
• amount
of
free
lime
(
fCaO
)
• type
and
amount
of
sulphate
added
CALCIUM
SULPHATE
• hemi-­‐hydrate
• micronized
gypsum
• anhydrite

5. choice
of
type
of
CALUMEX
CALCIUM
SULPHO
ALUMINATE
CEMENT
Content
of
• CALUMEX
CSA
–
ground
clinker
;
• Al2O3
content
~
46
%
• SiO2
~
3
%
• fCaO
0
• CaSO4
~
7,5
%
• CALUMEX
Quick
• Al2O3
content
~
32
%
• SiO2
~
3
%
• fCaO
0
• CaSO4
~
20
%
• BELICEM
• Al2O3
content
~
32
%
• SiO2
~
10
%
• fCaO
0
• CaSO4
~
10
%

6. why
is
sulphate
added
to
OPC
?
Portlandcement
mainly
forms
minerals;
• C3S
–
alite
• C2S
–
belite
• C3A
–
tri-­‐calcium
aluminate
C3A
is
the
most
reactive
phase
–
it
forms
with
water
rapidly
C4AH
crystals
at
the
surface
of
C3S
–
causing
rapid
setting
of
the
cement
To
retard
the
quick
setting
gypsum
or
anhydrite
or
a
combination
of
both
is
added
at
the
grinding
stage
of
the
cement
clinker.
As
this
generates
heat
sometimes
part
of
the
gypsum
is
converted
to
hemi-­‐hydrate.
The
sulphate
reacts
with
the
alumina
and
enrobes
a
layer
of
ettringite
around
the
C3A
particles.
Thus
preventing
them
to
go
in
solution
quickly.

7. binary
system
CSA+OPC
When
CSA
cement
is
used
most
of
the
sulphate
of
the
OPC
is
absorbed
immediately
by
the
additional
aluminates.
It
therefor
cannot
act
as
a
retarder
of
the
C3A
phase
leading
to
rapid
setting
of
the
matrix.
The
strength
development
however
is
limited
because
still
the
amount
ettringite
is
relatively
low.
Also
the
long
term
strength
is
reduced
because
C3A
is
putting
a
gel
around
the
C3S
and
C2S
phases
preventing
a
regular
hydration.

8. binary
system
CSA+OPC
CSA
is
more
soluble
than
anhydrite
but
less
soluble
than
gypsum
and
hemi-­‐
hydrate.
So
when
Calumex
is
mixed
with
an
OPC
that
contains
anhydrite
–
Calumex
will
dissolute
quickly
enough
to
react
with
the
sulphate
ions
released
by
anhydrite
thus
preventing
them
to
retard
the
C3A
phase
of
the
OPC,
giving
rapid
set
at
relative
low
dosage.
When
on
the
other
hand
an
OPC
is
used
containing
hemi-­‐hydrate
–
the
dissolution
is
higher,
sulphate
ions
are
released
more
quickly
and
react
with
the
C3A.
In
this
case
a
higher
dosage
is
needed
to
give
the
same
acceleration.

9. binary
system
CSA+OPC
In
any
case
if
an
OPC
is
used
with
a
higher
C3A
content
it
will
contribute
to
a
rapid
set.
A
higher
free
lime
content
of
the
OPC
–
and/or
an
addition
of
calcium
ions
(calcium
oxide/hydroxide)
will
accelerate
the
formation
of
ettringite.
It
is
essential
to
choose
the
right
OPC
for
the
intent
use
of
the
mortar
In
any
case
a
stable
cement
is
essential
–
any
variation
in
free
lime
content
and
amount
and
type
of
calcium
sulphate
(di-­‐hydrated)
asks
for
re-­‐establishing
the
amount
of
CSA
to
be
used.

10. ternary
system
CSA+OPC+additional
CŠ
When
additional
calcium
sulphate
is
added
to
a
blend
of
CSA
and
OPC
more
ettringite
crystals
are
formed
i.e.
a
higher
initial
strength
is
obtained.
Ettringite
is
the
first
strength
found
CALUMEX
CSA
generally
releases
more
quickly
its
alumina
ions
compared
to
other
sources
of
calcium
aluminate.
Slow
soluble
anhydrite
is
by
far
the
preferred
source
of
sulphate
in
a
Calumex
system
–
aluminate
phases
go
in
solution
first
allowing
to
absorb
all
of
the
sulphate
(even
if
the
OPC
brings
hemi-­‐hydrate)
and
converts
it
into
ettringite
crystals.

11. ternary
system
CSA+OPC+additional
CŠ
Calumex
gives
no
lime
nor
reactive
silicates
which
guarantees
long
storage.
The
lime
needed
to
form
ettringite
is
taken
from
the
Portlandcement.
As
lime
is
taken
out
of
the
equation
–
normally
acting
as
a
gel
preventing
silicate
and
aluminate
phases
to
go
in
solution
–
this
further
contribute
to
the
increase
of
the
strength.
In
case
more
soluble
types
of
calcium
sulphate
are
being
used
(i.e.
hemi-­‐hydrate
–α
or
β
or
gypsum)
because
of
their
higher
solubility
–
they
will
react
only
with
the
aluminate
phases.
It
will
give
acceleration
of
the
set
–
by
early
formation
of
ettringite
–
but
to
a
lesser
extend
compared
to
anhydrite
The
higher
solubility
leads
to
slower
reaction
because
it
will
prevent
the
C3A
to
react.

12. ternary
system
CSA+OPC+additional
CŠ
To
overcome
this
effect
a
higher
dosage
of
CSA
is
needed
An
ideal
binder
system
combining
all
elements
of
rapid
set,
high
early
strength
and
shrinkage
compensation
could
be
2
parts
of
OPC
CEM
I
42,5R
to
1
part
of
Calumex
Quick.

13. binary
system
ACA+CŠ
An
ideal
binder
system
is
a
combination
of
amorphous
calcium
aluminate
and
calcium
sulphate
–
without
addition
of
OPC.
As
the
CaO
to
Al2O3
ratio
is
to
the
advantage
of
calcium
and
the
main
phase
formed
by
the
alumina
phase
is
C12A7
–
the
reaction
with
sulphate
is
much
faster
and
more
C4A3Š
is
formed
without
the
further
addition
of
lime
(i.e.
OPC)
The
reaction
in
short
is
;
C12A7+3CŠ
C4A3Š
+
AH3
When
used
as
an
addition
to
Portlandcement
the
excess
of
lime
will
give
an
instant
setting
of
the
binder
,
and
the
high
amount
of
ettringite
formed
gives
an
extreme
fast
strength
development.
There
is
no
risk
on
“conversion”
of
the
hydrates
in
time.

14. conclusion
CALTRA
offers
a
wide
range
of
calcium
aluminate
,
calcium
sulpho
aluminate
and
amorphous
calcium
aluminates
giving
formulators
the
complete
freedom
to
choose
the
correct
type
to
satisfy
their
needs.
CALTRA
continues
to
develop
binders
and
binder
systems
for
specific
applications.
Some
of
the
latest
;
CALUMEX
WHITE
–
a
white
CSA
for
decorative
screeds
,
terrazzo
,
decorative
prefab
concrete
–
GRC
panels
,
tile
grouts
–
natural
stone
adhesives
etc.
CEM-­‐FLUX
–
a
cement
designed
for
the
RMC
plants
as
a
ready
binder
for
pumpable
screeds
ULTRA-­‐FLUX
–
a
cement
for
decorative
overlayments

15. R&D
CALTRA
has
its
own
r&d
lab
–
ready
to
answer
any
queries
you
may
have.
To
further
improve
or
optimize
existing
products
or
help
develop
new
products.
We
work
closely
together
with
our
customers
in
strict
confidentiality
–
to
mutual
benefit.