https://www.scribd.com/presentation/613349802/AMORPHOUS-CALCIUM-ALUMINATE-CEMENT

1. Amorphous Calcium Aluminate

2. functionality in cement & dry mix applications
CALUMEX SC-A and XT-20
Both types of Amorphous Calcium Aluminate Cement (ACA), one of the latest developments in cement chemistry,
consist of CaO and Al2O3 in a mole ratio of 12:7
Main phase formed; 12CaO . 7Al2O3 (C12A7-mayenite) a most reactive phase in cement
hydration.
CALUMEX SC-A and XT-20 both have a high dissolution rate and are completely soluble.
Amorphous content is well over 95% - and ground to a high surface area with strict control on
particle size distribution - further improve the reactivity .
In water alumina ions are released promptly, rapidly consuming gypsum and calcite leading to
instant precipitation of ettringite crystals as first hydrate.
accelerated set
high efficiency binder system
high initial- and late strength
shrinkage compensation dimensional stable
dense cement matrix
quick drying
efflorescence reduction
lower dosage - 2x more efficient than crystalline calcium alumina cement
fast precipitation
used in white cement application
ettringite potential is 2 x higher than use of regular calcium alumina cement
no additional accelerator needed
high reactivity even at low ambient temperatures
Featuring
In todays new binder systems the amount of pure Portland clinker is increasingly
replaced by SCM’s often resulting in reduction of the initial strength and delay
setting time.
CALUMEX ACA addition gives a robust and high efficiency binder;
compensate the loss of early strength
accelerate the set
dimensional stability
quick drying
allows reduction of binder content up to 40%
depletion of efflorescence
low carbon footprint
50% industrial by-product production
calcination emits relative low amount carbon dioxide
REDUCTION
Environment
Part replacement to cement

3. changing the chemistry of XT-20 the reactivity of amorphous calcium
aluminate cement is more moderate giving a longer working time
0~20% replacement of Portlandcement gives a ~20 min.set, and a
more progressive increase of strength, rapid autogenous drying and
dimensional stability.It is used in tile adhesives, screeds, SLU, repair
mortars, 3D printing etc.
Amorphous Calcium Aluminate at 10~20% replacement of
Portlandcement gives an instant set, high early strength, fast drying,
Predominantly used in cements and mortars like Postfix, waterplug,
shotcrete, nuclear waste encapsulation etc. where a set of the binder
within seconds is required.

4. Regular chemical admixtures such as air entrainers, set modifiers, water reducers, etc. can be used in
cement matrix including amorphous calcium aluminate.
To further regulate setting times and/or adjusting strength development accelerators like aluminium-sulfate,
lithium carbonate, potassium sulfate can be added.
Allowing sufficient “ope time” retarders like borax, fruit acids, carboxylic acids, sodium gluconate etc. can be
used.
To facilitate the use of high reactive power accelerator CALUMEX ACA we developed a special powder
retarder having no impact on strength development.
Below graph shows the impact of DELTA20 even at low dosage compared to tartaric acid.
diagrams show the flexural and compressive in MPa - strength based on the following formulation:
360gr CEM I 52,5R and 40gr CALUMEX SC-A and TX-20 mixed with 160gr water (including 0,2% tartaric acid)