Abstract :
The influence of calcium and its content on
the structure formation, hardening, and performance
of fly ash based geopolymeric binder was the objective
of our investigation. Calcium hydroxide was added to
fly ash in different amounts. Since it is known that the
formed structure determines certain properties of the
material, the coherence between different types and
various ratios of the reaction products on thermal
properties such as strength after thermal treatment up
to 1,100 C, thermal resistance under load, creep in
compression, and axial dilation were investigated. The
results were compared to the type and composition of
the reaction product, which was detected, for example,
by 29Si NMR spectroscopy and X-ray diffraction.
Along with calcium containing zeolitic phases, the
calcium built C–S–H-phases using the silicon from the
fly ash, both of which crystallize or convert into new
phases at elevated temperatures
