T.D. As a lab instructor, recently I got a chance to introduce the topic of
geopolymers and ceramics to an international group of students. Students
made their own geopolymer samples from fly-ash, prepared moulds and
characterized them by FTIR using KBr pellets (for structural composition),
by DSC of fresh mixture (to obtain heat of hydration), by Instron machine
using ASTM standards, after wet, dry and wet-dry processing (to measure
compressive strength) and so on. The student feedback was overwhelming; they asked thought-provoking questions and became more and more
interested. What message do you have for student researchers like them?
Dr. Davidovits
Although geopolymerization does not rely on
toxic organic solvents
but only on water, it
needs strong alkalis
such as sodium hydroxide (NaOH) that may be
dangerous, and therefore requires some safety precautions. Because
I was a chemist, when I
started the research on
geopolymers I decided
to select alkaline conditions that could be classified as “mild”, i.e. userfriendly. Unfortunately,
this was not followed
by other engineers
and scientists involved
in the development of
geopolymeric systems.
Apparently, these scientists never put their
finger into their reaction mixture, which
has a SiO2:Na2O ratio
of 0.20 or 0.60. The
problem is that practically all papers dealing
with “alkali-activated”
cements describe recipes that are not userfriendly. To recommend
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them for regular building and civil engineering operations, where
people are working with
bare hands, is nonsense.
This could explain why
geopolymer
cement
technology has not
reached mass applications and remains confined to high-tech niche
markets. So my message is: develop “userfriendly” systems.