Ispectrum Magazine Ispectrum Magazine #06 - Page 62

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 61 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.