Innovations et nouvelles recherches

Chapter 9: Calcium-based geopolymer
“There is production of two geopolymers: hydrated gehlenite and (Na,K)–poly(sialate-siloxo), and in addition calcium di-siloxonate hydrate (CSH cement type). Further research is needed on this very interesting topic of ancient Roman technology. (…) We could also assume that, in the hydrated state, our geopolymeric structures are more flexible than the rigid anhydrous chains. Their molecular arrangement might comply with the replacement of K⁺ with Ca⁺⁺. Further research is needed to clarify this important issue.”

Chapter 10: Rock-based geopolymer
“The extrapolation from the solid solution structures set forth in Chapter 9 would probably focus on the Ca-siloxonate-hydrate, and its resonance at -78 ppm for Q₁ structure in the ²⁹Si spectrum of Figure 10.5. However, in addition to the dimer Ca-di-siloxonate hydrate molecule, one could get higher oligomers: trimer, tetramer, pentamer, hexamer, with cyclic structures similar to those depicted for soluble silicates in Figure 5.13 of Chapter 5 as well as in Figure 2.8 of Chapter 2. Further research is needed.”

Chapter 11: Silica-based geopolymer
“The geopolymer composite has a high potential for fire-heat resistant coatings as well as corrosion resistant paint for steel. With tailored ceramic fillers one obtains heat stable materials with remarkable heat resistance. Further research is needed. (…) These results highlight the need for caution during the use and disposal of these manufactured nanomaterials to prevent unintended environmental impacts, as well as the importance of further research on tailored formulations aimed at preventing any risk.”

Chapter 12: Fly ash-based geopolymer
“Overall, the geopolymer matrix gives a Si:Al molar ratio ranging from 1.56–2.14 corresponding to a poly(sialate-siloxo) with inclusions of siloxonate-hydrate molecules consisting of higher oligomers: trimer, tetramer, pentamer, hexamer, with cyclic structures similar to those depicted for soluble silicates in Figure 5.13 of Chapter 5 as well as in Figure 2.8 of Chapter 2. Further research is needed. (…) Gasifier slag consists of four main components: silica, alumina, iron oxide and calcium oxide, mainly added as a flux in the gasification process. The gasifier slag composition is similar to that of iron blast-furnace slag (Sullivan and Hill, 2001). In other words, a possible shortage of iron blast-furnace slag would be easily compensated by the production of gasifier slag, opening new perspectives for the industrial implementation of geopolymers issuing from coal combustion in electrical power plants. Further research is needed.”