Topic
Geopolymer
About: Geopolymer is a research topic. Over the lifetime, 6776 publications have been published within this topic receiving 157991 citations. The topic is also known as: geopolymers.
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TL;DR: In this article, the authors developed mortars and concrete from fly ash and bottom ash and compared the characteristics deriving from either of these products by mixing the ashes with sodium silicate and sodium hydroxide as activator solution.
177 citations
TL;DR: In this article, the results of the pore-forming process in the case when two different foaming agents, i.e., aluminium powder amounting to 0.07, 0.13 and 0.20 mass, were added to a fly-ash geopolymer matrix.
177 citations
TL;DR: In this article, the reaction kinetics and mechanism of geopolymers are studied and a characteristic time for the setting of the reaction mixture is derived from isothermal Dynamic Mechanical Analysis experiments.
Abstract: The reaction kinetics and mechanism of geopolymers are studied. The dissolved silicate concentration decreases from the beginning of the reaction. A characteristic time ‘t
0,vit’ for the setting of the reaction mixture is derived from isothermal Dynamic Mechanical Analysis experiments. ‘t
0,vit’ increases with SiO2/R2O but goes through a minimum for increasing water content. The reaction is slower for K compared to Na-silicate based systems. 29Si and 27Al solution NMR are used to probe the molecular changes. 27Al NMR and FTIR reveal that an ‘intermediate aluminosilicate species’ (IAS) is formed from the start of the reaction. The concentration decrease of OH− during low-temperature reaction is related to the formation of IAS. The rate law of this process seems to be obeyed by a total reaction order of 5/3, with a partial order of 1 for OH− and 0 for Na+ in the silicate solution. During first heating after polymerization water is lost leading to a distortion of the Al environment. According to XRD, no crystallization occurs below 900 °C. However, between 950 and 1100 °C a crystallization exotherm of nepheline is observed with DSC for a geopolymer with SiO2/Na2O = 1.4. Neither T
g of the amorphous geopolymer, nor the shrinkage and expansion around T
g during first heating, cause a measurable heat effect.
177 citations
TL;DR: In this paper, the suitability of illite/smectite clay to form a geopolymer after thermal and alkaline activation was investigated and the performance of the binder in terms of strength as well as the phase composition was studied.
177 citations
TL;DR: In this paper, the microstructure, reaction products, and reactivity of fly ash/slag binders synthesized at various mixture ratios of two raw materials were examined using various experimental techniques (NMR, ICP-OES, EDS, FT-IR and TGA).
176 citations