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 paper, the chemical interactions between natural siliceous aggregates and a low-Ca alkali-activated cement (geopolymer) were studied by leaching ideal aluminosilicate minerals such as kaolinite and albite in various alkaline solutions with or without soluble silicates.
80 citations
TL;DR: In this paper, the thermal stability of binary geopolymers with fly ash and high magnesium nickel slag (HMNS) was investigated, and the results showed that incorporating HMNS mitigates dehydration induced mass loss and volume shrinkage of the geopolymer samples between room temperature and 250°C, and increases their residual strengths when exposed to high temperatures between 600°C and 800°C.
80 citations
TL;DR: The preparation and characterization of metakaolin-based geopolymer mortars containing an organic epoxy resin are presented here for the first time and the microstructural characterization allows to point out the presence of an Interfacial Transition Zone similar to that observed in cement based mortars and concretes.
Abstract: The preparation and characterization of metakaolin-based geopolymer mortars containing an organic epoxy resin are presented here for the first time. The specimens have been prepared by means of an innovative in situ co-reticulation process, in mild conditions, of commercial epoxy based organic resins and geopolymeric slurry. In this way, geopolymer based hybrid mortars characterized by a different content of normalized sand (up to 66% in weight) and by a homogeneous dispersion of the organic resin have been obtained. Once hardened, these new materials show improved compressive strength and toughness in respect to both the neat geopolymer and the hybrid pastes since the organic polymer provides a more cohesive microstructure, with a reduced amount of microcracks. The microstructural characterization allows to point out the presence of an Interfacial Transition Zone similar to that observed in cement based mortars and concretes. A correlation between microstructural features and mechanical properties has been studied too.
80 citations
TL;DR: In this paper, the phase transformation, microstructural and mechanical changes that occur in the geopolymer composites when fine aggregates of quartz sand are added were examined, showing good polycondensation and more cohesion resulting in high strength due to the better dissolution of RHA that provides soluble reactive silica to equilibrate the Si/Al and Si/Fe molar ratios.
79 citations
01 Jan 2009
TL;DR: In this article, the stability of amorphous geopolymer gels is examined through the use of accelerated ageing tests, and the effect of conversion to crystalline phases is examined.
Abstract: In this chapter the stability of amorphous geopolymer gels is examined, in particular through the use of accelerated ageing tests. Some assumptions regarding the persistence of the amorphous gel and the effect of conversion to crystalline phases are examined. Amorphous geopolymer gels synthesised from metakaolin, previously thought to be stable, are found to form crystalline zeolites upon ageing, accompanied by major restructuring of the gel and a dramatic loss of performance. Physically, the process bears some similarity to the well-known conversion phenomenon in calcium aluminate cements. Although some of the same reactions are observed in fly ash based geopolymer gels, they do not result in major strength regression, possibly due to the overlap between primary gel formation and crystallisation reactions. The presence of calcium appears to suppress crystallisation of zeolites.
79 citations