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: The incorporation of water improved the workability of geopolymer mortar more effectively than the use of napthalene-based superplasticizer with similar slight reduction in strengths and the addition of NaOH solution slightly improves the workable of the mix while maintaining the strength of the geopolym mortars.
392 citations
TL;DR: It was found that synthesised geopolymer matrixes were only effective in the chemical immobilisation of a number of elements of environmental concern contained in fly ashes, reducing (especially for Ba), or maintaining their leachable contents after the geopolymisation process, but not for those elements present as oxyanions.
388 citations
TL;DR: In this paper, the increase in strength and evolution of crystalline phases in inorganic polymer cement, made by the alkali activation of slag, Class C and Class F fly ashes, was followed using compressive strength test and synchrotron X-ray diffraction in order to increase the crystallinity of the product.
388 citations
TL;DR: In this article, a set of sodium metasilicate-activated fly ash/slag blends using a synchrotron beamline instrument is segmented into pore and solid regions, and pore tortuosity is calculated by a random walker method.
387 citations
TL;DR: In this paper, the effect of varying silica and alumina contents on setting, phase development, and physical properties of high calcium fly ash (ASTM Class C) geopolymers was investigated by adjusting SiO2/Al2O3 ratio of the starting mix, via series of mixes formulated with varying SiO 2 or Al2O 3 contents to achieve Si O 2/Al 2O3 in the range 2.87-4.79.
Abstract: This study investigates the effect of silica and alumina contents on setting, phase development, and physical properties of high calcium fly ash (ASTM Class C) geopolymers. The characteristic rapid setting properties and, hence, limited workability range of high calcium fly ash geopolymers has restricted both development and potential application of these binder systems compared to conventional geopolymer binders derived from bituminous coal, i.e., (ASTM Class F) sources or from calcined kaolin feedstocks. For this study, control of setting and hardening properties were investigated by adjusting SiO2/Al2O3 ratio of the starting mix, via series of mixes formulated with varying SiO2 or Al2O3 contents to achieve SiO2/Al2O3 in the range 2.87–4.79. Foremost is the observation that the effect of varying silica and alumina in high calcium fly ash systems on setting and hardening properties is markedly different from that observed for traditional Class F geopolymer systems. Overall, increases in either silica or alumina content appear to shorten the setting time of high calcium-based systems unlike conventional geopolymer systems where increasing Al2O3 accelerates setting. The setting process was associated primarily with CSH or CASH formation. Furthermore, there appears to be a prevailing SiO2/Al2O3 ratio that prolongs setting, rather than Ca2+ ion content itself, while NASH primarily contributes to strength development. SiO2/Al2O3 ratios in the range of 3.20–3.70 resulted in products with highest strengths and longest setting times. These results suggest that initial predominance of Ca2+ ions and its reactions effectively help maintaining a SiO2/Al2O3 ratio at which amorphous geopolymer phase is stable to influence setting and initial strength development.
384 citations