Journal ArticleDOI
Effect of SiO2 and Al2O3 on the setting and hardening of high calcium fly ash-based geopolymer systems
Prinya Chindaprasirt,Pre De Silva,Kwesi Sagoe-Crentsil,Kwesi Sagoe-Crentsil,Sakonwan Hanjitsuwan +4 more
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TLDR
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.read more
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Geopolymer concrete: A review of some recent developments
TL;DR: An overview of advances in geopolymers formed by the alkaline activation of aluminosilicates is presented along with opportunities for their use in building construction as mentioned in this paper, with respect to fresh and hardened states, interfacial transition zone between aggregate and geopolymer, bond with steel reinforcing bars and resistance to elevated temperature.
Journal ArticleDOI
One-part alkali-activated materials : a review
Tero Luukkonen,Zahra Abdollahnejad,Juho Yliniemi,Paivo Kinnunen,Paivo Kinnunen,Mirja Illikainen +5 more
TL;DR: A review of one-part AAMs in terms of raw materials, activators, additives, mechanical and physical properties, curing mechanisms, hydration products, and environmental impacts can be found in this paper.
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An overview on the influence of various factors on the properties of geopolymer concrete derived from industrial by-products
TL;DR: In this article, the authors present a concise review of the current studies on the utilization of industrial by-products as the primary binder materials in the fabrication of geopolymer concrete.
Journal ArticleDOI
Effects of sodium hydroxide and sodium silicate solutions on compressive and shear bond strengths of FA–GBFS geopolymer
Tanakorn Phoo-ngernkham,Akihiro Maegawa,Naoki Mishima,Shigemitsu Hatanaka,Prinya Chindaprasirt +4 more
TL;DR: In this article, the effects of sodium hydroxide and sodium silicate solutions on the properties of fly ash (FA)-granulated blast furnace slag (GBFS) geopolymer were investigated.
Journal ArticleDOI
Effects of NaOH concentrations on physical and electrical properties of high calcium fly ash geopolymer paste
Sakonwan Hanjitsuwan,Sitchai Hunpratub,Prasit Thongbai,Santi Maensiri,Vanchai Sata,Prinya Chindaprasirt +5 more
TL;DR: In this article, the effects of sodium hydroxide (NaOH) concentration on setting time, compressive strength and electrical properties at the frequencies of 100 Hz-10MHz of high calcium fly ash geopolymer pastes were investigated.
References
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Journal ArticleDOI
A review on the utilization of fly ash
TL;DR: In this article, the utilization of fly ash in construction, as a low-cost adsorbent for the removal of organic compounds, flue gas and metals, light weight aggregate, mine back fill, road sub-base, and zeolite synthesis is discussed.
Journal ArticleDOI
Influence of nano-SiO2 addition on properties of hardened cement paste as compared with silica fume
TL;DR: In this paper, the influence of nano-SiO 2 (NS) addition on properties of hardened cement paste (hcp) as compared with silica fume (SF) has been studied through measurement of compressive and bond strengths of hcp, and by XRD and SEM analysis.
Journal ArticleDOI
The coexistence of geopolymeric gel and calcium silicate hydrate at the early stage of alkaline activation
TL;DR: In this paper, the effects of ground granulated blast furnace slag (GGBFS) on the microstructure and mechanical properties of metakaolin (MK) based geopolymers were studied.
Journal ArticleDOI
Compatibility studies between N-A-S-H and C-A-S-H gels. Study in the ternary diagram Na2O–CaO–Al2O3–SiO2–H2O
TL;DR: In this article, the compatibility relationship between C-A-S-H and N-Aluminum-modified calcium silicate hydrate (C-A,S,H) gels is assessed.
Journal ArticleDOI
NaOH-activated ground fly ash geopolymer cured at ambient temperature
Kiatsuda Somna,Chai Jaturapitakkul,Puangrat Kajitvichyanukul,Puangrat Kajitvichyanukul,Prinya Chindaprasirt +4 more
TL;DR: In this paper, ground fly ash (GFA), with a median particle size of 10.5μm, was used as source material for making geopolymers cured at room temperature, and compressive strength tests and microstructure observations using SEM, EDX, XRD and FTIR were performed.