Role of microwave radiation in curing the fly ash geopolymer

• Published in: Advanced powder technology : the international journal of the Society of Powder Technology, Japan Japan, 2013-05, Vol.24 (3), p.703-707
• Main Authors: Chindaprasirt, Prinya, Rattanasak, Ubolluk, Taebuanhuad, Sompop
• Format: Article
• Language: English
• Subjects: Compressive strength; Curing; Densification; Energy conservation; Fly ash; Geopolymer; Microstructure; Microwave radiation; Microwaves; Phases; Powder technology
• ISSN: 0921-8831; 1568-5527
• DOI: 10.1016/j.apt.2012.12.005

[Display omitted] ► Microwave radiation in conjunction with the conventional heat curing. ► Microwave radiation gave the enhanced densification. ► Microwave promoted dissolution of amorphous phases from fly ash. ► Microwave effectively enhanced the geopolymerization and strength of geopolymer. Fly ash geopolymer requires rather long heat curing to obtain reasonable strength development at an early age. However, the long heat curing period limits the application of the fly ash geopolymer. High strength development and a reduction in heat curing duration have been considered for energy saving. Therefore, this research proposed a process using 90-W microwave radiation for 5min followed by conventional heat curing for high-calcium fly ash geopolymer. Results showed that the compressive strengths of geopolymer with microwave radiation followed by conventional heat curing were comparable to those of the control cured at 65°C for 24h. Microwave radiation gave the enhanced densification. In addition, SEM images showed that the gels formed on the fly ash particles owing to the promoted dissolution of amorphous phases from fly ash. This method accelerated the geopolymerization and gave the high compressive strength comparable to the conventional curing.