The Effect of Microwave Curing on the Strength Development of Class-F Fly Ash-Based Geopolymer Mortar

Khaleel F., Atiş C. D., Durak U., İlkentapar S., Karahan O.

Erciyes Üniversitesi Fen Bilimleri Enstitüsü Dergisi, vol.37, no.1, pp.118-129, 2021 (Peer-Reviewed Journal)


This study investigates the influence of microwave (MW) curing on the strength development of geopolymer. Since applying conventional oven heat curing makes the heat move from the outer edge to the center of the specimen, it leads to a non-uniform of distributing heat within the specimen, which affects the mechanical properties of the geopolymer. On the other hand, the use of MW reduces the curing time and allows uniform heat distribution within samples, and provides higher mechanical properties in a short period. The influence of conventional heat curing and MW curing on class F fly ash based geopolymer activated with sodium hydroxide and sodium metasilicate was investigated. The conventional heat curing was applied at 75 and 90°C for 6 and 24 hours; on the other hand, additional MW curing was applied for a different period (5-60 minutes) and different energy level (100, 180 and 300W) on hardened geopolymer samples cured with conventional oven curing. The results show that the use of conventional heat curing for 6 hours, followed by MW curing, gave higher or equivalent strength compared to only conventional heat curing. While 24 hours conventional heat curing results with a geopolymer having 39.1 MPa compressive strength, 6 hours conventional heat curing followed by 1 hour MW curing at 180W energy level results with a geopolymer with compressive strength in the order of 80 MPa.