Conventional thermal curing remains time-consuming and energy-intensive; therefore, this study introduces microwave (MW) curing as a rapid and more energy-efficient alternative. This study investigates MW-assisted curing of metakaolin (MK)–volcanic ash (VA) geopolymers, which are activated using a 10 M NaOH solution with a Na₂SiO₃/NaOH ratio of 1.5. VA is used as a replacement for MK at levels ranging from 0% to 100%. Unconfined compressive strength (UCS), phase composition, and microstructure are evaluated and compared with those of ambient-cured samples. The highest UCS of 10.99 MPa is obtained for the 50% VA mixture cured under MW at 400 W for 15 min, representing a 64% increase relative to 28-day ambient curing. Under identical conditions, the 100% VA geopolymer achieves 8.44 MPa, nearly two orders of magnitude higher than its ambient-cured counterpart. SEM reveals a dense N–A–S–H gel with minimal unreacted particles, and XRD confirms higher crystalline phases and a dominant geopolymer gel.
Hosseini et al. (Wed,) studied this question.