The high-temperature behavior of ternary geopolymers reinforced with polyimide fibers (PIF) remain insufficiently understood. This work systematically evaluates the composite properties of PIF doping metakaolin–fly ash–coal gangue geopolymers (MFCG) via mechanical property, shrinkage, and high-temperature (200 °C, 400 °C, 600 °C, 800 °C, 1000 °C) resistance tests. The results showed that the optimal PIF content was 0.8 %, when the compressive and flexural strengths were increased by 24.8 % and 19.0 %, respectively, and the early shrinkag...
