Fast‐setting mineral‐impregnated carbon‐fiber (MCF) reinforcements based on geopolymers

Mineral‐impregnated carbon‐fiber (MCF) reinforcements are an innovative type of fiber‐reinforced composites, which combine the valuable properties of high‐performance fibers with durable inorganic matrix materials. The application of mineral‐based matrices to produce MCFs offers a wide range of advantages, such as high resistance to elevated temperatures, low cost, adequate physical and chemical bond with concrete substrates and high technological flexibility in automated processing. In particular, specific‐designed geopolymer (GP) impregnation suspensions allow stable rheological properties with a sufficient long‐lasting processing window as well as moderate curing temperatures to accelerate a fast setting on demand ‐ similar to organic based thermosets. The paper at hand studies the effect of various thermal curing regimes of a GP impregnation matrix and for the forming process of the resulting MCF composite. The fabrication of MCFs were performed by using commercially available raw materials and a continuous pultrusion line with subsequent oven heating at 50 °C and 75 °C. A wide range of experimental investigations at multiple scales have been performed to understand the GP matrix development, fiber‐matrix interface and final MCF properties.