Sustainable single and hybrid fiber reinforcement of ternary geopolymer composites with waste marble powder: Synergistic effects of micro steel, basalt, and carbon fibers

Ordinary Portland cement (OPC) production raises environmental concerns, driving research into sustainable alternatives like alkali-activated geopolymer composites (GPC). This study examines the mechanical, durability, and thermal properties of ternary GPCs made with 85% fly ash, 15% metakaolin, and 5% silica fume. Steel, basalt, and carbon (CF) fibers were added in varying amounts to assess their impact. Waste marble powder (WMP) and quartz aggregate (QA) served as fillers to enhance strength and durability. GPCs were cured at 90 degrees C for 16 h and tested for compressive strength, flexural strength, dry unit weight, porosity, water absorption, sorptivity, freeze-thaw resistance, and high-temperature resistance at 200, 400, and 800 degrees C. Fiber reinforcement significantly improved mechanical properties, with CF showing the best performance. The highest compressive strength (40.23 MPa, +21.49%) was recorded in the 1.5% CF mix. CF-reinforced mixtures also had the lowest porosity (6.76%) and water absorption (6.55%), improving durability. At high temperatures, all mixtures gained strength at 200 degrees C due to matrix densification. Strength loss at 800 degrees C ranged from 10.1% to 20.6%, with CF-reinforced composites exhibiting the highest thermal resistance. Freeze-thaw tests showed that CF mixtures had the lowest strength loss (12.7%), confirming their durability benefits. These findings demonstrate that hybrid fiber reinforcement enhances the performance of geopolymer composites, making them suitable for structural applications requiring superior strength, durability, and thermal stability.

Journal

STRUCTURAL CONCRETE

Year

2026

Volume

27

Issue

1

Pages

1205-1233

ISSN

1464-4177

eISSN

1751-7648

DOI

10.1002/suco.70173

WoS UID

WOS:001501076200001