Synergistic effect of steel and PVA fibers on the mechanical and microstructural performance of ceramic waste-GGBS-based green composites

This study investigates the mechanical properties of alkali-activated composites formulated with ground granulated blast furnace slag (GGBS) and ceramic waste powder (CWP). The composites also contain 0.7 % polyvinyl alcohol and 1.3 % steel fiber. The evaluations focus on key properties such as compressive strength, flexural strength, splitting tensile strength, and fracture energy. Assessments were conducted at various stages: early ages (1, 3, 7, and 28 days) and long-term ages (56, 90, 180, and 365 days). Microstructural analyses were conducted on the 28th and 365th days using XRD, FT-IR, and SEM-EDS techniques. Based on the test results, fc/fc28 ratio increased from 0.857 to 1.142 in non-fibrous specimens after one day and to 1.231 in fibrous specimens, showing enhanced long-term compressive strength. Similarly, ff/ff28 for fiber-reinforced specimens reached 1.265 after 28 days, indicating fibers can slow crack propagation and improve flexural strength. Furthermore, fibrous composites exhibited significant improvements in ductility and fracture resistance over time, as assessed by fracture energy measurements. Thus, fiber reinforcement not only enhances early-age strength but also contributes to the long-term mechanical properties, positioning it as a promising option for durable concrete structures.