Lightweight and ultra-high ductility engineered geopolymer composite for marine application: Design and material characterization

This study focused on revealing the effects of the key design parameters including GGBS content, fiber content, and heating curing time on the mechanical properties of lightweight and ultra-high ductility engineered geopolymer composite (EGC) through the Taguchi method and proposed the optimal level. A total of 9 sets of mixtures were tested according to the L9 array with 3 factors and 3 levels by performing compressive and uniaxial tensile tests. In addition, XRD and TG techniques were employed to reveal the underlying mechanisms. The results indicated that GGBS content was the most important factor affecting the mechanical properties with the optimal GGBS content of 0.7. Fiber content and heating curing time had a slight effect. Remarkably, a low fiber content of only 0.8%, decreasing by 60% compared to the traditional 2%, could achieve an ultra-high ductility of above 9%. Based on mechanical properties, cost and energy consumption, the optimal fiber content and heating curing time were 0.8% and 1d. A decrease in GGBS content reduced the quantity of geopolymerization products of C(N)-A-S-H gels, which compromised the matrix compactness but favored the multiple cracks and high ductility. The heating curing time had a negligible effect on the geopolymerization reaction. The current findings can facilitate the optimal design of EGC towards lightweight and high performance, promoting its application in marine engineering.