PSI - Issue 70

Nithin A V et al. / Procedia Structural Integrity 70 (2025) 215–222

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Flexure cracks

Fig.4. a) Crack patterns on optimum two-way TBGCS

Fig.4. b) load-steel strain plots for TBGC slabs

4. Conclusions

In this study, the impact of binder composition and fine aggregate replacement on the behaviour of two-way ternary blended geopolymer concrete slabs were investigated.

• The optimum mix ratios of binder materials were obtained at 30% fly ash (FA), 30% hydrous clay (HC), and 40% ground granulated blast furnace slag (GGBS) and fine aggregates at 40% copper slag (CS) and 60% manufactured sand (M-sand). • The slab specimen with mix F30H30G40-CS40 exhibited enhanced load-bearing capacity, delayed onset of first cracking, and greater ductility compared to the control slab with mix F60G40. • Partial replacement of fine aggregate with copper slag contributed to more uniform stress distribution, narrower crack widths, and stronger interfacial bonding • All slabs exhibited flexural failure modes, having diagonal crack propagation originating from the mid-span and extending toward the slab corners. • Reinforcement bars in the F30H30G40-CS40 slab reached yield at a higher load (28.6 kN) than in the control mix (24.3 kN), indicating more effective stress transfer and improved structural engagement. • The addition of 40% CS in F30H30G40-CS40 slab type enhanced energy absorption capacity, with a 9.2% increase in the area under the load – deflection curve, suggesting better toughness. • Strain gauge measurements confirmed that the optimum mix allowed the reinforcement to undergo plastic deformation, contributing to higher ductility and post-yield behaviour Acknowledgements The authors gratefully acknowledge the Structural Engineering Laboratory at the College of Engineering Trivandrum for providing the necessary facilities and support for this research. References Altay Eren, N. (2022). Punching shear behavior of geopolymer concrete two-way flat slabs incorporating a combination of nano silica and steel fibers. Construction and Building Materials, 346, 128351. https://doi.org/10.1016/J.CONBUILDMAT.2022.128351 Bhuvaneshwari, P., Suchitra, B., & Divya, R. (2024). Toughness Characteristics of Microfiber-Based Geopolymer Concrete Voided Slabs under Soft Impact. Journal of Testing and Evaluation, 52(4), 2483–2502. https://doi.org/10.1520/JTE20230634 Chen, C., Zhang, X., Hao, H., & Sarker, P. K. (2025). Experimental and numerical study of steel fibre reinforced geopolymer concrete slab under impact loading. Engineering Structures, 322, 119096. https://doi.org/10.1016/J.ENGSTRUCT.2024.119096 Gharieb, M., & Khater, H. M. (2025). Valorization study of mixing aluminum slag with binary geopolymer blends to produce lightweight geopolymer concrete. Construction and Building Materials, 466, 140288. https://doi.org/10.1016/J.CONBUILDMAT.2025.140288