Performance Evaluation of Nano TiO₂–Basalt Fiber Hybrid Geopolymers: Mechanical Response, Long-Term Durability, and Metal Immobilization Efficiency
J. Environ. Nanotechnol., Volume 15, No 1 (March 2026) pp. 21-34
Abstract
Geopolymers have emerged as promising low-carbon alternatives to Portland cement; however, their quasi-brittle behavior and sensitivity to microcracking limit broader structural adoption. This study investigates the synergistic effects of basalt fiber and TiO₂ nanoparticle reinforcement on the mechanical, durability, microstructural, and leaching performance of fly ash–slag based geopolymers. Five mix formulations were prepared with varying basalt fiber volume fractions (0–1.0%) and TiO₂ nanoparticle dosages (0–2.0%). Comprehensive characterization—including compressive, flexural, and tensile testing; permeability, acid/sulfate exposure, freeze–thaw cycling; SEM, XRD, FTIR analyses; and TCLP-based leachate evaluation—was conducted. Results show that TiO₂ incorporation substantially refines the matrix through accelerated geopolymerization and pore densification, while basalt fibers enhance crack bridging, tensile resistance, and structural stability. The hybrid mix containing 1.0% basalt fiber and 1.0% TiO₂ (GP-B1T1) exhibited the best performance, with compressive strength exceeding 68 MPa, reduced sorptivity (≈0.19 mm/min¹ᐟ²), minimal freeze–thaw damage, superior chemical resistance, and up to 30% reduction in heavy metal leaching compared to the control. Microstructural analyses confirmed the formation of a highly compacted gel network with strong fiber–matrix bonding and minimal microdefects. These findings demonstrate that multi-scale reinforcement using TiO₂ nanoparticles and basalt fibers can significantly elevate the structural reliability, durability, and environmental stability of geopolymer composites, positioning them as viable candidates for sustainable infrastructure applications.
Full Text
Reference
Arab, M. A. E. S., Mohamed, A. S., Taha, M. K. and Nasr, A., Microstructure, durability and mechanical properties of high strength geopolymer concrete containing calcinated nano-silica fume/nano-alumina blend, Constr. Build. Mater., 472, 140903 (2025).
https://doi.org/10.1016/j.conbuildmat.2025.140903
Bouchikhi, A., Mamindy-Pajany, Y., Maherzi, W., Albert-Mercier, C., El-Moueden, H., Benzerzour, M. and Abriak, N. E., Use of residual waste glass in an alkali-activated binder–Structural characterization, environmental leaching behavior and comparison of reactivity, J. Build. Eng., 34, 101903 (2021).
https://doi.org/10.1016/j.jobe.2020.101903
de Azevedo, A. R., Cruz, A. S., Marvila, M. T., de Oliveira, L. B., Monteiro, S. N., Vieira, C. M. F. and Daironas, M., Natural fibers as an alternative to synthetic fibers in reinforcement of geopolymer matrices: A comparative review, Polymers, 13(15), 2493 (2021).
https://doi.org/10.3390/polym13152493
Han, B., Ding, S., Wang, J. and Ou, J., Basic principles of nano-engineered cementitious composites, Nano-Eng. Cementitious Compos., 1–96 (2019).
https://doi.org/10.1007/978-981-13-7008-1_1
Hashem, F. S., Razek, T. A., Mashout, H. A. and Selim, F. A., Fabrication of slag/CKD one-mix geopolymer cement reinforced by low-cost nano-particles: Mechanical behavior and durability performance, Sci. Rep., 14(1), 2549 (2024).
https://doi.org/10.1038/s41598-024-52549-3
Hegyi, A., Lăzărescu, A. V., Ciobanu, A. A., Ionescu, B. A., Grebenişan, E., Chira, M. and Stoian, V., Developing cementitious or geopolymer composites by exploiting photocatalytic properties of TiO₂ nanoparticles, Materials, 16(10), 3741 (2023).
https://doi.org/10.3390/ma16103741
John, V. J. and Dharmar, B., Influence of basalt fibers on the mechanical behavior of concrete—A review, Struct. Concr., 22(1), 491–502 (2021).
https://doi.org/10.1002/suco.202000248
Kahla, N. B., Raza, A., Elhag, A. B. and Haider, H., Synergistic effects of hybrid microfibers on mechanical, thermal, and microstructural characterization of nanocomposites, Environ. Sci. Pollut. Res., 31(17), 25991–26005 (2024).
https://doi.org/10.1007/s11356-024-32145-6
Korayem, A. H., Tourani, N., Zakertabrizi, M., Sabziparvar, A. M. and Duan, W. H., Dispersion of nanoparticles in cementitious matrices: Nanoparticle geometry perspective, Constr. Build. Mater., 153, 346–357 (2017).
https://doi.org/10.1016/j.conbuildmat.2017.07.089
Li, Z., Li, J., Lu, W. and Zhang, Y., Research progress and application prospects of plant fibers in geopolymer concrete: A review, Materials, 18(10), 2342 (2025).
https://doi.org/10.3390/ma18102342
Liu, J. and Lv, C., Durability of cellulosic-fiber-reinforced geopolymers: A review, Molecules, 27(3), 796 (2022).
https://doi.org/10.3390/molecules27030796
Maiti, M., Sarkar, M., Maiti, S., Malik, M. A. and Xu, S., Modification of geopolymer with size-controlled TiO₂ nanoparticle for enhanced durability and catalytic dye degradation, J. Clean. Prod., 255, 120183 (2020).
https://doi.org/10.1016/j.jclepro.2020.120183
Mohamed, H., Deutou, J. G. N., Kaze, C. R., Beleuk à Moungam, L. M., Kamseu, E., Chinje Melo, U. and Leonelli, C., Mechanical and microstructural properties of geopolymer mortars from meta-halloysite with TiO₂ addition, SN Appl. Sci., 2(9), 1573 (2020).
https://doi.org/10.1007/s42452-020-03371-4
Mohd Basri, M. S., Mustapha, F., Mazlan, N. and Ishak, M. R., Rice husk ash-based geopolymer binder: Strength, FTIR and fire-retardant potential, Polymers, 13(24), 4373 (2021).
https://doi.org/10.3390/polym13244373
Nanthini, M., Ganesan, R. and Jaganathan, V., Durability of ambient-cured metakaolin-based geopolymer concrete under sustainable environments, J. Environ. Nanotechnol., 13(2), 1–9 (2024).
https://doi.org/10.13074/jent.2024.09.242754
Ojaghi, K., Kalateh, F. and Yaghin, M. A. L., Impact of nanoparticle additives on fiber adhesion in UHPC for corrosive traffic environments, Int. J. Transp. Eng., 12(4), 1947–1972 (2025).
https://doi.org/10.22119/IJTE.2025.1947
Raza, A., Azab, M., Baki, Z. A., El Hachem, C., El Ouni, M. H. and Kahla, N. B., Micro-carbon fiber reinforced geopolymer with nano-TiO₂: Mechanical and microstructural study, Alexandria Eng. J., 64, 451–463 (2023).
https://doi.org/10.1016/j.aej.2022.11.036
Raut, J. M., Pande, P. B., Madurwar, K. V., Bahoria, B. V., Bhagat, R. M., Kakade, N. T. and Muley, M., Performance optimization of hybrid nano-engineered geopolymer binders-based UHPC, Nano-Struct. Nano-Objects, 42, 101469 (2025).
https://doi.org/10.1016/j.nanoso.2025.101469
Sivasakthi, M., Jeyalakshmi, R. and Rajamane, N. P., Thermomechanical properties of nano-TiO₂ admixed geopolymer for thermal resistance, J. Mater. Eng. Perform., 30(5), 3642–3653 (2021).
https://doi.org/10.1007/s11665-021-05742-9
Sujitha, V. S. and Ramesh, B., Influence of nano-alumina reinforced SAP on cementitious materials, J. Build. Eng., 79, 107780 (2023).
https://doi.org/10.1016/j.jobe.2023.107780
Vignesh, J., Ramesh, B. and Xavier, J. R., Effects of nanomaterials on mechanical properties of high-strength concrete, J. Adhes. Sci. Technol., 38(20), 3737–3768 (2024).
https://doi.org/10.1080/01694243.2024.2314567
Vignesh, J., Ramesh, B., and Xavier, J. R., A comprehensive review of materials, processing, and performance of nano-doped engineered geopolymer composites for construction applications, Case Studies in Construction Materials, 2025, e05625.
https://doi.org/10.1016/j.cscm.2025.e05625
Yusuf, M. O., Bond characterization in cementitious binders using FTIR spectroscopy, Appl. Sci., 13(5), 3353 (2023).
