Puput Risdanareni, Vita Ayu Kusuma Dewi, Ruri Agung Wahyuono, Januarti Jaya Ekaputri, Monita Olivia, Yaghoob Farnam, Nele De Belie
Hydrogel-based self-healing mortar often experiences strength decrease that may impact concrete performance under mechanical load. While the addition of commercial colloidal nano silica can improve the strength of hydrogel-based self-healing mortar, they can be relatively expensive. This work examines the synthesis of an alternative and affordable nano-silica, aiming to improve the mechanical strength of hydrogel-based self-healing mortar. Nano silica is extracted from abundantly available mineral admixture, i.e., fly ash through chemical purification methods. Two concentrations of 2 % and 5 % nano silica by mass replacement of cement are used in the mortar mixture. X-ray diffraction was conducted to ensure that nano silica produced is in amorphous form. The hydration kinetics of resulting paste, workability, compressive strength, healing capacity and capillary water absorption of resulting mortar were investigated. The results prove the production of high-quality nano silica from fly ash with sufficient amorphous phase. The hydration kinetics indicate that the incorporation of nano-silica derived from fly ash at a dosage of 2 % accelerates the hydration reaction. This acceleration corresponds with the observed enhancement in the compressive strength of hydrogel-loaded mortar, where the addition of 2 % nano-silica fly ash produced strength values comparable to those of the reference sample while maintaining the self-healing capability. Therefore, a dosage of 2 % nano-silica fly ash by cement weight is recommended as an effective mineral additive for improving the mechanical performance of hydrogel-based self-healing mortars. © 2025 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC license. http://creativecommons.org/licenses/by-nc/4.0/
Department of Civil Engineering and Planning, Faculty of Engineering, State University of Malang, Semarang Street 5, Malang, 65145, Indonesia; Department of Engineering Physics, Faculty of Industrial Technology and System Engineering, Institut Teknologi Sepuluh Nopember (ITS), Campus ITS Sukolilo, Surabaya, 60111, Indonesia; Department of Civil Engineering, Faculty of Faculty of Civil, Planning, and Geo Engineering, Institut Teknologi Sepuluh Nopember (ITS), Campus ITS Sukolilo, Surabaya, 60111, Indonesia; Department of Civil Engineering, Faculty of Engineering, Universitas Negeri Riau, Riau, Pekan baru, 28293, Indonesia; Department of Civil, Architectural, and Environmental Engineering, Drexel University, 3141 Chestnut St., Philadelphia, 19104, PA, United States; Magnel-Vandepitte Laboratory for Structural Engineering and Building Materials, Ghent University, Tech Lane Ghent Science Park, Campus A, Technologiepark Zwijnaarde 60, Ghent, B-9052, Belgium
