Title: The impact of colloidal nanosilica on concrete performance: compressive strength, ductility, and microstructural analysis

Authors: Mahmoud Malakouti Oloun Abadi; Sajjad Mousavi; Mojtaba Aslami; Seyed Shaker Hashemi; Abdoreza Fazeli

Addresses: Department of Civil Engineering, School of Engineering, Persian Gulf University (PGU), Mahini Ave., 7516913817, Bushehr, Iran ' Department of Civil Engineering, School of Engineering, Persian Gulf University (PGU), Mahini Ave., 7516913817, Bushehr, Iran ' Department of Civil Engineering, Faculty of Engineering, Fasa University, Fasa, 74616-86131, Iran ' Department of Civil Engineering, School of Engineering, Persian Gulf University (PGU), Mahini Ave., 7516913817, Bushehr, Iran ' Department of Civil Engineering, School of Engineering, Persian Gulf University (PGU), Mahini Ave., 7516913817, Bushehr, Iran

Abstract: In this study, we investigate the effects of colloidal nanosilica on the compressive behaviour and ductility of concrete. The primary objective is to understand how varying percentages of colloidal nanosilica, influence the mechanical properties and microstructure of concrete over different curing periods. The methodology involves preparing concrete specimens with specified nanosilica content and conducting comprehensive tests, including compressive strength, field emission scanning electron microscopy, and X-ray diffraction analysis. Key findings indicate that while the incorporation of colloidal nanosilica generally reduces the compressive strength of concrete, it significantly enhances its ductility. For instance, at seven days, the ductility increases by 26%, 36%, and 65% for samples containing 5%, 10%, and 15% nanosilica, respectively. The FESEM analysis reveals that nanosilica improves the microstructure by reducing porosity and promoting pozzolanic reactions. However, higher nanosilica content results in an irregular nanoparticle structure, contributing to the reduced compressive strength.

Keywords: colloidal nanosilica; concrete ductility; compressive strength; microstructure improvement.

DOI: 10.1504/IJSTRUCTE.2025.146921

International Journal of Structural Engineering, 2025 Vol.15 No.2, pp.194 - 218

Received: 16 Sep 2024
Accepted: 09 Apr 2025
Published online: 26 Jun 2025 *

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