Influence of Silica Fume and Fly Ash on the Performance Characteristics of High-strength Self-compacting Concrete (HSSCC)

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Ahmed Aliyu Azare, Mohd Haziman Wan Ibrahim, Abdullah Faisal Alshalif, Baiq. Sri Umniati, Ramadhansyah Putra Jaya

2026 Iranian Journal of Science and Technology - Transactions of Civil Engineering Article Cited by 0

Abstract

The study examines how silica fume (SF) and fly ash (FA) affect the fresh, mechanical, and durability qualities of high-strength self-compacting concrete (HSSCC). Different percentages of SF and FA were used as partial substitutes for ordinary Portland cement (OPC) to determine their effects on workability, filling capacity, compressive strength, and water absorption. The optimization of the mixture proportions using silica fume content, fly ash replacement, and water-binder ratio was performed using Response Surface Methodology (RSM) in Minitab. The findings indicate that the use of supplementary cementitious materials is a sure way of enhancing the performance of HSSCC. Silica fume increases early-age strength and cohesiveness due to its high pozzolanic reactivity and microfilling effect, whereas fly ash increases workability and develops long-term strength. The best combination, with 5% silica fume and 20% fly ash, had better slump flow, higher compressive strength, and less water absorption than the control mix. The additional hydration products that formed and led to microstructural densification were confirmed by X-ray diffraction (XRD) analysis. The results show that ternary combinations of SF and FA can partially substitute for OPC to enhance durability and reduce cement use and the environmental footprint. © The Author(s) 2026.

Affiliations

Faculty of Civil Engineering and Built Environment, Universiti Tun Hussein Onn Malaysia, Parit Raja Johor, 86400, Malaysia; Department of Civil and Environmental Engineering, Air Force Institute of Technology, Kaduna, Nigeria; Department of Civil Engineering and Planning, Faculty of Engineering, Universitas Negeri Malang, Malang, Indonesia; Faculty of Civil Engineering and Technology, Universiti Malaysia Pahang Al- Sultan Abdullah, Pahang, Gambang, 26300, Malaysia