Nevy Sandra, Keiyu Kawaai, Isao Ujike, Rendy Thamrin, Jafril Tanjung, Willick Nsama, Muhammad Akbar Caronge
The longevity of reinforced concrete is mainly influenced by its ability to resist the penetration of harmful substances such as chloride ions, carbon dioxide, and moisture. Particularly in marine environments, the corrosion of steel reinforcement is expected to be quite severe, depending on the availability of oxygen and moisture involved in cathodic reactions. This research seeks to examine the durability characteristics of concrete that includes copper slag (CUS) and a combined mixture of copper slag and fly ash (FACUS) as partial substitutes for fine aggregates, with an emphasis on their ability to improve resistance against chloride-induced corrosion. A variety of assessments, including Mercury Intrusion Porosimetry (MIP), bleeding, and electrochemical tests, were performed to examine how these materials influence pore structure, permeability, and resistance to corrosion caused by chlorides. FACUS demonstrates excellent pore refinement, characterised by a significant reduction in critical pore diameter and a refined pore network, leading to lower permeability and improved resistance to chloride-induced corrosion. Bleeding experiments show that fly ash effectively reduces the excessive bleeding present in CUS mixtures, which is vital for preserving the integrity of horizontal reinforcements in vertical castings. Electrochemical assessments reinforce these conclusions, demonstrating a delayed initiation of corrosion and lower corrosion rates in FACUS samples, which are attributed to the densified microstructure and reduced capillary porosity. Analysis using SEM-EDX validated a compacted microstructure with an ideal arrangement of essential elements such as calcium, silicon, aluminum, and iron. XRF findings emphasized the combined advantage of copper slag and fly ash in enhancing the concrete formulation. This study highlights the advantages of FACUS mixtures for the sustainable utilization of industrial by-products while improving concrete performance in challenging conditions, establishing FACUS as a practical option for strengthening concrete structures and increasing durability. © 2025 Institution of Structural Engineers. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Department of Civil Engineering, Faculty of Engineering, Universitas Negeri Padang, Indonesia; Department of Civil and Environmental Engineering, Faculty of Engineering, Ehime University, Japan; Department of Civil Engineering, Faculty of Engineering, Universitas Andalas, Indonesia; Department of Water Supply and Sanitation, Ministry of Water Development and Sanitation, Zambia; Department of Civil Engineering, Faculty of Engineering, Universitas Hasanuddin, Indonesia
