Development of Heavyweight Anti-Washout Self-Compacting Concrete Using Heavyweight Fine Aggregates Including Copper Slag

This study developed anti-washout self-compacting heavyweight concrete using industrial by-product copper slag. Fresh-state flow behavior, anti-washout performance, compressive strength, and resistance against chloride penetration were evaluated. Preliminary experiments on cement paste were conducted to obtain the proportion of anti-washout and high-range water-reducing agents for anti-washout self-compacting concrete and anti-washout self-compacting heavyweight concrete. Copper slag and magnetite ore fine were used as heavyweight fine aggregates. The results showed that appropriate control of high range water reducer is critical for stable underwater placement. Excessive demand of high range water reducer, particularly in mixtures incorporating heavyweight coarse aggregates or fibers, led to severe washout despite their higher flowability. In contrast, anti-washout self-compacting heavyweight concrete incorporating heavyweight fine aggregates exhibited stable underwater casting with minimal washout, and achieved 28-day compressive strengths comparable to those of the corresponding AW-SCC mixtures. All anti-washout self-compacting heavyweight concrete satisfied the required air-to-underwater strength ratio, and chloride resistance was classified as low penetrability. These results demonstrate that the strategic use of heavyweight fine aggregates enables the production of anti-washout self-compacting heavyweight concrete with adequate underwater casting stability, providing a practical solution for construction of marine and underwater infrastructure.