Experimental Investigation on the Influence of High Water-to-Binder Ratio on the Properties of Self-Compacting Concrete Incorporating Ceramic Waste Powder as a Cement Replacement

Abstract

High-performance, sustainable construction materials are urgently needed to reduce CO2 emissions from cement production and to valorize growing volumes of ceramic tile waste; incorporating finely ground ceramic waste powder (CWP) as a partial cement replacement in self‑compacting concrete (SCC) offers a promising route to both objectives. However, SCC containing pozzolanic or inert mineral additions frequently requires modified mix proportions and superplasticizer dosages to maintain fresh-state self-compactability, and the effects of elevated water-to-binder (w/b) ratios on the combined fresh and hardened behavior of CWP‑blended SCC remain poorly quantified in published literature. This study therefore investigates the influence of water-to-binder ratio and ceramic waste powder replacement level on the fresh and hardened properties of self-compacting concrete. SCC mixes were prepared with water-to-binder ratios of 0.45 and 0.50 and ceramic waste powder replacement levels from 0% to 30% by mass of cement. Fresh properties were assessed using slump flow, T500 time, V-funnel, L box, and segregation resistance tests, while hardened properties were evaluated through compressive, split tensile, and flexural strength at 7, 28, and 90 days. The results showed that increasing the water-to-binder ratio improved flowability but reduced stability and strength. Moderate ceramic waste powder content, particularly in the range of 5% to 15%, maintained acceptable SCC performance and in some cases improved long-term strength, whereas higher replacement levels caused strength reduction and loss of cohesiveness. These findings support sustainable SCC mix designs that reuse ceramic waste while maintaining performance targets. Overall, this study highlights the potential of ceramic waste powder as a sustainable construction material, provided that the water-to-binder ratio and replacement level are carefully optimized.