Burnt and Unburnt Ceramic Waste Powder with Magnetized Water for Durable and Sustainable Concrete

The combined use of ceramic waste powder (CWP) as a supplementary cementitious material and magnetized water (MW) as mixing water represents a promising strategy for producing sustainable concrete with reduced cement consumption while maintaining mechanical performance and durability. However, the synergistic effects of burnt ceramic waste powder (BCWP) and unburnt ceramic waste powder (UBCWP) combined with MW, particularly under aggressive environmental conditions, remain insufficiently investigated. This study evaluates the influence of BCWP and UBCWP, used as partial replacements for ordinary Portland cement (OPC) at replacement levels of 10%, 20%, and 30% by weight, together with conventional tap water (TW) and MW produced using a dual-field magnetic device (0.9 T and 1.5 T). A total of fourteen concrete mixtures were investigated through compressive strength tests at 7, 28, and 120 days; indirect tensile and flexural strength tests at 28 and 120 days; sulfate resistance after 120 days of MgSO4 immersion; residual strength after thermal exposure at 200 °C; and microstructural characterization using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The results indicate that increasing the CWP replacement level progressively reduced the mechanical properties of concrete; however, MW consistently mitigated these reductions by promoting cement hydration and producing a denser cementitious matrix. The mixture containing 20% BCWP with MW achieved a 120-day compressive strength comparable to that of the TW control, demonstrating that cement consumption can be reduced without compromising structural performance. Furthermore, MW mixtures exhibited significantly improved durability, with compressive strength losses of only 16–28% after sulfate attack compared with up to 42% for TW mixtures, and 1–13% after thermal exposure compared with up to 53% for TW mixtures. SEM and XRD analyses confirmed the development of denser microstructures with enhanced C–S–H gel formation in MW–CWP concretes. Overall, the findings demonstrate that the synergistic combination of ceramic waste powder and magnetized water provides an effective strategy for producing sustainable concrete with enhanced long-term mechanical performance, improved durability under aggressive environmental conditions, and reduced environmental impact.