Influence of magnetized water on the Properties of hollow Concrete blocks Made with fully Recycled Aggregate

With accelerated global urbanization, construction waste has become an increasingly severe problem and drives growing interest in recycled aggregate utilization. This study pioneers the application of magnetized water technology in hollow concrete block systems fabricated exclusively with recycled aggregates. The study utilized ordinary Portland cement, recycled coarse/fine aggregates, and solid waste cementitious materials. Magnetized water was prepared using custom-designed equipment with controlled magnetic parameters. Concrete hollow blocks with varied mix proportions were fabricated and systematically evaluated for water absorption, drying shrinkage, compressive strength, freeze–thaw resistance, and microstructural properties. Results demonstrate that magnetized water treatment increases compressive strength by 5.3%, decreases water absorption by 5%, and enhances post-freeze-thaw strength retention by 14.95%. From a microstructural perspective, the specimens prepared with magnetized water exhibit enhanced compactness, which can be attributed to the reduced clustering of water molecules and the densification of the interfacial transition zone (ITZ). The RC66-A group exhibited the best performance improvement with optimal magnetized water parameters of 2000 Gs magnetic field strength, 2.25 m/s flow rate, and one cycle.