Development and Performance of Sound‐Absorbing Materials From Solid Waste Cementitious Materials and Fly‐Ash Cenospheres

Urban low‐frequency noise is an increasingly urgent environmental issue. This study explores the development of low‐carbon, sound‐absorbing materials using fly‐ash cenospheres as lightweight aggregates and solid waste cementitious materials as binders. Fly‐ash cenospheres plates were fabricated using varying cementitious material/bead mass ratios and bead sources. The results demonstrated that both parameters significantly influenced the mechanical and acoustic properties of the composites. Notably, plates prepared with 20–40 mesh fly‐ash cenospheres at a cementitious material/bead ratio of 1.5:1 exhibited superior sound‐absorbing performance. Without a backing cavity, the maximum and average sound absorption coefficients within 50–1600 Hz were 0.65 and 0.39, respectively. With a 40‐mm cavity, the peak sound absorption reached 0.98, and the average coefficient within 100–500 Hz was 0.56. These findings support the feasibility of using recycled industrial waste to produce efficient low‐frequency sound‐absorbing materials, offering both environmental and functional benefits.