Investigating the Acoustical Characteristics of Stabilized Soils for Sustainable Construction

Sustainable construction increasingly demands materials that balance environmental performance with functional properties such as acoustic insulation. This study investigates the acoustical characteristics of two Hejaz region soils stabilized with ordinary portland cement (OPC), hydrated lime, and cement kiln dust (CKD), aiming to assess their potential as sound-absorbing construction materials. Using impedance tube testing, the normal incidence sound absorption coefficient was measured across the 250–1,250 Hz frequency range for soil samples treated with varying stabilizer concentrations (0%–15%). The findings reveal that untreated soils exhibit moderate to high absorption at middle frequencies, particularly at 500 and 630 Hz. Among the stabilizers, CKD consistently enhanced absorption in the middle-frequency range, achieving coefficients up to 0.63, while OPC and lime produced variable or diminishing effects depending on frequency and dosage. Notably, lime frequently suppressed acoustic performance due to increased material stiffness. This study contributes a comparative evaluation of stabilizers for acoustic functionality, identifying CKD as the most effective additive in frequency-sensitive applications. Stabilized soil mixtures, especially those incorporating CKD, can serve as effective middle-frequency acoustic materials for use in partition walls and interior panels. These results emphasize the importance of acoustic profiling in the material selection process and highlight the feasibility of integrating locally sourced, low-carbon materials into acoustically sensitive architectural applications.