Evaluation of pore structure, mechanical properties, and sound absorption of composite foamed gypsum

Abstract

The effects of material design parameters (animal protein foaming agent concentration, and white Portland cement content) on the lightweight gypsum composites prepared by combined foaming process (physical and chemical foaming) were investigated in terms of their pore structure, physical property, mechanical property, and sound absorption. The sound absorption coefficient was tested using an impedance tube, and the pore structure was detected using optical microscopy (OM) and scanning electron microscope (SEM). Pearson correlation analysis was conducted for the examination of the effect of pore structure parameters on materials’ macroscopic performance. According to analysis results, the animal protein foaming agent concentration crucially affected the performance of lightweight gypsum composites, and the white Portland cement content greatly affected the material’s pore morphology and strength development. When the concentration of the animal protein foaming agent decreased from 20 g/L to 3.3 g/L, the pore walls became thin and incomplete, leading to increased pore connectivity, accordingly resulting in an increment of 19.7 % for the average sound absorption coefficient. The white Portland cement content exerted a larger influence on the material’s mechanical properties than on the sound absorption properties. With the addition of 15.0 wt% white Portland cement, the pore size of the material was refined, and the weighted sound absorption coefficient (α_w) value increased by 50 %. Furthermore, there was a strong correlation between the distribution of pore size and roundness, and the physical, mechanical, and sound absorption properties of the material.