In this paper, the effect of ceramsite aggregate size and gradation on the sound absorption and mechanical properties of the materials were studied and the relationship between material’s pore structure and its sound absorption were discussed. It can be found from the results that the sound absorption and mechanical properties of the ceramsite sound-absorbing materials increase with the content of the fine ceramsite increased due to the decrease of the median pore diameter of the ceramsite sound-absorbing materials where the improvement of the sound absorption at the high frequency band is more significant suggesting that fine pores have a better sound-absorbing effect for high-frequency noise. Higher effective porosity doesn’t mean better sound absorption, because materials with coarse pores have shorter internal routes for sound waves and less friction during sound waves passing through pores, which conversely decreases the material’s sound absorption. Ceramsite with higher internal porosity and more uniform pore diameter distribution can produce materials with better sound absorption.
In this paper, a research was performed which considers the material characteristics of autoclaved aerated concrete (AAC) blocks and the weather characteristics in Pearl River Delta region. The AAC blocks laws of absorption and desorption and its thermal conductivity under different equilibrium moistures were measured. The experimental results show that equilibrium moisture content (EMC)is 6.27% for AAC blocks with a B07 density in hot and humid areas in the Pearl River Delta region including the city of Guangzhou, and the correction coefficient of the thermal conductivity is 1.5.
To improve the porosity of ceramsite concrete can also improve its sound-absorbing property. In this paper, the expanded perlite, polypropylene fibers and foaming agent were added to improve the porosity of the ceramsite concrete. The results show that these three kinds of raw materials can enhance the sound absorbing properties of samples. The relations between porosity and the sound absorption in different sound frequencies through microstructure analysis were established. The study also found that the polypropylene fiber can improve the strength of materials, on the contrast, expanded perlite and foaming agent can significantly reduce the strength. The mechanisms were analyzed by SEM photos.
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