| Road sound insulation barrier is applied more and more abroad in the practice. The material, adapting to it, becomes the emphasis of correlation fields in the world because of the requirement of excellent properties of sound absorption and durability, and limits of some kinds of materials, considering environment-friendly.The study is based on the performance request targets of sound absorbing materials used in Eastern Hong Kong railway engineering. By analyzing the sound absorbing mechanism of all kinds of materials and structures, the inorganic and porous effective material is chosen, and multi-structure including cavity resonance sound absorber, ply resonance sound absorber and wedge sound absorber is selected. According to the sound absorbing mechanism of porous sound absorbing materials, the theory of material preparation techniques, the durability design principle and deferrable steps of inorganic-nonmetal materials, and a great deal of material preparation experiments and acoustics tests, a new kind of high effective and durable sound absorbing material is prepared in this paper.In term of the relation between the micro-size and cavity resonance sound absorber, the structure is formed through the gas former techniques. And the new type of gas former X, which includes many proportional forming-gas functional components, is prepared by milling. Using X, the operating process of practical produce is simplified and the sound absorbing property is stabilized.The size of wedge absorber influences the sound absorbing performance. And the space between the concrete board and the sound absorbing material can enhance the sound absorbing performance. In this paper, the performance of sound absorption is improved through the structure-integration realizing by the special design of the mold and concrete board and inherent cavity resonance sound absorbing property of expanded perlite. The porous material with connected pore is produced by semi-dry stuff compression molding techniques. The compression ratio and the size of granules are controlled to modulate the hole-ratio and the structure gene. The technique parameters of the resistances of airflow and solution, et al. are exerted to study the characteristic of the structure.The Durafiber and the alkali-resistance fiberglass are used to increase the bending strength and compress strength. The binding material is Sulfoaluminate cement The corrosion-resistanceand the speed of pattern turnover is improved and the situation for gas former to exert its function is produced because of the characteristics of Sulfoaluminate cement, such as no Ca(OH)2 in the final hydrated products, lower alkali, earlier strength and the concentration of the hydration heat dissipation.The hating-water treatment of expanded perlite and the waterproof measure of products surfaces are designed according to the ply resonance sound absorbing principle. The technical process of the material preparation include mixture, watering and fiber disperse. Through this research, the practical producing parameters are selected, and long dado product line is designed for mass production.In this paper, the new type sound absorbing material is manufactured through the enhancing and improving the sound absorbing performance and durability of material. The Quality Test Center of Country Building Engineering and first-degree laboratory-EMPA laboratory of Switzerland, appointed by Eastern Hong Kong railwayengineering, test the sound absorbing performance. The coefficients of sound absorption, tested at frequencies of 125, 250, 500,1000, 2000, 4000Hz, are 0.21, 0.6, 0.82, 0.9, 1.04, 0.94, respectively. The average sound absorption coefficients of 18 1/3-octave from 100 to SOOOHz is beyond 0.8. The other performance targets, such as compress strength, fire-resistance, fire-dissemination, fuming and environmental protection, et al., all conform to the demands of engineering. According to the novelty search report of the Southwest Information Center of Sci-tech Ministry, the researches in this...
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