Acoustic Material Of Polypropylene Fiber Enhanced Cement-matrix And Organic-inorganic Composite For Highway

The high speed development of highway construction accelerate social development and prosperity. But the social problems led by traffic noise are more serious than before. Sound absorbing materials requested excellent properties such as better characteristic of sound absorbing, durability and environmental protection limit their application of many kinds of sound absorbing materials.In order to achieve stability, health and continual development of highway traffic nets in our country, perfect environment protest and solve noise pollution of highway, by analyzing sound absorbing mechanism of all kinds of sound absorbing materials and structure, choose expanded perlite or polyurethane materials which have better sound absorbing performance as sound absorbing system; explore preparation techniques and the best material composing of all kinds of sound absorbing material; utilize multi-structure including cavity resonance sound absorber, ply resonance sound absorber and wedge sound absorber and their sound absorbing mechanism, treat and process porous sound absorbing material; explore structure such as microstructure, macrostructure and acoustics structure to integrative influencing of sound absorbing materials' performance.In the course of material preparation, the binding material is low alkali cement, some characteristics such as low alkali, earlier strength and high ratio of hydration heat dissipation at the beginning are made use of enhancing the durability, accelerate the circle of pattern turnover and producing conditions in favor of gas former exerting function. The polypropylene fiber is used to enhance the bending strength and compress strength. The shape of hole and reasonable microstructure which are needed in sound absorbing materials are formed by the gas former techniques, the micro-holes with mutual connectivity and distributing uniformity are formed in the material by controlling and corresponding water-cement ratio, the content of expanded perlite, the content ofgas former and libration time, the micro-hole can increase the sound absorbing performance.The better performance of polyurethane sound absorbing material was gained by confecting suitable binding slurry and using to injection technology in the vacuum to achieve binding slurry cover and solidify appropriately polyurethane. The performance of sound absorbing materials was tested by the method of stationary wave cannulation, the results show that the average sound absorbing coefficients are 0.55, 0.64 and the reducing noise coefficients are 0.51, 0.63 in the expanded perlite sound absorbing materials and polyurethane sound absorbing materials, respectively, the influencing of sound absorbing performance was studied through thickness and the materials' back cavity under the condition of simulating reality. Considered integrately economy and reality, thickness and the size materials' back cavity are 8cm , 5cm, respectively.