| Large and medium-sized cities in China have the characteristics of heavy traffic and dense buildings.Urban residents are under great pressure of acoustic environmental pollution.With the widespread popularity of automobiles,as a refractory solid waste,waste tires have become a black pollution problem that needs to be properly solved.Therefore,in this paper,the scrap tire rubber particles and cement were made into composite materials,and the noise barrier system for road and railway traffic was studied by combining theoretical research,numerical simulation and experimental verification.In this paper,according to the order of composite material performance,sound barrier configuration optimization and sound barrier structure system design,a complete set of noise barrier manufactured by the crumb rubber-cement composites technology had been formed.It provides a new idea for solving urban noise and black pollution of waste tyres.Firstly,the compressive strength and acoustic properties of crumb rubber-cement composites were studied experimentally,and the mix ratio of the composites was optimized.According to the gradation and content of rubber particles and the content of foaming agent,the mix ratio of the composites was determined,and then the compressive,sound absorption and sound insulation properties were tested.The experimental results show that the sound insulation performance of the composites without blowing agent is better,and the transmission loss can reach more than 35 dB.The composites with blowing agent have certain sound absorption performance.The sound absorption performance of the composites is the best in the range of 400-600 Hz,and the maximum sound absorption coefficient can reach 0.8.Compressive and acoustic properties of composites with different particle sizes are better than those with single particle size.Among them,rubber with 3-5mm particle size has the best performance.Secondly,the numerical simulation method of sound field distribution under the interaction between noise barrier and environment was established,and the scale model was used to test and verify.A numerical simulation method of interaction between noise barrier and environment was established by using Virtual Lab Acoustics.The results show that the noise barrier has a very effective noise reduction effect,and the higher the frequency,the more obvious the noise reduction effect.The comprehensive noise reduction effect of the noise barrier is about 15 dB.According to the geometric model of the numerical simulation noise barrier,the crumb rubbercement composites noise barrier was poured with the mixture ratio obtained in the first part,and the noise reduction effect was tested under the semi-anechoic chamber.The comparison test results show that the errors between numerical simulation results and experimental results are less than 5 dB on the whole,the error rate is less than 20%,and the thematic errors are concentrated in about 10%,which verifies the accuracy and reliability of the numerical simulation method.Thirdly,the geometric configuration of the noise barrier was optimized by the above-mentioned numerical simulation method.Five different sound barrier structures were simulated and analyzed.Three-dimensional planar sound pressure level cloud images of the protected area behind the sound barrier were obtained at different frequencies for each working condition,and the noise reduction effect of the sound barrier structure was analyzed.The results of numerical simulation show that at the same equivalent height,the noise reduction effect of straight-plate noise barrier is the worst.The noise reduction effect of folded-plate and arc-plate noise barrier is better than that of straight-plate noise barrier.The maximum difference can reach 5dB.Finally,the composite noise barrier system was designed as a whole,which provides a basis for the engineering application of the sound barrier.The design of composite sound barrier mainly includes acoustics,structure and landscape design. |
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