Structure Design And Performance Control Of Gypsum-Absorbing Material

In the environmental noise pollution, the use of sound absorption materialsprocessing is an important measure. The materials that being put into use not only hasthe fine high frequency sound absorption performance, also should have fairly goodmiddle-low frequency sound absorption function, we should also consider themechanical properties of materials, environmental protection, as well as price. Sound-absorbing materials have become a focus of research in related fields at home andabroad.Analysis of all the raw materials and acoustic absorption mechanism ofstructural analysis, choosing good durability, high-intensity, low-prices, better lowfrequency sound absorption properties of glass fiber-gypsum system as asound-absorbing material system. Preparation of sound-absorbing material to explorethe best materials and components. Adopt the classics acoustic absorption theory thatRayleigh founds, establishing acoustic absorption theory model by the orderlinessthat the change sound impedance. Make full use of theory to guide the experiment,and the experimental validation of the theory that could turn. The acousticcharacteristics of the porous materials and acoustic absorption mechanism for apreliminary discussion.Make use of high-strength gypsum as a major strong gel raw material. Withindoped glass fiber, increase the absorption properties of materials, flexural strengthand durability; Portland cement is used to enhance the material of hydrationresistance and strength. Vesicant technologies using porous materials needed hole andreasonable microstructure. The citric acid control time to make the slurry gascondensation pace with the speed of adaptation, and the porous structure with a viewto developing appropriate, to facilitate the construction; Factors of the content offiber, gas former, water-gypsum ratio and thickness were controlled, and the materialforming the internal connectivity, uniform distribution of micro-hole, with a view toenhancing the absorption properties of porous sound-absorbing material; Effects of the material thickness, porosity, pore size were investigated, and the influenceddegree was reviewed about sound absorption performance, thus a more directunderstanding of the acoustic characteristics of materials.The sound absorption coefficient of the material was tested by standing wavetube method. The results show that gypsum composite materials with betterlow-frequency acoustic absorption properties, especially from 125Hz to 500Hz werehighlighted. The vertical wave method tests the absorption coefficient. The resultshows that the average absorption coefficient for the six frequencies at 0.58, and thenoise reduction coefficient of the material at 0.6, and the absorption coefficient was ashigh as 0.3 at 125Hz. The material has better sound absorption properties when theporosity from 60% to 70% and the pore size from 300μm to 400μm. The material ofstrength increase 20% when glass fiber was treated with heat and acid. Gypsumclotting time was added with citric acid of 0.2%.