Study On Sound Absorption Performance Of Aerated Concrete

With the construction of ecological civilization and the implementation of resource and environment friendly society in China,the national policy strengthens the research,promotion and application of new wall materials.As a new wall material,aerated concrete has high internal porosity,so it has good sound absorption performance.But the characteristics of raw materials and its content,and the different erosion environments(such as wet content,carbonation and acid rain,etc.)will have an impact on sound absorption performance of aerated concrete.Aiming at the climate characteristics of Hunan,this thesis investigates the climate and environmental characteristics of the region.Based on the characteristics of raw materials and their content,the effect of different erosion environment on the sound absorption performance of aerated concrete,the variation law of sound absorption performance of aerated concrete under the condition of moisture-carbonization and acid rain-carbonization coupling were discussed in depth.The microstructure of aerated concrete was tested by XRD and SEM test methods to reveal the deterioration mechanism of the aerated concrete sound absorption performance in Hunan area,which can lay a theoretical foundation for the optimization design and preparation of aerated concrete.The main achievements of this thesis are as follows:(1)Based on the single variable method,the aerated concrete with compressive strength not less than 2.5 MPa,absolutely dry density between 600 kg/m~3 and 650 kg/m~3 and sound absorption performance not less than 0.2 was successfully prepared.(2)The influence of three single erosion conditions contains wet content,carbonation and acid rain on the sound absorption of aerated concrete were studied.The results show that the sound absorption performance of aerated concrete decreases with the increase of wet content,firstly increases and then decreases with the increase of carbonization age,and decreases with the increase of acid rain cycles.A mathematical model of sound absorption performance of aerated concrete under three single erosion conditions,namely moisture content,carbonization and acid rain,was established.The correlation of both the average sound absorption coefficient and noise reduction coefficient of aerated concrete is above 0.8480,and the agreement between the predicted value and the measured value is good.(3)The effect of wet-carbonation and acid rain-carbonation on sound absorption performance of aerated concrete was studied.The results show that the effect of wet content and carbonation coupling action of on the sound absorption performance of aerated concrete is similar to that of single carbonation,that is,it increases first and then decreases with the increase of carbonization age.The coupling effect of acid rain and carbonation has the most significant effect on the sound absorption performance of aerated concrete,and its sound absorption performance decreases obviously.After only 5 acid rain-carbonization cycles,the average sound absorption coefficient and noise reduction coefficient of aerated concrete tend to be stable.(4)The main hydration products and micro-morphology of aerated concrete were tested by means of XRD and SEM.The changes of the effective porosity of aerated concrete after single carbonization,single acid rain and acid rain-carbonization were measured by means of vacuum and water saturation method.The results showed that,the effect of carbonization on the effective porosity of the aerated concrete is not great;and the effective porosity of the aerated concrete is greatly reduced by the single acid rain cycles and the acid rain-carbonization coupling effect,and the effect of acid rain-carbonization coupling is more significant than that of the single acid rain cycles.(5)The construction technology and quality assurance system of aerated concrete are proposed,which has certain guiding significance for the promotion and application of aerated concrete.