scholarly journals Preparation of Porous Ceramsite with Ammonium Acetate as Low-Temperature Decomposition Foaming Agent and Its Sound Absorption Performance

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4124
Author(s):  
Huiqin Wu ◽  
Huansheng Huang ◽  
Rongjun Pan ◽  
Yeyang Chun ◽  
Ling Zhu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Heating Rate ◽  
Sound Absorption ◽  
Ammonium Acetate ◽  
Pore Diameter ◽  
Apparent Porosity ◽  
Diameter Distribution ◽  
Foaming Agent ◽  
Temperature Decomposition ◽  
Absorption Performance

The sound absorption performance of porous ceramisite is determined by its pore structure, which is mainly governed by a foaming agent and heating rate during a foaming process. By tuning the heating rate and foaming agent concentration, ceramisite with different pore structures was prepared by using flyash, cement, quick lime, and plaster as raw materials as well as ammonium acetate as a low-temperature decomposition foaming agent in this work. The phase composition, microstructure, and sound absorption performance of the prepared porous ceramisite were investigated. Results demonstrate that the apparent porosity and the pore diameter increased with the increase of foaming agent concentration, accompanied with the broadening of the pore diameter distribution. The apparent porosity is positively correlated with heating rate until the temperature is higher than 20 °C·min−1, while the pore diameter is negatively correlated. The pore diameter distribution becomes narrow as a function of the heating rate. The sound absorption performance is positively correlated with the apparent porosity. An optimal pore diameter might exist, meaning diameter sizes that are larger or smaller than the optimal diameter are not conducive to the optimization of the sound absorption performance of the overall frequency band. It was determined that the curing time was not a key factor for optimizing the pore structure.

Studies on sound absorption performance of porous materials at low temperature

2019 ◽  
Vol 145 (3) ◽  
pp. 1805-1805
Author(s):  
Xiwei Wang ◽  
Xiang Yan ◽  
Hui Li ◽  
Xiaoyan Xue
Keyword(s):  
Low Temperature ◽  
Porous Materials ◽  
Sound Absorption ◽  
Absorption Performance

Effect of Aggregate Size and Gradation on the Ceramsite Sound-Absorbing Materials

2011 ◽  
Vol 216 ◽  
pp. 450-457
Author(s):  
Xiang Yu Luo ◽  
Wen Fang Li ◽  
Xue Li Jin
Keyword(s):  
Mechanical Properties ◽  
High Frequency ◽  
Sound Absorption ◽  
Pore Diameter ◽  
Aggregate Size ◽  
Effective Porosity ◽  
Diameter Distribution ◽  
Frequency Noise ◽  
Sound Waves ◽  
Absorbing Materials

In this paper, the effect of ceramsite aggregate size and gradation on the sound absorption and mechanical properties of the materials were studied and the relationship between material’s pore structure and its sound absorption were discussed. It can be found from the results that the sound absorption and mechanical properties of the ceramsite sound-absorbing materials increase with the content of the fine ceramsite increased due to the decrease of the median pore diameter of the ceramsite sound-absorbing materials where the improvement of the sound absorption at the high frequency band is more significant suggesting that fine pores have a better sound-absorbing effect for high-frequency noise. Higher effective porosity doesn’t mean better sound absorption, because materials with coarse pores have shorter internal routes for sound waves and less friction during sound waves passing through pores, which conversely decreases the material’s sound absorption. Ceramsite with higher internal porosity and more uniform pore diameter distribution can produce materials with better sound absorption.

scholarly journals Mechanical and Microstructural Characteristics of Calcium Sulfoaluminate Cement Exposed to Early-Age Carbonation Curing

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3515
Author(s):  
Weikang Wang ◽  
Xuanchun Wei ◽  
Xinhua Cai ◽  
Hongyang Deng ◽  
Bokang Li
Keyword(s):  
Cement Paste ◽  
Pore Diameter ◽  
Performance Enhancement ◽  
Diameter Distribution ◽  
Early Age ◽  
Calcium Sulfoaluminate ◽  
Starting Point ◽  
And Performance ◽  
Curing Pressure ◽  
Carbonation Curing

: The early-age carbonation curing technique is an effective way to improve the performance of cement-based materials and reduce their carbon footprint. This work investigates the early mechanical properties and microstructure of calcium sulfoaluminate (CSA) cement specimens under early-age carbonation curing, considering five factors: briquetting pressure, water–binder (w/b) ratio, starting point of carbonation curing, carbonation curing time, and carbonation curing pressure. The carbonization process and performance enhancement mechanism of CSA cement are analyzed by mercury intrusion porosimetry (MIP), thermogravimetry and derivative thermogravimetry (TG-DTG) analysis, X-ray diffraction (XRD), and scanning electron microscope (SEM). The results show that early-age carbonation curing can accelerate the hardening speed of CSA cement paste, reduce the cumulative porosity of the cement paste, refine the pore diameter distribution, and make the pore diameter distribution more uniform, thus greatly improving the early compressive strength of the paste. The most favorable w/b ratio for the carbonization reaction of CSA cement paste is between 0.15 and 0.2; the most suitable carbonation curing starting time point is 4 h after initial hydration; the carbonation curing pressure should be between 3 and 4 bar; and the most appropriate time for carbonation curing is between 6 and 12 h.

Sound absorption performance of flexible polyurethane/silicon dioxide perforated coating composites

2021 ◽  
pp. 004051752110155
Author(s):  
Min Peng ◽  
Xiaoming Zhao ◽  
Weibin Li
Keyword(s):  
Silicon Dioxide ◽  
Sound Absorption ◽  
Woven Fabric ◽  
Perforation Rate ◽  
Cavity Depth ◽  
Resonant Frequencies ◽  
The Matrix ◽  
Absorption Performance ◽  
Traditional Sense ◽  
Flexible Polyurethane

Perforated materials in the traditional sense are rigid, usually dense, costly and inflexible. For this study, polyester/cotton blended woven fabric as the base fabric, nano-SiO2 (silicon dioxide) as the functional particles and PU (polyurethane) as the matrix were selected. Accordingly, flexible PU/SiO2 perforated coating composites with different process parameters were developed. The influence of the nano-SiO2 content, perforation diameter, perforation rate, number of fiber felt layers and cavity depth on the sound absorption coefficient were investigated. The resonant frequencies of materials with different cavity depths were evaluated by both theoretical calculation and experimental method. It was found that the flexible perforated composite has good sound absorption and mechanical properties, and has great potential for applications requiring soft and lightweight sound absorption materials.

scholarly journals Diffuse Sound Absorptive Properties of Parallel-Arranged Perforated Plates with Extended Tubes and Porous Materials

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1091 ◽  
Author(s):  
Dengke Li ◽  
Daoqing Chang ◽  
Bilong Liu
Keyword(s):  
Boundary Condition ◽  
Porous Material ◽  
Porous Materials ◽  
Sound Absorption ◽  
Azimuthal Angle ◽  
Octave Band ◽  
Frequency Range ◽  
Absorption Coefficients ◽  
Perforated Plates ◽  
Absorption Performance

The diffuse sound absorption was investigated theoretically and experimentally for a periodically arranged sound absorber composed of perforated plates with extended tubes (PPETs) and porous materials. The calculation formulae related to the boundary condition are derived for the periodic absorbers, and then the equations are solved numerically. The influences of the incidence and azimuthal angle, and the period of absorber arrangement are investigated on the sound absorption. The sound-absorption coefficients are tested in a standard reverberation room for a periodic absorber composed of units of three parallel-arranged PPETs and porous material. The measured 1/3-octave band sound-absorption coefficients agree well with the theoretical prediction. Both theoretical and measured results suggest that the periodic PPET absorbers have good sound-absorption performance in the low- to mid-frequency range in diffuse field.

scholarly journals Application of transparent microperforated panel to acrylic partitions for desktop use: A case study by prototyping

2021 ◽  
Author(s):  
Kimihiro Sakagami ◽  
Midori Kusaka ◽  
Takeshi Okuzono ◽  
Shigeyuki Kido ◽  
Daichi Yamaguchi
Keyword(s):  
Adverse Effect ◽  
Sound Absorption ◽  
Acoustic Environment ◽  
Actual Use ◽  
Acrylic Sheet ◽  
Absorption Performance ◽  
The Subject ◽  
Droplet Penetration ◽  
Absorption Characteristics

There are various measures currently in place to prevent the spread of COVID-19; however, in some cases, these can have an adverse effect on the acoustic environment in buildings. For example, transparent acrylic partitions are often used in eating establishments, meeting rooms, offices, etc., to prevent droplet infection. However, acrylic partitions are acoustically reflective; therefore, reflected sounds may cause acoustic problems such as difficulties in conversation or the leakage of conversation. In this study, we performed a prototyping of transparent acrylic partitions to which a microperforated panel (MPP) was applied for sound absorption while maintaining transparency. The proposed partition is a triple-leaf acrylic partition with a single acrylic sheet without holes between two MPP sheets, as including a hole-free panel is important to a possible droplet penetration. The sound absorption characteristics were investigated by measuring the sound absorption in a reverberation room. As the original prototype showed sound absorption characteristics with a gentle peak and low values due to the openings on the periphery, it was modified by closing the openings of the top and sides. The sound absorption performance was improved to some extent when the top and sides were closed, although there remains the possibility of further improvement. This time, only the sound absorption characteristics were examined in the prototype experiments. The effects during actual use will be the subject of future study.

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