| 摘要: |
| 制备了矿渣粉煤灰基地质聚合物混凝土（SFGC），通过抗压强度试验及超声波检测，研究了不同温度、不同冷却方式下SFGC强度及波速的变化规律，并运用小波包变换方法对所得声波测试信号进行分析.结果表明：利用小波包分析技术可以准确、清晰地反映出不同工况下SFGC声谱特征的变化规律；随着温度的升高以及试件损伤的演化发展，其强度、波速不断减小，各子频带内的功率谱及能量显著改变，频谱及能量谱中心向低频端移动；喷水冷却后SFGC的力学、声学特性较自然冷却情况变化更为明显；基于小波包变换的声谱特征参数对高温损伤的敏感性较好，可用以判别SFGC的工况类型及损伤程度. |
| 关键词: 地质聚合物混凝土 高温 超声波检测 小波包分析 |
| DOI：103969/j.issn1007 9629201402019 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目（51078350,51208507） |
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| Wavelet Packet Analysis on Acoustic Spectral Characteristics ofGeopolymeric Concrete after Elevated Temperature |
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REN Weibo1, XU Jinyu1, ZHANG Zeyang2, LIU Yuanfei1
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1.Department of Airfield and Building Engineering, Air Force Engineering University, Xian 710038, China;2.College of Civil Engineering, Hunan University, Changsha 410082, China
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| Abstract: |
| Slag fly ash based geopolymeric concrete（SFGC） was prepared. Compressive strength and longitudinal wave velocity of SFGC under various temperatures and different cooling methods were investigated through compressive strength and ultrasonic test. The acoustic signals were analyzed by using wavelet packet transformation（WPT). The results indicate that acoustic spectral characteristics obtained by wavelet packet analysis is more accurate and sensitive under different working conditions. With the raise of temperature and progress of damage, compressive strength and longitudinal wave velocity decrease constantly, power spectrum and signal energy in each sub band change significantly, and the frequency spectrum and energy spectrum center shift to the lower frequency side. The mechanical and acoustic characteristics of SFGC cooled by spraying water change greatly compared with that cooled naturally. The WPT based spectrogram parameters are sensitive to the thermal damage so that they can be used to distinguish the working condition and damage degree of SFGC. |
| Key words: geopolymeric concrete(GC) elevated temperature ultrasonic testing wavelet packet analysis |
